USGS Mineral Resources Data System
Type: Historical mine record
Supports:
- mine identity
- development status
- commodities
- underground eligibility evidence
California · Napa County
Twin Peaks Mine
Unconfirmed Mercury Underground
Key facts
- State
- California
- County
- Napa
- Development status
- Past Producer
- Mine type
- Underground
- Primary commodity
- Mercury
- Verification
- Unconfirmed
Mine Location
Approximate AreaDocumented underground workings
Mindat locality description
A former Hg-Cr-Ni mine located in sec. 4, T9N, R6W, MDM, 1.5 km (5,100 feet) S of Twin Peaks. Mineralization is related to a serpentine - sandstone contact and is hosted in serpentinite. Production data are found in: U.S. Bureau of Mines file data.
Historical mapped workings
USGS historical topographic mapping. Features may no longer exist.
- 3 adit symbols
View individual source records (2)
Every underlying record used to build the summary above, for research/verification use.
- Derived from MRDS oper_type (existing operation): Underground
- MRDS oper_type documents existing underground operation (dev_stat=Past Producer): Underground · oper_type
Verification
Unconfirmed
Source records support underground workings, but UndergroundMines has not yet independently verified this mine.
Why it's listed
USGS source data documents underground workings for this record.
History & operations
Historical record
- Development status: Past Producer
Commodities & minerals
Reported minerals
- Chromite
- Cinnabar
- Millerite
- Saponite
- Serpentinite
Access & recent conditions
- Land
- unknown
Community reports
No community field reports yet.
I Visited This MineSources & evidence
USGS Historical Topographic Mine Features
Type: Historical mapped physical features
Dataset: DOI 10.5066/P9TAALR6
Supports:
- mapped adit symbols (3)
Historical mapped features may no longer exist.
Mindat
Type: Mineralogical locality database
Record: Mindat Locality: 83722
Supports:
- locality identity
- reported minerals (5)
A Mindat locality match does not by itself establish underground workings.
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