B08_SOL_ATT-2_(Exhibit_9).pdf

Form 3060-1 (July 1984)

UNITED STATES

DEPARTMENT OF THE INTERIOR

BUREAU OF LAND MANAGEMENT

MINERAL REPORT

Serial Number

(IDID106088828)

Mineral Potential Report For

Proposed Land and Water Conservation Fund Acquisition of Private Lands Along Picket Pin Creek in the Boise Foothills.

IDID106088828

Ada County, Idaho

LANDS INVOLVED

Boise Meridian, T. 3 N., R. 3 E., Sec 8, S½NW¼NE¼, NE¼NW¼NE¼

Consisting of 30.37 acres more or less

Prepared By:

(Signature)

(Title)

(Date)

Technical Approval:

(Signature)

(Title)

Management Acknowledgement:

(Signature)

(Title)

U.S. Government Printing Office: 1994-573-004/01002

Harrison Huttanus

Geologist, Four Rivers Field Office

Chief Mineral Examiner, CRME 033

4/10/25

4/11/25

HARRISON

HUTTANUS

Digitally signed by HARRISON

HUTTANUS

Date: 2025.04.10 17:21:52 -06'00'

Rocky Canyon Mineral Potential Report – (IDID106088828)

Executive Summary for Managers Summary Conclusions Recommendations

1.0 Introduction

2.0 Land Status and Record Data

2.1 Lands Involved

2.2 Land Uses, Rights of Way, Claims/Leases/Permits, and Other Concerns

3.0 Description of Subject Site and Geology

3.1 Physiography

3.2 Geologic Setting and Historical Geology

3.3 Site Geology and Rock Units

4.0 Description of Energy and Mineral Resources

4.1 Production History and Known Mineral Deposits

4.2 Mineral Exploration and Development Work

5.0 Potential for the Occurrence of Mineral Resources

5.1 Coal

5.2 Oil and Gas

5.3 Geothermal

5.4 Phosphate, Sodium and Potassium

5.5 Locatable Minerals

5.6 Critical Mineral

5.7 Uranium and Thorium

5.8 Mineral Materials

References Appendix A: Land Patent for Subject Lands Appendix B: Active BLM Mining Claim Data for Surrounding Lands Appendix C: Claims Recordation Notices from State of Idaho Historic Archives Appendix D: Nearby Closed Federal Oil & Gas Leases Appendix E: Water Well Drillers Logs for Wells Adjacent to the Subject Lands

Executive Summary for Managers

Summary

This mineral potential report was prepared for the United States Department of the Interior, Bureau of Land Management (BLM) for private lands that are proposed for acquisition by the Federal government using the Land and Water Conservation Fund (LWCF). The purpose of the report is to: (1) identify mineral potential to assist in establishing fair market value of the land; (2) assist the authorized officer in giving consideration of the mineral potential of the land when considering the public interest, management needs, and alternatives to the proposed acquisition; and (3) identify any mineral concerns in acquiring the land (e.g., potential liabilities associated with the mineral estate; surface uses that would interfere with the development of the mineral estate; etc.). The subject lands consist of approximately

12.29 hectors (30.37 acres) 1 of private land.

Conclusions

Coal This report concluded that there is no potential for coal resources within the subject lands because none of the sedimentary sequences capable of containing coal are located within the subject lands.

Furthermore, the igneous rocks found within the subject lands would have destroyed any beds that might have existed prior to the volcanism that formed the granitic rocks now found within the subject lands.

Oil & Gas This report concluded that there is no potential for oil and gas resource within the subject lands because none of the sedimentary sequences capable of forming or capturing oil and gas resources exist within the subject lands. Furthermore, the igneous rocks found withing the subject lands would have destroyed any oil or gas deposits that might have existed prior to the volcanism that formed the granitic rock not found within the subject lands.

Geothermal This report concluded that there is moderate potential for geothermal resources to exist in the subject lands. National Renewable Energy Laboratory (NREL) data projects the subject lands as having a 1000 m (3281 ft) reservoir temperature of up to 75° C (167° F). According to the U.S. Department of Energy the fluid temperature should be at least 149° C (300° F) but could be as low as 107° C (210° F) for a geothermal plant to operate (NREL, 2018). It is unlikely that geothermal resources capable of supporting power production exist in the site, but it is possible that a resource capable of supporting direct heating might exist within the subject lands.

Phosphate, Sodium, and Potassium This report concluded that there is no potential for Phosphate, Sodium, or Potassium resources to exist in the subject lands because none of the sedimentary sequences capable of hosting such deposits exist onsite, and the granitic rock of the Idaho Batholith don’t contain any of the igneous rock types associated with such resources.

Locatable & Critical Minerals This report concluded that there is moderate potential for locatable mineral and low potential for critical mineral resources to exist in the subject lands. There are no known locatable mineral deposits within the

1 Metric units are used in this report pursuant to 15 USC 205a et seq but are followed by the equivalent Imperial units in brackets to conform to land survey, topographic map, and mining data.

subject lands. However, there are four historic gold mines located less than 1.6 km (1 mile) away from the subject lands. These mines were last reported to be active in early 1900s and were reported to be producing ore2 which averaged 4.51-49.66 g/t (0.15-1.60 oz t./ton) of gold. The potential for locatable mineral resources within the subject lands is based on the proximity to historically active mining sites, and the possibility that undiscovered gold mineralization exists in the subsurface of the subject lands.

