GM 11-21 North Fork Flathead Geotechnical Recommedations Memo.pdf

158377846

M E M O R A N D U M Western Federal Lands Highway Division

610 E. Fifth Street Vancouver, WA 98661

DATE: March 15, 2021

TO: Mike Traffalis Project Manager

FROM: Evan Garich, Geotechnical Engineer

SUBJECT: Geotechnical Memo 11-21 Geotechnical Recommendations North Fork of the Flathead River Project and Glacier Drive Project

MT FLATHEAD 486(1)

Flathead County, MT

INTRODUCTION

This memorandum provides the final geotechnical recommendations for the North Fork of the Flathead River project as well as the Glacier Drive project.

PROJECT DESCRIPTION

North Fork Road begins in Columbia Falls, MT and follows the North Fork of the Flathead River approximately 56 miles north to the Canadian border at the Trail Creek Port of Entry. It serves as the sole access to the small community of Polebridge, MT, the Glacier National Park Polebridge Entrance, the Trail Creek Port of Entry, and approximately 300 private residences. The road also provides a recreation travel corridor including access to multiple open USFS roads and nine high use recreation sites on the Flathead National Forest. The road is unpaved and the current condition of the road provides very rough and dusty driving conditions as well as segments of narrow road width with limited sight distance. Polebridge Loop extends from North Fork Road to the town of Polebridge. Glacier Drive extends from the town of Polebridge to the Glacier National Park Polebridge Entrance.

The proposed North Fork of the Flathead River project includes:

• North Fork Road improvement consisting of reconstruction from MP 50.0 to the Canadian border (MP 55.15) to provide a 18-foot wide roadway and 6-inch thick aggregate surface course.

• Obtaining the required aggregate and soil materials for the project from the Forest Service owned Whale Creek Pit.

The following work elements were planned to be included in this project; however, they are now planned to be included in a separate Glacier Drive project to be constructed at a later date.

• Reconstruction of Glacier Drive for 1.3 miles from the end of the Polebridge Bridge to the intersection with Polebridge Loop (MP 0.2 to 1.5) to provide a 20-foot wide roadway;

and

• Reconstruction of Polebridge Loop for 0.3 miles from the intersection with Glacier Drive to the North Fork Road (MP 1.5 to 1.84) to provide a 22-foot wide roadway.

The project vicinity is displayed in Figure A-1.

TOPOGRAPHY AND GEOLOGY

The North Fork Road is located within the northwest/southeast trending North Fork of the Flathead River valley within the project area. The North Fork of the Flathead River forms the boundary between the Flathead National Forest on the west and Glacier National Park on the east. The road, located west of the river, is generally on side slope terraces 100 to 400 feet above the nearby river, except near the northernmost terminus of the project where the road is within approximately 10 feet of the elevation of the river. The mountains to the west rise to over 7,000 feet in elevation. On the east side of the river, the mountains within Glacier National Park rise to over elevation 10,000 feet, forming the continental divide. The road ranges from approximately elevation 4,000 feet to 4,200 feet within the project limits. The terrain along the road is rolling hills to hilly.

Whale Creek Pit (location shown in Figure A-1) is located at an elevation of approximately 4,200 feet on a gently sloping terrace above Whale Creek.

Glacier Drive is located on a flat plain adjacent to the North Fork of the Flathead River. There is very little topographic relief surrounding the road. The elevation of Glacier Drive ranges from approximately 3,530 feet to 3,560 feet.

The geology of North Fork Road and Whale Creek Pit are mapped as till (Qg) consisting of ground moraines of unsorted, subrounded to subangular boulder rubble and lesser amounts of sand, silt, and clay. The geology of Glacier Drive is mapped as alluvium (Qal) consisting of sand and gravel deposits locally containing thin lenses of silt (Harrison et al., 1992; Whipple, 1992).

GEOTECHNICAL INVESTIGATION

The geotechnical investigation consisted of a site visit and the following explorations:

• 9 test pits excavated along North Fork Road

• 5 test pits excavated within Whale Creek Pit

• 4 test pits excavated along Glacier Drive

The site visit and investigations were performed on June 16-17, 2020. The test pits were excavated with a Gradall XL 3100 wheeled excavator provided and operated by Flathead County. WFL geotechnical engineer Evan Garich logged the test pits. The test pits were generally located at approximately 0.5 mile intervals along North Fork Road and 0.25 mile intervals along Glacier Drive. The Whale Creek Pit test pits were located throughout the pit based on access conditions and time constraints. Test pits along North Fork Road and Glacier drive were excavated to depths ranging from 3.5 to 5.5 feet to characterize the subgrade soils.

Test pits in Whale Creek Pit extended from 6 feet to 10 feet deep, the practical maximum depth of the excavator. Grab samples were obtained from all test pits to characterize the materials encountered. Figures A-2 through A-5 display the investigation locations.

Laboratory testing of samples collected during the investigations were performed to evaluate index properties and aggregate characteristics of the soils encountered. The laboratory test program was performed by the WFL materials laboratory and included the following tests:

• Moisture content (AASHTO T 265)

• Atterberg Limits (AASHTO T 89/T 90)

• Sieve Analysis (AASHTO T 11/T 27)

• Specific Gravity (AASHTO T 100)

• Los Angeles Abrasion (AASHTO T 96)

• Soundness of Aggregate (AASHOT T 104)

• Durability Index (AASHTO T 210)

• DMSO/Accelerated weathering of aggregates

Laboratory test results are provided in Attachment D.

Whale Creek Pit Material Test Results In addition to the samples obtained during the geotechnical investigation, three samples were obtained from the pit in 2019 by the project scoping team and tested at the WFL materials laboratory. Sample GS19-01 was obtained from the exposed cut face at the southern extent of mining. Sample GS19-02 was obtained from the exposed cut face at the northern extent of mining. Sample GS-03 was obtained from the aggregate stockpile in the pit. Table 1 presents laboratory quality testing results from the 2019 and 2020 samples.

