| Basis for focus area |
Outline of placer localities in MRDS with PGE production listed by Peterson (1994); localities may not be exact. |
| Identified resources |
Historical production of gold and PGE. |
| Production |
Rough and Ready placer produced Pt in a black sand concentrate; Relief Hill produced 9 lbs of concentrates from 1 ton of gravel with a grade of about 500 ppb Pt. |
| Status |
Past placer mining. |
| Estimated resources |
Unknown. |
| Geologic maps |
Saucedo and Wagner (1992), scale 1:250,000. |
| Geophysical data |
Inadequate aeromagnetic and aeroradiometric coverage. |
| Favorable rocks and structures |
Placers and tailings deposits. |
| Deposits |
Rough & Ready placer (MRDS dep_id: 10261992), Relief Hill Placer (MRDS dep_id: 10038014). |
| Evidence from mineral occurrences |
MRDS; other MRDS sites in and near this focus area are described as Au-PGE placers, but the presence of PGE is not substantiated at all localities. |
| Geochemical evidence |
No data. |
| Geophysical evidence |
Unknown. |
| Evidence from other sources |
None. |
| Comments |
Reworking of historical tailings, especially if coupled with mercury cleanup, could provide potential PGE resources if technology and economic incentives warranted the effort. |
| Cover thickness and description |
Surface alluvial/tailings deposits. |
| Authors |
Jane M. Hammarstrom, Erica Key. |
| New data needs |
Updated geologic mapping, geochemistry, aeromagnetic and aeroradiometric surveys. |
| Geologic mapping and modeling needs |
Updated geologic mapping. |
| Geophysical survey and modeling needs |
High-resolution, Rank 1 aeromagnetic and aeroradiometric surveys. |
| Digital elevation data needs |
Lidar complete. |