The only listed critical mineral known to occur in the Boise Ridge is zinc, but there is no data on if any was historically produced from the area.

Uranium and Thorium This report concluded that there is low potential for uranium and thorium resources to exist in the subject lands because they contain Idaho Batholith rocks which are the source of the radioactive placer deposits that are attributed to the uranium and thorium potential of the western Snake River Plain region.

However, none of the placer deposits themselves exist in significant quantities within the subject lands so the potential for these resources is low.

Mineral Materials This report concluded that there is moderate potential for mineral material resources within the subject lands. None of the deposits that are being utilized locally as an aggregate source exist in the subject lands, but the granitic rocks present throughout the site are themselves considered a low-quality mineral material and might see limited use.

Table 1. below summarizes the site’s potential for the mineral commodities addressed within this report.

Each commodity is subject to different disposal laws and regulations within the United Sates. The first letter reflects the potential for a mineral commodity and the letters are associated with the following potentials, O = no potential, L = low potential, M = moderate potential, H = high potential, ND = potential not determined. The second letter reflects the level of certainty given to the mineral potential classification based on the amount of data available and the letters are associated with the following levels of certainty, A = data insufficient, B = low certainty, C = moderate certainty, D = high certainty.

Table 1: Summary of Mineral Potential

Coal Oil & Gas Geothermal Sodium and Potassium

Locatable (& Critical)

Minerals

Uranium and

Thorium

Mineral Materials

O-D O-D M-B O-D M-C (& L-C) L-B M-C

Recommendations

1) No additional mineral evaluation/exploration of the subject land should be made pursuant to the proposed acquisition of the land by the U.S.

2) The U.S. should determine if the mineral estate is owned by the same party as the surface estate and if so, acquire the mineral estate of the land per BLM policy pursuant to the proposed acquisition of the land by the US (BLM 2005).

3) The BLM should confirm that title to the land is not encumbered by any mineral actions such as a non-Federal mineral lease. (No State leases were found by this report, but a private agreement might be in place.)

4) There is no reason from a mineral perspective why the U.S. should not acquire the subject land.

2 The term ore herein refers to a concentration of a mineral which has or has had a reasonable economic potential to make a profit.

1.0 Introduction

This report describes the mineral potential of a parcel of privately owned land3 that is the subject of a proposed LWCF acquisition. This report has been prepared in accordance with the requirements of the Federal Land Policy and Management Act of 1976 Section 205: Acquisitions. The subject lands are located approximately 6.4 km (4 miles) east of the Idaho State Capital Building in the Boise Foothills and just south of a historic toll road leading to Idaho City, Idaho.

The term mineral herein refers to all energy and mineral resources, whether solid, fluid, locatable, leasable, or salable. The term mineral potential refers only to the potential for the occurrence of a concentration of a mineral resource. The term does not imply that such occurrence might have potential for economic extraction and milling, processing, or refining. The term known mineral value means a mineral right in land containing a geologic formation valuable in the monetary sense for exploring, developing, or producing a natural mineral deposit (43 CFR 2720.0-5).

Source information used for the writing of this report was gathered from the BLM Boise District Library, accessing available United States Geologic Survey (USGS) reports, accessing available reports on the Idaho Geologic Survey (IGS) Website, reviewing past mineral potential reports for the general area and performing online searches for any other scholarly articles available. After the preliminary research was conduction on the subject lands, the subject lands were field examined on October 22, 2023, to document the physiography, evaluate the surficial geology, and evaluate potential for locatable, leasable, and salable mineral resources based on any surface exposures. Bureau of Land Management, Four Rivers Field Office geologist, Harrison Huttanus, conducted the field examinations. Photos taken during the field examination are provided below and they show the vegetative cover, topography and the lack of abundance of geologic outcrops present on the subject lands (see Photo 1 and Photo 2 below).

2.0 Land Status and Record Data

2.1 Lands Involved

The subject lands are located entirely in Ada County, Idaho, approximately 6.40 kilometers (3.98 miles) east of the city of Boise. There is no public driving access to the site, but the site can be reached on foot by driving east from the Boise Capitol Building to the Five Mile Gulch #2 trailhead. From the Capitol Building proceed 0.8 km (9.2 miles) southeast on State St. then turn northeast on Reserve St. and proceed for 730 m (2,395 ft) until turning southeast onto Shaw Mountain Rd (also called Rocky Canyon Rd). Once on Shaw Mountain Rd. proceed for 7.9 km (4.9 miles) until reaching the Five Mile Gulch #2 trailhead. There is not currently a trail that leads to the subject lands but from the trailhead one can walk cross-country for about 1.7 km (1.06 miles) southwest at a heading of 220 degrees across BLM administrated lands to reach the subject lands. Map 1. Below shows the location of the subject lands in relation to the city of Boise.

The legal land description for the subject land is the S½NW¼NE¼, NE¼NW¼NE¼, of Section 8, Township 3 North, Range 3 East, Boise Meridian which encompasses approximately 12.29 hectors (30.37 acres) of land and is comprised of a single contiguous parcel. A copy of the original land patent can be found in Appendix A of this document which shows that the U.S. did not retain any mineral rights for the subject lands.

3 land herein refers to land or interests in land including minerals, water rights, timber, conservation easements, etc.

Map 1: Subject Land Location Map.

Map is projected on a composite of USGS 7.5-minute quadrangle topo maps. (Map created on 2025-04-03 by H. Huttanus)

Site Photographs

Photo 1: Northwest facing view of the subject lands as seen when standing at the southeast corner of the land. The red lines are a rough outline of the property which have not been corrected for topography.