The Whale Creek Pit has been sampled and tested in the past. Test results performed by Flathead National Forest in 1984 are provided in Attachment D and summarized in Table 1.

Table 1. Selected Whale Creek Pit laboratory test results from.

SUBSURFACE CONDITIONS

A summary of the subsurface conditions encountered during the geotechnical investigation is discussed below. Site photographs taken during the geotechnical investigation are shown in Attachment B. The test pit logs are provided in Attachment C and laboratory test results are provided in Attachment D. Unified Soil Classification System (USCS) Group Symbols and Group Names are included on the test pit logs when confirmed by laboratory testing.

North Fork Road Six of the nine test pits along the North Fork Road encountered silty sand with gravel or silty gravel with sand from the ground surface to depths ranging from 1 foot to the bottom of excavation. Test pits NF20-03TP and NF20-06TP encountered gravelly lean clay with sand at the ground surface to depths of 3 feet and the bottom of excavation, respectively. Test pit NF20-07TP encountered silty clayey gravel with sand from a depth of 0 to 2 feet.

Exploration No.

LA

Abrasion

(T 96)

Soundness of Agg.

(T 104)

Durability Index, fine/coarse (T 210)

Liquid Limit (T 89)

Plasticity Index (T 90)

Percent Passing

#200 (T 11/ T 27)

GS19-01 15% NT 49% / 54% NP NP 4.9

GS19-02 15% NT 42% / 54% 20 3 11.0

GS19-03 16% NT 50% / 54% 20 3 9.4

WC20-01TP ~ ~ ~ 20 3 4.1

WC20-02TP ~ ~ ~ NP NP 4.2

WC20-03TP ~ ~ ~ 25 5 3.7

WC20-04TP

0-2.5’ depth

~ ~ ~ NP NP 44.8

WC20-04TP

2.5-5’ depth

~ ~ ~ 20 5 39.3

WC20-04TP

5-6’ depth

~ ~ ~ 23 8 36.2

WC20-05TP ~ ~ ~ NP NP 1.8

WC20-01TP

to

WC20-05TP

13% 0.625% 69% / 65% ~ ~

70-7-84 NT NT 66% / 48% NP NP 2.2

71-7-84 21% NT 59% / 49% NP NP 6.4

72-7-84 21% NT 44% / 45% NP NP 4.0

GS19-01, GS19-02 hand dug grab samples GS19-03 aggregate stock pile WC20-01TP – WC20-05TP tested as a combined sample for T 96, T 104, T 210 70,71,72-7-84 samples collected and tested by Flathead NF in 1984 NT = Not tested

Below the uppermost soil layers, the test pits encountered sandy silt, gravelly lean clay with sand, clayey gravel with sand, and/or sandy silt with gravel. Cobbles or cobbles and boulders up to 18 inches in diameter were present in every test pit. Test pit NF20-03TP encountered claystone at a depth of 3 feet. Groundwater was encountered at a depth of 4 feet in NF20- 04TP. Groundwater was not encountered in the other test pits at the time of excavation.

Whale Creek Pit Of the five test pits performed at Whale Creek Pit, WC20-01TP, -02TP and -05TP encountered only well graded gravel with sand. WC20-03TP also encountered well graded gravel with sand below a 1 foot thick layer of sandy silt. WC20-04TP encountered silty sand from 0-2.5 feet depth, silty clayey sand with gravel from 2.5-5 feet depth, and clayey gravel and sand from 5-6 feet depth, at which point practical excavator refusal occurred. Cobbles and boulders up to 2 feet in diameter were commonly encountered. In WC20-04 refusal was met at 6 feet depth. Groundwater was encountered at a depth of 4 feet in WC20-04TP.

Groundwater was not encountered in the other test pits at the time of excavation.

Glacier Drive Test pit GD20-01TP encountered silty sand from 0-1.5 feet depth and well graded gravel with silt and sand from 1.5-3.5 feet depth. Test pit GD20-02TP encountered silty gravel with sand from 0-0.5 feet depth, poorly graded sand with silt and gravel from 0.5-2.0 feet depth, and well graded gravel with silt and sand from 2.0-4.0 feet depth. Test pits GD20-03TP and GD20-04TP encountered poorly graded gravel with sand from 0-4.0 feet depth in both excavations. All gravel layers encountered cobbles up to 12 inches in diameter. Groundwater was encountered at depths of 3.5-4.0 feet in pits GD20-01TP, -02TP, and -04TP.

Groundwater was not encountered in GD20-03TP.

SITE OBSERVATIONS

The site observations discussed below have been developed based on the conditions present during the geotechnical investigation performed on June 16-17, 2020.

North Fork Road A distinct layer of surface aggregate was not present at any of the nine test pits excavated along North Fork Road. The road surface was smooth and graded for much of the road.

Severe rutting and potholing was present in wetter areas, which were more common within the north extents of the project It is understood the condition of the road changes throughout the year based on weather conditions, usage, and how recently maintenance has been performed.

Cut and fill slopes along the road are generally 1.5H:1V or flatter with several sections of 1H:1V less than 5 feet height. From approximate STA 305+00 to 311+50 and 316+50 to 319+50 existing slopes of 1H:1V up to 25 feet in height are present on both the cut and fill side of the road. The slopes appear to be performing adequately in these locations with no visual indications of instability.

Whale Creek Pit The Whale Creek Pit has been mined in the past. Figure A-4 shows an aerial view of the pit.

