2021.04.05_YMCA_Mineral_Lake_Geotechnical_ReportEarth Science + Technology
Geotechnical Engineering Services Report
Mineral Lake Property Due Diligence
Mineral Lake, Washington
for
YMCA Seattle
March 16, 2021
Geotechnical Engineering Services Report
Mineral Lake Property Due Diligence
Mineral Lake, Washington
for
YMCA Seattle
March 16, 2021
1101 South Fawcett Avenue, Suite 200
Tacoma, Washington 98402
253.383.4940
Geotechnical Engineering Services Report
Mineral Lake Property Due Diligence
Mineral Lake, Washington
File No. 6565-008-00
March 16, 2021
Prepared for:
YMCA Seattle
14230 Bel-Red Road
Bellevue, Washington 98007
Attn: Josh Sutton
Prepared by:
GeoEngineers, Inc.
1101 South Fawcett Avenue, Suite 200
Tacoma, Washington 98402
253.383.4940
Stuart S. Thielmann, PE
Geotechnical Engineer
Dennis (D.J.) Thompson, PE
Associate Geotechnical Engineer 3/16/2021
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Disclaimer: Any electronic form, facsimile or hard copy of the original document (email, text, table, and/or figure), if provided, and any attachments are only a copy
of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record.
March 16, 2021 | Page i File No. 6565-008-00
Table of Contents
EXECUTIVE SUMMARY ...................................................................................................................................... ES-1
1.0 INTRODUCTION AND PROJECT UNDERSTANDING ........................................................................................ 1
2.0 PURPOSE AND SCOPE OF SERVICES ............................................................................................................ 1
3.0 SITE CONDITIONS ............................................................................................................................................ 2
3.1. Site Vicinity and History .............................................................................................................................. 2
3.2. Conceptual Development Areas ................................................................................................................. 2
3.3. Surface Conditions...................................................................................................................................... 2
3.4. Literature Review ........................................................................................................................................ 3
3.4.1. Geologic Setting .......................................................................................................................... 3
3.4.2. Geologic Maps ............................................................................................................................. 3
3.4.3. Natural Resources Conservation Service (NRCS) Description ................................................. 4
3.4.4. Water Well Reports ..................................................................................................................... 4
3.5. Subsurface Conditions ............................................................................................................................... 4
3.5.1. Methodology ................................................................................................................................ 4
3.5.2. Soil Conditions ............................................................................................................................ 5
3.5.3. Test Pit Area 1 (Northwest of Mineral Lake) ............................................................................. 5
3.5.4. Test Pit Area 2 (Low-Lying Area between Mineral Lake and Mineral Creek) ........................... 6
3.5.5. Groundwater Conditions ............................................................................................................. 7
4.0 CONCLUSIONS AND RECOMMENDATIONS ................................................................................................... 8
4.1. Critical Areas Review .................................................................................................................................. 8
4.1.1. Methodology ................................................................................................................................ 8
4.1.2. Erosion Hazard Areas ................................................................................................................. 8
4.1.3. Steep Slope Areas ....................................................................................................................... 8
4.1.4. Landslide Hazard Areas .............................................................................................................. 9
4.1.5. Seismic Hazard Areas .............................................................................................................. 10
4.1.6. Volcanic Hazard ....................................................................................................................... 10
4.2. Seismic Design Considerations ............................................................................................................... 10
4.2.1. International Building Code Seismic Design Parameters ...................................................... 10
4.2.2. Liquefaction, Lateral Spreading, and Surface Rupture ......................................................... 11
4.3. Shallow Foundations ............................................................................................................................... 12
4.3.1. General ..................................................................................................................................... 12
4.3.2. Footing Bearing Surface Preparation ..................................................................................... 12
4.3.3. Allowable Soil Bearing Pressure ............................................................................................. 13
4.3.4. Foundation Settlement ............................................................................................................ 13
4.3.5. Water Storage Tank ................................................................................................................. 13
4.4. Infiltration Feasibility Assessment .......................................................................................................... 14
4.4.1. General ..................................................................................................................................... 14
4.4.2. On-Site Sewage Systems ......................................................................................................... 14
4.4.3. Stormwater Infiltration ............................................................................................................. 15
4.5. Site Development and Earthwork ........................................................................................................... 17
4.5.1. General ..................................................................................................................................... 17
4.5.2. Clearing, Stripping and Demolition ......................................................................................... 17
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4.5.3. Temporary Excavations and Cut Slopes ................................................................................. 17
4.5.4. Permanent Cut and Fill Slopes ................................................................................................ 18
4.5.5. Groundwater Handling Considerations .................................................................................. 18
4.5.6. Surface Drainage ..................................................................................................................... 19
4.5.7. Subgrade Preparation.............................................................................................................. 19
4.5.8. Subgrade Protection and Wet Weather Considerations ........................................................ 19
4.6. Fill Materials ............................................................................................................................................. 20
4.6.1. General ..................................................................................................................................... 20
4.6.2. On-Site Soil ............................................................................................................................... 21
4.6.3. Structural Fill ............................................................................................................................ 21
4.6.4. Select Granular Fill .................................................................................................................. 21
4.7. Fill Placement and Compaction .............................................................................................................. 22
4.7.1. General ..................................................................................................................................... 22
4.7.2. Area Fills and Pavement Bases .............................................................................................. 22
5.0 ADDITIONAL INVESTIGATIONS .................................................................................................................... 22
6.0 LIMITATIONS ................................................................................................................................................ 23
LIST OF FIGURES
Figure 1. Vicinity Map
Figure 2. Presubmission Package Vicinity Map
Figure 3. Presubmission Package Conceptual Development Areas
Figure 4. Geologic Map - 1:100,000-scale
Figure 5. Site Plan - Test Pit Overview
Figure 6. Site Plan - Test Pit Area 1
Figure 7. Site Plan - Test Pit Area 2
Figure 8. Erosion Hazard - NRCS
Figure 9. Erosion Hazard Areas - Lewis County
Figure 10. Steep Slope Areas
Figure 11. Landslide Hazard Areas
Figure 12. Volcanic Hazards
Figure 13. Liquefaction Susceptibility
Figure 14. Hydrologic Soil Group
APPENDICES
Appendix A. Subsurface Explorations and Laboratory Testing
Figure A-1 -- Key to Exploration Logs
Figures A-2 through A-25 – Logs of Test Pits
Figures A-26 and A-27 – Sieve and Hydrometer Analysis Results
Appendix B. Water Well Reports
Appendix C. Report Limitations and Guidelines for Use
March 16, 2021 | Page ES-1 File No. 6565-008-00
EXECUTIVE SUMMARY
The YMCA is in discussions to purchase all or portions of an approximate 2,118-acre privately owned,
commercial forest tract adjacent to Mineral Lake, within Lewis County, Washington. The overall project goal
is to develop and operate a year-round youth and family camp on the property. Project development is still
in the conceptual phase and anticipated site improvements include new buildings and roadway
construction for camp facilities, water supply development, wastewater systems and stormwater facilities.
Based on our understanding of the project, our review of subsurface explorations completed as part of this
study and our experience, it is our opinion the Mineral Lake property is suitable for camp development as
currently envisioned. We do not see any limiting factors that would prohibit overall project design and
construction with regard to geotechnical considerations. Project layout and design will need to incorporate
geotechnical considerations including, but not limited to, soil type and groundwater conditions, critical
areas, seismic design, roadway design and foundation bearing and settlement. In our opinion these
geotechnical considerations can be managed through appropriate site layout, engineering design and
construction methods.
A preliminary summary of primary geotechnical considerations for the proposed development is provided
below.
■ Based on recently completed test pits, we have divided subsurface conditions at the site into four soil
units for the purposes of design: (1) fill, (2) residual soils, (3) bedrock and (4) glacial drift.
Fill encountered appears to consist of reworked native soils (including bedrock) placed during
construction of existing access roads.
Residual soils are derived from weathered basalt bedrock and consist of significant clay
material.
Bedrock was encountered below residual soils in some of our explorations and exposed
bedrock outcrops were also observed in some areas at the project site. These are indications
of shallow depths to bedrock in portions of the site. If shallow bedrock is encountered during
site development, we anticipate specialty rock excavation equipment or blasting will be
required to excavate.
Residual soils and bedrock appear to extend over a larger area than indicated on geologic
maps. Consequently, fewer granular glacial drift type soils were encountered than expected
from review of the geologic mapping.
Glacial drift soils appear to be more favorable for infiltration. Glacial drift was encountered in
the lowest elevation test pit excavations adjacent to Mineral Creek.
■ Groundwater conditions vary across the site. In our opinion groundwater seepage observed within
residual soils at the property are consistent with perched groundwater. What we interpret to be static
groundwater was observed within glacial drift soils adjacent to Mineral Creek. We anticipate static
groundwater levels adjacent to Mineral Creek are interconnected with water levels in the creek.
■ Based on criteria outlined in the Lewis County Code erosion, steep slope, landslide and seismic hazard
areas are present at the property and should be reviewed as project design progresses. We anticipate
these geotechnical related hazards can be managed through site layout, site grading, horizontal
setbacks and other engineering controls.
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■ In general, it is our opinion the risk of liquefaction within the majority of the site is low. It is our opinion
that potentially liquefiable layers could be present adjacent to Mineral Creek. Based on planned
construction, we expect that structures can be adequately located and/or designed to mitigate adverse
effects from potential liquefaction induced settlements.
■ We envision that proposed structures for camp development can be adequately supported on shallow
foundations, reinforced mats and slabs-on-grade.
Clay soils (e.g., residual deposits encountered in our test pits) are potentially compressible and
could consolidate when subjected to new loads such as structures or fill placed to raise site
grades. We do not anticipate settlement as controlling factor for design of proposed roadways
and lightly loaded camp structures; however, to mitigate settlement risk we recommend
heavier structures (e.g., water storage tank) bear on bedrock or dense glacial drift soils.
■ We anticipate slow to very slow design infiltration rates within residual soils. We anticipate more
favorable rates will be attained within glacial drift soils (adjacent to Mineral Creek). Vertical and
horizontal separations (e.g., depth to bedrock, depth to groundwater, distance from water sources, etc.)
will likely control septic and stormwater infiltration design.
After purchase of the property is finalized and the proposed camp developments have been sited, we can
provide additional considerations, recommendations on further explorations and geotechnical design for
specific site development. Ultimately, site and project specific geotechnical design is recommended once
initial planning and design has been completed.
This Executive Summary should be used only in the context of the full report for which it is intended.
March 16, 2021 | Page 1 File No. 6565-008-00
1.0 INTRODUCTION AND PROJECT UNDERSTANDING
The YMCA is in discussions to purchase and/or develop all or portions of a privately owned, commercial
forest tract adjacent to Mineral Lake, within Lewis County, Washington. The overall project goal is to develop
and operate a year-round youth and family camp on the property. This report presents the results of our
geotechnical engineering due diligence services for the proposed YMCA Mineral Lake Camp.
Our understanding of this project is based on our communications with the YMCA, Heartland LLC and other
members of the design team, including our previous and ongoing attendance at design team meetings,
review of background documents and preliminary permit discovery application submittals throughout
2020. This also includes review of “YMCA Seattle Mineral Lake Site Due Diligence and Permitting Technical
Services” Request For Proposal (RFP) obtained in an electronic mail dated October 30, 2019 and “Mineral
Lake Program, version 2” project summary.
Project development is still in the early stages of conceptual planning and design. Property development is
anticipated to occur in phases over a period of up to 20 years. It is anticipated that the maximum area of
disturbance for the camp and associated site improvements will not exceed a total of about 100 acres; the
remaining undeveloped portion of the property will be used for hiking and recreation and will either remain
in forestry production or be placed into conservation easements.
Preliminary design considerations focus on portions of the site around Mineral Lake. There are four primary
areas being considered for development, including a Camp Entrance west of the lake, a Family Camp
located northwest of the lake, a Youth Camp located east of the lake, and a primary road (mostly occupying
the existing logging roads) between the Family Camp and the Youth Camp. Currently proposed site
improvements include:
■ Construction of new structures including a camp lodge, program shelters/classrooms, cabins, staff
housing and utility/maintenance. Individual buildings are anticipated to be up to about 9,000 square
feet or less and be supported by slab-on-grade and conventional shallow foundations.
■ Expansion of the existing access road from Mineral Hill Road for passenger vehicles, delivery trucks
and emergency vehicles. A parking lot (or multiple lots) will also be developed to accommodate vehicle
traffic.
■ Recreational trails throughout the property.
■ Water access and up to two dock features near the northern portion of the lake.
■ Development of a water supply system for the camp, including a water storage tank (or multiple tanks).
■ Wastewater conveyances and septic drainfields.
■ Stormwater facilities to collect, treat, infiltrate and/or discharge stormwater.
2.0 PURPOSE AND SCOPE OF SERVICES
Our services have been provided in accordance with our existing agreement with the YMCA of Seattle dated
March 4, 2020 and signed March 16, 2020. Details regarding our specific scope of services for the project
March 16, 2021 | Page 2 File No. 6565-008-00
can be reviewed in our agreement or provided upon request. Our services have been split into three tasks,
consisting of:
■ Task 100: Phase 1 Environmental Site Assessment
■ Task 200: Geotechnical Engineering Services
■ Task 300: Environmental Permitting and Sensitive Areas Review
This report summarizes the results of our Task 200 Geotechnical Engineering Services due diligence study.
Results of our Task 100 Phase 1 Environmental Site Assessment and Task 300 Environmental Permitting
and Sensitive Areas Reviews will be provided in separate letter reports or memorandums, as appropriate.
The purpose of our Task 200 Geotechnical Engineering Services for this due diligence study is to explore
subsurface soil and groundwater conditions at the property and use that information to provide our
preliminary opinion on the suitability of the property for the proposed camp development. The results of our
services will support decisions on potential purchase of the property and future planning.