(Photo taken 2023-10-22 by Harrison Huttanus)

Photo 2: Southeast facing view of the corner post at the lower (southernmost) northwest corner of the subject lands. (Photo taken 2023-10-22 by Harrison Huttanus)

2.2 Land Uses, Rights of Way, Claims/Leases/Permits, and Other Concerns

The BLM land status records of the subject lands were examined and show that both surface and mineral estate are owned by a private party. It is currently unknown whether the surface owner also owns the mineral estate. The subject lands are not subject to any Federal mineral leases and because they are privately owned there are no mining claims on the lands either. There are no active, closed, or pending mineral resource projects within or adjacent to the subject lands, but there are two historic mineral exploration notices, and one authorized mining plan of operations on the Adelmann Mine which is located 6.25 km (3.88 miles) west southwest of the subject lands. The BLM mining claim records for both the Boise meridian, T. 3 N., R. 3 E. & T. 4 N., R. 3 E. show that there are currently sixteen active mining claims on both BLM and Forest Service lands in the two townships surrounding the subject lands as shown in Appendix B.

Four Rivers Field Office staff geologist Harrison Huttanus visited the State of Idaho’s Historic Archive on June 16, 2024, and reviewed the “quartz” (lode) mining claims recordation books for any claims that appeared to be located within the subject lands. No location maps were found for the claims, so the location notices had to be reviewed for land features and location names to get an approximate idea of the area where the claims were located. Nineteen mining claims were found that appeared to have been located for the lands between Picket Pin Creek and the old Idaho City toll road (now Rocky Canyon Rd.). Based on the location notices seems likely that there were mineral interests for the subject lands in the past but given that the land patent was issued under the 1862 Homestead Act and not through a mining claim patent it seems evident that the primary usage of the land had switched from mining to agriculture by 1923 when the land patent was issued. Appendix C contains copies of the “quartz” (lode) mining claims that appear to have been located in the vicinity of the subject lands.

Idaho Department of Lands records were checked for any mineral leases in the area and one State of Idaho mineral lease was found for lands 8 km (4.97 miles) south southwest of the subject lands (IDL, 2025). That State mineral lease is for a gravel quarry extracting sediments located down in the Snake River Plain. There are no Federal mineral leases or mineral material sales in the area surrounding the subject lands. The closest Federal Mineral Leases are some 56.3 km (35 miles) to the northwest and are Oil & Gas leases in the Payette, Idaho area. These Oil and Gas leases are located in a separate sedimentary basin along the Payette River. Several Federal Oil and Gas leases were issued between 1982 and 1983 which were located 7.7 km (4.8 miles) to the south and 8.9 km (5.5 miles) to the northwest, but none of those leases ever went into produced and they were all closed a few years after they were issued. See Appendix D for copies of the Federal oil & gas lease’s serial register pages.

There is currently a power transmission line running north to south across the subject lands. There is a BLM right of way issued for this power line (serialized IDID105996403) for the BLM administrated lands north of the subject lands. No supports for this transmission line are currently situated in the subject lands as said lands encompass the valley bottom along Picket Pin Creek and the subject lands do not extent to the ridge tops where the power line’s support structures currently lie.

The subject lands lay adjacent to the BLM’s Boise Front Area of Critical Environmental Concern (Boise Front) as designated in the Four Rivers Field Office Resource Management Plan Record of Decision (BLM, 2023). Currently there are no restrictions for salable or locatable minerals in the Boise Front, but there is a no surface occupancy restriction on all leasable minerals withing the Boise Front (BLM, 2023). It is unknown whether the subject lands would be incorporated into the Boise Front.

The subject lands lay within the area covered by the State of Idaho’s Geothermal Groundwater development moratorium (IDWR, Moratorium Orders, 2024). This moratorium puts a halt on any further development of the geothermal water resources in the area surrounding the city of Boise in an effort to mitigate the decline in the geothermal aquifer’s water level.

3.0 Description of Subject Site and Geology

3.1 Physiography

The subject lands are situated at an elevation of about 1,097 m (3,600 ft) and are located near the boundary between the Payette Section of the Columbia Plateau physiographic province (or Western Snake River Plain), and the Northern Rocky Mountain physiographic province (Fenneman & Johnson, 1946). Physiographic provinces are regions which can be delineated by similar terrain characteristics and were shaped by a common geologic history. The subject lands lie at about the halfway elevation between the Snake River Plain to the southwest and the Boise Ridge to the northeast in an area locally known as the Boise Foothills or Boise Front. The land uses of Boise Foothills are primarily recreational, but both sheep & cattle grazing and smaller agricultural developments growing hay or grains are common is some of the high valleys (Ross & Savage, 1967).

The Boise Foothills mark the southwestern boundary of the Northern Rocky Mountain region, which is characterized by high, massive mountains and deep intermontane valleys. The entire Northern Rocky Mountain province shows a general northwest-southeast trend and much of Central Idaho’s mountain country is underlain by dissected granitic rocks of the Idaho batholith, but Precambrian rocks of the Belt Supergroup dominate much of the northern part of the province (Ross & Savage, 1967).

The Western Snake River Plain lies to the southwest of the subject lands and is characterized by thick lacustrine and fluvial sediments that are extensively interbedded with basalt flow. Much of the relatively level areas within the Snake River Plain have been reclaimed from wasteland and have been placed under irrigation as the silty sediments in the plain have proven to be highly productive. Within this section is the largest population concentration in Idaho, the most intensively developed agricultural lands, many industrial operations, and the State capitol city of Boise (Ross & Savage, 1967).

