158377846

M E M O R A N D U M

Western Federal Lands Highway Division

610 E. Fifth Street

Vancouver, WA 98661

DATE: November 6, 2025

TO: Wendy Schmidt

Project Manager

FROM: Nicholas Ferreira

Geotechnical Engineer

Mark Swank

GEO Functional Manager

SUBJECT: Geotechnical Memo 30-25

Twin Cabins Quarry Material Source Testing

National Forest System Road 221 Rehabilitation

ID NEZPR117 221(1)

Idaho County, Idaho

INTRODUCTION

We understand the Twin Cabins Quarry, located in the Nez Perce-Clearwater National Forests, may be used as the primary material source for the National Forest System Road (NFSR) Road

221 Rehabilitation Project (project). This memorandum summarizes Western Federal Lands

Highway Divisions (WFLHD) site observations, subsurface conditions, laboratory testing results, and recommendations for use.

The project will require substantial quantities of rock materials for the proposed construction, including, but not limited to, subbase, base, and surface coarse aggregate materials.

SITE CONDITIONS

The NFSR 221 in the southwest part of the Idaho panhandle, approximately 8 miles south of

Grangeville and leads into the Nez Perce-Clearwater National Forests, is used by several active timber harvest operations along with recreational and local users. The road is between 24 and

32 feet wide depending on the shoulder widths with an average gradient of approximately 2.5 percent with a maximum gradient of 4.5 percent. The elevations (EL) range between EL 5,000 and EL 5,900 feet, generally increasing and peaking near MP 25.5 and then descends to the end of the project limits. The project vicinity map is shown on Figure 1.1 in Attachment 1.

The Twin Cabins Quarry is located at latitude 45.7815° and longitude -116.0666°, within the southwest quarter of the northeast quarter of Section 10, Township 28 North, Range 3 East, Boise Meridian. The site features exposed bedrock slopes that range from moderately steep to near vertical along its northern, eastern, and western boundaries. Situated on the northern side of Grangeville-Salmon Road, the surrounding landscape is predominantly covered with trees and brush. The Twin Cabins Quarry site map is shown on Figure 1.2 in Attachment 1

The Twin Cabins Quarry is an active hard rock pit that has historically been utilized for processing materials for fire access roads. During our site reconnaissance on October 10, 2024, we observed operational infrastructure, including crushing equipment and conveyor belts for processing aggregates (Photo 1) along with several stockpiles of differing material sizes, including an approximately 675 feet long, 70 feet wide, and 40 feet tall stockpile of crushed gravel with fines (Photo 2).

Dark gray, fine-grained, fresh to slightly weathered, strong (R4) basalt rock is exposed in the quarry walls. The discontinuities in the rock outcrops are closely to widely spaced, in good to fair condition (Photo 3). Loose basalt material was also noted across the site, with clasts ranging in size from coarse gravel (>0.75 inches) to cobbles up to approximately 12 inches in dimension.

Most of the cobbles are between 4 and 8 inches in size (see Photo 4 for visual reference). The quarry rim and upper areas are predominately vegetated with small to large conifer trees.

Photo 1. Looking north from the southeast side of Twin Cabins Quarry

Photo 2. Looking southwest at the existing stockpile on the west side of the quarry

Photo 3. Looking northwest at the existing stockpile on the east side of the quarry

Photo 4. View of cobbles seen in a stock pile.

GEOLOGIC SETTING

The project alignment is on the western boundary of the Nez Perce-Clearwater National Forests and winds roughly south to north between the Columbia Plateau and Rocky Mountain physiographic provinces in north-central Idaho (Lewis et al., 2012). The basement rocks underlying the project area include cratonic and accreted terrane assemblages juxtaposed along a north-south zone. The cratonic assemblage consists of Proterozoic metamorphic and

Cretaceous intrusive rocks. The accreted terrane assemblage includes Permian to Cretaceous volcanic, volcaniclastic, sedimentary, and intrusive rocks with varying degrees of metamorphism.

Miocene Columbia River Basalt Group lava flows and minor interbedded sediments cover much of the ground surface and lie unconformably on the older basement rocks. Remnants of Tertiary gravels locally cap the flows. Pleistocene glacial deposits are present in the higher elevation and Pleistocene to Holocene alluvial deposits form terraces and stream deposits along the major rivers and tributary streams. Landslide and mass-wasting deposits, also of Pleistocene to Holocene age, are common throughout area, especially in areas of steep relief.

Local Geology

Based on the geologic maps in the area (Kauffman et al., 2008; Kauffman et al., 2011; Kauffman et al., 2014), the project alignment traverses the juxtaposed cratonic and accreted assemblages formations that are unconformably capped with Columbia River Basalts and mantled with younger, unconsolidated Pleistocene and Holocene glacial and alluvial deposits, and artificial fill.