Photographs of the pit and explorations are presented in Attachment B. The previously mined area extends up to 250 feet north of the entrance and 400 feet south of the entrance. At some time after the aerial image used in Figure A-4 was captured, the vegetation was cleared on the north side of the pit, extending approximately 50 to 100 feet beyond WC20-04TP. The southern pit sidewall is approximately 8 to 10 feet in height. The northern pit wall, located at WC20-05TP and at the edge of vegetation shown in Figure A-4 is approximately 4 to 6 feet in height. The existing pit floor is relatively flat. Two gravel stockpiles were present in the central portion of the pit. Numerous partially burnt logs and slash piles were present in the central and southern portion of the pit. Beyond the southernmost mined portions of the pit, conifer trees are present and the ground slopes gently up towards the west.

Glacier Drive Very little gravel surfacing was present on Glacier Drive. A distinct layer of surface aggregate was not present an any of the four test pits excavated along Glacier Drive. The driving surface consisted primarily of native alluvial silts, sands, gravel, and cobbles. The road has little to no drainage as grading operations have resulted in the driving surface being below the surrounding terrain.

RECOMMENDATIONS

Slopes It is recommended to grade final slopes to 1.5H:1V or flatter. Sliver fills should be properly benched and keyed into the existing slopes. Excavations and embankments should be constructed in accordance with Section 204 of the FP.

Material Usage It is recommended to use Whale Creek Pit as a material source for the project. The samples obtained and tested from Whale Creek Pit meet the quality requirements for 703.05(c) surface course aggregate. The material tested from the pit does not meet the requirements for Plasticity Index for surface course aggregate. With the addition of a fine-grained plastic soil, it is believed the material can be processed to meet the gradation, fractured faces, and Plasticity Index requirements for surface course aggregate. The material should be processed, and/or blended with offsite material (or appropriate onsite material if encountered) to meet the required specifications for that portion of work.

Material excavated from North Fork Road should be considered unsuitable roadway excavation and should not be used as suitable roadway excavation.

Drainage Several locations of ditches with standing water have been observed along North Fork Road.

Ditches with standing water should be reconditioned to drain properly to the nearest culvert.

Construction Recommendations A wide range of soils will be encountered at subgrade elevation, most of which will be moisture sensitive because of the silt and clay content. On-site moisture sensitive soils will be susceptible to disturbance and will generally provide inadequate support of construction equipment when the soil moisture content is above optimum and during wet weather conditions. These soils will be difficult to compact if they are over optimum moisture content and use of vibratory compactors may cause pumping of subgrade soils. If pumping occurs, the soil should be dried to a moisture content near optimum (±2 percent of optimum moisture) and static compaction methods should be used.

Boulders were encountered in numerous explorations. The contractor should be prepared to encounter boulders of at least 2 feet in diameter in excavations. The contractor should be prepared to encounter boulders larger than 2 feet in diameter at Whale Creek Pit.

REFERENCES

Harrison, J.E., E.R. Cressman, and Whipple, J.W., 1992. Geologic and structure maps of the Kalispell 1 degree x 2 degrees quadrangle, Montana, and Alberta and British Columbia: U.S.

Geological Survey, Miscellaneous Investigations Series Map I-2267, scale 1:250,000.

Whipple, J.W., 1992. Geologic map of Glacier National Park, Montana: U.S. Geological Survey, Miscellaneous Investigations Series Map I-1508-F, scale 1:100,000.

CLOSING

Please contact Evan Garich at (360) 619-7824 or Evan.Garich@dot.gov with any questions regarding this memorandum.

Attachments: Figure A-1 – Project Map

Figures A-2, A-3 – North Fork Road Test Pit Locations Map Figure A-4 – Whale Creek Pit Test Pit Locations Map Figure A-5 – Glacier Drive Test Pit Locations Map Attachment B – Site Photographs Attachment C – Test Pit Logs Attachment D – Laboratory Testing Results mailto:Evan.Garich@dot.gov

Attachment A – Figures

Figure A-2 - North Fork Road 2020 Test Pit Locations

Legend

Mile Post (approx)

Test Pit Location

2000 ft

N

N

© 2021 Google

© 2021 Google

Figure A-3 - North Fork Road

Legend

Mile Post (approx)

Test Pit Location

2000 ft

N

N

© 2021 Google

Figure A-4 - Whale Creek Pit

Legend

Test Pit Location

400 ft

N ➤➤N

© 2021 Google

© 2021 Google Image date: 7/24/2017

Figure A-5 - Glacier Drive

Legend

Test Pit Location

3000 ft

N

N © 2021 Google

Attachment B – Site Photographs

Attachment B, Page 1

Test pit NF20-01TP

Cobble/boulder sized clasts in test pit NF20-02TP.

Attachment B, Page 2

Test pit NF20-02TP.

Excavation of test pit NF20-03TP

Attachment B, Page 3

Test pit NF20-03TP

Slope adjacent to test pit NF20-03TP

Attachment B, Page 4

Test pit NF20-04TP

Ditch with standing water adjacent to test pit NF20-04TP

Attachment B, Page 5

Test pit NF20-05TP

North Fork road after backfilling test pit NF20-06TP, note water in ditch

Attachment B, Page 6

North Fork road after backfilling test pit NF20-07TP

Excavated material from test pit NF20-08TP

Attachment B, Page 7

Excavated material from test pit NF20-09TP

Whale Creek Pit, facing southwest pit wall

Attachment B, Page 8

Whale Creek Pit, a portion of the southwest pit wall

Whale Creek Pit, facing northwest showing numerous partially burnt logs on the pit floor and edges

Attachment B, Page 9

Whale Creek Pit, facing north

Whale Creek Pit, facing south

Attachment B, Page 10

Whale Creek Pit, facing northeast

Whale Creek Pit, facing north. WC20-03TP and WC20-04TP are located in the upper terrace, which has been cleared at some date after the aerial photo used in Figure A-4 was captured.