3.0 SITE CONDITIONS
3.1. Site Vicinity and History
The property is located at the north end of Mineral Lake, approximately 1 mile north-northeast of the town
of Mineral, Washington, as shown on the Vicinity Map, Figure 1. The property is currently owned by
Forecastle Timber Company LLC and is used for timber production and harvesting. Historically, the site has
also been used as a gravel source for construction of access roads on site. The property consists of several
parcels, which are grouped into four areas as shown on the Presubmission Package Vicinity Map, Figure 2.
■ Area A: Approximately 500 acres along the north and east shorelines of Mineral Lake
■ Area B: Approximately 143 acres of forest reserve along the western property boundary
■ Area C: Approximately 371 acres for along Mineral Creek and the eastern property boundary
■ Area D: Approximately 1,104 acres of forest reserve at the northern property boundary
3.2. Conceptual Development Areas
We understand portions of Area A and Area C described above have been identified by the YMCA and project
team for potential camp development, as shown on Presubmission Package Conceptual Development
Areas, Figure 3. We, therefore, concentrated our geotechnical services to target these potential
development areas.
3.3. Surface Conditions
The property is generally bounded by Nisqually River to the north, Mineral Creek to the east, Mineral Lake
and Roundtop Creek to the south and Mineral Hill Road to the west. Adjacent properties generally consist
of forested areas and large acreage single-family residences. The unincorporated town of Mineral is located
at the southwest end of Mineral Lake.
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Predominant site features near the conceptual development areas include the Mineral Lake shoreline,
Mineral Creek water frontage and a steep ridge that runs generally east-west through the northern half of
the property.
The property is largely undeveloped forest and heavily vegetated, although areas of the site have been clear
cut in recent history and are, therefore, sparsely vegetated. Vegetation generally consists of grasses, brush
and young to mature trees. Several creek and wetland areas with associated vegetation are also present.
A gravel-surfaced access road serves the property, accessed from Mineral Hill Road at the southwestern
corner of the property. A series of smaller gravel-surfaced roads provide additional access throughout the
property. Two antenna towers and associated structures are located near the top of the steep ridge in the
north-central portion of the site.
Occasional areas of exposed bedrock are present at the site, as observed via satellite imagery and adjacent
to access roads while we were on site for test pit excavations. Exposed bedrock appears to be most notably
present along steep slope areas. Some areas of bedrock adjacent to access roads show evidence of
previous quarry/borrow pit activities.
Numerous streams are present on site, flowing from the higher ridgeline elevations into Mineral Lake,
Nisqually River, Mineral Creek and Roundtop Creek.
Ground surface elevations are on the order of Elevation 1,400 feet along the Mineral Lake shoreline,
Elevation 1,300 feet at Nisqually River and Mineral Creek. Elevations increase up to about 2,600 feet at
the top of the ridge in the north-central portion of the site. A smaller ridge up to about Elevation 2,100 feet
is located in the southeast portion of the property, between Mineral Lake and Roundtop Creek. Elevations
referenced herein refer to the North American Vertical Datum of 1988 (NAVD 88) and should be considered
approximate.
3.4. Literature Review
3.4.1. Geologic Setting
The property is located approximately 20 miles west-southwest of Mount Rainier, an active volcano within
the central portion of the Washington State Cascade Mountain Range. Mount Rainier and surrounding
foothills generally consist of Tertiary-aged andesitic to basaltic volcanic and volcanoclastic rocks deposited
by the accumulation of lava flows and pyroclastic flows. Throughout its history Rainier has produced debris
flows and lahars (volcanic mudflows), which have reached as far as Puget Sound. The most recent lava
flows occurred about 2,200 years ago and the most recent pyroclastic flows as recently as about
1,100 years ago. Also present in the project area are glacial deposits from alpine glaciation and alluvial
deposits in areas surrounding local rivers, creeks and streams.
3.4.2. Geologic Maps
We reviewed published geologic maps of the project vicinity, including “1:100,000-scale Geologic Mapping”
available online from the Washington Department of Natural Resources (DNR) Geologic Information Portal
(Jackson et al. 2000), the “Geologic Map of Washington State” (Schuster 2005) and our in-house files. For
visual reference, a portion of the “1:100,000-scale Geologic Mapping” is reproduced in this report as
Geologic Map - 1:100,000-scale, Figure 4.
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The maps indicate the higher elevations of the site are underlain by volcanic bedrock consisting of basaltic
andesite and flow breccia. Volcanic rock is labelled as Mvba(1) or Tv on the maps reviewed. Unweathered
basalt exposures are described as black to greenish black. The upper few feet of basalt can be weathered,
typically weathering into clay minerals and gray to moderate yellow-brown in color.
Low-lying elevations of the project area are mapped as glacial drift, labelled as Qap(h) or Qad on the maps
reviewed. Glacial drift is generally mapped immediately southwest and east of Mineral Lake, including the
area along Mineral Creek. Glacial drift is described as undifferentiated glacial sand, gravel and till, and
includes areas of glacial outwash and recent alluvial deposits.
Other geologic units mapped outside of the project area include mass-wasting deposits (Qls) and
sedimentary rocks (Ec[2pg]).
3.4.3. Natural Resources Conservation Service (NRCS) Description
The United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Web
Soil Survey indicates approximately 21 soil types (not including slope classifications) are mapped within
the total property area. No singular soil unit appears to cover more than about 15 percent of the total
property surface area. The literature generally describes the soils as derived from andesite, igneous rocks,
volcanic ash and glacial till.
3.4.4. Water Well Reports
We were provided two water well reports for review. Copies of these well reports are provided in Appendix
B. The well reports include a log of soil types encountered in the borings as well as static water level
readings. We understand these wells were completed at the property; however, detailed location or
elevation information is not provided on the well reports.
The well report with Ecology Tag ID No. AGE820 indicates “top soil” and “clay with boulders” were
encountered to a depth of 13 feet below ground surface (bgs). Soils were underlain by shale to the full
depths explored, 203 feet bgs. Static water level is recorded at 23 feet below top of well on January 13,
2002.
The well report with Ecology Tag ID No. AGE821 indicates “clay with boulders” was encountered to a depth
of 12 feet bgs. Soil was underlain by shale to a depth of 173 feet bgs, underlain by sandstone to a depth
of 243 feet bgs (bottom of boring). Static water level is recorded at 161 feet below top of well on January
4, 2002.
3.5. Subsurface Conditions
3.5.1. Methodology
We explored subsurface conditions at the site by advancing 24 test pit explorations between March 26,
2020 and March 27, 2020. Test pit excavations were advanced using a track-mounted excavator with a
toothed-bucket provided and operated by Kelly’s Excavating, Inc. under subcontract to GeoEngineers. As
previously indicated in Section 3.2 of this report, test pit locations were selected to target conceptual
development areas. Approximate test pit locations are shown on the attached Site Plan - Test Pit Overview,
Figure 5. Details regarding the subsurface exploration program, including summary logs of the explorations,
are provided in Appendix A.
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Due to the large site area and our limited time on site, test pit locations are relatively far apart. We anticipate
soil conditions in unexplored areas and between our test pit locations are somewhat similar to those
observed in nearby test pits as described in this report; however, transitions between dissimilar geologic
units will likely be present.
Selected samples from our explorations were tested to evaluate engineering properties and to confirm or
modify field classifications. Our testing program consisted of grain-size distribution analyses, hydrometer
analyses, percent fines determinations and moisture content determinations. Details and the results of our
laboratory testing program are provided in Appendix A.
3.5.2. Soil Conditions
We observed what we interpret to be four general soil units at the site: (1) fill consisting of reworked on-site
material, (2) residual soils derived from weathered bedrock, (3) bedrock consisting of basalt or granite and
(4) glacial drift. In test pits advanced in vegetated areas, we observed about 3 to 6 inches of surficial forest
duff, sod and/or underbrush.
In general, soils in upland areas at the site (e.g., Test Pit Area 1 and higher elevations within Test Pit Area
2) appear to generally consist of varying amounts of residual soils overlying basaltic bedrock. We observed
what we interpret to be glacial drift soils in low-lying elevations within Test Pit Area 2, adjacent to Mineral
Creek. These observations are generally consistent with the geologic mapping of the site (see Figure 4).
However, residual soils and basaltic bedrock encountered in the test pits appear to extend over a larger
area than mapped, resulting in fewer glacial drift soils than expected, based on the geologic mapping.
A detailed description of soils observed in the test pits is provided in the sections below.
3.5.3. Test Pit Area 1 (Northwest of Mineral Lake)
3.5.3.1. General
Eight test pits (TP-1.01 through TP-1.08) were located in Test Pit Area 1 in the western project area,
immediately northwest of Mineral Lake and near the property entrance off Mineral Hill Road. Test Pit Area
1 is shown in detail on Site Plan - Test Pit Area 1, Figure 6. Ground surface elevation at Area 1 test pit
locations varied between about Elevation 1,464 feet (TP-1.05, nearest Mineral Lake) to Elevation 1,783
feet (TP-1.07, approximately 1,000 feet laterally upslope from Mineral Lake).
3.5.3.2. Fill
We observed what we interpret to be fill material in two test pits (TP-1.03 and TP-1.08), which were located
adjacent to existing logging roadways. Observed fill thickness was on the order of 1½ to 2 feet. Fill typically
consisted of variable amounts of medium dense/stiff clay, sand, gravel and cobbles consistent with
reworked native residual soils. We expect that fill in these test pits may have been generated and placed
during grading for the logging roads.
3.5.3.3. Residual Soils
Residual soils were observed in all eight test pits in Test Pit Area 1. Residual soils were typically comprised
of varying amounts of clay, sand and gravel in a loose/soft to very dense/hard condition. Cobbles and
boulders were also occasionally encountered. The density and/or stiffness of residual soils appeared to
generally increase with depth. We expect that the variety in composition and gradation of residual soils
observed was dependent on the degree of weathering of the soils and underlying bedrock. Five test pits
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(TP-1.01 through 1.03, 1.05 and 1.06) were terminated within residual soils at depths between 9 and
14½ feet bgs.
3.5.3.4. Bedrock
What we interpret to be volcanic basalt bedrock was observed below residual soils in three test pits
(TP-1.04, TP-1.07 and TP-1.08) at depths between about 9 and 13½ feet bgs. The upper approximate
3 inches of bedrock was in a weathered condition and was able to be ripped with the backhoe. However,
intact bedrock was encountered immediately below the weathered zone and could not be ripped using the
backhoe. Three test pits (TP-1.04, TP-1.07 and TP-1.08) met practical excavation refusal on intact bedrock
at depths ranging from 9¼ to 13¾ feet bgs.
3.5.4. Test Pit Area 2 (Low-Lying Area between Mineral Lake and Mineral Creek)
3.5.4.1. General
Sixteen test pits (TP-2.01 through TP-2.16) were located at Test Pit Area 2 in the eastern project area,
generally between Mineral Lake and Mineral Creek. Test Pit Area 2 is shown in detail on Site Plan - Test Pit
Area 2, Figure 7. Ground surface elevation at Area 2 locations varied between about Elevation 1,341 feet
(TP-2.12, adjacent to Mineral Creek) to Elevation 1,562 feet (TP-2.15, upland area between Mineral Lake
and Roundtop Creek).
We observed residual soils were encountered within the highest elevation test pits at Test Pit Area 2,
(between Elevation 1,362 and 1,562 feet). Glacial drift soils were encountered at the lower elevation test
pits (Elevation 1,341 to 1,361 feet).
3.5.4.2. Fill
Material we interpret to be fill was encountered in one test pit (TP-2.02) in Test Pit Area 2. Fill material
consisted of angular rock fragments in a medium dense condition extending from the ground surface to
about 3½ feet bgs. Based on the material type and location, we anticipate that the fill consists of native
volcanic basalt bedrock processed and placed for logging road construction.
3.5.4.3. Residual Soils
We observed what we interpret to be residual soils in ten test pits (TP-2.01 through TP-2.06 and TP-2.13
through TP-2.16). Residual soils were typically comprised of varying amounts of loose/soft to dense/stiff
clay, sand and gravel. We expect that the variety in composition and gradation of residual soils observed
was dependent on the degree of weathering of the soils and underlying bedrock.
Residual soils in TP-2.06 were encountered from the ground surface to a depth of approximately 5½ feet
and were underlain by glacial drift soils. Residual soils in seven test pits (TP-2.01, TP-2.02, TP-2.05 and
TP-2.13 through TP-2.16) extended from the ground surface to depths between approximately 7½ and
12½ feet bgs (full depths explored).
3.5.4.4. Bedrock
What we interpret to be bedrock (volcanic basalt and/or granite) was observed below residual soils in two
test pits (TP-2.03 and TP-2.04). The upper approximate 3 to 6 inches of bedrock was in a weathered
condition and was able to be ripped with the backhoe. However, intact bedrock was encountered
immediately below the weathered zone and could not be ripped using the backhoe. Two test pits (TP-2.03
and TP-2.04) met practical excavation refusal on intact bedrock at depths of 10¾ and 8 feet bgs,
respectively.
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3.5.4.5. Glacial Drift
What we interpret to be glacial drift was observed in seven test pits (TP-2.06 through TP-2.12) in Test Pit
Area 2. Glacial drift was encountered at the ground surface or immediately below a surficial layer of forest
duff/underbrush except in TP-2.06, which encountered glacial drift below residual soils.
Glacial drift was generally comprised of loose to dense gravel with varying amounts of silt and sand, as well
as occasional layers of silt and sand. Cobbles and boulders were occasionally observed within the glacial
drift soils. We interpret glacial drift encountered as recent alluvial deposits from Mineral Creek. TP-2.06
through TP-2.12 were terminated within glacial drift soils at depths between about 8 and 13 feet bgs.
3.5.5. Groundwater Conditions
3.5.5.1. Test Pit Area 1 (Northwest of Mineral Lake)
Groundwater seepage was observed in five out of eight test pits (TP-1.01 through TP-1.05) in Test Pit Area
1 at depths ranging from approximately 4 to 12 feet bgs. Soils underlying observed seepage areas were in
a moist condition. Groundwater seepage was not observed in the remaining test pits in Test Pit Area 1
(TP-1.06 through TP-1.08). We also observed occasional mottled soil coloring and iron-oxide staining in the
test pits, as noted in the logs, which are indications of fluctuations in the groundwater level.