Unconsolidated

Deposits

Holocene alluvial deposits in local drainages (Qas) Stratified silt, sand, and clay typically between 5 and 20 feet thick.

Columbia River

Basalts

Miocene Grande Ronde Basalt, R2 unit (Tgr2) Medium to dark gray, fine-grained basalt, commonly with a sugary texture with uncommon to common plagioclase phenocrysts and reverse magnetic polarity.

Consists of one or two flows and a unit thickness generally less than 100 feet. Local thickening and thinning may result from structures developed on earlier Grande Ronde Basalt or from erosion on the earlier basalt surface.

Miocene Grande Ronde Basalt, N1 unit (Tgn1) Dark gray, fine-grained generally aphyric to plagioclase-microphyric basalt and normal magnetic polarity. The number of flows is estimated to be from three to five with a total unit thickness from 400 to 600 feet The flows near the top of sequence commonly 50 to 70 feet thick with a sugary texture and flows lower in the sequence are typically thicker, generally from 100 to 200 feet.

Colonnades of thin flows and entablatures of thick flows tend to form tiered cliffs on steep canyon slopes.

Miocene Grande Ronde Basalt, R1 unit (Tgr1) Dark gray, fine-grained aphyric to microphyric basalt with uncommon and reverse magnetic polarity. Outcrop characteristics of flows are similar to those in the

Grande Ronde N1 unit and an exposed thickness of about 700 to 800 feet.

Intrusive Rocks Cretaceous Tonalite and trondhjemite (Kto) The tonalite is biotite- and hornblende-bearing, with large biotite plates that create a distinctive mottled appearance and weathers to light tan grus, medium-grained. This unit belongs to a group of tonalite and trondhjemite plutons along the

Salmon River suture of an age of around 111 million years.

Metamorphic

Rocks

Permian to Cretaceous Ultramafic rocks (KPum) Metamorphosed pyroxenite or peridotite with clusters of anthophyllite, talc, and chlorite.

These rocks are light green to orange on fresh surfaces and gray where weathered, occurring as elongate, discontinuous bodies forming low, rounded ridges within the KPgs unit.

Permian to Cretaceous Gneiss and schist (KPgs) Fine to medium grained gneiss that grades into schist. Also includes calc-silicate rocks and quartzite. Light gray or green to black, weathering to a fine gray brown soil. Although some plagioclase-amphibole gneiss may be metavolcanic in origin, most (if not all) of the unit is probably metasedimentary.

SUBSURFACE CONDITIONS

Geotechnical borings were drilled at the Twin Cabins Quarry expansion to explore the subsurface conditions during previous investigation by AllWest in 2022 and our recent work in

July 2025. The previous investigation performed in September 12 to 13, 2022 advanced 3 geotechnical borings with a track-mounted CME-850 drill rig using a combination of hollow stem augers (HSA) and rock coring techniques.

Between July 8 and 23, 2025, Haztech Inc. advanced 9 geotechnical borings with a track-mounted CME-850 drill rig using a combination of HSA and rock coring techniques. Disturbed soil samples were obtained in our borings at 2.5- to 5-foot intervals using the Standard

Penetration Test (SPT) in general accordance with the ASTM International (ASTM) D1586, Standard Test Method for Standard Penetration Test (SPT) and Split-Barrel Sampling of Soils

(ASTM, 2025). Rock samples were collected using HQ3 triple tube wireline coring system.

Boring details are presented in Table 1 below.

Table 1. Geotechnical Boring Locations and Depths

Boring Depth (ft) Latitude(1) Longitude(1) Surface EL (ft)

W F

L H

D

BH24-01 66 45.7820 -116.0677 5,244

BH24-02 50 45.7813 -116.0670 5,233

BH24-03 65 45.7827 -116.0659 5,289

BH24-04 85 45.7822 -116.0648 5,313

BH24-05 65 45.7817 -116.0644 5,304

BH24-06 49.5 45.7813 -116.0649 5,284

BH24-07 69 45.7815 -116.0657 5,289

BH24-08 45 45.7809 -116.0660 5,259

BH24-09 94.5 45.7821 -116.0661 5,298

A ll

W e s t B-1 50 45.7815 -116.0659 5,300

B-2 50 45.7817 -116.0656 5,296

B-3 50 45.7821 -116.0657 5,285

Notes: 1 – Based on NAVD88 GEOID18, in decimal degrees

Boring logs summarizing the subsurface conditions and rock core photographs are presented in Attachment 2. Field identifications of the soils were performed in general accordance with

ASTM D2488 Standard Practice for Description and Identification of Soils (Visual-Manual

Procedure) (ASTM, 2025). The terminology used in the soil and rock characterization and other modifiers are defined and presented on the attached Descriptive Terminology for Boring Logs, Boring Log Legend. Laboratory test results are presented in Attachment 3.