The climate in the area is relatively mild and dry seeing a mean annual temperature of 10.6 °C (51 °F), mean annual precipitation 29.2 cm (11.5 inches) (Ross & Savage, 1967). The higher elevations of the Boise Foothills are dominated by stands of Douglas-fir, ponderosa pine, lodgepole pine, and various other fir specie. Whereas the middle and lower elevations are host to more of a shrub-steppe ecosystem.

The major shrub species in these communities are big sagebrush (Artemisia tridentata), low sagebrush (Artemisia arbuscula), grey and green rabbit-brush (Chrysothamnus viscidiflorus and Ericameria nauseosa), and bitterbrush (Purshia tridentata). Several perennial bunchgrasses co-dominate sagebrush-steppe communities. The main native species are bluebunch wheatgrass (Pseudoroegneria spicata), Sandberg bluegrass (Poa secunda), bottlebrush squirreltail (Elymus elymoides), Thurber’s needlegrass (Achnatherum thurberianum), Idaho fescue (Festuca idahoensis), bulbous oniongrass (Melica bulbosa), basin wildrye (Leymus cinereus), mountain brome (Bromus marginatus), and the major non-native seeded species are crested wheatgrass (Agropyron cristatum), Russian wildrye (Psathyrostachys juncea), and bulbous bluegrass (Poa bulbosa, which can be annual, biennial, or short-lived perennial, and is no longer intentionally seeded). Forbs are the most diverse group of vascular plants in shrub-steppe communities. Some common genera are biscuitroot, hawksbeard, onion, balsamroot, and phlox (BLM, 2020).

3.2 Geologic Setting and Historical Geology

The subject lands are located within the Payette Section of the Columbia Plateau physiographic province just southwest of the Northern Rocky Mountains Province. More specifically the subject lands lay within the granitic rocks of the Idaho Batholith just north of the Western Snake River Plain on the foothill leading, northeast, into the mountains of the Idaho Batholith. Map 2 below shows that the subject lands located within the granitic rocks of the Idaho Batholith, but that they are very near the sedimentary rocks associated with the Western Snake River Plain.

The Columbia Intermontane Province, Columbia Plateau, is generally characterized by large areas basalt flows that are seldom more than 30.5 m (100 ft) thick for a signal flow, but combined they average several thousands of feet in thickness. Most of the basalt flows are associated with two major periods of volcanic activity, Miocene to Pliocene and Pliocene to Recent (Ross & Savage, 1967). The Western Snake River Plain within the Columbia Plateau is a rift or graben-like structural low with synclinal features that make exact geologic interpretations difficult. This large structural low is partially filled with basalt flows and continental sediments of Miocene to recent age that extend to below sea level.

Silicic volcanics underlay these formations and may in turn be underlain by earlier basalts (Mabey, 1982). Some interpretations of the Western Snake River Plain tie the feature into plate tectonic models involving righting and/or a migrating hot spot.

The Northern Rocky Mountain Province is generally characterized as containing massive mountains with deep intermontane valleys. In the southcentral region of Idaho, the Northern Rocky Mountain Province consists of mostly the granitic intrusive rocks of the Idaho Batholith, but portions are overlain with extrusive volcanic rocks associated with either the Columbia River Basalts or the Challis Volcanics (Ross & Savage, 1967). The Idaho Batholith was formed by a period of deep granitic intrusions that occurred in the late Cretaceous and formed a massive region of granitic rock which spans the eastern edge of Idaho for over 482 km (300 miles) north-south and is over 129 km (80 miles) wide. The area of the present-day batholith was then uplifted, and the deep granitic basement rock was exposed by the early Eocene (Link & Hackett, 1988).

3.3 Site Geology and Rock Units

Within the foothills leading up to the Boise Ridge the geologic units are not very complex in their variety. The vast majority of the lands both north and east of the subject lands along with the majority of the subject lands themselves are composed almost entirely of the igneous rocks of the Idaho Batholith.

In this area of the Idaho batholith the rocks are composed of muscovite and biotite granite or granodiorite that is occasionally cut by various veins or dikes (Lindgren & Knowlton, 1898). Another igneous unit mapped in the area of the subject lands is the basalt of the Picket Pin Canyon (Othberg & Stanford, 1992). The Picket Pin basalts are easily identified by the presence of small rosettes of white plagioclase that occur within the rocks. These basalts were canyon filling and mapped on a series of ridge tops starting just northeast of the subject lands and continuing in a generally south-southwest direction from there. Lastly, the bulk of the other geologic units mapped in the immediate vicinity of the subject lands are all sedimentary units associated with the erosion of the two ingenious units described above. Map 3 below depicts the subject lands overlaid on the more detailed geologic mapping completed by the Idaho Geological Survey in the early 90s (Othberg & Stanford, 1992).

The sedimentary units mapped within a few miles of the subject lands can be broken down into three main categories. First, there are the alluvial fan and talus deposits that represent the most recently eroded materials form the Idaho batholith. Next, there are perched gravel deposits also derived from the granites which have mostly collected along the down dropped side of the normal faults that occur within the

Map 2. Regional Geologic Map

Map shows geologic data from Idaho Geologic Survey, Statewide Geologic Map. (Created on 2025-04-03 by H. Huttanus) lower portions of the Boise Foothills west of the subject lands. Lastly, there are some volcaniclastic sediments and tuffs associated with more recent and generally mafic eruptions.

