Latitude: 33°26'14"N
Longitude: 110°46'11"W
A former surface and underground copper mine located on the western flank of Black Peak along the east side of Big Johnnie Gulch. Developed prior to 1901. The mine closed and was unwatered in 1915 by the Old Dominion Copper Co.
Mineralization is a vein deposit with a linear ore body. The deposit is in an irregular block of quartzite that crops out on the western flank of Black Peak. The block is composed of Pioneer formation, Barnes conglomerate, and Dripping Spring quartzite and is completely surrounded and underlain by diabase. The sedimentary strata dip 10º to 40ºSE. A little displacement along the NW contact between the quartzite and diabase was sufficient to permit the passage of mineraling solutions, and the contact fissure has been slightly mineralized for more than 6,000 feet along the strike. Northeastward from the Big Johnnie Mine, the contact fissure contains less copper but increasing amounts of managanese minerals. In the northeastern part on the Superior and Globe property, considerable manganese ore has been mined from shallow workings.
For about 500 feet near the south end of the quartzite outcrop the west or hanging wall of the contact fissure is formed by a small triangular block of Pioneer formation and Dripping Spring quartzite; and from the north edge of this small block, a branch fault cuts northeastward diagonally across the main quartzite outcrop. The portion of the main quartzite block south of the branch fault has been relatively depressed several hundred feet, probably at the time of the diabase intrusion.
The Big Johnnie vein is along the branch fault and along the segment of the main contact fault that is south of the junction. Both faults dip 80º to 85ºNW.
Mineralization involves replacements of limestone and/or diabase along the Old Dominion fault system. Very good copper ore occurs in quartzite breccia. The average width of the fault breccia is less than 2 feet. It consists of fragments of quartzite cemented and partly replaced by cuprite, malachite, chrysocolla, and specularite.
On both the 2nd. & 3rd. levels, the footwall of the vein is quartzite, and the hanging wall is diabase.
The Big Johnnie shaft was sunk in the diabase hanging wall near the intersection of the two vein faults. Two crosscuts were driven to intersect the vein at intervals of 100 and 200 feet, respectively, below the adit level and were designated the 2nd. & 3rd. levels. After the vein had been explored for only 130 feet by drifts from the 2nd.-level crosscut, the mine was closed. After unwatering the drift on the 2nd. level was extended northeastward and exposed the vein for a total distance of 706 feet along the strike.
References
Ransome, F.L. (1903a), Geology of the Globe copper district, Arizona, USGS PP 12: 153.
Sanders, J. (1911), Hematite in veins of Globe district, Engineering and Mining Journal: 92: 1191-1192.
Galbraith, F.W. & D.J. Brennan (1959), Minerals of Arizona: 53.
Peterson, N.P. (1962), Geology and ore deposits of the Globe-Miami district, Arizona, USGS PP 342: 72, 97, 115-116.
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.: 245, 285.
MRDS database Dep. ID #10102493, MRDS ID #M003106; and Dep. ID #10258356, MAS ID #0040070176.
Mineral List
4 entries listed. 3 valid minerals.
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