Soil and Rock

Subsurface conditions were inferred from the subsurface explorations, laboratory tests on select samples, and review of the geologic literature. The soil and rock units observed in the borings include overburden and residual soils, Miocene Grande Ronde Basalt, R2 unit (Tgr2), Permian to Cretaceous Gneiss and schist (KPgs), and Permian to Cretaceous Ultramafic rocks (KPum).

Material descriptions and thickness estimates are provided in Table 2, Table 3, and Table 4.

Overburden Materials

Table 2. Geotechnical Boring Locations and Depths

Boring Depth Range

(ft bgs)

Top EL

(ft)

Bottom EL

(ft) Material Description

BH24-01 0 to 20 5,244 5,224 Layers of silty SAND with gravel (SM), silty GRAVEL with sand (GM), SILT with sand and gravel (ML), and CLAY with sand and gravel (CL)

BH24-02 0 to 5.25 5,233 5,228 Layers of poorly graded GRAVEL with sand (GP) and silty GRAVEL with sand (GM)

BH24-03 0 to 5 5,289 5,284 Silty SAND with gravel (SM)

BH24-04 0 to 2.5 5,313 5,311 Poorly graded GRAVEL (GP)

BH24-05 -- -- -- --

BH24-06 -- -- -- --

BH24-07 0 to 1 5,289 5,288 TOPSOIL

BH24-08 0 to 5 5,259 5,254 Poorly graded GRAVEL with sand (GP)

BH24-09 0 to 1.5 5,298 5,297 TOPSOIL

B-1 -- -- -- --

B-2 0 to 1.5 5,296 5,295 Silty GRAVEL (GM)

B-3 0 to 25 5,285 5,260 Silty GRAVEL with cobbles (GM) and well graded

GRAVEL with silt and sand (GW-GM)

Notes: -- = Not Encountered

Columbia River Basalts (Primary Material Source)

Table 3. Geotechnical Boring Locations and Depths

Boring Depth Range

(ft bgs)

Top EL

(ft)

Bottom EL

(ft) Material Description

BH24-01 20 to 28 5,224 5,216 Strong (R4), fresh to slightly weathered BASALT

BH24-02 5.25 to 45 5,228 5,188 Medium strong to strong (R3 to R4), fresh to highly weathered BASALT

BH24-03 5 to 57.25 5,284 5,232 Strong (R4), fresh weathered BASALT

BH24-04 2.5 to 79 5,311 5,234 Strong (R4), fresh BASALT

BH24-05 0 to 56.5 5,304 5,248 Strong (R4), fresh to slightly weathered BASALT

BH24-06 0 to 40 5,284 5,244 Strong (R4), fresh BASALT

BH24-07 1 to 64 5,288 5,225 Strong (R4), fresh BASALT

BH24-08 5 to 35 5,254 5,224 Strong (R4), fresh BASALT

BH24-09 1.5 to 89.5 5,297 5,209 Strong (R4), fresh to slightly weathered BASALT

B-1 0 to 50 5,300 5,250 Strong to very strong (R4 to R5), fresh to slightly weathered BASALT

B-2 1.5 to 50 5,295 5,246 Strong to very strong (R4 to R5), fresh to slightly weathered BASALT

B-3 25 to 50 5,260 5,235 Strong to very strong (R4 to R5), slightly weathered BASALT

Metamorphic Rocks (Schist and Ultramafic Rock)

Table 4. Geotechnical Boring Locations and Depths

Boring Depth Range

(ft bgs)

Top EL

(ft)

Bottom EL

(ft) Material Description

BH24-01 28 to 66 5,216 5,178

Extremely weak (R0), highly to completely weathered SCHIST;

Very weak to strong (R1 to R4), moderately to highly weathered ULTRAMAFIC ROCK

BH24-02 45 to 50 5,188 5,183 Weak to medium strong (R2 to R3), highly weathered SCHIST

BH24-03 57.25 to 65 5,232 5,224 Extremely weak (R0), completely weathered

SCHIST

BH24-04 79 to 85 5,234 5,228 Extremely weak (R0), completely weathered

SCHIST

BH24-05 56.5 to 65 5,248 5,239 Extremely weak (R0), completely weathered

SCHIST

BH24-06 40 to 49.5 5,244 5,235 Extremely weak (R0), completely weathered

SCHIST

BH24-07 64 to 69 5,225 5,220 Extremely weak (R0), completely weathered

SCHIST

BH24-08 35 to 45 5,224 5,214 Extremely weak (R0), completely weathered

SCHIST

BH24-09 89 to 94.5 5,209 5,204 Extremely weak (R0), completely weathered

SCHIST

B-1 -- -- -- --

B-2 -- -- -- --

B-3 -- -- -- --

Notes: -- = Not Encountered

Groundwater

Unvented vibrating wire piezometers (VWPs) equipped with single-channel dataloggers were installed in borings BH24-01, BH24-04, and BH24-08 and secured in above-ground protective steel casings. Readings are being collected at 12-hour intervals since late July 2025. Table 5 summarizes the installations and the collected VWP readings.

