Mia
| Location | Historic Resources | Status |
|---|---|---|
|
Custer County, Idaho |
n/a |
Under Contract |
Summary and Location
High-grade historical assays on multiple veins with values up to 1.11 oz/ton gold and 178.8 oz/ton silver. The 660-acre property contains at least four known mineralized lode structures with vein widths ranging from narrow stringers to over 8 feet, all of which are open to expansion.
A 1983 geological report for the project operator concluded the potential to locate ore reserves is “very good,” identifying several “excellent exploration targets.” The project was consolidated for a comprehensive exploration and development program in the early 1980s.
The Mia project is in the Seafoam Mining District of Custer County, Idaho, approximately 31 road miles northwest of the town of Stanley. While historically considered remote, the area is now accessible via a good gravel road, making it well-suited for modern exploration activities.
Geology
Exploration and History
The project targets multiple, steeply dipping, fissure veins and shear zones hosted within the Idaho Batholith. The host rock is primarily biotite granodiorite and leucocratic granite, which has been intruded by numerous andesitic to rhyolitic dikes that share the dominant northwest structural trend of the mineralization. The veins are accompanied by locally intense hydrothermal alteration and are part of an extensive underlying system.
Metals contained within the veins include gold, silver, lead, zinc, and copper. Ore minerals identified in reports and hand specimens include argentiferous galena, auriferous pyrite, malachite, arsenopyrite, cerargyrite, and mimetite, with a quartz-calcite gangue. Gold is reported to occur in a free state as well as being associated with pyrite. High-grade mineralization is often found in heavily oxidized, porous, and earthy material, with reports specifically noting a “greenish-yellow mineral, probably cerargyrite” in high-silver samples.
Mineralization was first discovered in the Seafoam district in the 1880s, with early work confined to small-scale “high grading.” The current property was consolidated and held by Northwest Minerals Development Corporation in the early 1980s with the intent to conduct modern, systematic exploration.
In 1982, the U.S. Bureau of Mines examined the claims in conjunction with regional studies, and their sampling confirmed the area’s mineral potential. Subsequently, in 1983, consulting geologist Michael R. Free conducted a detailed property examination and sampling program which identified several high-grade, drill-ready targets. Highlights from this historical work include:
– Canary Yellow Vein: Grab samples assayed up to 178.8 oz/ton silver and 0.20 oz/ton gold.
– Longshot Veins: Assays returned values up to 1.11 oz/ton gold and 12.4 oz/ton silver.
– Betty Ruth Vein: Sampling returned assays up to 0.204 oz/ton gold and 42.95 oz/ton silver.
– Golden Promise Vein: Assays included 0.34 oz/ton gold and 2.4 oz/ton silver.
Based on these results, a comprehensive, two-stage exploration program including geophysics, drilling, and a potential vat leach operation was planned for 1984. In 1983, Sunshine Mining Company reviewed the project data, calling the mineralization “certainly very interesting” and warranting “additional exploration,” but ultimately passed on the project at that time.