The subject lands were field examined on October 22, 2023, and during that examination it was noted that most of the surface of the subject lands they are covered by unconsolidated sediments which obscure the bedrock making it difficult to determine where any contacts would occur between the potentially different rock types that might exist withing the subject lands. These sediments are light tan in color and are composed of approximately 10 percent disintegrated angular granite fragments ranging in size from medium sized sand particles to pebble sized particles with occasional rounded pebbles and cobbles in float. The other 90 percent of the sediment cover were noted as clay to silt sized particles which comprised most of the topsoil present in the site. All exposed outcrops within the subject lands were composed of the two-mica granite (granite containing biotite and occasionally muscovite) that is typical for the Idaho Batholith in this area of Idaho. There were no well exposed cut banks on the hill side or along Picket Pin Creek which might have given an approximation of the average thickness of the topsoil covering the site, but the U. S. Department of Agriculture Natural Resources Conservation Service soil data was consulted and it shows that the average soil thickness in this part of the Picket Pin Canyon is generally between 66 to 129.5 cm (26 to 51 inches) thick on the south facing slopes and between 198 to 350 cm (78 to 138 inches) thick on the north facing slopes (NRCS, 2019).

4.0 Description of Energy and Mineral Resources

4.1 Production History and Known Mineral Deposits

General mining exploration has occurred in the Snake River Plain for over 100 years. Sand and gravel and silica sand deposits have been the most important mineral deposits in the Snake River Plain.

Extensive use of these resources is expected to continue. Lode and placer gold mining has occurred in the areas north of the Snake River Plain with the bulk of the gold produced coming from the Boise Basin’s placer mines located 33.8 km (21 miles) to the northeast of the subject lands, but mining in these areas has significantly dropped since the 1940s (USGS, 1964).

Coal Coal beds are known to have existed 27.7 km (17.2 miles) to the northwest of the subject lands in the Horseshoe Bend Mining District (Bowen, 1913). The coal beds in that district occurred within a part of the Payette Formation which is confined to a north-south section of the Payette River that lies upstream of Horseshoe Bend, Idaho. The Payette formation is about 12.9-14.5 km (8-9 miles) long and between 1.6-6.4 km (1 to 4 miles) wide and has been dated to the upper Eocene base on Fossil evidence. The coal in this formation consists of thin beds at most 35.6 cm (14 inches) thick of subbituminous coal and lignite. These coal beds are no longer under production and there is no indication for why the district became inactive, but most likely the lack of modern production in due to the thin bedded and low quality nature of the coal that was found in the area.

Oil & Gas Two gas producing field have been developed in the Payette, Idaho area 90 km (56 miles) to the northwest of the subject lands, and a few other wells have detected some potential for additional fields in the Snake River Plain (Breedlovestrout, 2017). The gas producing fields in the Payette area are still in production to this day (IDL, 2025).

Map 3. Fine Scale Site Geologic Map.

Map is projected using data from Idaho Geological Survey, Boise Valley map (Othberg & Stanford, 1992) (Created by H.

Huttanus on 2025-04-03)

Map Unit Descriptions:

Ql – Landslide Deposits - Highly variable rock and soil masses varying from transported coherent blocks to unsorted, unstratified colluvium. Includes scar area at the head of the landslide. Derived from slumps, slides, and debris flows.

Most slides represent slope failures within basaltic tuff (Tbt) and surface soils of granitic rocks.

Qg – Gravel of Boise Front Terraces, Undivided – Sandy Pebble and cobble gravel with subangular boulders, Thickness 1- 6 meters, (3-20 ft) thick. Forms terraces along canyons and gulches and on flat divides near the merging of the foothills.

Tpb – Basalt of the Picket Pin Canyon – Dark gray basalt flow with a cumulo-phyric texture of distinctive rosettes of white plagioclase., Position suggests inverted topography of a canyon-filling lave, maximum thickness in 9 meters (30 ft).

Tf – Alluvial Fan Deposit – composed of poorly sorted, silty and sandy gravels with subangular cobbles and boulders in crudely stratified layers and lenses; mostly oxidized to a red brown near the surface. Alluvial fan remnants deposited by debris flows and ephemeral streams from foothills. Up to 61 meters (200 ft) thick.

Tbt – Tuff and volcaniclastic sediments – brown basaltic tuff and volcaniclastic sediments. Minor beds of arkosic sand, pumice, and rhyolitic ash. Up to 107 meters (350 ft) thick.

Tr – Rhyolite of The Boise Front - Pinkish gray porphyritic rhyolite, dark gray vitrophyre, and gray perlite.

Ts – Sand and Mudstone of Stream and Lake Sediments – Medium to coarse-grained arkosic sand, sandstone, and claystone. Includes interbeds of fine gravel, locally cemented, and sandy siltstone. Structures vary from large foreset beds of sand to thin-bedded claystone, Undifferentiated unit reflects a variety of stream and lake depositional environments along the northeastern and southwestern margin of the ancestral western Snake River Plain. Includes parts of the Payette, Poison Creek, and Succor Creek Formations, the tuffaceous sediments of Ferns (1989), and the Terteling Springs Formation of W.L. Burnham and S.H. Wood (written communication- unpublished manuscript).

g – Granitic Rocks of the Idaho Batholith – light gray biotite granite and granodiorite. Medium to coarse grained and equigranular to porphyritic. Includes pegmatite zones and dikes of rhyolite and basalt.