In our opinion, observations of groundwater seepage in Test Pit Area 1 are consistent with perched
groundwater.
3.5.5.2. Test Pit Area 2 (Low-Lying Area between Mineral Lake and Mineral Creek)
Residual soils were encountered to the depths explored in nine out of sixteen test pits in Area 2 (TP-2.01
through TP-2.05 and TP-2.13 through TP-2.16). These test pits were located at higher elevations in Test Pit
Area 2 (Elevation 1,362 to 1,562 feet) and distant from Mineral Creek. Groundwater seepage within the
residual soils was observed in one test pit (TP-2.13) at 1 foot bgs. Soils underlying the observed seepage
area were in a moist condition. We also observed occasional mottled soil coloring and iron-oxide staining
in the test pits, as noted in the logs, which are indications of fluctuations in the groundwater level.
Residual soils underlain by glacial drift soils were observed in one test pit (TP-2.06, EL 1357 feet). What
we interpret to be static groundwater was observed at a depth of 5 feet bgs at this location. Top of glacial
drift soils consisting of gravel was observed at 5.5 feet bgs.
Glacial drift soils were observed in six test pits in Area 2 (TP-2.07 to TP-2.12). These test pits were located
at lower elevations in Test Pit Area 2 (Elevation 1,341 to 1,361 feet) and adjacent to Mineral Creek. What
we interpret to be static groundwater was observed in each of these test pits at depths between 6 to 11 feet
bgs (Elevation 1,332 to 1,352 feet) and extending to the full depths explored.
In our opinion, observations of groundwater seepage within residual soils at Test Pit Area 2 are consistent
with perched groundwater. What we interpret to be static groundwater was observed within glacial drift
soils and adjacent to Mineral Creek.
3.5.5.3. Discussion
Perched groundwater encountered is likely due to infiltration of surface water that slows or terminates atop
underlying less permeable layers of residual soils or bedrock. It is common for perched groundwater to be
present near contacts where soil that is more permeable overlies soil that is less permeable (e.g., relatively
loose/soft residual soils over bedrock). The quantity and location of perched groundwater, if encountered,
March 16, 2021 | Page 8 File No. 6565-008-00
is expected to be dependent on infiltration of surface water. Site grading can affect infiltration and
therefore, the quantity and location of perched groundwater.
We anticipate static groundwater adjacent to Mineral Creek are interconnected with water levels in the
creek. When creek levels are high water will flow from the creek into the ground; when creek levels are low
water will flow from the ground into the creek.
It is not clear whether the groundwater seepage, static groundwater and wet conditions observed in the
test pits remain year-round, including throughout the relatively drier summer months. Groundwater levels
can fluctuate depending on soil conditions, rainfall amounts, irrigation activities and other factors. We
anticipate groundwater levels will generally be highest during the wet season, typically October through May
in western Washington.
4.0 CONCLUSIONS AND RECOMMENDATIONS
4.1. Critical Areas Review
4.1.1. Methodology
We reviewed Lewis County Code Chapter 17.38 “Critical Areas”, which classifies and designates critical
areas within Lewis County. Specifically, we reviewed site conditions as they relate to (1) erosion hazards,
(2) steep slope areas, (3) landslide hazard areas, (4) seismic hazards and (5) volcanic hazards.
4.1.2. Erosion Hazard Areas
Lewis County Code Section 17.38.640 defines erosion hazard areas as “areas that have severe or very
severe erosion potential as detailed in the soil descriptions contained in the Web Soil Survey for Lewis
County, Washington”. For visual reference, erosion hazard at the property as mapped by the NRCS Web
Soil Survey is reproduced as Erosion Hazard - NRCS, Figure 8. Erosion hazard at the property as mapped
by Lewis County is reproduced in this report as Erosion Hazard Areas - Lewis County, Figure 9. Based on
our review of the NRCS and Lewis County maps, a large percentage of the property is mapped as underlain
by soils with severe to very severe erosion hazard.
Based on our understanding of the project, we understand site grading and ground disturbing activities will
be limited as much as practical. The majority of the property will remain undeveloped and heavily forested,
will be used for hiking and recreation and will either remain in forestry production or be placed into
conservation easements.
We anticipate erosion hazards can be mitigated through engineering controls such as limited ground
disturbance, site grading, planting and other erosion control measures. The presence of erosion hazards,
in in our opinion, are not a limiting factor in determining feasibility of the proposed development.
4.1.3. Steep Slope Areas
Steep slope hazard areas are defined in Lewis County Code Section 17.38.650 as areas not mapped as a
landslide hazard but with slopes greater than or equal to 35 percent (about 2.9 horizontal:1 vertical) with
a vertical relief of 10 feet or more. The presence of a steep slope may indicate potential slope stability
problems.
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We reviewed provided survey of the property and available online maps of the property. For visual reference,
a map available online from Lewis County, which depicts slope grades is reproduced in this report as Steep
Slope Areas, Figure 10. In addition, while on site during test pit excavations we observed occasional near-
vertical slopes, particularly at areas of exposed bedrock.
In our opinion, steep slope areas at the property can be mitigated through site grading and horizontal
offsets. Additional discussion is provided in Section 4.1.4 Landslide Hazard Areas below. Overall, it is our
opinion that the presence of landslide hazards is not a limiting factor in determining feasibility of the
proposed development and that landslide hazards can be mitigated through proper engineering controls.
4.1.4. Landslide Hazard Areas
4.1.4.1. Landslide Hazard Criteria
Landslide hazard areas are defined in Lewis County Code Section 17.38.650. In particular, the following
criteria is included when defining landslide hazard areas:
■ Areas subject to previous slope failures, including areas of unstable old or recent landslides.
■ Areas with slopes having gradients greater than 80 percent (38.7 degrees) subject to rockfall during
seismic shaking.
■ Areas that meet the following criteria:
Slope greater than 15 percent (8.5 degrees).
Hillsides intersecting geologic contacts with a relatively permeable sediment overlying a
relatively impermeable sediment or bedrock.
Springs or groundwater seepage.
■ Areas mapped as landslide hazard areas in maps available from the Washington DNR.
While performing our test pit explorations we observed no evidence of unstable slopes or old or recent
deep-seated landslides on site. However, we did observe occasional shallow scarps and tension cracking
in areas of the site, particularly within upland areas in the north-central ridge of the property, which are an
indication of slope movement and surficial sloughing. We also observed occasional rock debris at the
bottom of exposed bedrock areas, which are an indication of rockfall and topple.
We reviewed published online landslide hazard maps provided by the Washington DNR and Lewis County,
reproduced as Figure 11 in this report. Our review indicates the site only contains small and isolated areas
mapped as landslide hazard areas.
4.1.4.2. Landslide Hazard Discussion
Based on the criteria presented in the Lewis County Code and reproduced in part above, potential landslide
hazard areas are present on site. However, based on our observations while on site and the relatively
shallow depths to bedrock observed in our test pits within sloped areas, it is our opinion the risk of deep-
seated or global failures and instability on site is low. We anticipate landslide hazards at the property can
be mitigated through engineering controls such as site grading and horizontal offsets from the toe and crest
of landslide hazard areas, or potentially shoring and rock restraint systems.
Existing slopes could experience shallow surficial sloughing over the long term. Sloughing is typically due
to natural processes such as seepage, saturation of shallow soils during heavy rain events, decay of roots,
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or root removal of blown down trees. The magnitude and volume of material involved in shallow surficial
sloughing depends on several factors including steepness of slope, time of year, rainfall, and activity of
burrowing animals. Because sloughing is a natural process that occurs with or without development,
mitigation measures are often limited to monitoring and maintenance.
4.1.5. Seismic Hazard Areas
Seismic hazard areas are addressed in Lewis County Code Section 17.38.660. Our detailed evaluation of
seismic and liquefaction hazards at the property are included in Section 4.2.2 below.
4.1.6. Volcanic Hazard
Volcanic hazard areas are addressed in Lewis County Code Section 17.38.670. Volcanic hazards are
defined as locations where risk to life and property by a large volcanic event is high, primarily consisting of
damage from lahars and near volcano hazards (such as lava flow). Lewis County does not consider volcanic
tephra (ash) a volcanic hazard subject to regulation. We reviewed available online maps of the property,
which indicates portions of the property adjacent to the Nisqually River and Mineral Creek are mapped as
volcanic hazards. For visual reference, a map available online from Lewis County is reproduced in this report
as Volcanic Hazards, Figure 12.
Overall, it is our opinion that the presence of volcanic hazards at the site is not a limiting factor in
determining feasibility of the proposed development and that volcanic hazards can be mitigated through
proper siting and engineering controls.
4.2. Seismic Design Considerations
4.2.1. International Building Code Seismic Design Parameters
4.2.1.1. Design Methodology
We anticipate seismic design of proposed structures will be performed using procedures outlined in the
2018 International Building Code (IBC). Per the 2018 IBC structures shall be designed and constructed to
resist the effects of earthquake motions in accordance with American Society of Civil Engineers (ASCE)
7-16.
Soils observed in the test pits varied from soft to stiff clays (residual soils), loose to dense granular soils
(glacial drift) and bedrock. Based on conditions observed in our explorations, our review of geologic maps
and our experience in the area we anticipate variable near surface soils and depth to bedrock across the
property. For preliminary design, analysis and cost estimating we recommend seismic design criteria
corresponding to Site Class D (stiff soil).
We should be contacted as project design and building locations advance to determine if a change in Site
Class and recommended seismic design criteria are appropriate. In our opinion, Site Class B (rock) or Site
Class C (very dense soil and soft rock) may be suitable for some of the structures bearing on intact or
weathered bedrock. Site Class F (requiring site response analysis) may be appropriate adjacent to Mineral
Creek as liquefiable layers may be present as discussed in the sections below.
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4.2.1.2. Seismic Design Criteria
We used map-based values available online as recommended by the United States Geological Survey
(USGS) to determine the seismic design spectrum in accordance with ASCE 7-16. We recommend the
parameters provided in Table 1 below be used for preliminary design.
TABLE 1. PRELIMINARY SEISMIC DESIGN CRITERIA
2018 IBC (ASCE 7-16) Seismic Design Parameters
Site Class D
Spectral Response Acceleration at Short Periods (SS) 1.12g
Spectral Response Acceleration at 1-Second Periods (S1) 0.40g
Design Spectral Response Acceleration at Short Periods (SDS) 0.79g
Design Spectral Response Acceleration at 1-Second Periods (SD1) null1
Design Site Modified Peak Ground Acceleration (PGAM) 0.54g
Note:
1 A ground motion hazard analysis may be required in accordance with Section 11.4.8 of ASCE 7-16.
In accordance with ASCE 7-16 Section 11.4.8 a ground motion hazard analysis is required for the site (due
to Site Class D site with spectral response acceleration at 1-second periods (S1) greater than or equal to
0.2). However, an exception is allowed in Section 11.4.8 provided specific requirements are satisfied
related to the fundamental period of the structure. Based on our understanding of the conceptual site
design, we anticipate proposed structures will be designed such that a ground motion hazard analysis will
not be required. We should be contacted if it is determined a ground motion hazard analysis is required for
the project.
4.2.2. Liquefaction, Lateral Spreading, and Surface Rupture
4.2.2.1. Liquefaction Potential
Liquefaction refers to a condition where vibration or shaking of the ground, usually from earthquake forces,
disturbs the soil structure (i.e., the arrangement of individual soil particles) within saturated and
unconsolidated soils. Water in the pore spaces between soil particles will resist the natural tendency of the
soils to re-arrange into a denser and more stable state during shaking, resulting in development of excess
pore pressures. As porewater pressures increase, soil particles may lose contact with each other and the
affected soil deposit may lose much of its stiffness and strength. Liquefaction susceptibility is difficult to
predict and not all soils are susceptible to liquefaction. The degree of susceptibility depends in part on the
soil grain size. In general, soils most susceptible to liquefaction include loose to medium dense “clean” to
silty sands below the water table. However, research and case histories indicate other loose granular soils
such as silts and gravels may also be susceptible to liquefaction.
We reviewed the “Liquefaction Susceptibility Map of Lewis County, Washington” (Palmer et al. 2004). We
also reviewed a liquefaction susceptibility map available online through Lewis County, reproduced as
Liquefaction Susceptibility, Figure 13 in this report. In general, our review indicates the upland areas of the
property (north-central and southeast ridge areas) are mapped as bedrock and not liquefiable. The western
and eastern site areas adjacent to Mineral Lake and/or Mineral Creek are mapped as having a very low
potential for liquefaction.
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Based on soil and groundwater conditions observed in our explorations and our interpretation of the
regional geology, it is our opinion that the risk for liquefaction is very low in the upland areas of the site
underlain by residual soils and shallow bedrock. In the eastern site area adjacent to Mineral Creek, we
observed glacial drift soils, including relatively cleaner layers of sand and gravel, as well as static
groundwater on the order of 5 to 11 feet bgs. Based on current information, potentially liquefiable layers
could be present within glacial drift soils encountered adjacent to Mineral Creek. We anticipate cleaner
sand layers encountered in our test pits (e.g., TP-2.07 and TP-2.09) will be most susceptible to liquefaction
and the dense gravels encountered have relatively low potential for liquefaction. This should be
investigated again once the size and type and location of structures has been determined. Based on
proposed development, it is our opinion that the potential for liquefaction is not a controlling factor in
determining site development requirements. We anticipate that liquefaction can be mitigated through
proper engineering controls.
4.2.2.2. Lateral Spreading Potential
Lateral spreading related to seismic activity typically involves lateral displacement of large, surficial blocks
of non-liquefied soil when an underlying soil layer loses strength during seismic shaking. Lateral spreading
usually develops in areas where sloping ground or large grade changes (including retaining walls) are
present. Based on our understanding of the subsurface conditions, liquefaction risk and current site
topography, it is our opinion the risk of lateral spreading is low.