Attachment B, Page 11

Test pit WC20-01TP side wall

Test pit WC20-02TP excavated material

Attachment B, Page 12

Test pit WC20-02TP, note boulders

Test pit WC20-03TP

Attachment B, Page 13

Test pit WC20-04TP

Test pit WC20-05TP, excavated material

Attachment B, Page 14

Test pit GD20-01TP, excavated material

Test pit GD20-01TP, note water at bottom of test pit

Attachment B, Page 15

Test pit GD20-02TP

Utility marked near test pit GD20-03TP

Attachment B, Page 16

Test pit GD20-03TP

Utility marked near test pit GD20-04TP

Attachment B, Page 17

Test pit GD20-04TP

Test pit GD20-04TP, note water at bottom of test pit

Attachment C – Test Pit Logs

10/04/2018

SOIL CLASSIFICATION CHART

Criteria for Assigning Group Symbols and Group Name Using Laboratory TestsA Group

Symbol Group NameB

COARSE-GRAINED

SOILS

More than 50% retained on No. 200 Sieve

GRAVELS

More than 50% of coarse fraction retained on No. 4 Sieve

Clean GRAVELS Less than 5% fines E

Cu ≥ 4 and 1 ≤ Cc ≤ 3C GW Well-graded GRAVEL D

Cu < 4 and/or 1 > Cc > 3 C GP Poorly-graded GRAVEL D

GRAVELS with fines More than 12% fines E

Fines classify as ML or MH GM Silty GRAVEL D,F Fines classify as CL or CH GC Clayey GRAVEL D,F

SANDS

Less than 50% retained on No. 4 Sieve

Clean SANDS Less than 5% fines I

Cu ≥ 6 and 1 ≤ Cc ≤ 3 C SW Well-graded SAND H

Cu < 6 and/or 1 > Cc > 3 C SP Poorly-graded SAND H

SANDS with fines More than 12% fines I

Fines classify as ML or MH SM Silty SAND F,H Fines classify as CL or CH SC Clayey SAND F,H

FINE-GRAINED

SOILS

50% or more passes the No. 200 Sieve

SILTS and CLAYS Liquid limit less than 50

Inorganic PI > 7 and plots on or above the “A” line J CL Lean CLAY K,L,M PI < 4 or plots below “A” line J ML SILT K,L,M

Organic Liquid limit – oven dried Liquid limit – not dried < 0.75 OL Organic CLAY K,L,M,N

Organic SILT K,L,M,O

SILTY and CLAYS Liquid limit 50 or more

Inorganic PI plots on or above “A” line CH Fat CLAY K,L,M PI plots below “A” line MH Elastic SILT K,L,M

Organic Liquid limit – oven dried Liquid limit – not dried < 0.75 OH Organic CLAY K,L,M,P

Organic SILT K,L,M,Q

HIGHLY ORGANIC

SOILS Primarily organic matter, dark in color, and organic odor PT PEAT A Based on material passing the 3-inch sieve.

B If field sample contains cobbles or boulders, add “with cobbles” or “boulders” or both, to group name.

C Cu = D60/D10 Cc = (D30)2 / (D10 x D60) D If soil contains ≥15% sand, add “with sand” to group name.

E Gravels with 5 to 12% fines require dual symbols:

GW-GM well-graded GRAVEL with silt GW-GC well-graded GRAVEL with clay GP-GM poorly-graded GRAVEL with silt GP-GC poorly-graded GRAVEL with clay

F If fines classify as CL-ML, use dual symbol GC-GM or SC-SM G If fines are organic, add “with organic fines” to group name.

H If soil contains ≥15% gravel, add “with gravel” to group name.

I Sand with 5 to 12% fines require dual symbols:

SW-SM well-graded SAND with silt SW-SC well-graded SAND with clay SP-SM poorly-graded SAND with silt SP-SC poorly-graded SAND with clay J If Atterberg limits plot in hatched area, soil is a CL-ML, silty

CLAY.

K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel”, whichever is predominant.

L If soil contains ≥ 30% plus No. 200, predominantly sand, add “sandy” to beginning of group name.

M If soil contains ≥ 30% plus No. 200, predominantly gravel, add “gravelly” to beginning of group name.

N PI ≥ 4 and plots on or above “A” line.

O PI < 4 or plots below “A” line.

P PI plots on or above “A” line.

Q PI plots below “A” line.

APPARENT DENSITY OF COARSE-

GRAINED SOIL

SPT N-value (blows per foot) Apparent Density

0 to 4 Very Loose

5 to 10 Loose

11 to 30 Medium Dense

31 to 50 Dense

> 50 Very Dense

CONSISTENCY OF

FINE-GRAINED SOIL

SPT N-value (blows per foot) Consistency

0 to 1 Very Soft

2 to 4 Soft

5 to 8 Firm

9 to 15 Stiff

16 to 30 Very Stiff

> 30 Hard

SOIL STRUCTURE TERMS

Stratified Alternating layers of varying material or color with layers > 1/4 inch (6 mm), note thickness and inclination.

Laminated(1) Alternating layers of varying material or color with layers < 1/4 inch (6 mm), note thickness and inclination.

Fissured(1) Breaks along definite planes of fracture with little resistance to fracturing.

Slickensided(1) Fracture planes appear polished or glossy, sometimes striated.

Blocky(1) Cohesive soil that can be broken down into smaller angular lumps which resists further breakdown.

Disrupted Soil structure is broken and mixed. Infers that material has moved substantially -landslide debris.

Homogeneous Same color and appearance throughout.

Lensed Inclusion of small pockets of different soil, such as small lenses of sand scattered through a mass of clay; < 1/4 inch (6 mm) note thickness.

(1) Do not use laminated, fissured, slickensided, or blocky for coarse-grained soils.