Table 5. VWP Groundwater Measurement Depths and Elevations

Boring Surface EL

(ft.)(1)

Groundwater Levels

Date High EL

(ft)

Depth

(ft bgs)

Depth

(ft bgs)

Low EL

(ft) Date

BH24-01 5244 7/12/25 5,206.5 37.4 40.7 5,203.2 10/25/25

BH24-04 5313.5 7/31/25 5,254.8 58.6 64.8 5,248.6 10/25/25

BH24-08 5259 10/20/25 5,223.7 35.3 36.6 5,222.4 7/30/25

Notes: 1 – Based on NAVD88 GEOID18

These three months of data capture the anticipated seasonal low groundwater table typically occurring in the summer and fall and the groundwater levels would be expected to be higher in the winter and spring.

LABORATORY TESTING

In addition to this quarry expansion geotechnical investigation, WFLHD performed a limited site reconnaissance of Twin Cabins Quarry on October 10, 2024, and collected three samples of rock at the location (identified as Grab Sample) shown on Figure 1.3 in Attachment 1.

The following tests were completed on the collected rock samples from the geotechnical investigation and the limited site reconnaissance:

• Accelerated Weathering – D WMSO-19

• Soundness of Aggregate (Fine and Coarse) – AASHTO T 104

• Resistance to degradation by LA Machine – AASHTO T 96

• Aggregate Durability Index (Fine and Coarse) – AASHTO T 210

Laboratory test results are summarized in Table 6 below and the full reports are provided in

Attachment 3.

Table 6. Summary of Laboratory Test Results

Boring

Sample

Depth

(ft bgs)

AASHTO T210 AASHTO T104 Weathering

D WSMO‐19

AASHTO

T96(2)

(% Loss)

Fine(1)

Coarse(1)

Fine(1)

Coarse

BH24-02 13 to 37.5 31 63 9 2.4 1 19

BH24-03 5 to 28 49 68 9 2.1 0.9 13

BH24-04 42 to 67 27 63 11 1.5 0.7 14

BH24-05 21.8 to 48 27 63 10 1.5 1.4 15

BH24-06 7.8 to 33.5 30 73 6 1.2 1.3 16

BH24-07 32 to 54.5 32 76 8 1.3 0.7 15

BH24-08 5 to 29 25 60 17 5.8 2.3 21

BH24-09 56.5 to 81 27 58 12 6 4.8 19

S-1 N/A 37 -- 6 -- -- 14

S-2 N/A 34 31 27 4.9 4.5 16

S-3 N/A 23 59 20 3.5 1.8 15

Notes: 1 - Highlighted value indicates the result did not meet the minimum requirements for subbase, base, and surface coarse aggregate per FP-24 Section 703.05.

AASHTO T210 minimum percentage = 35%

AASHTO T104 maximum percentage = 12%

2 - Based on Grading “B”. Grading refers to the size distribution (sieve fractions) of the aggregate sample being tested. For a grading of “B”, 11 steel spheres are used and the test contains material passing the ¾ in. Sieve and retained on the 3/8 in. sieve.

MATERIAL QUALITY ASSESSMENT

The basalt samples test results indicate the material meets most quality requirements for subbase, base, and surface coarse aggregate. In our opinion, clay infilling in the rock core samples affected the laboratory results, leading to AASHTO T210 durability values below the minimum required percentages, primarily for fine fraction, in most of the tested samples. We consider the basalt rock, due to its high estimated uniaxial compressive strength (based on

ISRM [1978, 1981] field tests), is suitable as a material source and can be used on the project, if certain conditions are met:

• Basalt from the Twin Cabins Quarry should consist solely of sound basalt rock, excluding overburden or bank material.

• The coarse fraction (material retained on the No. 4 sieve) should be used as subbase, base, and surface course aggregate.

• Additional quality testing should be assumed. Please refer to the project SCRs in Section

105 for further guidance.

A summary of test results compared to material quality contract requirements is provided in

Attachment 4.

Additionally, based on the subsurface conditions encountered and the quarry expansion area:

• The estimated amount of available material is sufficient for constructing the NFSR 221 project.

REFERENCES

ALLWEST (2022) Preliminary Pit Evaluation, Twin Cabins Pit, Nez Perce-Clearwater National

Forest, Grangeville-Salmon Road, Vicinity of Grangeville, Idaho, ALLWEST Project No. 322-

111G.

ASTM International (ASTM), 2025, 2025 Annual Book of ASTM Standards, West

Conshohocken, Pennsylvania.

International Society for Rock Mechanics (ISRM). 1978. Commission on Standardization of

Laboratory and Field Tests. Suggested Methods for the Quantitative Description of

Discontinuities in Rock Masses, International Journal of Rock Mechanics, Minerals, Science, and Geomechanics Abstract. Vol. 15, pp 319-368.