4.2.2.3. Surface Rupture Potential
According to the Washington State DNR Interactive Natural Hazards Map (accessed November 3, 2020),
the nearest seismic fault is mapped about 2 miles southwest of the project site and does not appear to
trend towards the site. Accordingly, it is our opinion the risk for seismic surface rupture at the site is low.
4.3. Shallow Foundations
4.3.1. General
As the project is in the early phases of planning and design the type, size and location of proposed
structures is not available at this time. Based on our understanding of the proposed development at the
time of this report and our explorations at the project site, it is our opinion lightly loaded structures (e.g.,
single- and two-story wood framed structures) can be adequately supported on shallow foundations,
reinforced mats and slab-on-grade. For heavier structures (e.g., water storage tank), more stringent bearing
surface preparation requirements and settlement analysis may be appropriate such as bearing on bedrock
through overexcavation or possibly pile foundations, depending on the thickness of the upper residual units.
4.3.2. Footing Bearing Surface Preparation
We recommend foundations for proposed structures not bear directly on relatively loose soils (including fill,
residual and/or glacial drift soils) without improvements. Depending on final development locations, site
grading and foundation grade, compaction improvements to existing loose soils could be required.
Depending on thickness, some removal and replacement (overexcavation) may also be necessary.
Foundation bearing surfaces should be compacted as necessary to a firm, non-yielding condition. Loose or
disturbed materials present at the base of footing excavations must be removed or compacted. If soft or
otherwise unsuitable areas are revealed during evaluation, which cannot be compacted to a stable and
uniformly firm condition, the following options may be considered: (1) unsuitable soils be moisture
conditioned and recompacted; (2) unsuitable soils be overexcavated and replaced with compacted
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structural fill, as needed; or (3) it may be possible to push, seat, and compact quarry spalls into soft soils
to stabilize the surface and build upon.
4.3.3. Allowable Soil Bearing Pressure
For bearing surfaces prepared as described above, we estimate allowable bearing capacities in the range
of 2,000 to 4,000 pounds per square foot (psf) will be satisfactory for residual and/or glacial drift soils. For
the purposes of preliminary design, we have assumed groundwater may be present at or below the bearing
surface elevation and foundation drainage will be provided to prevent the foundation elements from
becoming submerged.
Depending on structure type and location, higher bearing pressures are attainable where weathered
bedrock deposits exist and/or within intact bedrock. Once structure type and location have been
determined we can provide alternative bearing pressure values, depending on the building location.
Weathered rock deposits expected at this site can have allowable bearing pressures of 5,000 to 10,000 psf
or more. Intact basalt bedrock has at least this amount and likely more. We recommend we review proposed
construction and building locations during design to assist and determine if higher bearing pressures are
warranted.
These bearing pressures apply to the total of dead and long-term live loads and may be increased by one-
third when considering total loads, including earthquake or wind loads. These are net bearing pressures.
The weight of the footing and overlying backfill can be ignored in calculating footing sizes.
4.3.4. Foundation Settlement
Shallow foundations can typically experience two types of static (non-seismic) settlement: elastic and
consolidation. Elastic (short-term) settlement typically occurs at the time of load placement or shortly
thereafter. Consolidation (long-term) settlement may occur for weeks or months after loads are placed,
depending on soil type, and is primarily a result of soft fine-grained and/or organic compressible soil. The
amount of settlement that could occur during and after site development is dependent on three major
factors: (1) the thickness and nature of the compressible soil layers; (2) the loading of the site, including
additional fill; and (3) the loading history of the site. Compressible soils generally experience: (1) initial
settlements as loads are being applied and (2) consolidation settlements that can continue for weeks or
months.
Some soils observed in our test pit explorations (specifically, clay observed within residual soils) may be
compressible. We do not anticipate settlement as a controlling factor for design of lightly loaded site
improvements (e.g., roadways and single- and two-story wood framed structures). Heavier structures (e.g.,
water storage tank) are discussed in more detail in Section 4.3.5 of this report.
We can provide more detailed settlement estimates as building type, size, location and foundation grades
are determined. Ultimately, additional explorations may be warranted to better define soil characteristics
and determine settlements based on actual structure type and loading conditions. It is possible settlement
can be mitigated through overexcavation and replacement, pre-loading, or other suitable methods.
4.3.5. Water Storage Tank
We understand current conceptual design a water supply system for the camp includes a water storage
tank (or multiple tanks). We understand tank sizing and preferred location has not yet been determined.
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For preliminary cost estimating and design we recommend planning for the water storage tank to not bear
on residual soils encountered in the test pits due to reduced foundation bearing support and increased risk
of foundation settlements on these soils. We anticipate intact bedrock and/or dense glacial drift soils as
encountered in the test pits will provide suitable bearing and settlement performance as well as the
condition where structural fill extends to these soils.
4.4. Infiltration Feasibility Assessment
4.4.1. General
On-site sewage systems and stormwater infiltrations facilities will be designed in accordance with Lewis
County Code. Due to the presence of shallow groundwater and/or depth to bedrock observed in our test
pits, it is our opinion maintaining vertical separation below the bottom of facilities will be a primary factor
in controlling design of infiltration facilities. We provide preliminary but specific design recommendations
for on-site sewage systems and infiltration facilities below.
4.4.2. On-Site Sewage Systems
Currently proposed on-site sewage systems include septic drain fields. We reviewed Lewis County Code
Chapter 8.40, which provides design guidelines for these facilities. Based on laboratory grain-size analyses,
we provide United States Department of Agriculture (USDA) soil textural classifications for selected soil
samples from our test pit excavations in Table 2 below.
TABLE 2. USDA SOIL TEXTURAL CLASSIFICATIONS
Exploration
Sample
Depth
(feet)
Sample
Elevation
(feet)
Geologic
Unit
USCS Symbol
(Description) USDA Texture
TP-1.02 3.5 1480.5 Residual SC
(clayey sand with occasional gravel) Very fine sandy loam
TP-1.05 5 1459 Residual SC
(clayey sand with gravel)
Gravelly very fine
sandy loam
TP-1.08 7 1746 Residual SC
(clayey sand with gravel)
Gravelly sandy clay
loam
TP-2.03 4 1489 Residual CL
(sandy clay) Loam
TP-2.07 3.5 1354.5 Glacial Drift GP-GM
(gravel with silt, sand & cobble)
Extremely gravelly
loamy fine sand
TP-2.10 3.5 1357.5 Glacial Drift GP-GM
(gravel with silt, sand & occ. cobble)
Extremely gravelly
loamy fine sand
TP-2.10 8 1353 Glacial Drift GW-GM
(gravel with silt, sand & cobble)
Extremely gravelly
loamy fine sand
Based on our review of Lewis County Code, we anticipate that required vertical separation (e.g., depth to
groundwater, bedrock, or other restrictive layer) and horizontal separations (e.g., aquifer, spring, surface
water, etc.) of on-site sewage systems will need to be considered during design.
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4.4.3. Stormwater Infiltration
4.4.3.1. General
Plans to manage stormwater runoff at the site include infiltration facilities. Soils are classified by the NRCS
into four Hydrologic Soil Groups (A, B, C and D) based estimates of the soil's runoff potential. Group A is
defined as having a low runoff potential (high infiltration rate), while Group D is defined as having high
runoff potential (low infiltration rate). For visual reference, a portion of the NRCS Web Soil Survey is
reproduced in this report as Hydrologic Soil Group - NRCS, Figure 14.
Chapter 15.45 of the Lewis County Code refers to the latest edition of the Washington State Department
of Ecology (Ecology) Stormwater Management Manual for determining and designing stormwater infiltration
facilities. Accordingly, we evaluated the infiltration potential of selected soil samples from our test pits using
methods outlined in the 2019 Ecology Stormwater Management Manual for Western Washington
(SWMMWW).
4.4.3.2. Calculation of Preliminary Infiltration Rates
Typically, the grain-size analysis method is suitable to determine design infiltration rates for soils that have
not been consolidated by glacial advance. Based on our experience and test pit explorations at the site, we
anticipate that native soils (residual soils and glacial drift) are not glacially consolidated and therefore, the
grain-size analysis method is generally acceptable at the project site.
Preliminary initial saturated hydraulic conductivity of the soil sample is calculated based on the soil grain
size analysis using the Massmann method. For long-term design infiltration rates, correction factors are
applied to reduce the calculated initial saturated hydraulic conductivity. Correction factors in the SWMMWW
are based on site variability, number of tests conducted, uncertainty of the test method, and the potential
for long-term clogging due to siltation and bio-buildup. We included the correction factors presented in
Table 3 below when calculating preliminary long-term infiltrations.
TABLE 3. 2019 ECOLOGY SWMMWW CORRECTION FACTOR SUMMARY
Issue Partial Correction Factor
Site Variability and Number of Locations Tested (CFv) 0.331
Uncertainty of Test Method (CFt) 0.4
Degree of Influent Control to Prevent Siltation and Bio-Buildup (CFm) 0.9
Total Correction Factor = CFv x CFty x CFm CF = 0.12
Note:
1 Correction factor for site variability assumed and must be verified for final design.
Table 4 below summarizes our preliminary initial (short-term) and design (long-term) infiltration rates of the
selected soil samples with correction factors applied.
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TABLE 4. PRELIMINARY INFILTRATION RATE SUMMARY
Exploration
Sample
Depth (feet)
Sample
Elevation
(feet) Geologic Unit
USCS
Soil Type
Percent
Fines
Ksati1
(in/hr)
Ksatd2
(in/hr)
TP-1.02 3.5 1,480.5 Residual SC 37 6.3 0.8
TP-1.05 5 1,459 Residual SM 20 9.3 1.1
TP-1.08 7 1,746 Residual SM 25 10.4 1.2
TP-2.03 4 1,489 Residual CL 60 2.2 0.3
TP-2.07 3.5 1,354.5 Glacial Drift GP-GM 8 32.1 3.8
TP-2.10 3.5 1,357.5 Glacial Drift GP-GM 8 34.9 4.1
TP-2.10 8 1353 Glacial Drift GW-GM 9 25.0 3.0
Notes:
1 Preliminary initial saturated hydraulic conductivity as determined by the grain-size analysis method presented in the 2019 Ecology
SWMMWW without correction factors.
2 Preliminary long-term design infiltration rate including appropriate correction factors.
Based on our analysis of the selected soil samples, observed soil layering and site topography, we interpret
two different infiltration profiles on site.
■ Residual soils generally consisting of varying amounts of clay, silt, sand and gravel. These soils were
typically observed in the higher elevations of the project site. Preliminary design infiltration rates within
residual soil samples obtained ranged from about 0.3 to 1.2 inches per hour based on grain-size
analyses. Residual soils were typically underlain by bedrock.
■ Glacial drift soils were generally observed in the lower elevations of the site adjacent to Mineral Creek.
Glacial drift soils were generally comprised of gravel with varying amounts of silt and sand. Preliminary
design infiltration rates within glacial drift soil samples obtained range from approximately 3 to
4.1 inches per hour. Test pits that encountered glacial drift also encountered relatively shallow
groundwater, on the order of 5 to 11 feet bgs.
4.4.3.3. Discussion
Note that samples for laboratory grain-size testing were generally selected after visually determined to be
most favorable for infiltration. Therefore, the results presented above may not represent the full range of
soil types present at the site.
The preliminary rates presented above do not account for soil layering, underlying impermeable layers or
groundwater separation as required for final design. In particular, we anticipate depth to bedrock (residual
soils, upland areas of site) and depth to groundwater (glacial drift, adjacent to Mineral Creek) will affect
design of infiltration facilities.
Our explorations are somewhat limited in number and depth, and we observed varying subsurface
conditions. As such, we recommend GeoEngineers review proposed stormwater infiltration facilities after
design to confirm the anticipated performance can be achieved based on the soil conditions encountered
or to provide additional recommendations. Additional explorations, testing (including Pilot Infiltration Tests
[PITs]), or analysis (e.g., infiltration receptor characterization, groundwater mounding analysis, etc.) may be
warranted upon review. We also recommend we be retained during construction to observe soil conditions
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at the base of the infiltration facilities and verify exposed soil conditions are as anticipated for the proposed
design.
4.5. Site Development and Earthwork
4.5.1. General
We anticipate site development and earthwork activities on site will include clearing and stripping vegetated
areas; site grading; mass fill placement; establishing subgrades for roads, parking areas, and building
foundations; and placing and compacting fill and backfill materials. We expect the majority of site grading
and earthwork can be accomplished with conventional earthmoving equipment. However, we observed
bedrock in some of our explorations and bedrock outcrops were observed in some areas at the project site,
indicating shallow depths to rock. Further discussion is presented below on excavation through bedrock. In
general, the site development and earthwork sections provided are to allow the design team to consider
further construction efforts that may be needed for costing and development analysis. Additional
explorations and more site-specific earthwork recommendations could be required in the future.
4.5.2. Clearing, Stripping and Demolition
Existing surfaces should be cleared and stripped of all vegetation and organics prior to site development.
Based on conditions observed in our explorations, minimum stripping depths at the site will likely be up to
about 12 inches. However, greater stripping depths could be required to remove localized zones of loose
or organic-rich soil, especially in areas of the site currently vegetated with large brush or trees. During
clearing and stripping, stumps and primary root systems of shrubs and trees should be completely removed.
Voids caused by removal of stumps and/or root systems should be backfilled with compacted structural
fill. Stripped material should be transported off site or processed and used as fill in landscaping areas.
Based on our explorations we anticipate soils exposed after stripping have a high fines content and, thus,
be susceptible to disturbance when wet. Care should be taken to avoid allowing these soils to become
saturated and disturbed. We provide recommendations for subgrade protection in the “4.5.8 Subgrade
Protection and Wet Weather Considerations” section below.
We observed cobbles and boulders in our explorations. The contractor should be prepared for the presence
of cobbles or boulders in areas to be excavated or re-graded. Boulders may be removed from the site or
used in landscape areas. Voids caused by boulder removal should be backfilled with structural fill.