Descriptive Terminology for Boring Logs

Field descriptions of borings are based on the FLH Soil and Rock Description and Identification Guidelines that generally follow the Visual-Manual Procedure (ASTM D 2488). The soil classifications shown on the boring logs are based on laboratory tests (ASTM D 2487) when the two-letter group symbol follows the group name in parenthesis.

Standard Penetration Test (SPT): the SPT consists of driving a 2 in (50 mm) O.D. split barrel sampler a depth of 18 in (450 mm) or 24 in (600 mm) using a 140 lb (63.6 kg) hammer with a 30 in (750 mm) drop. The blow count is the number of blows recorded for each 6 inch (50 mm) increment.

The N-value is the total number of blows for the second and third increments. Note that the N-values shown on the boring logs do not include any corrections for non-standard sampler size, hammers, drill rods, etc.

ANGULARITY OF

COARSE-GRAINED SOILS

Angular

Sharp edges and relatively plane sides with unpolished surfaces

Subangular

Similar to angular description, but with rounded edges

Subrounded

Nearly plane sides, but will have well-rounded corners and edges.

Rounded

Smoothly curved sides and no edges

PARTICLE SIZE OF COARSE-GRAINED SOILS

Component Grain Size Limits

Boulders > 12” (> 300 mm)

Cobbles 3 – 12” (75 – 300 mm)

Coarse Gravel 3/4 - 3" (19 - 75 mm)

Fine Gravel #4 Sieve - 3/4" (4.75 - 19 mm)

Coarse Sand #10 - #4 Sieve (2.00 - 4.75 mm)

Medium Sand #40 - #10 Sieve (0.425 - 2.00 mm)

Fine Sand #200 - #40 Sieve (0.075 - 0.425 mm)

10/04/2018

GRAIN/CRYSTAL SIZE FOR ROCKS (MODIFIED AFTER WENTWORTH, 1972)

Grain Size Description Criteria Less than 0.003 inches (<0.075 mm)

Very fine grained Cannot be distinguished by unaided eye. Few to no mineral grains are visible with a hand lens.

0.003 to 0.02 inches (0.075 to 0.425 mm) Fine grained

Few grain/crystal boundaries are visible; grains can be distinguished with difficulty by the unaided eye but can be somewhat distinguished by hand lens.

0.02 to 0.08 inches (0.425 to 2 mm) Medium grained Most grain/crystal boundaries are visible; grains distinguishable by eye and with the aid of a hand lens.

0.08 to 0.2 inches

(2 to 4.75 mm) Coarse grained Grain/crystal boundaries are visible; grains distinguishable with the naked eye and hand lens.

Greater than 0.2 inches

(>4.75 mm)

Very coarse grained

Grain/crystal boundaries are Clearly visible; grains are distinguishable with the naked eye.

GRAIN SHAPE (FOR SEDIMENTARY ROCKS)

Description Characteristic

Angular Showing very little evidence of wear. Grain edges and corners are sharp. Secondary corners are numerous and sharp.

Subangular

Showing definite effects of wear. Grain edges and corners are slightly rounded off. Secondary corners are slightly less numerous and slightly less sharp than in angular grains.

Subrounded Showing considerable wear. Grain edges and corners are rounded to smooth curves. Secondary corners are reduced greatly in number and highly rounded.

Rounded Showing extreme wear. Grain edges and corners are smoothed off the broad curves. Secondary corner are few in number and rounded.

Well-rounded Completely worn. Grain edges or corners are not present. No secondary edges or corners are present. DEGREE OF WEATHERING

Term Description Grade

Fresh No visible sign of rock material weathering; slight discoloration on major discontinuity surface is possible. I

Slightly Weathered

Discoloration indicates weathering of rock material and discontinuity surfaces. All rock material may be discolored by weathering and the external surface may be somewhat weaker than in its fresh condition.

II

Moderately Weathered

Less than half the rock material is decomposed and/or disintegrated to a soil.

Fresh or discolored rock is present either as a discontinuous framework or as corestones. A minimum 2-inch (50 mm) diameter sample cannot be broken readily by hand across the rock fabric.

III

Highly Weathered

More than half of the rock is decomposed and/or disintegrated to soil. Fresh or discolored rock is present either as a discontinuous framework or as corestones.

A minimum 2-inch (50 mm) diameter sample can be broken readily by hand across the rock fabric.

IV

Completely Weathered

All rock material is decomposed and/or disintegrated to soil. The original mass structure is still largely intact. Material can be granulated by hand. If rock is considered to be completely weathered, use FLH Soil Description and Identification Guidelines to describe the residual soil material.

V

Residual Soil

All rock material is converted to soil. The mass structure and material fabric are destroyed but the apparent structure remains intact. There may be a large change in volume, but the soil has not been significantly transported. Material can be easily broken-down by hand. If rock is considered to be completely weathered, use FLH Soil Description and Identification Guidelines to describe the residual soil material.

VI

RELATIVE STRENGTH OF SOIL INFILLING (ISRM, 1978 & 1981)

Grade Description Field Identification Approximate

Uniaxial Compressive

Strength

S1 Very Soft Easily penetrated several inches by fist

<3.5 psi (<25 kPa)

S2 Soft Easily penetrated severl inches by thumb

3.5 - 7 psi (25 - 50 kPa)

S3 Firm

Can be penetrated several inches by thumb with moderate effort

7 - 14.5 psi (50 - 100 kPa)

S4 Stiff

Readily indented by thumb but penetrated only with great effort

14.5 - 36 psi (100 - 250 kPa)

S5 Very Stiff Readily indented by thumbnail

36 - 72.5 psi (250 - 500 kPa)

S6 Hard Indented with difficulty by thumbnail

>72 psi (>500 kPa)

RELATIVE STRENGTH OF INTACT ROCK SPECIMENS (ISRM, 1978 &1981)

Grade Description Field Indentificaiton Approximate Uniaxial Compressive Strength

R0 Extremely Weak Rock Specimen can be indented by thumbnail 35 - 150 psi

(250 - 1,000 kPa)

R1 Very Weak Rock

Specimen crumbles under sharp blow with point of geological hammer, and can be peeled with a pocket knife.