International Society for Rock Mechanics (ISRM). 1981. Committee on Standardization of

Laboratory and Field Tests. Suggested Methods: Rock characterization testing, and monitoring. E.T. Brown, ed. Pergamon Press, London, Great Britian, pp 211.

Kauffman, J.D., et al. (2008) Geologic Map of the Goodwin Meadows Quadrangle, Idaho County, Idaho. Latitudes 43° - 44°, Idaho Geological Survey, Miscellaneous Investigation Series Map

I-1891.

CLOSING

Please contact Nicholas Ferreira at (360) 619-7816 or nicholas.ferreira@dot.gov or contact

Mark Swank at (360) 619-7946 or mark.swank@dot.gov with any questions regarding this memorandum.

Attachments:

Attachment 1 – Twin Cabins Quarry Vinicity Map, Site Map, and Sample Location Map

Attachment 2 – Twin Cabins Quarry Boring Logs, Rock Core Photographs, and

Summary Hydrograph

Attachment 3 – Laboratory Test Results

Attachment 4 – Comparison of Test Results to Material Quality Contract Requirements

ATTACHMENT 1

Twin Cabins Quarry Vicinity Map, Site Map, and Sample Location Map

610 East Fifth Street

Vancouver, WA 98661

FigureVICINITY MAP Project No.

ID NEZPR117 221 (1)

1.1

NATIONAL FOREST SYSTEM ROAD 221

REHABILITATION

IDAHO COUNTY, IDAHO

Scale

N/A

File Name:

FIGURE 1-1.PPTX

Date:

OCTOBER 2025

Vancouver, WA 98661

FIGURE TWIN CABINS QUARRY SITE MAP

Project No.

ID NEZPR117 221 (1)

1.2

NATIONAL FOREST SYSTEM ROAD 221

REHABILITATION

IDAHO COUNTY, IDAHO

Scale

N/A

File Name:

FIGURE 1-2.PPTX

AUGUST 2025

Vancouver, WA 98661

FIGURE TWIN CABINS QUARRY SAMPLE LOCATION MAP

Project No.

ID NEZPR117 221 (1)

1.3

NATIONAL FOREST SYSTEM ROAD 221

REHABILITATION

IDAHO COUNTY, IDAHO

Scale

N/A

File Name:

FIGURE 1-3.PPTX

OCTOBER 2025

ATTACHMENT 2

Twin Cabins Quarry Boring Logs, Rock Core Photography, and Summary Hydrograph

07/31/2024

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

SILTS 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

31 to 60 Hard

> 60 Very 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 Report Boring Logs Boring field descriptions are based on FLH Soil and Rock Description and Identification Guidelines that generally follow the Visual-Manual Procedure (ASTM D 2488) and International Society for Rock Mechanics (ISRM) standards. The soil classifications shown on the report boring logs are based on laboratory tests (ASTM D 2487), as indicated when the Group Symbol follows the Group Name.

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

07/31/2024

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 several 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 Identification 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

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

Extremely Closely Spaced

<3/4 inches (<20 mm)

APERTURE OPENING WIDTH

Description Width

Very Tight Less than

0.004 inches

Tight

0.004 to 0.02 inches

Moderately Open

51 to 750.02 to

0.10 inches

Open

0.10 to 0.40 inches

Wide Greater than

0.40 inches

ROCK QUALITY AND RQD %

Description Width

Very Poor 0 to 25

Poor 26 to 50

Fair 51 to 75

Good 76 to 90

Excellent 90 to 100

𝑅𝑅𝑅𝑅𝑅𝑅 (%) =

𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿ℎ 𝑜𝑜𝑜𝑜 𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 𝑖𝑖𝑖𝑖 𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝 > 4 𝑖𝑖𝑖𝑖. (100 𝑚𝑚𝑚𝑚)

𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿ℎ 𝑜𝑜𝑜𝑜 𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 𝑅𝑅𝑅𝑅𝑅𝑅 𝑥𝑥 100

𝐹𝐹𝐹𝐹 =

𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁 𝑜𝑜𝑜𝑜 𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛 𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓

𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙ℎ 𝑜𝑜𝑜𝑜 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟 (𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓)

𝐶𝐶𝐶𝐶 (%) = �

𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿ℎ 𝑜𝑜𝑜𝑜 𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅

𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿ℎ 𝑜𝑜𝑜𝑜 𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 𝑅𝑅𝑅𝑅𝑅𝑅 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷

� ∗ 100 ep th Sc al e

Sy m bo l

M et ho d

Au ge r ( H ol lo w -S te m

EL 5244 ftGround Surface

Material Description

Silty SAND with gravel; medium dense, brown, moist; low plasticity; fine to coarse sand; fine to coarse, subrounded to subangular gravel