Geothermal Geothermal well drilling has been conducted in the region surrounding the subject lands mostly centered within a short distance of downtown Boise 6.40 kilometers (3.98 miles) to the west. The Boise area has seen extensive geothermal development since as early as 1890, but the hot water aquifer levels had dropped by as much as 15.24 m (50 ft) by the mid-1980s (Wood & Burnham, 1987). In 1987 the water resources in the Boise area were made part of the Boise Front Designated Groundwater Management Area by the Idaho Department of Water Resources, and in 1993 a moratorium was placed on further development of the geothermal resource which has persisted until present day (IDWR, Moratorium Orders, 2024). There has been no new development in the Boise area geothermal systems since 1999 when an injection well was installed in the cities heating systems and part of the Boise State University campus was added to existing heating system (Mink, 2017). In 1983 a geothermal well was drilled to 701 m (2300 ft) in the downtown Boise area. That well was shown to be producing waters from 73.9-

80.6 °C (165-177 °F) (Mink, 2017). A study of the geothermal system suggested that the hot waters were being supplied from upward flow through a series of faults along the Boise Foothills (Wood & Burnham, 1987). There has been moderate development of geothermal resources in the nearby area for building heating systems, but no geothermal power development has occurred in the Boise area.

Locatable Minerals The subject lands are located within the Shaw Mountain mining district (Gustafson 1987, Ross 1941) or within the Boise mining district according to earlier reports by the USGS (Lindgren & Knowlton, 1898).

The names for the Boise and Shaw Mountain districts are reversed between the 1898 and 1941 reports.

However, the geology and precious metal mineralization is consistent between the Boise, Shaw Mountain, and Black Hornet mining districts. All three districts border one another in the Boise foothills and are characterized by series of granite porphyry dikes, lamprophyre dikes, and quartz veins containing free gold and other sulfide minerals that are hosted in Idaho Batholith granitic rocks. The gold in these districts is contained in veins of mostly quartz ranging from 0.6 m (2 ft) to rarely 3 m (10

ft) thick and which averaged concentrations of 6.86-25.71 g/t (0.2-0.75 oz t./ton) (Ross C. P., 1941).

According to Ross the placer mining associated with these three mining districts has been negligible.

Critical Minerals Strategic and critical minerals must be discussed in detail if these minerals are present in quantities within 30 percent of the grade and size of deposits being commercially mined (BLM, 1994). No evidence was found in the literature searches for the production of critical minerals listed by either the USGS or the Department of Energy for the Boise Ridge area. Lindgren & Knowlton’s 1898 USGS report on the mining districts in Idaho did mention that the mineralization associated with the Boise, Shaw Mountain, and Black Hornet mining districts die contain a zinc blend within the sulfides associated with the gold bearing veins, but that report made no mention on if the zinc from those sulfides were ever recovered. The area closest to the subject lands that is known to host critical mineral are the placer deposits in the Boise Basin some 33 km (20.5 miles) to the northeast (Ross & Savage, 1967). Additional reports published by the Idaho Geological Survey in 2011, and 2024 indicate that the placer deposits in the Boise Basin are the closest know source of critical minerals to the subject lands (Gillerman, 2011), (Knudsen, Steven, Lewis, & Gillerman, 2024).

Uranium and Thorium The subject lands are located within a speculative uranium resource area within Region K of the National Uranium Resource Evaluation (NURE) datasets as depicted in Map 4. below (NURE, 1976).

This speculative resource area is approximately 57 km (35.42 miles) wide northeast to southwest and approximately 280 km (174 miles) long running along the Snake River Plan. The 1976 NURE report classifies the potential uranium resources of each region by stating the probable, possible & speculative amount of uranium that is expected to be found in the respective regions. Region K is listed as having only speculative resources of uranium. The Report shows that the Idaho Group (sediments from Pleistocene Lake Idaho) were projected to have a speculative resource of around 9,000 tons U3O8 at a $30/lbs. concentration. The Uranium resources attributed to this area by the NURE report were presumed to be mainly from Tertiary and Mesozoic nonmarine clastic rock of intermontane basins.

A report completed by the Idaho Bureau of Mines and Geology in 1957 analyzed the resource potential for recovering radioactive minerals from placer deposits originating from the Idaho Batholith (Mackin & Schmidt, 1957). This report indicates that monazite is the chief radioactive mineral that is recovered from the southern part of the batholith. The 1957 report focuses on samples taken from Cascade ID 101 km (63 miles) to the north, the Bear Valley 101 km (63 miles) to the northeast, and Haily, ID 150 km (93 miles) to the east of the subject lands, but no values were reported from the Boise area.

Mineral Materials The BLM has no active, mineral material sites in the Boise Ridge. The nearest mineral materials site is the Table Rock quarry 2.6 km (1.62 miles) to the southwest of the subject lands where a silicified sandstone is mined for the local market but this quarry has not been active since the early 1900s (Savage, 1958). Another economic source of minerals materials extraction in the area consists of removing decorative moss and lichen covered landscaping rock from the Boise Foothills, but based on the site survey conducted on October 22, 2023, there was no evidence of mineral materials onsite of the type and quality that has been mined in the nearby material sites. The major source of mineral materials in the Boise area are sourced from the sedimentary river sands and gravels deposited by the Boise River, and they supply the bulk of the aggregate needs of the valley for the last hundred years (Savage, 1958).