150 - 725 psi (1,000 - 5,000 kPa)

R2 Weak Rock Shallow cuts or scrapes can be made in a specimen with a pocket knife. A firm blow with a geological hammer point creates shallow indents.

725 - 3,500 psi (5,000 - 25,000 kPa)

R3 Medium Strong Rock

Specimen cannot be scraped or cut with a pocket knife.

Specimen can be fractured with a single firm blow with a geologic hammer point.

3,500 - 7,250 psi (25,000 - 50,000 kPa)

R4 Strong Rock Specimen requires more than one firm blow of the geologic hammer point to fracture.

7,250 - 14,500 psi (50,000 - 100,000 kPa)

R5 Very Strong Rock

Specimen requires many firm blows from the hammer end of the geologic hammer to fracture.

14,500 - 36,250 psi (100,000 - 250,000 kPa)

R6 Extremely Strong Rock

Specimen can only be chipped with firm blows from the hammer end of the geologic hammer.

>36,250 psi (>250,000 kPa)

JRC RANGES (ISRM, 1978 &1981)

DISCONTINUITY CONDITION (ISRM, 1978, 1981)

Condition Description

Excellent Condition

Very rough surfaces, no separation, hard discontinuity wall (>R2).

Good Condition

Slightly rough surfaces, separation less than ~0.04 inches (1 mm), hard discontinuity wall (>R2).

Fair Condition

Slightly rough surface, separation greater than ~0.04 inches (1 mm), soft discontinuity wall (<R3).

Poor Condition

Slickensided surfaces, or soft gouge less than ~0.2 inches (5 mm) thick, or open discontinuities between ~0.4 and 0.2 inches (1 to 5 mm).

Very Poor Condition

Soft gouge greater than ~0.2 inches (5 mm), or open discontinuities greater than ~0.2 inches (5 mm).

DISCONTINUITY SPACING (INCLUDES

JOINTS/FRACTURES, BEDDING, AND FAULTS

Description Spacing of Discontinuity Extremely Widely

Spaced >20 feet (>6 m)

Very Widely Spaced

~6 to 20 feet (2 to 6 m)

Widely Spaced ~2 to 6 feet (600 mm to 2 m)

Moderately Spaced

~8 inches to 2 feet (200 to 600 mm)

Closely Spaced ~2 to 8 inches (60 to 200 mm)

Very Closely Spaced

~3/4 to 2 inches (20 to 60 mm)

Extremely Closely Spaced

<3/4 inches (<20 mm)

𝑅𝑅𝑅𝑅𝑅𝑅 (%) =

𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿ℎ 𝑜𝑜𝑜𝑜 𝑆𝑆𝑜𝑜𝑆𝑆𝐿𝐿𝑆𝑆 𝐶𝐶𝑜𝑜𝐶𝐶𝐿𝐿 𝑖𝑖𝐿𝐿 𝑝𝑝𝑖𝑖𝐿𝐿𝑝𝑝𝐿𝐿𝑝𝑝 > 4 𝑖𝑖𝐿𝐿𝑝𝑝ℎ𝐿𝐿𝑝𝑝 (100 𝑚𝑚𝑚𝑚)

𝑇𝑇𝑜𝑜𝐿𝐿𝑇𝑇𝑇𝑇 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿ℎ 𝑜𝑜𝑜𝑜 𝐶𝐶𝑜𝑜𝐶𝐶𝐿𝐿 𝑅𝑅𝑆𝑆𝐿𝐿

𝑥𝑥 100

𝐹𝐹𝐹𝐹 =

𝑁𝑁𝑆𝑆𝑚𝑚𝑁𝑁𝐿𝐿𝐶𝐶 𝑜𝑜𝑜𝑜 𝐿𝐿𝑇𝑇𝐿𝐿𝑆𝑆𝐶𝐶𝑇𝑇𝑇𝑇 𝑜𝑜𝐶𝐶𝑇𝑇𝑝𝑝𝐿𝐿𝑆𝑆𝐶𝐶𝐿𝐿𝑝𝑝

𝑇𝑇𝑜𝑜𝐿𝐿𝑇𝑇𝑇𝑇 𝑇𝑇𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿ℎ 𝑜𝑜𝑜𝑜 𝑝𝑝𝑜𝑜𝐶𝐶𝐿𝐿 𝐶𝐶𝐿𝐿𝑝𝑝𝑜𝑜𝑟𝑟𝐿𝐿𝐶𝐶𝐿𝐿𝑆𝑆 (𝑜𝑜𝐿𝐿𝐿𝐿𝐿𝐿)

𝐶𝐶𝑅𝑅 (%) = �

𝑇𝑇𝑜𝑜𝐿𝐿𝑇𝑇𝑇𝑇 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿ℎ 𝑜𝑜𝑜𝑜 𝐶𝐶𝑜𝑜𝐶𝐶𝐿𝐿 𝑅𝑅𝐿𝐿𝑝𝑝𝑜𝑜𝑟𝑟𝐿𝐿𝐶𝐶𝐿𝐿𝑆𝑆

𝑇𝑇𝑜𝑜𝐿𝐿𝑇𝑇𝑇𝑇 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿ℎ 𝑜𝑜𝑜𝑜 𝐶𝐶𝑜𝑜𝐶𝐶𝐿𝐿 𝑅𝑅𝑆𝑆𝐿𝐿 𝑅𝑅𝐶𝐶𝑖𝑖𝑇𝑇𝑇𝑇𝐿𝐿𝑆𝑆

� ∗ 100

S-1

Bulk Fines = 11%

Silty SAND, brown, moist, fine sand, non plastic, with gravel, occasional clasts up to 12" dia.

