San Manuel Mine (Apex Lead & Vanadium Mining Corp Mine; Quarelli group), San Manuel, San Manuel District, Pinal Co., Arizona, USA
|Latitude & Longitude (WGS84):||32° 41' 46'' North , 110° 41' 20'' West|
|Latitude & Longitude (decimal):||32.69611,-110.68889|
|Other regions containing this locality:||Sonoran Desert, North America|
|Köppen climate type:||BSk : Cold semi-arid (steppe) climate|
A former surface and underground Cu-Ag-Mo-Au-Ti-Rh-V mine located in sec. 35, T8S, R16E, about 6¾ miles NW of San Manuel and about 4¼ miles SW of Mammoth, on private land (NOTE: mineral rights are a combination of patented and leased from the state). Originally discovered in 1879 by Frank Schultz. Main body discovered 1942 by Henry W. Nichols. Drilling exploration extended from 1943-1948. First shaft sunk in 1948 with first production in 1955.
Mineralization is a porphyry copper deposit hosted in the Ruin (Oracle) Granite and Gila Conglomerate. The San Manuel ore body is tabular with a strike of N61E & N55E, dipping 50S & 15S, 300 meters thick, plunging 10NE; at the east end of the mine - NE, depth-to-top of 520 meters, width of 1160 meters, and 2400 meters long. The Kalamazoo ore body is also U-shaped with a strike of N61E & N55E, dipping 50S & 15S, with a depth-to-top of 1140 meters. Ore control was rock permeability due to fracturing and contact between the Ruin (Oracle) Granite and Cretaceous quartz monzonites. Ore concentration was hydrothermal with secondary supergene enrichment and oxidation of the upper zone of the San Manuel ore body. The orebodies are tabular and "U" shaped. Alteration is potassic, phyllic, argillic, propyllitic. The ore zone overlaps the potassic and phyllic zones.
The mineralization is associated with intrusion of Lower Cretaceous- Early Tertiary monzonite porphyry and mineralization occurs in both the porphyry and the Precambrian intrusive rocks. The ore body has two main parts (created by faulting of the original ore body), separated by a zone of scarce sulfides. At depth the two parts converge. The San Manuel fault divided the original cylindrical ore body into two halves, the upper San Manuel and the lower Kalamazoo ore bodies, with a displacement of about 8000 feet.
Local structures include NNW-trending block faulting, the San Manuel Fault striking N66°W and dipping 26°SW, which displaces the ore body. Also younger, normal faults.
This great mine was operated by Magma before being bought out by BHP and closed. It is a massive sulfide deposit mined with five shafts, each over 1,000 meters deep, and with headframes over 60 meters high. Over 700,000,000 tons of ore were extracted using the block caving method. Workings were divided into the sulfide mine and the oxide mine (Chrysocolla and Tenorite). Specimens are very rare due to the security of the operation and minimal number of showy specimens encountered. The entire huge site was scheduled for reclamation.
The mineralized zone, which includes the ore deposit, is about 8,000 feet to 9,000 feet wide and more than 9,300 feet long. It trends ENE.
Mineral ListMineral list contains entries from the region specified including sub-localities
50 valid minerals. 1 (TL) - type locality of valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Quaternary - Miocene|
0 - 23.03 Ma
|Cenozoic sedimentary rocks|
Age: Cenozoic (0 - 23.03 Ma)
Lithology: Sedimentary rocks
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. 
1400 - 1600 Ma
|Middle Proterozoic granitic rocks|
Age: Calymmian (1400 - 1600 Ma)
Description: Mostly porphyritic biotite granite with large microcline phenocrysts, with local fine-grained border phases and aplite. Associated pegmatite and quartz veins are rare. This unit forms large plutons, including the Oracle Granite, Ruin Granite, granite in the Pinnacle Peak - Carefree area northeast of Phoenix, and several bodies west of Prescott. (1400-1450 Ma)
Comments: ~ 1.4 Ga
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052.