4.2 Mineral Exploration and Development Work

Geothermal While no data was found for any geothermal exploration or development projects in the vicinity of the subject lands, but some insight can be gained by examining the water well logs of the area to gather data

Map 4. Speculative Uranium Resource Area in Region K.

Map depicts the location on the subject lands overlaid with NURE data on the extent of the speculative resource area in the western Snake River Plain. (Created on 2025-04-09 by H. Huttanus) on the groundwater temperatures that were reported. Well log data from the ground water wells within

1.6 km (1 mile) of the subject lands were gathered from the Idaho Department of Water Resources website and compiled into Table 2. to illustrate the ground water temperatures that have been observed in the area surrounding the subject lands (IDWR, 2025). Most wells in the area were drilled in small housing developments for domestic and irrigation purposes which limits the available data to a hand full of shallow wells. Where multiple well were drilled in close proximity to one another only the deepest of the well’s reports containing temperature data were listed on the table below. See Appendix E for copies of the well driller’s reports used in Table 2.

Table 2. Water Well Temperature Data Well ID Township Range Section QQ Depth (ft) Temp. (°F) 297317 3 North 3 East 08 NESW 618 n/a* 389026 3 North 3 East 08 SWSW 555 69° 400831 3 North 3 East 08 NESE 800 65° 403608 3 North 3 East 05 SESW 205 55° 420843-1 3 North 3 East 08 NESW 617 67° 420843-2 3 North 3 East 08 NESW 649 72° 445574 3 North 3 East 09 NWNW (lot 4) 900 60° 455170 3 North 3 East 08 NESE 345 65°

* - Temperature not reported on the Well Driller’s Report (Appendix E)

Locatable Minerals Data on the locatable mineral exploration and development work that has been conducted near to the subject lands is limited to a few references for mines that were either described as being located along Picket Pin Creek, or which are shown on the Idaho Geological Survey’s (IGS) interactive map as being located less than 1.6 km (1 mile) from the subject lands (IGS, 2025). Data from IGS was found on three small historic gold mines the Constant Group, the Keltic Gold Mine, and the Picket Pin Mine each of which occurred within 1.3 km (0.8 miles) of the subject lands as seen on Map 5. below. The mines were actively worked as recently as 1909, but gold mining had largely ceased in the Boise Foothills by the 1930s (Ross C. P., 1941). Reports indicate that these three mines averaged around $3-7/ton or about.

4.51-10.53 g/t (0.145-0.339 oz t./ton) with paystreaks a high as $1000/ton or about 1505 g/t (48.38 oz t./ton) (Bell, 1907), (Bell, 1908), & (Moore, 1910). Those reports also indicate that there were mill buildings onsite for at least one of the mines so the values reported could have been for materials processed after mechanical separation and concentration had occurred. Additionally, there is a report form 1898 by the USGS which describes a mine called the Golden Star which was described as being located in Picket Pin Gulch (Lindgren & Knowlton, 1898). This mine was described as consisting of two parallel veins that were crosscut by a third. The report also mentioned that an arrastre was built on the mine which was reported to have produced ore yielding $33 per ton or 49.66 g/t (1.60 oz t./ton). The report also mentions that a mill was constructed on the site but that it did not run for long. However, no development has occurred withing the Boise, Shaw Mountain, or Black Hornet mining districts outside from occasional exploration projects since about the 1942 (Savage, 1958). Table 3. below summarizes the gold grades that were reported for the four mines that production data could be found on. None of the granite porphyry dikes, lamprophyre dikes or quartz veins noted as hosting the gold and sulfide mineralization nor the sericitization or calcification associated with the mineralized alteration zones were noted within subject lands during the field examination.

Map 5. Known Mining Activity and Mines Referenced in this Report.

Map depicts subject lands in relation to IGS data on mining district boundaries (pink), known mines and prospects (diamonds), and the four gold mines referenced in this report (pickaxes). (Crated on 2025-04-04 by H. Huttanus)

Table 3. Historic gold production data from nearby mine sites.

Mine Site 1898 1906 1907 1909

Keltic Gold Mine

No data $6/ton

9.03 g/ton

0.29 oz t./ton

$4-7/ton 6.02-10.53 g/ton 0.19-0.34 oz t./ton

$3-5/ton 4.51-7.52 g/ton 0.15-0.24 oz t./ton

Picket Pin Mine

No data $32/ton

48.15 g/ton

1.55 oz t./ton

$9/ton

13.54 g/ton

0.44 oz t./ton

No data

Constant Group

No data No data No data $50-1000/ton 75.24-1505 g/ton 2.42-48.38 oz t./ton

Golden Star

$33/ton

49.66 g/ton

1.60 oz t./ton

No data No data No data

Note: US gold prices at the time were fixed at $20.67 per troy ounce.

5.0 Potential for the Occurrence of Mineral Resources

This report classifies the subject lands based on the potential for the occurrence of concentrations of salable, leasable, and locatable minerals, and identifies any known minerals and the known mineral value at the subject lands. The mineral potential is classified as either; not determined, low, moderate, or high for each mineral category. There is no discussion of minerals for which a plausible model of ore deposition could not be identified. The land is implicitly classified as “no potential” for such minerals.

The level of certainty for each classification is noted by letters A through D, with increasing letters indicating increasing certainty (see Table 1. in Executive Summary for Managers section). The land is further classified as known to be valuable, prospectively valuable, or not prospectively valuable for leasable minerals. The land is classified as prospectively valuable for leasable minerals if, based on geologic data and inference, specific criteria are met (BLM, 1987). Such classification considers the intrinsic value of the potential deposit (e.g., quality, thickness, and depth) to determine whether it is both practicable and technologically feasible to extract the mineral.