1.5 ft Well graded GRAVEL with silt and sand (GW-GM), brown, moist, non plastic, clasts up to 12" dia.

3.5 ft Bottom of borehole at 3.5 ft.

Groundwater Depth:

While Drilling: --- At Completion: 3.5 ft After Drilling: ---

Notes:

Located at NB edge of Glacier Drive.

Latitude: 48.7657° Longitude: -114.285°

Weather: 50's

Date Started: 6/17/20 Date Completed: 6/17/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT GD20-01TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

NP

G ra ph ic

L og

Bulk

S-2

Fines = 7%

Silty GRAVEL with sand, brown, moist, non plastic, fine to coarse sand and gravel, subrounded to subangular clasts.

0.5 ft Poorly graded SAND with silt and gravel (SP-SM), brown, moist, non plastic, fine to medium sand, fine to coarse gravel, subrounded to rounded gravel.

2 ft Well graded GRAVEL with silt and sand, brown, moist, non plastic, and cobbles, fine to coarse sand and gravel, subrounded to rounded clasts to 8" dia.

4 ft Bottom of borehole at 4 ft.

Groundwater Depth:

While Drilling: --- At Completion: 4 ft After Drilling: ---

Notes:

Located at NB edge of Glacier Drive.

Latitude: 48.7693° Longitude: -114.2831°

Weather: 50's

Date Started: 6/17/20 Date Completed: 6/17/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT GD20-02TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

NP

G ra ph ic

Fines = 4%

Poorly graded GRAVEL with sand (GP), brown, moist, non plastic, fine to coarse sand and gravel, subrounded to round clasts up to 8" dia..

4 ft Bottom of borehole at 4 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Located at NB edge of Glacier Drive.

Latitude: 48.7733° Longitude: -114.28°

Weather: 50's

Date Started: 6/17/20 Date Completed: 6/17/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT GD20-03TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

NP

G ra ph ic

Poorly graded GRAVEL with sand (GP), brown, moist, low plasticity, fine to coarse sand and gravel, subrounded to rounded clasts up to 12" dia.

4 ft Bottom of borehole at 4 ft.

Groundwater Depth:

While Drilling: --- At Completion: 4 ft After Drilling: ---

Notes:

Located at NB edge of Glacier Drive.

Latitude: 48.7789° Longitude: -114.2805°

Weather: 50's

Date Started: 6/17/20 Date Completed: 6/17/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT GD20-04TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

G ra ph ic

Bulk Fines = 17%

SG = 2.69

Silty GRAVEL with sand (GC-GM), brown, moist, fine to coarse sand and gravel, subrounded to rounded, with cobbles up to 12" dia..

4.5 ft Sandy SILT, brown, moist, low plasticity, fine sand.

5.5 ft Bottom of borehole at 5.5 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Located at SB edge of North Fork Road. ~MP 55.0

Latitude: 48.9991° Longitude: -114.4783°

Weather: 50's

Date Started: 6/16/20 Date Completed: 6/16/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT NF20-01TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

G ra ph ic

S-2

Bulk

S-3

Fines = 68%

SG = 2.72

Silty GRAVEL with sand (GM), brown, moist, fine to coarse sand and gravel, subrounded to angular crushed gravel, with occasional cobbles up to 12" dia, Fill.

1 ft Gravelly lean CLAY with sand (CL), mottled tan and brown, moist, low plasticity, trace organics.

4.5 ft Bottom of borehole at 4.5 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Located at SB edge of North Fork Road. ~MP 54.5

Latitude: 48.9922° Longitude: -114.4755°

Weather: 50's

Date Started: 6/16/20 Date Completed: 6/16/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT NF20-02TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

G ra ph ic

Gravelly lean CLAY with sand, brown, moist, low plasticity, with cobbles, fine to coarse gravel, rounded, cobbles up to 12" dia.

3 ft CLAYSTONE, grey, extremely weak rock (R0).

5 ft Bottom of borehole at 5 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Cut slope along SB lane of North Fork Road. ~MP 54.0

Latitude: 48.9867° Longitude: -114.4723°

Weather: 50's

Date Started: 6/16/20 Date Completed: 6/16/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT NF20-03TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

G ra ph ic

SG = 2.62

Fines = 49%

Silty SAND with gravel (SM), dark brown, moist, with organics, with cobbles, fine to coarse gravel, subrounded to rounded gravel and cobbles, 3" wood fiber at 1' and 1.5' depth.

becomes light brown, wet

4.5 ft Bottom of borehole at 4.5 ft.

Groundwater Depth:

While Drilling: --- At Completion: 4 ft After Drilling: ---

Notes:

Located at NB edge of North Fork Road. ~MP 53.5

Latitude: 48.9795° Longitude: -114.4751°

Weather: 50's

Date Started: 6/16/20 Date Completed: 6/16/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT NF20-04TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

G ra ph ic

Fines = 40%

SG = 2.69

Silty GRAVEL with sand (GM), brown, moist, with cobbles, fine to coarse sand and gravel, subrounded to rounded gravel.

5 ft Bottom of borehole at 5 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Located at SB edge of North Fork Road. ~MP 53.0

Latitude: 48.9728° Longitude: -114.4712°

Weather: 50's

Date Started: 6/16/20 Date Completed: 6/16/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT NF20-05TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

NP

G ra ph ic

Gravelly lean CLAY with sand, brown, moist, with cobbles, and boulders, occasional organics, boulders up to 18" dia.

