Virginia metamorphic sulfide

Region East, Southeast
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Prospective geology and historical mining activity in an area covering approximately 5 square miles; disseminated Ni-bearing pyrrhotite with pyrite, chalcopyrite and pentlandite reportedly containing 0.4% Co, >1.75% Ni, and <1% Cu. Also includes the adjacent Brinton Arsenic Mine. The metal deposits may have a structural control related to the regional Fries Fault system.
Identified resources Historical production of pyrrhotite for copperas mined prior to Civil War; historical production of arsenic at the Brinton mine (1903-1919).
Production Brinton mine (1903-1919): estimated 75-100 tons of processed arsenic (99.75% As2O3) (Dietrich, 1959).
Status Past mining. Exploration work by USBM in 1943-44 included shaft dewatering and drilling at Brinton mine. No modern exploration.
Estimated resources Unknown.
Geologic maps Walsh-Stovall and others (2015), scale 1:24,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric data: Rank 4 aeromagnetic and Rank 5 aeroradiometric surveys.
Favorable rocks and structures Granulite facies layered sequence of hornblende-peridotite, gabbro, norite of Mesoproterozoic age, variably altered; Fe-Ni-Co-Cu sulfides, disseminated and structurally controlled veins, possibly post-metamorphic replacement as opposed to magmatic in origin. Structural complexity may obscure blind targets. Post-magmatic arsenopyrite in greisen.
Deposits Brinton mine (MRDS dep_id: 10080132), Vest prospect (MRDS dep_id: 10080131), Lick Fork prospect (MRDS dep_id: 10068222), Sugar Run prospect (MRDS dep_id: 10080130).
Evidence from mineral occurrences MRDS; Virginia Geological Survey mineral resource files.
Geochemical evidence Soil geochemistry shows anomalous Ni.
Geophysical evidence Unknown.
Evidence from other sources Region shows significant metallic mineralization possibly associated with the extensive Fries Fault system.
Comments Under explored.
Cover thickness and description Known deposits in exposed bedrock, but blind targets may exist in structural zones.
Authors William L. Lassetter.
New data needs Geologic mapping, geophysical surveys, geochemical sampling needed to access unweathered rocks containing sulfides.
Geologic mapping and modeling needs Unpublished 1:24,000 map is available. Additional detailed site mapping needed to resolve structural complexity and potential for blind targets.
Geophysical survey and modeling needs High resolution aeromagnetic and aeroradiometric coverage. Aeromagnetic data may image mafic rocks, associated structures, and possibly alteration zones. Radiometric data can help with geologic mapping in vegetated terrane. Electromagnetic data may assist with imaging sulfides.
Digital elevation data needs Lidar available.