The Mineral Potential Classification System and the methodologies used in this report are consistent with sections .23, .5, .34, and illustration 3 of the BLM Manual 3031, Energy and Mineral Resources Assessment. Level of potential, or mineral potential, is based on direct and indirect evidence supporting the presence of mineral resources. Level of certainty is based on the relevance and detail of the evidence used to determine the mineral potential. The levels of potential and certainty are described below (Illustration 3, Manual 3031.34) (BLM, 1985):

Level of Potential:

O. The geologic environment, the inferred geologic processes, and the lack of mineral occurrences do not indicate potential for accumulation of mineral resources.

L. The geologic environment and the inferred geologic processes indicate low potential for accumulation of mineral resources.

M. The geologic environment, the inferred geologic processes, and the reported mineral occurrences or valid geochemical/geophysical anomaly indicate moderate potential for accumulation of mineral resources.

H. The geologic environment, the inferred geologic processes, the reported mineral occurrences and/or valid geochemical/geophysical anomaly, and the known mines or deposits indicate high potential for accumulation of mineral resources. The “known mines and deposits” do not have to be within the area that is being classified but have to be within the same type of geologic environment.

ND. Mineral(s) potential not determined due to lack of useful data. This notation does not require a level-of-certainty qualifier.

Level of Certainty:

A. The available data is insufficient and/or cannot be considered as direct or indirect evidence to support or refute the possible existence of mineral resources within the respective area.

B. The available data provide indirect evidence to support or refute the possible existence of mineral resources.

C. The available data provide direct evidence but are quantitatively minimal to support or refute the possible existence of mineral resources.

D. The available data provide abundant direct and indirect evidence to support or refute the possible existence of mineral resources.

5.1 Coal

Coal beds are known to have existed 27.7 km (17.2 miles) to the northwest of the subject lands in the Horseshoe Bend Mining District (Bowen, 1913), but the sedimentary sequences that host those deposits have not been shown to occur within the subject lands. The rock units mapped to and observed within the subject land are igneous in nature and as such cannot contain deposits of coal. There is no potential

(O) for the occurrence of coal at the subject lands with high level of certainty (D) due to the rock units withing the subject land being unable to contain coal beds. Furthermore, the subject lands should not be classified as being prospectively valuable for coal leasing based upon the previously discussed criteria.

5.2 Oil and Gas

There are no known oil and gas deposits within 16 km (10 miles) of the subject lands, nor are there any geologic units mapped within the subject lands where such a deposit is expected to occur. The igneous rocks mapped to and observed within the subject lands could not have contained the organic matter needed to for oil and gas deposits to form and the temperatures associated with the magmas of such igneous intrusions would have destroyed any oil and gas deposit that might have been present prior to the magmatic intrusions. There is no potential (O) for the occurrence of oil and gas deposits at the subject lands with a high level of certainty (D). Furthermore, the subject lands should not be classified as being prospectively valuable for oil and gas leasing based upon the previously discussed criteria.

5.3 Geothermal

The Relative Favorability of Deep Enhanced Geothermal System (EGS) dataset, provided by the National Renewable Energy Laboratory (NREL) was consulted to determine the geothermal potential of the subject lands. The EGS dataset displays the relative favorability of those systems within the contiguous U.S. The data is based on the levelized cost of electricity estimated from a combination of adequate temperature and depth. The data is represented on a scale of 1–5 with 1 being the most favorable and 5 being the least favorable, or as 999 if the depth to target temperatures is beyond what current technology can reach. The area of the subject lands has a rating of 2 on the NREL EGS rating system indicating that it is in the second most favorable type of environment for potential geothermal development as shown on Map 6. below. The NREL temperature data from the favorability of EGS shows that that subject lands have been identified as having a probable 1000 m (3281 ft) reservoir temperature of up to 75° Celsius (167°F). According to the U.S. Department of Energy the fluid temperature should be at least 149° C (300° F) and could be as low as 107° C (210° F) for a geothermal plant to operate (NREL, 2018). Therefore, temperatures high enough to operate a geothermal powerplant haven’t been shown to potentially occur in the subject lands. There however exists the possibility of leasing for the direct use of the geothermal resource for heating purposes. Other criteria to consider are the availability of make-up water for evaporative cooling, gas content of geothermal fluids, and proximity to existing transmission lines.

The potential for the existence of geothermal resources within the subject lands is Moderate (M) and there is abundant available data providing indirect evidence (B) supporting the possible existence of geothermal resources in the area. None of the water temperatures reported from nearby domestic water wells were 40 °F greater than ambient air temperature therefore there is little potential for the development of geothermal power on the subject lands and they should not be classified as being prospectively valuable for geothermal leasing based upon the previously discussed criteria.

5.4 Phosphate, Sodium and Potassium

Phosphate, sodium and potassium deposits generally required sedimentary units to host these types of mineral deposits in the form of evaporite lake beds, ancient marine deposits, or decomposed alkalic igneous sediments. None of those sedimentary deposits or host rocks are known to exist near the subject lands, which are composed of almost entirely of granite or granodiorite from the Idaho Batholith save for the small amounts of stream sediments found along Picket Pit Creek. There is no potential (O) to find phosphate, sodium, or potassium on the subject lands which is supported by abundant direct evidence of the geologic environment (D).