Basalt bedrock was also encountered, primarily in the upland areas of the project site. Decomposed and
weathered bedrock should be rippable with standard heavy construction equipment, such as excavators
with toothed buckets and dozers with ripping teeth. In our explorations, the weathered zone within
encountered bedrock was on the order of 3 to 6 inches thick. If excavation of underlying intact bedrock is
necessary, specialty rock excavation equipment or rock blasting may be required. Additional considerations
on equipment type will be necessary to excavate substantial amounts of the intact basalt.
4.5.3. Temporary Excavations and Cut Slopes
Based on our explorations shallow excavations on site might experience caving, especially if excavations
extend near or below the groundwater level. Excavations deeper than 4 feet should be shored or laid back
at a stable slope if workers are required to enter. Shoring and temporary slope inclinations must conform
to the provisions of Title 296 Washington Administrative Code (WAC), Part N, “Excavation, Trenching and
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Shoring.” Regardless of the soil type encountered in the excavation shoring, trench boxes or sloped
sidewalls will be required under Washington Industrial Safety and Health Act (WISHA). The contract
documents should specify that the contractor is responsible for selecting excavation and dewatering
methods, monitoring the excavations for safety and providing shoring, as required, to protect personnel
and structures.
In general, for preliminary considerations, temporary cut slopes into soils should be inclined no steeper
than about 1.5H to 1V (horizontal to vertical). Temporary cut slopes into intact basalt at inclinations may
be able to be cut near vertical for excavations less than 20 feet deep. These guidelines assume all surface
loads are kept at a minimum distance of at least one-half the depth of the cut away from the top of the
slope and seepage is not present on the slope face. Flatter cut slopes will be necessary where seepage
occurs or if surcharge loads are anticipated. Temporary covering with heavy plastic sheeting should be used
to protect these slopes during periods of wet weather.
As the design progresses, we should review areas where over-steepened slopes are expected to be
constructed. Further investigation of rock type, fractures, and quality will need to be completed to verify if
near vertical cut slopes can be constructed.
4.5.4. Permanent Cut and Fill Slopes
In general, we recommend permanent slopes be constructed at a maximum inclination of 2H to 1V. Where
2H to 1V permanent slopes are not feasible, protective facings and/or retaining structures should be
considered.
Where slope material consists of intact basalt, we recommend a preliminary maximum slope inclination of
1H to 6V for permanent slope construction planning. This guideline assumes less than about 5 feet of soil
is present on top the basalt. Ultimately, sloping conditions in the intact basalt may change or require
modifications during construction due to dipping planes and fractures in the rock. Further study should be
considered once a grading plan has been established. Where soil is present above and around the bedrock,
it should be sloped as previously recommended.
These guidelines assume all surface loads are kept at a minimum distance of at least one-half the depth
of the cut away from the top of the slope and seepage is not present on the slope face. Flatter cut slopes
will be necessary where seepage occurs or if surcharge loads are anticipated. We recommend
GeoEngineers review proposed grading plans when they become available to confirm our opinions are
appropriate.
To achieve uniform compaction, we recommend fill slopes be overbuilt and subsequently cut back to
expose well-compacted fill. Fill placement on existing slopes steeper than 5H to 1V should be benched into
the slope face. The configuration of benches depends on the equipment being used and the inclination of
the existing slope. Bench excavations should be level and extend into the slope face. Exposed areas should
be re-vegetated as soon as practical to reduce potential surface erosion and sloughing. Temporary
protection should be used until permanent protection is established.
4.5.5. Groundwater Handling Considerations
As previously discussed, groundwater varies at the project site. Slow to moderate seepage interpreted to
be perched groundwater was observed in Test Pit Area 1 within residual soils underlain by basalt bedrock.
March 16, 2021 | Page 19 File No. 6565-008-00
We observed what we interpret to be static groundwater within glacial drift soils in Test Pit Area 2. In some
cases, particularly within granular glacial drift soils, groundwater seepage caused significant caving within
the test pits that prohibited excavation deeper than about 10 feet.
Groundwater handling needs will typically be lower during the late summer and early fall months. In general,
we expect shallow perched groundwater will be the primary condition encountered for shallow excavations
in the upland site areas and can typically be handled adequately with sumps, pumps, and/or diversion
ditches, as necessary. Excavations below the static groundwater level or in areas with heavy groundwater
seepage may require additional measures such as well points. We provide additional recommendations
further for subsurface explorations, including the installation of monitoring well(s) in order to better quantify
the depth to water. Ultimately, we recommend the contractor performing the work be made responsible for
controlling and collecting groundwater encountered.
4.5.6. Surface Drainage
Surface water from roofs, driveways and landscape areas should be collected and controlled. Curbs or
other appropriate measures such as sloping pavements, sidewalks and landscape areas should be used
to direct surface flow away from buildings, erosion sensitive areas and from behind retaining structures.
Roof and catchment drains should not be connected to wall or foundation drains.
4.5.7. Subgrade Preparation
Subgrades that will support structures and roadways should be thoroughly compacted to a uniformly firm
and unyielding condition on completion of stripping and before placing structural fill or pavement base fill.
We recommend subgrades for structures and roadways be evaluated, as appropriate, to identify areas of
yielding or soft soil. Probing with a steel probe rod or proof-rolling with a heavy piece of wheeled construction
equipment are appropriate methods of evaluation.
If soft or otherwise unsuitable subgrade areas are revealed during evaluation that cannot be compacted to
a stable and uniformly firm condition, we recommend: (1) the unsuitable soils be scarified (e.g., with a
ripper or farmer’s disc), aerated and recompacted, if practical; or (2) the unsuitable soils be removed and
replaced with compacted structural fill, as needed.
4.5.8. Subgrade Protection and Wet Weather Considerations
Site soils encountered in our explorations contain a significant amount of fines and will be susceptible to
disturbance during periods of wet weather, sensitive to small changes in moisture and will be susceptible
to disturbance from construction traffic when wet or if earthwork is performed during wet weather. When
the moisture content of the soil is more than a few percent above the optimum moisture content, the soil
can become muddy and unstable and it will be challenging to meet the required compaction criteria. The
wet weather season generally begins in October and continues through May in western Washington;
however, periods of wet weather can occur during any month of the year. In our opinion, earthwork at the
site should take place during the summer months or during periods of extended dry weather. If wet weather
earthwork is unavoidable, we offer the following recommendations:
■ The ground surface in and around the work area should be sloped so that surface water is directed
away from the work area. The ground surface should be graded so that areas of ponded water do not
March 16, 2021 | Page 20 File No. 6565-008-00
develop. Measures should be taken by the contractor to prevent surface water from collecting in
excavations and trenches. Measures should be implemented to remove surface water from work areas.
■ Earthwork activities should not take place during periods of heavy precipitation.
■ Slopes with exposed soils should be covered with plastic sheeting.
■ The contractor should take necessary measures to prevent on-site soils and other soils to be used as
fill from becoming wet or unstable. These measures may include the use of plastic sheeting, sumps
with pumps and grading. The site soils should not be left uncompacted and exposed to moisture.
Sealing exposed soils by rolling with a smooth-drum roller prior to periods of precipitation will help
reduce the extent to which these soils become wet or unstable.
■ Construction traffic should be restricted to specific areas of the site, preferably areas that are surfaced
with working pad materials not susceptible to wet weather disturbance.
■ Construction activities should be scheduled so that the length of time that soils are left exposed to
moisture is reduced to the extent practical.
■ Protective surfacing such as placing asphalt-treated base (ATB) or haul roads made of quarry spalls or
a layer of free-draining material such as well-graded pit-run sand and gravel may be necessary to
protect completed areas from construction traffic. Typically, minimum gravel thicknesses on the order
of 24 inches are necessary to provide adequate subgrade protection.
■ Foundation bearing surface protection should also be considered. We provide additional
recommendations in the “4.3 Shallow Foundations” section of this report.
4.6. Fill Materials
4.6.1. General
We provide preliminary recommendations below for consideration of fill materials and to provide some
guidance should the design team need to consider further construction efforts needed for costing and
development analysis. Additional explorations and more site-specific earthwork recommendations will be
required in the future once final development plans are determined.
Material used for fill must be free of debris, organic contaminants and rock fragments larger than 6 inches.
The workability of material for use as fill will depend on the gradation and moisture content of the soil.
Generally, soil with a higher fines content is more sensitive to changes in moisture. Below we provide
recommendations for general fill materials we anticipate will be used for this project. We recommend
GeoEngineers review contractor submittals for alternate fill materials.
We provide recommendations below for fill materials to be used in dry and wet weather conditions. Dry
weather conditions assume that groundwater is controlled and no standing water is present. If standing
water is present, wet weather fill material may not be appropriate and alternatives such as quarry spalls
should be considered.
If earthwork occurs during a typical wet season, or if the soils are persistently wet and cannot be dried back
due to prevailing wet weather conditions, we recommend the use of imported structural fill or select
granular fill. Other fill materials, such as crushed rock or quarry spalls, may also be used during wet weather.
Budgets should include provisions for import granular fill, especially if construction is planned during the
March 16, 2021 | Page 21 File No. 6565-008-00
wet weather season. We can provide specific recommendations for imported material specific for its
intended use once site development planning is near construction.
4.6.2. On-Site Soil
Based on our experience, the some of the site soils encountered in our test pits (e.g., residual soils and
silty layers within glacial drift) contain a significant percentage of fines, are extremely moisture sensitive
and will be difficult or impossible to properly compact when wet. In addition, it is possible existing soils will
be generated at moisture contents above optimum.
Residual soils encountered in the test pits also typically contained significant amounts of clay and will
require specific drying and compaction techniques to be considered for use as a structural fill. In general,
we recommend that the use of residual soils as structural fill be avoided. Once site development plans are
determined, more specific direction on the use of on-site residual soils could be investigated and
considered.
Relatively cleaner layers of glacial drift observed in our test pits may be considered for use as structural fill
provided the material:
■ Has maximum particle size of 6 inches,
■ Is used during extended periods of dry weather,
■ Can be adequately moisture conditioned and placed and compacted as recommended,
■ Does not contain debris, organics or other deleterious material, and
■ Meets any special requirements related to its end use.
4.6.3. Structural Fill
Material used for structural fill should be free of debris, organic contaminants and rock fragments larger
than 6 inches in maximum dimension. We recommend structural fill consist of material similar to “Select
Borrow” or “Gravel Borrow” as described in Section 9-03.14 of the Washington State Department of
Transportation (WSDOT) Standard Specifications.
We recommend crushed rock or select granular fill (described below) be used for structural fill during the
wet season. If prolonged dry weather prevails during the earthwork phase of construction, materials with a
somewhat higher fines content such as “Select Borrow” or “Gravel Borrow” as described in Section 9-03.14
of the WSDOT Standard Specifications may be acceptable.
4.6.4. Select Granular Fill
Select granular fill should consist of well-graded sand and gravel or crushed rock with a maximum particle
size of 6 inches and less than 5 percent fines by weight based on the minus ¾-inch fraction. Organic matter,
debris or other deleterious material should not be present. Material with gradation characteristics similar
to WSDOT Specification 9-03.9 (Aggregates for Ballast and Crushed Surfacing), or 9-03.14 (Borrow) is also
suitable for use as select granular fill, provided the fines content is less than 5 percent (based on the minus
¾-inch fraction) and the maximum particle size is 6 inches.
March 16, 2021 | Page 22 File No. 6565-008-00
4.7. Fill Placement and Compaction
4.7.1. General
To obtain proper compaction, fill material should be compacted near optimum moisture content and in
uniform horizontal lifts. Lift thickness and compaction procedures will depend on the moisture content and
gradation characteristics of the soil and the type of equipment used. Generally, 12-inch thick loose lifts are
appropriate for steel-drum vibratory roller compaction equipment. The maximum allowable moisture
content varies with the soil gradation and should be evaluated during construction. Compaction should be
achieved by mechanical means. During fill and backfill placement, sufficient testing of in-place density
should be conducted to verify adequate compaction is being achieved.
4.7.2. Area Fills and Pavement Bases
Fill placed to raise site grades as well as materials under pavements and structural areas should be placed
on subgrades prepared as previously recommended. Fill material placed below structures, footings and
pavement sections must be compacted to at least 95 percent of the theoretical maximum dry density (MDD)
per ASTM International (ASTM) D 1557. In landscaping areas, fill should be compacted to a firm condition
that will support construction equipment, as necessary, typically around 85 to 90 percent of the MDD.
5.0 ADDITIONAL INVESTIGATIONS
Depending on the structures proposed and site design, additional explorations may be warranted for final
project design. Potential additional geotechnical investigations that may be required or useful for final
design are listed below:
■ At this time, the project is in the conceptual design phase and proposed structure locations and design
are not fully developed. We will provide specific foundation recommendations and settlement
estimates once this information is available.
■ If structures are planned to be constructed on the intact basalt bedrock, we suggest additional test pits
or borings be performed at proposed locations so that the depth and condition of the rock can be
observed and planned for. The depth and number of borings will depend on structures being
considered. We suggest planning for at least two borings for larger structures, such as water towers.
For single-story, wood-framed structures, it is possible that a few test pits around the development area
will suffice.
■ Where bedrock is to be cut to expose near vertical slopes, we suggest rock coring to investigate rock
quality and potential fracturing prior to planning of near vertical slopes for sitework design. This should
be especially considered where near vertical slopes will be adjacent to improvements such as roads,
building, and other facilities where infrastructure needs to be maintained or where property could be
damaged.
■ Relatively shallow static groundwater was encountered in test pits in the eastern site area near Mineral
Creek. If stormwater infiltration is planned within this area, we anticipate that additional analysis
(groundwater mounding) and/or investigations (PITs or groundwater well monitoring) will be required
for final design.
March 16, 2021 | Page 23 File No. 6565-008-00
6.0 LIMITATIONS
We have prepared this report for YMCA Seattle for the Mineral Lake Site Due Diligence project in Mineral
Lake, Washington. YMCA Seattle may distribute copies of this report to authorized agents and regulatory
agencies as may be required for the project.
