Overview
The Mineral Hill Rare Earth Elements Project is comprised of unpatented mining claims covering an area of approximately 2,100 acres. This project is located within the Mineral Hill Mining District, approximately 30 miles northwest of Salmon, Idaho. In Idaho, most of the lode REE occurrences lie along a northwest trending line that extends from Lemhi Pass, through Diamond Creek, to the Mineral Hill District, before crossing the Idaho-Montana state line. This lineament stretches more than 70 miles across central Idaho. Rare earth elements (REE) mineralization in the Mineral Hill District was first discovered in the early 1950’s. Studies conducted by A. T. Abbott (1954) and A. L. Anderson (1958) from the Idaho Geological Survey, and E. P. Kaiser (1956) with the USGS, pioneered recognition of these REE occurrences. Abbott reported cutting a 2.5-foot sample across the Roberts Lode (controlled by IDR), where the carbonatite outcrops at surface, that returned 21.5% combined rare earth oxides and thoria.
Mineralization
The Mineral Hill Project contains multiple identified carbonatite occurrences outcropping at surface characterized by exceptional REE concentrations. Rare earth ore minerals have been identified as primarily phosphate minerals such as monazite, bastnasite, and xenotime with lower relative thorium concentrations compared to elsewhere in the Idaho Rare Earth Belt. The various carbonatite and rare earth occurrences at Mineral Hill are known as: Lower Roberts, Upper Roberts, Cardinal, Lower Lee Buck, and Phyllis Gross. IDR geologists have traced high-grade REE mineralization over a 0.5-mile strike length at the Lower Roberts prospect, with a continuous 1,500-foot carbonatite seam up to 10 feet thick, locally exceeding 23% total rare earths.
Idaho Rare Earth Belt
The Idaho Rare Earth Belt stretches along a northwest trending zone measuring approximately 70 miles long by 8 miles wide. This belt possesses most of the REE lode occurrences in Idaho. Along this 70-mile Belt, IDR controls the Mineral Hill Property in the northwest, the Diamond Creek Property in the middle; and its greatly expanded Lemhi Pass Property in the southeast.
Roberts Carbonatite Prospect
| Sample | Cе | Dy | Ег | Еu | Gd | Но | Lа | Lu | Nd | Рr | Sm | Тb | Тm | Yb | ррm | TREO % |
| 98370 | 116500 | 89.1 | 19.8 | 301 | 477 | 10.4 | 83000 | 1.32 | 27000 | 9500 | 1940 | 32.8 | 1.87 | 10 | 238883 | 28.6 |
| 98371 | 84000 | 120 | 27.6 | 287 | 513 | 14.75 | 58900 | 1.84 | 20500 | 7000 | 1685 | 38.4 | 2.67 | 13.4 | 173104 | 20.8 |
| 98372 | 101000 | 142.5 | 32.8 | 342 | 627 | 17.35 | 70600 | 1.95 | 24300 | 8500 | 2020 | 46.7 | 3.2 | 15.4 | 207649 | 24.9 |
| 98373 | 103000 | 79.3 | 22.7 | 232 | 369 | 10.3 | 75500 | 2.04 | 23100 | 8400 | 1570 | 26 | 2.55 | 15.1 | 212329 | 25.5 |
| 98374 | 108000 | 74.1 | 20.5 | 239 | 377 | 9.66 | 79200 | 1.89 | 24000 | 8700 | 1610 | 25.8 | 2.29 | 13.3 | 222274 | 26.7 |
| 98375 | 87400 | 84.9 | 26.1 | 223 | 370 | 11.65 | 64000 | 2.42 | 20400 | 7100 | 1420 | 26.7 | 3.08 | 17.2 | 181085 | 21.7 |
| 98376 | 95000 | 82.6 | 24.5 | 234 | 380 | 11.05 | 70200 | 2.2 | 22500 | 7700 | 1530 | 27.8 | 2.78 | 16.4 | 197711 | 23.7 |
| 98377 | 137500 | 80.2 | 17.6 | 304 | 460 | 9.19 | 103000 | 1.44 | 30100 | 10900 | 2000 | 30.4 | 1.82 | 10.1 | 284415 | 34.1 |
Cardinal Carbonatite Prospect
| Sample | Ce | Dy | Er | Eu | Gd | Ho | La | Lu | Nd | Pr | Sm | Tb | Tm | Yb | ppm | TREO % |
| 98756 | 40600 | 105 | 35.9 | 174.5 | 345 | 15.7 | 22300 | 3.65 | 11450 | 3820 | 960 | 32.8 | 4.44 | 26.4 | 91488 | 11.0 |
| 98758 | >50000 | 93.6 | 21.9 | 188.5 | 366 | 11.55 | 30600 | 1.09 | 14050 | 4870 | 1075 | 33.7 | 1.78 | 7.9 | >98721 | >12.3 |
| 98759 | >50000 | 130 | 28 | 283 | 529 | 15.6 | 45200 | 1.29 | 21000 | >5000 | 1610 | 48.3 | 2.12 | 8.8 | >123856 | >14.8 |
| 98760 | >50000 | 225 | 41.2 | 545 | 1040 | 25.1 | >50000 | 1.2 | 38000 | >5000 | 3180 | 84.7 | 2.83 | 8.1 | >148153 | >17.6 |
| 98766 | 23300 | 110.5 | 36.7 | 148 | 310 | 16.15 | 12450 | 2.83 | 7340 | 2360 | 736 | 30.2 | 4.18 | 22 | 46867 | 5.6 |
| 98767 | 7760 | 62 | 23.5 | 51.6 | 118 | 10.2 | 4740 | 2.14 | 2230 | 743 | 224 | 14.35 | 2.88 | 16.2 | 15998 | 1.9 |
| 98772 | >50000 | 114 | 21.2 | 283 | 522 | 12.1 | >50000 | 0.87 | 23000 | >5000 | 1720 | 45.7 | 1.45 | 5.8 | 130726 | >15.6 |
Magnetics Survey
In 2025, Idaho Strategic completed a magnetics survey covering almost the entirety of its Mineral Hill project. The magnetics survey proved to be an extremely useful tool to identify carbonatite occurrences at the project due to the presence of magnetite within the monazite dominant carbonatite. The magnetics survey is expected to expedite future discovery and resource definition by reducing the amount up-front geology work needed to identify various prospects.
The map above shows the Total Magnetic Intensity (TMI) and identifies an extensive northwest trending, semi-linear zone of magnetic highs with a response consistent with a dike swarm. This zone extends 1.5 km southeast of the Cardinal prospect, through Cardinal, to the Lower Lee Buck prospect for a total of 3.5 km. The Roberts area displays a very strong circular magnetic anomaly.
The map above is a reduced-to-the-pole upward continued (RTP_UC) map generated from the processed magnetic survey data. This map indicates a deep sourced, large magnetic feature extending in a northeast orientation from Roberts to Cardinal. The southwest end of this feature is larger and deeper which is suggestive of an intrusion.
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