4 ft Bottom of borehole at 4 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Located at SB edge of North Fork Road. ~MP 52.0

Latitude: 48.9604° Longitude: -114.4634°

Weather: 50's

Date Started: 6/16/20 Date Completed: 6/16/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT NF20-06TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

G ra ph ic

Bulk

Fines = 46%

SG = 2.68

Fines = 48%

SG = 2.69

Silty clayey GRAVEL with sand (GC-GM), brown, moist, with cobbles, fine to coarse and subrounded to rounded sand and gravel, roots up to 3" dia, one 18" dia boulder.

2 ft Clayey GRAVEL with sand (GC), brown, moist.

5 ft Bottom of borehole at 5 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Located at SB edge of North Fork Road. ~MP 51.5

Latitude: 48.9539° Longitude: -114.4562°

Weather: 50's

Date Started: 6/16/20 Date Completed: 6/16/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT NF20-07TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

G ra ph ic

Silty SAND with gravel (SM), brown, moist, low plasticity, trace organics, fine to coarse and subrounded to rounded gravel, 12" dia. boulder.

1.5 ft Sandy SILT with gravel, light brown, moist, non plastic, some cobbles, and boulders, layered dark brown, fine to coarse and subrounded to rounded gravel.

5 ft Bottom of borehole at 5 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Located at SB edge of North Fork Road.~MP 51.0

Latitude: 48.9472° Longitude: -114.4506°

Weather: 50's

Date Started: 6/16/20 Date Completed: 6/16/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT NF20-08TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

G ra ph ic

Fines = 43%

SG = 2.68

Silty SAND with gravel (SM), light brown, moist, cobbles, and boulders, fine to coarse sand and gravel, subrounded to rounded clasts, 18" dia. boulder.

4 ft Bottom of borehole at 4 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Located at SB edge of North Fork Road.~MP 50.5

Latitude: 48.9472° Longitude: -114.4506°

Weather: 50's

Date Started: 6/16/20 Date Completed: 6/16/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT NF20-09TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

G ra ph ic

Bulk Fines = 4%

Well graded GRAVEL with sand (GW), brown, moist, and cobbles, and boulders, fine to coarse sand and gravel, subrounded to subangular clasts, sidwall ravelling, boulders up to 18" dia.

10 ft Bottom of borehole at 10 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Located along SE edge of mined area within Whale Creek Pit.

Excavation along pit wall and generally above mined pit floor.

Latitude: 48.8666° Longitude: -114.464°

Weather: 50's

Date Started: 6/17/20 Date Completed: 6/17/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT WC20-01TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

G ra ph ic and cobbles, and boulders, fine to coarse and subrounded to subangular sand and gravel, up to 2' dia. boulders, 2' think layer of boulders and cobbles from depths of 2' to 4'.

10 ft Bottom of borehole at 10 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Located in middle of Whale Creek pit. Excavated from existing pit floor.

Latitude: 48.8671° Longitude: -114.4637°

Weather: 50's

Date Started: 6/17/20 Date Completed: 6/17/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT WC20-02TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

NP

G ra ph ic

Sandy SILT, orange mottled brown, moist, fine sand, non plastic.

1 ft Well graded GRAVEL with sand (GW), brown, moist, and cobbles, fine to coarse sand and gravel, subrounded to subangular clasts up to 1' dia, sidewalls ravelling.

9 ft Bottom of borehole at 9 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Located along in northern portion of Whale Creek pit. Location has been cleard but not mined previously.

Latitude: 48.8679° Longitude: -114.4635°

Weather: 50's

Date Started: 6/17/20 Date Completed: 6/17/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT WC20-03TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

G ra ph ic

Bulk

Fines = 45%

Fines = 36%

Silty SAND (SM), brown, moist, fine sand.

2.5 ft Silty clayey SAND with gravel, brown, moist, and cobbles, fine to coarse and subrounded to subangular sand and gravel.

5 ft Clayey GRAVEL with sand (GC), brown, wet, and cobbles, fine to coarse and subangular sand and gravel.

Excavator refulsal at 6'.

6 ft Bottom of borehole at 6 ft.

Groundwater Depth:

While Drilling: --- At Completion: 4 ft After Drilling: ---

Notes:

Located along in northern portion of Whale Creek pit (north of WC20-03TP). Location has been cleard but not mined previously.

Latitude: 48.8681° Longitude: -114.4633°

Weather: 50's

Date Started: 6/17/20 Date Completed: 6/17/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT WC20-04TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

NP

G ra ph ic

Bulk Fines = 2% and cobbles, fine to coarse, subraouded to subangular clasts up to 12" dia.

8 ft Bottom of borehole at 8 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Located at NE edge of mined area within Whale Creek pit.

Excavated from existing pit floor.

Latitude: 48.8678° Longitude: -114.463°

Weather: 50's

Date Started: 6/17/20 Date Completed: 6/17/20 Driller/Company: Rick/Flathead County Hammer Type:

Drill: Gradall XL 3100

Logger/Company: Garich/WFLHD

TEST PIT WC20-05TP

Sheet: 1 of 1

Project Location: Flathead County

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: North Fork of the Flathead River D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

O G

F

H W

A _D

A T

A T

E M

P

LA

T E

_2

3.

G

D T

/1 5/

:5

C :\P

W -W

O R

K \D

\M T

F

LA

T H

E A

D

(1

N

O R

T H

F O

R K

O F

T H

E F

L A

T H

E A

D R

IV

E

R .G

P J

NP

G ra ph ic

Attachment D – Laboratory Testing Results

Materials Testing Laboratory

610 E. Fifth St, Vancouver, WA 98661

Test Report Issued: 18 Aug 2020

Lab Control Number: W-20-0777-SO

Project Name: NORTH FORK OF THE FLATHEAD RIVER Sample No: S-1 Project Number: MT FLATHEAD 486(1) Sampled By: EVAN GARICH

PE.K200.30 Date Sampled: 6/17/2020

Address:

Acct. No.: 1517302907861 510.

Submitted By: EVAN GARICH Phone:

Sample…