Our services were provided to assist preliminary site design, including site stabilization, roadway
development and design of foundations for structures to be located on or near sloping ground. Our
recommendations are intended to improve the overall stability of the site and to reduce the potential for
future property damage related to earth movements, drainage or erosion. Qualified engineering and
construction practices can help mitigate the risks inherent in construction on slopes, although those risks
cannot be eliminated completely. Favorable performance of structures in the near term is useful
information for anticipating future performance, but it cannot predict or imply a certainty of long-term
performance, especially under conditions of adverse weather or seismic activity.
Within the limitations of scope, schedule and budget, our services have been executed in accordance with
generally accepted practices for geotechnical engineering in this area at the time this report was prepared.
The conclusions, recommendations, and opinions presented in this report are based on our professional
knowledge, judgment and experience. No warranty, express or implied, applies to the services or this report.
Please refer to Appendix C titled “Report Limitations and Guidelines for Use” for additional information
pertaining to use of this report.
SITE
Vicinity Map
Figure 1
Mineral Lake Property Due DiligenceLewis County, Washington
4,000 4,0000
Feet
Data Source: Mapbox Open Street Map, 2016
Notes:1. The locations of all features shown are approximate.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication.
Projection: NAD 1983 UTM Zone 10N
P:\6\6565008\GIS\MXD\656500800t0200_F01_VicinityMap.mxd Date Exported: 11/11/20 by ccabrera
06565-008-00 Date Exported: 11/01/2020Notes:
1.This drawing has been prepared by other members of the project team. GeoEngineers cannot warrant or guarantee the accuracy or
completeness of information provided or compiled by others.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document.
GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will
serve as the official record of this communication.
Data Source: Presubmission conference submittal package for YMCA Camp Mineral Lake
Figure 2
Presubmission Package Vicinity Map
Mineral Lake Property Due Diligence
Lewis County, Washington
06565-008-00 Date Exported: 11/01/2020Notes:
1.This drawing has been prepared by other members of the project team. GeoEngineers cannot warrant or guarantee the accuracy or
completeness of information provided or compiled by others.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document.
GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will
serve as the official record of this communication.
Data Source: Presubmission conference submittal package for YMCA Camp Mineral Lake
Figure 3
Presubmission Package Conceptual Development Areas
Mineral Lake Property Due Diligence
Lewis County, Washington
Notes:
1.This drawing has been prepared by online resources provided by the Washington State Department of Natural Resources. GeoEngineers
cannot warrant or guarantee the accuracy or completeness of information provided or compiled by others.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document.
GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will
serve as the official record of this communication.
Data Source: Washington State Department of Natural Resources Geology Portal
Figure 4
Geologic Map -1:100,000-scale
Mineral Lake Property Due Diligence
Lewis County, Washington
06565-008-00 Date Exported: 11/06/2020
Legend:
Mvba(1)Tertiary volcanic rocks
Qap(h)Alpine glacial drift (Hayden Creek drift)
Qls Mass-wasting deposits
Ec(2pg)Tertiary sedimentary deposits or rocks
Approximate property area
500 0 500
Feet
Notes: 1. The locations of all features shown are approximate.2. This drawing is for information purposes. It is intendedto assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and contentof electronic files. The master file is stored by GeoEngineers, Inc.and will serve as the official record of this communication.
Projection: NAD 1983 StatePlane Washington South FIPS 4602 Feet
Legend
Test Pit Location (GeoEngineers, 2020)P:\6\6565008\GIS\MXD\656500800t0200_F05_SitePlan_Overview.mxd Date Exported: 11/11/20 by ccabrera Mineral Lake
TP-1.01
TP-1.02
TP-1.03 TP-1.04
TP-1.05
TP-1.06
TP-1.07 TP-1.08
TP-2.01 TP-2.02
TP-2.03 TP-2.04 TP-2.05 TP-2.06
TP-2.07 TP-2.08 TP-2.09
TP-2.10TP-2.11 TP-2.12TP-2.13
TP-2.14
TP-2.15 TP-2.16Mineral Hill RoadData Source: ESRI Clarity
Site Plan - Test Pit Overview
Mineral Lake Property Due DiligenceLewis County, Washington
Figure 5
300 0 300
Feet
Notes: 1. The locations of all features shown are approximate.2. This drawing is for information purposes. It is intendedto assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and contentof electronic files. The master file is stored by GeoEngineers, Inc.and will serve as the official record of this communication.
Projection: NAD 1983 StatePlane Washington South FIPS 4602 Feet
Legend
Test Pit Location (GeoEngineers, 2020)P:\6\6565008\GIS\MXD\656500800t0200_F06_SitePlan_PlanArea1.mxd Date Exported: 11/11/20 by ccabrera TP-1.01
TP-1.02
TP-1.03 TP-1.04
TP-1.05
TP-1.06
TP-1.07 TP-1.08MINERAL HILL RDMin
e
r
a
l
H
i
l
l
R
o
a
d
Data Source: ESRI Clarity
Site Plan - Test Pit Area 1
Mineral Lake Property Due DiligenceLewis County, Washington
Figure 6
300 0 300
Feet
Notes: 1. The locations of all features shown are approximate.2. This drawing is for information purposes. It is intendedto assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and contentof electronic files. The master file is stored by GeoEngineers, Inc.and will serve as the official record of this communication.
Projection: NAD 1983 StatePlane Washington South FIPS 4602 Feet
Legend
Test Pit Location (GeoEngineers, 2020)P:\6\6565008\GIS\MXD\656500800t0200_F07_SitePlan_PlanArea2.mxd Date Exported: 11/11/20 by ccabrera TP-2.01 TP-2.02
TP-2.03 TP-2.04 TP-2.05 TP-2.06
TP-2.07
TP-2.08
TP-2.09
TP-2.10
TP-2.11 TP-2.12TP-2.13
TP-2.14
TP-2.15 TP-2.16 Minera
l Creek Rd
Data Source: ESRI Clarity
Site Plan - Test Pit Area 2
Mineral Lake Property Due DiligenceLewis County, Washington
Figure 7
Figure 8
Erosion Hazard -NRCS
Mineral Lake Property Due Diligence
Lewis County, Washington
06565-008-00 Date Exported: 11/08/2020Notes:
1. This drawing has been prepared by online resources provided by the USDA Natural
Resources Conservation Service (NRCS). GeoEngineers cannot warrant or guarantee
the accuracy or completeness of information provided or compiled by others.2. This drawing is for information purposes. It is intended to assist in showing
features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by
GeoEngineers, Inc. and will serve as the official record of this communication.
Data Source: NRCS Web Soil Survey
Notes:
1.This drawing has been prepared by online resources provided by Lewis County. GeoEngineers cannot warrant or guarantee the accuracy
or completeness of information provided or compiled by others.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document.
GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will
serve as the official record of this communication.
Data Source: Lewis County GIS Web Map
Figure 9
Erosion Hazard Areas –Lewis County
Mineral Lake Property Due Diligence
Lewis County, Washington
06565-008-00 Date Exported: 11/08/2020
Notes:
1.This drawing has been prepared by online resources provided by Lewis County. GeoEngineers cannot warrant or guarantee the accuracy
or completeness of information provided or compiled by others.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document.
GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will
serve as the official record of this communication.
Data Source: Lewis County GIS Web Map
Figure 10
Steep Slope Areas
Mineral Lake Property Due Diligence
Lewis County, Washington
06565-008-00 Date Exported: 11/08/2020
Notes:
1.This drawing has been prepared by online resources provided by Lewis County. GeoEngineers cannot warrant or guarantee the accuracy
or completeness of information provided or compiled by others.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document.
GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will
serve as the official record of this communication.
Data Source: Lewis County GIS Web Map
Figure 11
Landslide Hazard Areas
Mineral Lake Property Due Diligence
Lewis County, Washington
06565-008-00 Date Exported: 11/08/2020
Notes:
1.This drawing has been prepared by online resources provided by Lewis County. GeoEngineers cannot warrant or guarantee the accuracy
or completeness of information provided or compiled by others.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document.
GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will
serve as the official record of this communication.
Data Source: Lewis County GIS Web Map
Figure 12
Volcanic Hazards
Mineral Lake Property Due Diligence
Lewis County, Washington
06565-008-00 Date Exported: 11/08/2020
Approx. Property
Extents
Notes:
1.This drawing has been prepared by online resources provided by Lewis County. GeoEngineers cannot warrant or guarantee the accuracy
or completeness of information provided or compiled by others.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document.
GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will
serve as the official record of this communication.
Data Source: Lewis County GIS Web Map
Figure 13
Liquefaction Susceptibility
Mineral Lake Property Due Diligence
Lewis County, Washington
06565-008-00 Date Exported: 11/08/2020
Figure 14
Hydrologic Soil Group
Mineral Lake Property Due Diligence
Lewis County, Washington
06565-008-00 Date Exported: 11/08/2020Notes:
1. This drawing has been prepared by online resources provided by the USDA Natural
Resources Conservation Service (NRCS). GeoEngineers cannot warrant or guarantee
the accuracy or completeness of information provided or compiled by others.2. This drawing is for information purposes. It is intended to assist in showing
features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by
GeoEngineers, Inc. and will serve as the official record of this communication.
Data Source: NRCS Web Soil Survey
APPENDIX A Subsurface Explorations and Laboratory Testing
March 16, 2021 | Page A-1 File No. 6565-008-00
APPENDIX A
SUBSURFACE EXPLORATIONS AND LABORATORY TESTING
Subsurface Explorations
Soil and groundwater conditions at the site were explored by observing 24 test pit excavations on March
26 and March 27, 2020. Locations of the test pits were determined via an electronic tablet with global
positioning system (GPS) software and are shown on the Site Plan - Test Pit Overview, Figure 5, as well as
detailed views on Figure 6 and Figure 7. The locations and elevations of the explorations should be
considered approximate.
Test pit excavations were performed using an excavator provided and operated by Kelly’s Excavating, Inc.
under subcontract to GeoEngineers. Test pits extended to depths between approximately 8 and 14½ feet
below surrounding grade. After each test pit was completed, the excavation was backfilled using the
generated material and compacted using the bucket of the excavator.
During the exploration program our field representative obtained soil samples, classified the soils,
maintained a detailed log of each exploration and observed groundwater conditions. The soils were
classified visually in general accordance with ASTM International (ASTM) D 2488. Figure A-1 includes a Key
to Exploration Logs. Summary logs of the explorations are included as Figures A-2 through A-25. The
densities noted on the test pit exploration logs are based on the difficulty of excavation, observations of
caving and our experience and judgment. Samples were retained in sealed plastic bags to prevent moisture
loss.
Laboratory Test Results
Soil samples obtained from the explorations were transported to GeoEngineers laboratory. Representative
soil samples were selected for laboratory tests to evaluate pertinent geotechnical engineering
characteristics of the soils and refine our field classification, as necessary. The following paragraphs
provide a description of the tests performed.
Moisture Content (MC)
The moisture content of selected samples was determined in general accordance with ASTM Test Method
D 2216. The test results are used to aid in soil classification and correlation with other pertinent
engineering soil properties. Test results are presented on the exploration logs corresponding to the sample
tested.
Sieve Analysis (SA)
Sieve analyses were performed on selected samples in general accordance with ASTM Test Method D
6913. This test method covers the quantitative determination of the distribution of particle sizes in soils.
Typically, the distribution of particle sizes larger than 75 micrometers (m) is determined by sieving. The
results of the tests were used to verify field soil classifications. Figures A-26 and A-27 present the results
of our sieve analyses.
Hydrometer Analysis (HA)
Hydrometer analyses were performed on selected samples in general accordance with ASTM Test Method
D 422. This test method covers the quantitative determination of the distribution of particle sizes in soils.
March 16, 2021 | Page A-2 File No. 6565-008-00
Typically, the distribution of particle sizes smaller than 75 μm is determined by a sedimentation process
using a hydrometer. The hydrometer analysis alone determines the distribution of particle sizes smaller
than 2 millimeters (mm). The results of the tests were used to verify field soil classifications and determine
pertinent engineering characteristics. Figure A-26 includes the results of our hydrometer analyses.
SYMBOLS TYPICAL
DESCRIPTIONS
GW
GP
SW
SP
SM
FINEGRAINED
SOILS
SILTS ANDCLAYS
NOTE: Multiple symbols are used to indicate borderline or dual soil classifications
MORE THAN 50%RETAINED ONNO. 200 SIEVE
MORE THAN 50%PASSINGNO. 200 SIEVE
GRAVEL
ANDGRAVELLYSOILS
SC
LIQUID LIMITLESS THAN 50
(APPRECIABLE AMOUNTOF FINES)
(APPRECIABLE AMOUNTOF FINES)
COARSEGRAINEDSOILS
MAJOR DIVISIONS GRAPH LETTER
GM
GC
ML
CL
OL
SILTS AND
CLAYS
SANDS WITHFINES
SANDANDSANDY
SOILS
MH
CH
OH
PT
(LITTLE OR NO FINES)
CLEAN SANDS
GRAVELS WITHFINES
CLEAN GRAVELS
(LITTLE OR NO FINES)
WELL-GRADED GRAVELS, GRAVEL -SAND MIXTURES
CLAYEY GRAVELS, GRAVEL - SAND -CLAY MIXTURES
WELL-GRADED SANDS, GRAVELLYSANDS
POORLY-GRADED SANDS, GRAVELLYSAND
SILTY SANDS, SAND - SILT MIXTURES
CLAYEY SANDS, SAND - CLAYMIXTURES
INORGANIC SILTS, ROCK FLOUR,CLAYEY SILTS WITH SLIGHTPLASTICITY
INORGANIC CLAYS OF LOW TOMEDIUM PLASTICITY, GRAVELLYCLAYS, SANDY CLAYS, SILTY CLAYS,LEAN CLAYS
ORGANIC SILTS AND ORGANIC SILTYCLAYS OF LOW PLASTICITY
INORGANIC SILTS, MICACEOUS ORDIATOMACEOUS SILTY SOILS
INORGANIC CLAYS OF HIGHPLASTICITY
ORGANIC CLAYS AND SILTS OFMEDIUM TO HIGH PLASTICITY
PEAT, HUMUS, SWAMP SOILS WITHHIGH ORGANIC CONTENTSHIGHLY ORGANIC SOILS
SOIL CLASSIFICATION CHART
MORE THAN 50%OF COARSEFRACTION RETAINEDON NO. 4 SIEVE
MORE THAN 50%OF COARSEFRACTION PASSINGON NO. 4 SIEVE
SILTY GRAVELS, GRAVEL - SAND -SILT MIXTURES
POORLY-GRADED GRAVELS,GRAVEL - SAND MIXTURES
LIQUID LIMIT GREATERTHAN 50
Continuous Coring
Bulk or grab
Direct-Push
Piston
Shelby tube
Standard Penetration Test (SPT)
2.4-inch I.D. split barrel
NOTE: The reader must refer to the discussion in the report text and the logs of explorations for a proper understanding of subsurface conditions.Descriptions on the logs apply only at the specific exploration locations and at the time the explorations were made; they are not warranted to berepresentative of subsurface conditions at other locations or times.