7 ft EL 5237 ft

Becomes very loose

Silty GRAVEL with sand; loose, brown, moist; non-plastic; fine to coarse sand; fine to coarse, subrounded to subangular gravel

9.5 ft EL 5234.5 ft

SILT with sand and gravel; firm, gray-brown, moist; medium plasticity; fine to coarse sand; fine to coarse, subrounded to subangular gravel

12 ft EL 5232 ft

Silty GRAVEL with sand; loose, gray-brown, moist; low plasticity;

fine to coarse sand; fine to coarse, subrounded to subangular gravel

14.5 ft EL 5229.5 ft

Lean CLAY with sand and gravel; stiff, gray-brown, moist;

medium plasticity; fine to coarse sand; fine to coarse, subangular to angular gravel

17 ft EL 5227 ft

Well-graded silty GRAVEL with sand; medium dense, gray-brown, moist; non-plastic; fine to coarse sand; fine to coarse, subrounded to subangular gravel

Sa m pl es

No. Type

S-1

S-2

S-3

S-4

S-5

S-6

S-7

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

(53)

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5244 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-01

_Date Started:

_Date Completed:

2025-07-09 2025-07-09

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78200

-116.0677

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

1 of 4Page:

_while drilling _Hammer _Weight (lbs): 140 _Hammer _Efficiency (%): 85.1 th Sc al e

Sy m bo l

M et ho d

H Q

D ia m on d

C or in g

Au ge r ( H ol lo w -S te m

Material Description

MIOCENE GRANDE RONDE BASALT (Tgr2) BASALT; strong rock (R4), fresh to slightly weathered (I to II), dark gray; fine grained

DISCONTINUITIES: moderately spaced; good to fair condition;

moderately open to wide separation; partially filled with clay;

JRC 6 to 12

28 ft EL 5216 ft

PERMIAN TO CRETACEOUS GNEISS AND SCHIST (KPgs) SCHIST; extremely weak rock (R0), highly to completely weathered (IV to V), green

DISCONTINUITIES: moderately spaced; poor to very poor condition; tight to wide separation; partially filled with green to yellow sandy clay; JRC 0 to 2

Sa m pl es

No. Type

R-1

S-8

R-2

R-3

R-4

R-5

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

(53)

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5244 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-01

_Date Started:

_Date Completed:

2025-07-09 2025-07-09

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78200

-116.0677

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

2 of 4Page:

_while drilling th Sc al e

Sy m bo l

M et ho d

H Q

D ia m on d

C or in g

Material Description

SCHIST; extremely weak rock (R0), highly to completely weathered (IV to V), green

(continued) PERMIAN TO CRETACEOUS GNEISS AND SCHIST (KPgs) SCHIST; extremely weak rock (R0), highly to completely weathered (IV to V), green

DISCONTINUITIES: moderately spaced; poor to very poor condition; tight to wide separation; partially filled with green to yellow sandy clay; JRC 0 to 2

50 ft EL 5194 ft

PERMIAN TO CRETACEOUS ULTRAMAFIC ROCKS

ULTRAMAFIC ROCKS; very weak (R1) grading to strong (R4), moderately to highly weathered (IV), dark gray to black; coarse grained

Sa m pl es

No. Type

R-5

R-6

R-7

R-8

R-9

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5244 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-01

_Date Started:

_Date Completed:

2025-07-09 2025-07-09

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78200

-116.0677

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

3 of 4Page:

_while drilling th Sc al e

Sy m bo l

M et ho d

H Q

D ia m on d

C or in g

Material Description

(continued)

PERMIAN TO CRETACEOUS ULTRAMAFIC ROCKS

ULTRAMAFIC ROCKS; very weak (R1) grading to strong (R4), moderately to highly weathered (IV), dark gray to black; coarse grained

66 ft EL 5178 ft

Test Hole Terminated at 66 ft

Sa m pl es

No. Type

R-9

R-10

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5244 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-01

_Date Started:

_Date Completed:

2025-07-09 2025-07-09

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78200

-116.0677

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

4 of 4Page:

_while drilling th Sc al e

Sy m bo l

M et ho d

Au ge r ( H ol lo w -S te m

H

Q

D ia m on d C or in g

EL 5233.1 ftGround Surface

Material Description

Poorly-graded GRAVEL with sand; very dense, black, dry; non-plastic; fine to coarse sand; fine to coarse, angular gravel

3.8 ft EL 5229.3 ft

Silty GRAVEL with sand; very dense, black, dry; non-plastic;

fine to coarse sand; fine to coarse, subrounded to subangular gravel 5.25 ft

EL 5227.85 ftMIOCENE GRANDE RONDE BASALT (Tgr2) BASALT; strong rock (R4), fresh (I), dark gray

DISCONTINUITIES: very closely to extremely closely spaced;

good to fair condition; very tight to tight separation; partially filled with clay; JRC 4 to 12

