Black Rock Group

The Black Rock Group is a manganese mine located in Greenlee county, Arizona at an elevation of 3,681 feet.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

Name: Black Rock Group  

State:  Arizona

County:  Greenlee

Elevation: 3,681 Feet (1,122 Meters)

Primary Mineral: Manganese

Lat, Long: 33.0775, -109.29278

Map: View on Google Maps

Satelite View

MRDS mine locations are often very general, and in some cases are incorrect. Some mine remains have been covered or removed by modern industrial activity or by development of things like housing. The satellite view offers a quick glimpse as to whether the MRDS location corresponds to visible mine remains.


Satelite image of the Black Rock Group

Black Rock Group MRDS details

Site Name

Primary: Black Rock Group
Secondary: Black Magic Prospects


Commodity

Primary: Manganese


Location

State: Arizona
County: Greenlee
District: Copper Mountain District


Land Status

Land ownership: BLM Administrative Area
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.


Holdings

Not available


Workings

Type: Surface/Underground


Ownership

Owner Name: Matt And Ed Danenhauer; N. T. Jackson; Ernest W Foote : Danenhauer Business Service
Years: 1956 -


Production

Not available


Deposit

Record Type: Site
Operation Category: Producer
Operation Type: Unknown
Year First Production: 1951
Discovery Year: 1906
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: N
Deposit Size: S


Physiography

General Physiographic Area: Intermontane Plateaus
Physiographic Province: Basin And Range Province
Physiographic Section: Mexican Highland


Mineral Deposit Model

Not available


Orebody

Form: IRREGULAR

Form: IRREGULAR


Structure

Type: R
Description: Ne Trending Large Fault Between Limestone And Precambrian Granite That Comprises Massivebluffs Overlooking The San Francisco River

Type: L
Description: Upper Contact Of Chert And Limestone Is Very Irregular; Most Ore Exposures Are Located On The Canyon Walls 20 To 40 Ft Above The Bed Of The Gulch


Alterations

Alteration Type: L
Alteration Text: Manganese Ore Occurs As Replacement Of Limestone Bordering Large Fault; Replacement Of Crushed Chert Particles In Brecciated Areas


Rocks

Name: Granite
Role: Associated
Age Type: Host Rock Unit
Age Young: Late Ordovician

Name: Granite
Role: Associated
Age Type: Host Rock
Age Young: Late Ordovician

Name: Granite
Role: Associated
Age Type: Associated Rock Unit
Age Young: Neoproterozoic

Name: Granite
Role: Associated
Age Type: Associated Rock
Age Young: Neoproterozoic


Analytical Data

Analytical Data: 1952 ASSAY VALUES RANGED FROM 12-48% MN.


Materials

Ore: Psilomelane
Ore: Pyrolusite


Comments

Comment (Location): 1/4 MILE NORTH OF LIMESTONE GULCH IN AN UNNAMED WASH; WASH IS LOCATED 1/4 MILE NE OF MOUTH OF LIMESTONE GULCH. ; INFO FROM LAND.ST :(1973)

Comment (Workings): DEVELOPMENTS INCLUDED 40 FT ADIT, 50 FT DEEP VERTICAL SHAFT, 27 FT DEEP SHAFT WITH 13 FT OF DRIFTS, 4 OPEN CUTS, SEVERAL SMALL OPEN PROSPECT PITS, AND SMALL MILL ON THE SAN FRANCISCO RIVER. MINING CONSISTED OF OPENING UP SMALL VEINS OR ORE LENSES ON THE SIDES OF THE CANYON WALLS AND SCRAPING OUT ORE.

Comment (Geology): WHERE FRACTURING WAS MODERATE, MANGANESE MINERALS WERE DEPOSITED IN THE FRACTURES AND REPLACED PART OF THE LIMESTONE WALLS. IN BRECCIATED AREAS, THE MANGANESE MINERALS REPLACED THE CRUSHED CHERT PARTICLES AND FORMED HIGH-GRADE POCKETS. MANGANESE ORE IS PRIMARILY LOCATED IN THE CHERT BED RATHER THAN IN THE LIMESTONE WALL ROCK OR GRANITE BEDS.

Comment (Deposit): PROPERTY TOTALS 9 UNPATENTED CLAIMS. STRIKE AND DIP ARE ESTIMATED. AT THE MOUTH OF THE CANYON, THE ERRATICALLY MINERALIZED CHERT BED IS ABOUT 50 FT THICK. 0.1 MILE FURTHER UP THE WASH, ORE-BEARING CHERT BEDS ARE EXPOSED TO LENGTHS OF 150 FT.

Comment (Development): OPERATORS INCLUDED GORDON S. BUTTORFF; TOM U. WOLFE; MANGANESE VALLEY MINES INC; MINES CONTRACTING INC; DANENHAVER BROTHERS; UNITED STATES MANGANESE CORPORATION (BROCK AND SCHUSTER)


References

Reference (Production): USBM I.C. 7990, P. 101.

Reference (Deposit): ADMR FILE DATA, BLACK ROCK MINES.

Reference (Deposit): BENNETT, K.C., 1975, GEOLOGY AND ORIGIN OF THE BRECCIAS IN THE MORENI-METCALF DISTRICT, GREENLEE COUNTY, ARIZONA: M.S. THESIS, UNIVERSITY OF ARIZONA, 153 P.

Reference (Deposit): ABGMT CLIPPINGS FILE, BLACK ROCK MINE.

Reference (Deposit): USGS PP 43, SAN FRANCISCO RIVER GEOLOGY COMMENTS.

Reference (Deposit): USBM FILES, BLACK ROCK GROUP.

Reference (Deposit): USBM IC 7990, P. 101-102.


Arizona Gold

Where to Find Gold in Arizona

"Where to Find Gold in Arizona" looks at the density of modern placer mining claims along with historical gold mining locations and mining district descriptions to determine areas of high gold discovery potential in Arizona. Read more at Where to Find Gold in Arizona.