Blowcount is recorded for driven samplers as the number ofblows required to advance sampler 12 inches (or distance noted).See exploration log for hammer weight and drop.
"P" indicates sampler pushed using the weight of the drill rig.
"WOH" indicates sampler pushed using the weight of thehammer.
Key to Exploration Logs
Figure A-1
Sampler Symbol Descriptions
ADDITIONAL MATERIAL SYMBOLS
NSSSMSHS
SYMBOLS
Asphalt Concrete
Cement Concrete
Crushed Rock/Quarry Spalls
Topsoil
GRAPH LETTER
AC
CC
SOD Sod/Forest Duff
CR
DESCRIPTIONS
TYPICAL
TS
%F%GALCACPCSDDDSHAMCMDMohsOCPMPIPLPPSATXUCVS
Groundwater Contact
Measured groundwater level in exploration, well, or piezometer
Measured free product in well or piezometer
Graphic Log Contact
Distinct contact between soil strata
Approximate contact between soil strata
Material Description Contact
Contact between geologic units
Contact between soil of the same geologic unit
Laboratory / Field Tests
Percent finesPercent gravelAtterberg limitsChemical analysisLaboratory compaction testConsolidation testDry densityDirect shearHydrometer analysisMoisture contentMoisture content and dry densityMohs hardness scaleOrganic contentPermeability or hydraulic conductivity Plasticity indexPoint load testPocket penetrometerSieve analysisTriaxial compressionUnconfined compressionVane shear
Sheen Classification
No Visible SheenSlight SheenModerate SheenHeavy Sheen
Dark brown to black sandy clay with trace organic matter (roots up to¼ inch) (stiff, moist) (residual soils)
Light brown clayey fine to medium sand with occasional gravel(medium dense, moist)
Grades to brown-gray with iron-oxide staining
Grades to with fractured rock approximately 1 inch in size
Grades to without fractured rock
Gray clay with trace sand and organic matter (decomposed roots) (stiff,moist)
CL
SC
CL
1
Minor groundwater seepage observed at 8 feet
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-1.01
Figure A-2
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)1507150615051504150315021501150014991498149714961495Depth (feet)1
2
3
4
5
6
7
8
9
10
11
12
13 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/27/2020 13.5
1508NAVD88 1219648514365 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
Dark brown to black sandy clay with trace organic matter (roots up to½ inch) (stiff, moist) (residual soils)
Gray with iron-oxide staining clayey fine to medium sand withoccasional gravel (medium dense, moist)
Grades with rock fragments, dense
CL
SC
1SA/HA
34
Moderate caving observed at 8 feet
Moderate groundwater seepage observed at 8½ feet
37
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-1.02
Figure A-3
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)14831482148114801479147814771476147514741473Depth (feet)1
2
3
4
5
6
7
8
9
10
11 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/27/2020 11.5
1484NAVD88 1219956514239 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
See "Remarks" section for caving observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
Brown clayey fine to coarse gravel with sand and cobbles (mediumdense, moist) (fill)
Light brown with iron-oxide staining sandy clay (medium stiff, moist)(residual soils)
Light gray with iron-oxide staining clayey fine to medium sand withoccasional gravel (medium dense, moist)
Grades to with fractured rock
Grades to with weathered rock
GC
CL
SC
Reworked residual soils
Minor caving observed at 10 feet
Minor groundwater seepage observed at 12 feet
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-1.03
Figure A-4
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)15321531153015291528152715261525152415231522152115201519Depth (feet)1
2
3
4
5
6
7
8
9
10
11
12
13
14 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/27/2020 14.5
1533NAVD88 1219686514599 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
See "Remarks" section for caving observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
3 inches underbrush
Gray with iron-oxide staining sandy clay (medium stiff, moist) (residualsoils)
Grades to light brown-gray
Brown-gray clayey fine to medium sand with occasional gravel(medium dense, moist)
Gray sandy clay with trace gravel (very stiff, moist)
Brown-gray fractured basalt (bedrock)
WD
CL
SC
CL
BEDROCK
1
Minor groundwater seepage observed at 6 feet
Moderately cemented
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-1.04
Figure A-5
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)1488148714861485148414831482148114801479147814771476Depth (feet)1
2
3
4
5
6
7
8
9
10
11
12
13 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/27/2020 13.75
1489NAVD88 1220118514541 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
3 inches underbrush
Dark brown clayey fine to medium sand with occasional gravel andtrace organic matter (fine roots) (medium dense, moist) (residualsoils)
Light gray with occasional iron-oxide staining sandy clay (medium stiff,moist)
Orange-gray with iron-oxide staining clayey fine to coarse sand withgravel (very dense, moist)
WD
SC
CL
SC
1SA/HA
43
Moderate groundwater seepage observed at 4 feetOccasional caving observed at 4 feet
20
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-1.05
Figure A-6
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)146314621461146014591458145714561455Depth (feet)1
2
3
4
5
6
7
8
9 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/27/2020 9
1464NAVD88 1220318514363 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
See "Remarks" section for caving observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
6 inches underbrush
Light brown with occasional iron-oxide staining sandy clay (mediumstiff, moist) (residual soils)
Dark brown sandy clay with occasional gravel and weathered rockfragments (hard, moist)
Grades to very stiff
Gray clayey fine to medium sand with gravel (dense, moist)
Grades to very dense
WD
CL
CL
SC
1
2
14-inch boulder at 5 feet
Moderately to heavily cemented
Less cemented
Moderately cemented
Heavily cemented
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-1.06
Figure A-7
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)14861485148414831482148114801479147814771476147514741473Depth (feet)1
2
3
4
5
6
7
8
9
10
11
12
13
14 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/27/2020 14.5
1487NAVD88 1220374514703 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
Groundwater not observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
Dark brown sandy clay with organic matter (underbrush) andoccasional gravel (soft, moist) (residual soils)
Brown-gray sandy clay with occasional gravel (medium stiff, moist)
Light brown clayey fine to coarse sand with occasional gravel andcobbles (medium dense, moist)
Brown-gray fractured basalt (bedrock)
CL
CL
SC
BEDROCK
1
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-1.07
Figure A-8
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)178217811780177917781777177617751774Depth (feet)1
2
3
4
5
6
7
8
9 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/27/2020 9.25
1783NAVD88 1220113515626 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
Groundwater not observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
Dark brown sandy clay with occasional gravel, cobbles and bouldersand trace organic matter (wood) (medium stiff, moist) (fill)
Light brown clayey fine to coarse sand with gravel and occasionalcobbles and boulders (medium dense, moist) (residual soils)
Grades to somewhat sandier
Brown-gray fractured basalt (bedrock)
CL
SC
BEDROCK
1
2SA/HA
29
Reworked residual soils
14-inch boulder
25
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-1.08
Figure A-9
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)1752175117501749174817471746174517441743174217411740Depth (feet)1
2
3
4
5
6
7
8
9
10
11
12
13 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/26/2020 13.75
1753NAVD88 1220592515658 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
Groundwater not observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
6 inches forest duff
Dark brown clayey fine to medium sand with trace organic matter(roots up to 1 inch diameter) (medium stiff, moist) (residual soils)
Light brown sandy clay with occasional gravel (medium dense, moist)
Grades to with gravel, stiff
DUFF
SC
CL
12-inch boulder at 7 feet (fractured bedrock?)
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.01
Figure A-10
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)15561555155415531552155115501549Depth (feet)1
2
3
4
5
6
7
8 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/26/2020 8
1557NAVD88 1224650514424 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
Groundwater not observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
6 inches sod
Dark brown angular rock fragments (medium dense, moist) (fill)
Dark brown sandy clay with occasional gravel and bedrock fragmentsand trace organic matter (tree roots) (stiff, moist) (residual soils)
Grades to brown-gray with occasional iron-oxide staining
SOD
CR
CL
1
2
Reworked native basalt appears related to adjacentroad construction
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.02
Figure A-11
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)138813871386138513841383138213811380137913781377Depth (feet)1
2
3
4
5
6
7
8
9
10
11
12 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/26/2020 12
1389NAVD88 1225278514434 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
Groundwater not observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
6 inches underbrush
Dark brown clayey fine to medium sand with gravel and occasional1-inch roots (loose, moist) (residual soils)
Light tan sandy clay with trace organic matter (charred wood) (mediumstiff, moist)
Grades to stiff
Gray fractured basalt (bedrock)
WD
SC
CL
BEDROCK
1SA/HA
2
47 60
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.03
Figure A-12
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)1492149114901489148814871486148514841483Depth (feet)1
2
3
4
5
6
7
8
9
10 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/26/2020 10.75
1493NAVD88 1224066513996 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
Groundwater not observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
6 inches underbrush
Dark brown clayey fine to medium sand with occasional gravel andtrace organic matter (roots to 1 inch diameter) (loose, moist)(residual soils)
Brown-gray with trace iron-oxide staining sandy clay with gravel(medium stiff, moist)
Grades to stiff
Orange clayey fine to medium sand (dense, moist)
Orange-gray fractured basalt and granite (bedrock)
WD
SC
CL
SC
BEDROCK
1
2
3
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2-04
Figure A-13
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)14531452145114501449144814471446Depth (feet)1
2
3
4
5
6
7
8 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/26/2020 8
1454NAVD88 1224769514007 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
Groundwater not observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
6 inches underbrush
Light tan with iron-oxide staining sandy clay (soft, moist) (residual soils)
Grades to gray, stiff
Grades to with coarse sand
WD
CL
1
2
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.05
Figure A-14
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)137513741373137213711370136913681367136613651364Depth (feet)1
2
3
4
5
6
7
8
9
10
11
12 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/26/2020 12.5
1376NAVD88 1225527513999 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
Groundwater not observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
6 inches sod
Light tan with iron-oxide staining sandy clay (soft, moist) (residual soils)
Brown-gray fine to coarse gravel with silt, sand and cobbles (dense,wet) (glacial drift)
SOD
CL
GP-GM
1
Moderate groundwater seepage observed at 5 feet
Minor caving observed at 6 feet
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.06
Figure A-15
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)135613551354135313521351135013491348Depth (feet)1
2
3
4
5
6
7
8
9 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/26/2020 9.5
1357NAVD88 1226028514027 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
See "Remarks" section for caving observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
6 inches sod
Dark brown silty fine to medium sand with gravel (medium dense,moist) (glacial drift)
Brown fine to coarse gravel with silt, sand and cobbles (mediumdense, moist)
Brown fine to coarse sand with trace silt (medium dense, moist)
Brown fine to coarse gravel with sand, cobbles and silt (mediumdense, wet)
SOD
SM
GP-GM
SP
GP-GM
1SA
10
Moderate groundwater seepage observed at 6 feet
8
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.07
Figure A-16
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)13571356135513541353135213511350Depth (feet)1
2
3
4
5
6
7
8 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/26/2020 8
1358NAVD88 1226049514223 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
Dark brown silty fine to medium sand with gravel and trace organicmatter (roots up to ½ inch diameter) (loose, moist) (glacial drift)
Brown fine to coarse gravel with silt, sand and cobbles (mediumdense, moist)
Brown fine to coarse gravel with sand, cobbles and trace silt (dense,moist)
Grades to wet
SM
GP-GM
GP-GM
1
Increased cobbles compared to above
Moderate groundwater seepage observed at 9 feet
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.08
Figure A-17
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)1357135613551354135313521351135013491348Depth (feet)1
2
3
4
5
6
7
8
9
10 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/27/2020 10.5
1358NAVD88 1226338514141 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
3 inches underbrush
Light brown silty fine to medium sand with gravel (medium dense,moist) (glacial drift)
Brown fine to coarse gravel with silt, sand and cobbles (mediumdense, moist)
Grades to with occasional boulders, dense
Brown fine to coarse sand with trace silt (dense, moist)
Grades to wet
Brown fine to coarse gravel with silt, sand and cobbles (dense, wet)
WD
SM
GP-GM
SP
GP-GM
1
2
3
Occasional caving observed at 9 feet
Slow groundwater seepage observed at 11 feet
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.09
Figure A-18
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)1342134113401339133813371336133513341333133213311330Depth (feet)1
2
3
4
5
6
7
8
9
10
11
12
13 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/27/2020 13
1343NAVD88 1226624514053 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
See "Remarks" section for caving observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
6 inches underbrush/sod
Dark brown silty fine to medium sand with gravel and occasionalcobbles (medium dense, moist) (glacial drift)
Brown fine to coarse gravel with silt and sand and occasional cobbles(dense, moist)
Brown fine to coarse gravel with silt, sand and cobbles (dense, moist)
Grades to wet
SOD
SM
GP-GM
GW-GM
1SA
2SA
10
12
Rounded gravel and cobbles
Increased cobbles
Moderate to heavy groundwater seepage observed at11 feetModerate caving observed at 11 feet
8
9
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.10
Figure A-19
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)136013591358135713561355135413531352135113501349Depth (feet)1
2
3
4
5
6
7
8
9
10
11
12 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/26/2020 12
1361NAVD88 1226284513953 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
See "Remarks" section for caving observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
Dark brown silty fine to medium sand with gravel and trace organicmatter (roots) (loose, moist) (glacial drift)
Brown sandy silt with occasional gravel and cobbles (medium stiff,moist)
Brown fine to coarse gravel with silt, sand and cobbles (dense, moist)
Grades to wet
Grades to with occasional boulders
SM
ML
GP-GM
1
Moderate groundwater seepage observed at 7½ feet
Increased cobbles
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.11
Figure A-20
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)1358135713561355135413531352135113501349Depth (feet)1
2
3
4
5
6
7
8
9
10 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/27/2020 10
1359NAVD88 1226105513831 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