Sa m pl es

No. Type

S-1

R-1

S-2

R-2

R-3

R-4

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

50/6

50/3

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

(100)

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5233.1 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-02

_Date Started:

_Date Completed:

2025-07-08 2025-07-08

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78130

-116.067

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

1 of 3Page:

_while drilling th Sc al e

Sy m bo l

M et ho d

H Q

D ia m on d

C or in g

Material Description

BASALT; strong rock (R4), fresh (I), dark gray

DISCONTINUITIES: becomes closely to very closely spaced;

good to poor condition; very tight to tight separation;

partially filled with gravelly clay; JRC 0 to 6

DISCONTINUITIES: becomes excellent to good condition

Becomes medium strong rock (R3), moderately to highly weathered (III to IV)

Sa m pl es

No. Type

R-5

R-6

R-7

R-8

R-9

R-10

R-11

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5233.1 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-02

_Date Started:

_Date Completed:

2025-07-08 2025-07-08

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78130

-116.067

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

2 of 3Page:

_while drilling th Sc al e

Sy m bo l

M et ho d

H Q

D ia m on d

C or in g

Material Description

BASALT; strong rock (R4), fresh to slightly weathered (I to II), dark gray

DISCONTINUITIES: becomes very closely spaced; fair to poor condition; very tight separation; partially filled with clay; JRC 0 to 4

(continued)MIOCENE GRANDE RONDE BASALT (Tgr2) BASALT; strong rock (R4), fresh (I), dark gray

DISCONTINUITIES: very closely to extremely closely spaced;

good to fair condition; very tight to tight separation; partially filled with clay; JRC 4 to 12

45 ft EL 5188.1 ft

PERMIAN TO CRETACEOUS GNEISS AND SCHIST

(KPgs) SCHIST; weak (R2) to medium strong rock (R3), highly weathered (IV), green

DISCONTINUITIES: moderately to very closely spaced; tight to moderately open separation; partially filled with clay; JRC 0 to 4 50 ft

EL 5183.1 ft Test Hole Terminated at 50 ft

Sa m pl es

No. Type

R-11

R-12

R-13

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5233.1 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-02

_Date Started:

_Date Completed:

2025-07-08 2025-07-08

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78130

-116.067

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

3 of 3Page:

_while drilling th Sc al e

Sy m bo l

M et ho d

H Q

D ia m on d

C or in g

Au ge r ( H ol lo w -S te m

EL 5289.5 ftGround Surface

Material Description

Silty SAND with gravel; very dense, dark gray, dry; non-plastic;

fine to coarse sand; fine to coarse, subangular gravel

5 ft EL 5284.5 ftMIOCENE GRANDE RONDE BASALT (Tgr2)

BASALT; strong rock (R4), fresh (I), dark gray; fine grained

DISCONTINUITIES: moderately to very closely spaced; good to fair condition; very tight to wide separation; JRC 6 to 10

DISCONTINUITIES: becomes JRC 6 to 12

DISCONTINUITIES: becomes JRC 4 to 6

DISCONTINUITIES: becomes partially filled with clayey gravel

DISCONTINUITIES: becomes JRC 10 to 12

DISCONTINUITIES: becomes JRC 4 to 10

Sa m pl es

No. Type

S-1

R-1

R-2

R-3

R-4

R-5

R-6

R-7

R-8

R-9

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

50/3

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

(100)

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5289.5 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-03

_Date Started:

_Date Completed:

2025-07-12 2025-07-12

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78270

-116.0659

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

1 of 4Page:

_while drilling th Sc al e

Sy m bo l

M et ho d

H Q

D ia m on d

C or in g

Material Description

BASALT; strong rock (R4), fresh (I), dark gray; fine grained

DISCONTINUITIES: becomes moderately to very closely spaced; good condition; tight to wide separation; JRC 4 to 10

DISCONTINUITIES: becomes JRC 2 to 6

DISCONTINUITIES: becomes moderately open to wide separation; JRC 8 to 12

DISCONTINUITIES: becomes JRC 8 to 12

Sa m pl es

No. Type

R-10

R-11

R-12

R-13

R-14

R-15

R-16

R-17

R-18

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5289.5 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-03

_Date Started:

_Date Completed:

2025-07-12 2025-07-12

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78270

-116.0659

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

2 of 4Page:

_while drilling th Sc al e

Sy m bo l

M et ho d

H Q

D ia m on d

C or in g

Material Description

BASALT; strong rock (R4), fresh (I), dark gray; fine grained

DISCONTINUITIES: becomes moderately to very closely spaced; good condition; open to wide separation; partially filled with clayey gravel; JRC 2 to 6

(continued)MIOCENE GRANDE RONDE BASALT (Tgr2) BASALT; strong rock (R4), fresh (I), dark gray; fine grained

DISCONTINUITIES: moderately to very closely spaced; good to fair condition; very tight to wide separation; JRC 6 to 10

57.25 ft EL 5232.25 ft

PERMIAN TO CRETACEOUS GNEISS AND SCHIST (KPgs)

Sa m pl es

No. Type

R-19

R-20

R-21

R-22

R-23

R-24

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5289.5 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-03

_Date Started:

_Date Completed:

2025-07-12 2025-07-12

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78270

-116.0659

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

3 of 4Page:

_while drilling th Sc al e

Sy m bo l

M et ho d

H Q

D ia m on d

C or in g

Material Description

SCHIST; extremely weak rock (R0), completely weathered (V), green

DICONTINUITIES: becomes moderately spaced; open separation; JRC 0

(continued) PERMIAN TO CRETACEOUS GNEISS AND SCHIST (KPgs)

65 ft EL 5224.5 ft

Test Hole Terminated at 65 ft

Sa m pl es

No. Type

R-25 Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5289.5 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-03

_Date Started:

_Date Completed:

2025-07-12 2025-07-12

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78270

-116.0659

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

4 of 4Page:

_while drilling th Sc al e

Sy m bo l

M et ho d

H Q

D ia m on d

C or in gAu ge r (

H ol lo w

-S te m

EL 5313.5 ftGround Surface

Material Description

Poorly graded GRAVEL; very dense, gray, dry; non-plastic; fine to coarse sand; fine to coarse, angular gravel

2.5 ft EL 5311 ftMIOCENE GRANDE RONDE BASALT (Tgr2)

BASALT; strong rock (R4), fresh (I), dark gray; fine grained

DISCONTINUITIES: closely to very closely spaced; good to poor condition; very tight to wide separation; partially filled with clay;

JRC 4 to 10

DISCONTINUITIES: becomes JRC 8 to 12

DISCONTINUITIES: becomes JRC 2 to 6

DISCONTINUITIES: becomes JRC 8 to 12

Sa m pl es

No. Type

S-1

R-1

R-2

R-3

R-4

R-5

R-6

R-7

R-8

R-9

R-10

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in 50/1

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

(300)

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5313.5 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-04

_Date Started:

_Date Completed:

2025-07-23 2025-07-23

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78220

-116.0648

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

1 of 5Page:

_while drilling th Sc al e

Sy m bo l

M et ho d

H Q

D ia m on d

C or in g

Material Description

BASALT; strong rock (R4), fresh (I), dark gray; fine grained

DISCONTINUITIES: becomes moderately to very closely spaced; good to poor condition; very tight to wide separation; JRC 2 to 8

DISCONTINUITIES: becomes JRC 8 to 12

DISCONTINUITIES: becomes JRC 6 to 10

(continued)

Sa m pl es

No. Type

R-11

R-12

R-13

R-14

R-15

R-16

R-17

R-18

R-19

R-20

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5313.5 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-04

_Date Started:

_Date Completed:

2025-07-23 2025-07-23

Haztech_Driller Company:

Nicholas Ferreira_Logger Name:

Latitude:

Longitude:

45.78220

-116.0648

Drill:

_Hammer Type:

CME850

Automatic

Station: Offset:

Instrumentation/Notes:

2 of 5Page:

_while drilling th Sc al e

Sy m bo l

M et ho d

H Q

D ia m on d

C or in g

Material Description

MIOCENE GRANDE RONDE BASALT (Tgr2) BASALT; strong rock (R4), fresh (I), dark gray; fine grained

DISCONTINUITIES: closely to very closely spaced; good to poor condition; very tight to wide separation; partially filled with clay; JRC 4 to 10 79 ft

EL 5234.5 ft

DISCONTINUITIES: becomes JRC 2 to 10 BASALT; strong rock (R4), fresh (I), dark gray; fine grained

DISCONTINUITIES: becomes moderately to very closely spaced; good condition; very tight to wide separation; JRC 4 to 8

DISCONTINUITIES: becomes JRC 6 to 12

DISCONTINUITIES: becomes JRC 2 to 8

Sa m pl es

No. Type

R-21

R-22

R-23

R-24

R-25

R-26

Bl ow

Co un ts pe r6 in Bl ow

Co un ts pe r6 in

Re co ve ry

RQ

D

Blowcount Plot

10 20 30 40

Atterberg Limits & Moisture Plot

20 40 60 80

WPL WLLW

R

SL

og

FH

W

A Bo rin g

Lo g

R ev is io n

- J ul y fh w a / N ic ho la s.

Fe rre ira

N ov em be r 0 4, :4

PM

ID FS NEZPR117 221(1)_Project No.:

_Project Name:

_Surface Elev.:

_Groundwater _Depth (ft):

Twin Cabins Quarry

5313.5 ft

BORING LOG

US Department of Transportation

Federal Highway Administration Federal Lands Highway DivisonBH24-04

_Date Started:

_Date…