Dark brown silty fine to medium sand with gravel and trace organicmatter (roots) (medium dense, moist) (glacial drift)
Brown fine to coarse gravel with silt, sand and cobbles (mediumdense, moist)
Brown fine to coarse gravel with silt, sand and cobbles (mediumdense, moist)
Grades to with boulders, dense
With 12- to 14-inch boulder
SM
GP-GM
GP-GM
1
Increased cobbles
Moderate groundwater seepage observed at 8 feet
Significant caving observed at 9 feet
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.12
Figure A-21
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)1340133913381337133613351334133313321331Depth (feet)1
2
3
4
5
6
7
8
9
10 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/27/2020 10
1341NAVD88 1226781513811 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
See "Remarks" section for caving observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
Dark brown sandy clay with trace organic matter (fine roots) (soft, wet)(residual soils)
Brown with iron-oxide staining sandy clay (medium stiff, moist)
Grades to light gray
Grades to stiff
Dark brown organic silt with organic matter (soft, moist)
CL
CL
OL
Slow groundwater seepage observed at 1 foot
Minor caving observed at 2 feet
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.13
Figure A-22
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)13611360135913581357135613551354135313521351Depth (feet)1
2
3
4
5
6
7
8
9
10
11 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/27/2020 11
1362NAVD88 1226361513746 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
See "Remarks" section for groundwater observed
See "Remarks" section for caving observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
6 inches underbrush
Dark brown clayey fine to medium sand with trace organic matter(roots to ½ inch diameter) (loose, moist) (residual soils)
Orange-brown sandy clay with trace organic matter (roots) (mediumstiff, moist)
Grades to with occasional gravel
WD
SC
CL
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.14
Figure A-23
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)1530152915281527152615251524Depth (feet)1
2
3
4
5
6
7 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/26/2020 7.5
1531NAVD88 1224336513308 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
Groundwater not observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
6 inches underbrush
Brown sandy clay with occasional gravel and cobbles (stiff, moist)(residual soils)
WD
CL
1
Angular rock fragments
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.15
Figure A-24
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)1561156015591558155715561555155415531552Depth (feet)1
2
3
4
5
6
7
8
9
10 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/26/2020 10
1562NAVD88 1224791513082 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
Groundwater not observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
6 inches underbrush
Dark brown clayey fine to medium sand with gravel and trace organicmatter (roots to 2 inches diameter) (loose, moist) (residual soils)
Light tan sandy clay (stiff, moist)
WD
SC
CL
Angular rock fragments at 6½ feet
Notes: See Figure A-1 for explanation of symbols.The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to ½ foot.Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:11/23/20 Path:P:\6\6565008\GINT\656500800.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number:
Project Location:
Project:
6565-008-00
Log of Test Pit TP-2.16
Figure A-25
Mineral Lake Property Due Diligence
Lewis County, WashingtonElevation (feet)14121411141014091408140714061405140414031402Depth (feet)1
2
3
4
5
6
7
8
9
10
11 Testing SampleGraphic LogSAMPLE
MATERIALDESCRIPTION
GroupClassificationSample NameTestingMoistureContent (%)REMARKS
FinesContent (%)DateExcavated
Surface Elevation (ft)Vertical Datum Coordinate SystemHorizontal DatumEasting (X)Northing (Y)
TotalDepth (ft)3/26/2020 11.5
1413NAVD88 1225964513056 WA State Plane SouthNAD83 (feet)
CJL
Checked By SST
Groundwater not observed
Caving not observedEquipment Komatsh PC120
Logged By Excavator Kelly's Excavating
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000PERCENT PASSING BY WEIGHT GRAIN SIZE IN MILLIMETERS
U.S. STANDARD SIEVE SIZE
2”
SAND SILT OR CLAYCOBBLESGRAVEL
COARSE MEDIUM FINECOARSEFINE
Test Pit Number Depth(feet)Soil Description
TP-1.02
TP-1.05
TP-1.08
TP-2.03
3.5
5
7
4
Clayey fine to medium sand (SC)
Clayey fine to medium sand with gravel (SC)
Clayey fine to coarse sand with gravel (SC)
Sandy clay (CL)
Symbol Moisture(%)
34
43
29
47
3/8”3”1.5”#4 #10 #20 #40 #60 #1003/4”Figure A-26Sieve Analysis ResultsMineral Lake Property Due DiligenceLewis County, Washington6565-008-00 Date Exported: 4/3/20
Note:This report may not be reproduced,except in full, without written approval of GeoEngineers,Inc.Test results are applicable only to the specific sample on which they were
performed,and should not be interpreted as representative of any other samples obtained at other times,depths or locations, orgenerated by separateoperations or processes.
The grain size analysis resultswere obtained in general accordance with ASTMC 136.GeoEngineers 17425 NE Union Hill RoadSte 250,Redmond,WA 98052
#2001”#140
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000PERCENT PASSING BY WEIGHT GRAIN SIZE IN MILLIMETERS
U.S. STANDARD SIEVE SIZE
2”
SAND SILT OR CLAYCOBBLESGRAVEL
COARSE MEDIUM FINECOARSEFINE
Test Pit Number Depth(feet)Soil Description
TP-2.07
TP-2.10
TP-2.10
3.5
3.5
8
Fine to coarse gravel with silt and sand (GP-GM)
Fine to coarse gravel with silt and sand (GP-GM)
Fine to coarse gravel with silt and sand (GW-GM)
Symbol Moisture(%)
10
10
12
3/8”3”1.5”#4 #10 #20 #40 #60 #1003/4”Figure A-27Sieve Analysis ResultsMineral Lake Property Due DiligenceLewis County, Washington6565-008-00 Date Exported: 4/3/20
Note:This report may not be reproduced,except in full, without written approval of GeoEngineers,Inc.Test results are applicable only to the specific sample on which they were
performed,and should not be interpreted as representative of any other samples obtained at other times,depths or locations, orgenerated by separateoperations or processes.
The grain size analysis resultswere obtained in general accordance with ASTMC 136.GeoEngineers 17425 NE Union Hill RoadSte 250,Redmond,WA 98052
#2001”#140
APPENDIX B Water Well Reports
APPENDIX C Report Limitations and Guidelines for Use
March 16, 2021 | Page C-1 File No. 6565-008-00
APPENDIX C
REPORT LIMITATIONS AND GUIDELINES FOR USE1
This appendix provides information to help you manage your risks with respect to the use of this report.
Read These Provisions Closely
It is important to recognize that the geoscience practices (geotechnical engineering, geology and
environmental science) rely on professional judgment and opinion to a greater extent than other
engineering and natural science disciplines, where more precise and/or readily observable data may exist.
To help clients better understand how this difference pertains to our services, GeoEngineers includes the
following explanatory “limitations” provisions in its reports. Please confer with GeoEngineers if you need to
know more how these “Report Limitations and Guidelines for Use” apply to your project or site.
Geotechnical Services are Performed for Specific Purposes, Persons and Projects
This report has been prepared for YMCA Seattle and for the Project(s) specifically identified in the report.
The information contained herein is not applicable to other sites or projects.
GeoEngineers structures its services to meet the specific needs of its clients. No party other than the party
to whom this report is addressed may rely on the product of our services unless we agree to such reliance
in advance and in writing. Within the limitations of the agreed scope of services for the Project, and its
schedule and budget, our services have been executed in accordance with our Agreement with YMCA
Seattle signed March 16, 2020 and generally accepted geotechnical practices in this area at the time this
report was prepared. We do not authorize, and will not be responsible for, the use of this report for any
purposes or projects other than those identified in the report.
A Geotechnical Engineering or Geologic Report is based on a Unique Set of Project-Specific
Factors
This report has been prepared for the Mineral Lake Property Due Diligence project located in Mineral Lake,
Washington. GeoEngineers considered a number of unique, project-specific factors when establishing the
scope of services for this project and report. Unless GeoEngineers specifically indicates otherwise, it is
important not to rely on this report if it was:
■ not prepared for you,
■ not prepared for your project,
■ not prepared for the specific site explored, or
■ completed before important project changes were made.
For example, changes that can affect the applicability of this report include those that affect:
■ the function of the proposed structure;
■ elevation, configuration, location, orientation or weight of the proposed structure;
1 Developed based on material provided by ASFE, Professional Firms Practicing in the Geosciences; www.asfe.org.
March 16, 2021 | Page C-2 File No. 6565-008-00
■ composition of the design team; or
■ project ownership.
If changes occur after the date of this report, GeoEngineers cannot be responsible for any consequences
of such changes in relation to this report unless we have been given the opportunity to review our
interpretations and recommendations. Based on that review, we can provide written modifications or
confirmation, as appropriate.
Environmental Concerns are Not Covered
Unless environmental services were specifically included in our scope of services, this report does not
provide any environmental findings, conclusions, or recommendations, including but not limited to, the
likelihood of encountering underground storage tanks or regulated contaminants.
Information Provided by Others
GeoEngineers has relied upon certain data or information provided or compiled by others in the
performance of our services. Although we use sources that we reasonably believe to be trustworthy,
GeoEngineers cannot warrant or guarantee the accuracy or completeness of information provided or
compiled by others.
Subsurface Conditions Can Change
This geotechnical or geologic report is based on conditions that existed at the time the study was performed.
The findings and conclusions of this report may be affected by the passage of time, by man-made events
such as construction on or adjacent to the site, new information or technology that becomes available
subsequent to the report date, or by natural events such as floods, earthquakes, slope instability or
groundwater fluctuations. If more than a few months have passed since issuance of our report or work
product, or if any of the described events may have occurred, please contact GeoEngineers before applying
this report for its intended purpose so that we may evaluate whether changed conditions affect the
continued reliability or applicability of our conclusions and recommendations.
Geotechnical and Geologic Findings are Professional Opinions
Our interpretations of subsurface conditions are based on field observations from widely spaced sampling
locations at the site. Site exploration identifies the specific subsurface conditions only at those points where
subsurface tests are conducted or samples are taken. GeoEngineers reviewed field and laboratory data
and then applied its professional judgment to render an informed opinion about subsurface conditions at
other locations. Actual subsurface conditions may differ, sometimes significantly, from the opinions
presented in this report. Our report, conclusions and interpretations are not a warranty of the actual
subsurface conditions.
Geotechnical Engineering Report Recommendations are Not Final
We have developed the following recommendations based on data gathered from subsurface
investigation(s). These investigations sample just a small percentage of a site to create a snapshot of the
subsurface conditions elsewhere on the site. Such sampling on its own cannot provide a complete and
accurate view of subsurface conditions for the entire site. Therefore, the recommendations included in this
report are preliminary and should not be considered final. GeoEngineers’ recommendations can be
March 16, 2021 | Page C-3 File No. 6565-008-00
finalized only by observing actual subsurface conditions revealed during construction. GeoEngineers
cannot assume responsibility or liability for the recommendations in this report if we do not perform
construction observation.
We recommend that you allow sufficient monitoring, testing and consultation during construction by
GeoEngineers to confirm that the conditions encountered are consistent with those indicated by the
explorations, to provide recommendations for design changes if the conditions revealed during the work
differ from those anticipated, and to evaluate whether earthwork activities are completed in accordance
with our recommendations. Retaining GeoEngineers for construction observation for this project is the most
effective means of managing the risks associated with unanticipated conditions. If another party performs
field observation and confirms our expectations, the other party must take full responsibility for both the
observations and recommendations. Please note, however, that another party would lack our project-
specific knowledge and resources.
A Geotechnical Engineering or Geologic Report Could Be Subject to Misinterpretation
Misinterpretation of this report by members of the design team or by contractors can result in costly
problems. GeoEngineers can help reduce the risks of misinterpretation by conferring with appropriate
members of the design team after submitting the report, reviewing pertinent elements of the design team’s
plans and specifications, participating in pre-bid and preconstruction conferences, and providing
construction observation.
Do Not Redraw the Exploration Logs
Geotechnical engineers and geologists prepare final boring and testing logs based upon their interpretation
of field logs and laboratory data. The logs included in a geotechnical engineering or geologic report should
never be redrawn for inclusion in architectural or other design drawings. Photographic or electronic
reproduction is acceptable, but separating logs from the report can create a risk of misinterpretation.
Give Contractors a Complete Report and Guidance
To help reduce the risk of problems associated with unanticipated subsurface conditions, GeoEngineers
recommends giving contractors the complete geotechnical engineering or geologic report, including these
“Report Limitations and Guidelines for Use.” When providing the report, you should preface it with a clearly
written letter of transmittal that:
■ advises contractors that the report was not prepared for purposes of bid development and that its
accuracy is limited; and
■ encourages contractors to confer with GeoEngineers and/or to conduct additional study to obtain the
specific types of information they need or prefer.
Contractors are Responsible for Site Safety on Their Own Construction Projects
Our geotechnical recommendations are not intended to direct the contractor’s procedures, methods,
schedule or management of the work site. The contractor is solely responsible for job site safety and for
managing construction operations to minimize risks to on-site personnel and adjacent properties.
March 16, 2021 | Page C-4 File No. 6565-008-00
Biological Pollutants
GeoEngineers’ Scope of Work specifically excludes the investigation, detection, prevention or assessment
of the presence of Biological Pollutants. Accordingly, this report does not include any interpretations,
recommendations, findings or conclusions regarding the detecting, assessing, preventing or abating of
Biological Pollutants, and no conclusions or inferences should be drawn regarding Biological Pollutants as
they may relate to this project. The term “Biological Pollutants” includes, but is not limited to, molds, fungi,
spores, bacteria and viruses, and/or any of their byproducts.
A Client that desires these specialized services is advised to obtain them from a consultant who offers
services in this specialized field.