|Latitude & Longitude (WGS84):||32° 42' 23'' North , 110° 40' 59'' West|
|Latitude & Longitude (decimal):||32.70639,-110.68306|
|Other regions containing this locality:||San Pedro river valley, Arizona/Sonora, USA/Mexico|
Sonoran Desert, North America
|Köppen climate type:||BSk : Cold semi-arid (steppe) climate|
A former Au-V-Pb-Zn-Mo-Cu-Ag-W-F (Fluorspar)-Ba (Baryte) mine located in the SW¼ sec. 26, T8S, R16E. (Mammoth 7.5 minute topo map), about 50 miles NNE of Tucson and 21 miles south of Winkleman, on the east slope of the Black Hills. First claims were located in 1879. Started in 1881 and closed in 1912 as the "Mammoth" mine. Later became the Mammoth-St Anthony mine and incorporated the Collins mine/vein. Worked 1916-1919 and 1935 to 1953. Owned by the Magma Copper Co. (1953 to end). Prior to that, it was owned by the Mammoth-St Anthony Mining, Ltd. (1935-1953). Additional names which apply to this property are Tiger property; Mammoth Gold Mines Ltd. property.
Mineralization in this district is a series of veins within shear zones that strike WNW-ward and dip steeply SW-ward. Their gangue consists of brecciated country rock cemented and replaced with quartz and calcite together with some baryte and fluorite. The quartz forms successive bands of which some of the latest generation show well-developed comb structure and are locally amethystine. Most of the gold occurs in an earlier generation of dense, greenish-yellow quartz. The gold tends to be fine-grained, but in places its particles are visible. Wall rock alteration along the veins consists mainly of chloritization and silicification. Such alteration, together with the texture and mineralogy of the veins, points to deposition in the epithermal zone.
The Mammoth ore body group run NW to SE (Mammoth, Mohawk & New Year), and appear to be one vein, termed the Mammoth vein. These veins dip steeply SW-ward. With approximately the same strike but steep NE-ward dip, the Mammoth fault comes to the surface near the Collins vein.
In the Mammoth mine, oxidation is complete to the 700-foot level. The ore on the 760-foot level is reported to be largely oxidized, with some residual bunches of galena. The galena is reported to contain 25 oz. Ag/T and 0.375 oz. Au/T. Apparently, there were 2 steeply SE-ward pitching ore shoots that diverged, branched, and became smaller upward. Between the 400-foot and 760-foot level, these shoots ranged from 45 to 150 feet apart, from 7 to 40 feet in width, and from $6.24 to $11.96 (period values) in gold per ton. The NW shoot ranged from 200 to 395 feet in length and the SE from 90 to 220 feet. The production of gold from the Mammoth and Collins mines through 1901 was over 150,000 ounces valued at more than $3,000,000 (period values). Total production of the Cap from 1881 thru 1947 was 1,889,375 tons of ore yielding 397,201 oz. Au, 983,918 oz. Ag, 3,456,121 lbs. Cu, 74,730,289 lbs. Pb, 48, 272,654 lbs. Zn, 6,314,822 lbs. MoO3, and 2,540,842 lbs. V2O5.
The camp was largely active from 1901 until 1915 when the wartime demand for molybdenum and vanadium resulted in reopening of the mines for a short period. In 1919 the metal prices fell, and the mines closed again.
The increase in the price of gold in 1933 caused renewed activity, and production of Au-V-Mo ores began in 1934 from the oxidized part of the veins. Mining continued until 1943 when the high prices and the need for base metals resulted in the development of the sulfide ore bodies below the 650 level of the Collins vein for Pb & Zn (galena & sphalerite).
The workings included a vertical shaft that was in the middle of the town of Tiger, which was later obliterated by the owners of the nearby San Manuel mining complex. The workings went to 1,125 feet deep. You may still stand on the rim of the pit resulting from the San Manuel mine operators desiring to kill 2 birds with one stone - use the high-silica rock for a smelter flux and recover the gold value; however, there proved to be too much lead in the mix and the effort was abandoned. The town is gone, the shaft is filled in and marked with four corner stakes of rebar at the bottom of the 20 to 30-foot deep pit. Look to the West and observe the cleft in the hill behind the former town as the caved area of the Collins vein. Look in the opposite direction to the East and observe the headframe of the former Mohawk mine outlined against the oxide ore leach heaps from the San Manuel oxide mine.
Mindat ArticlesA New Occurrence of Munakataite, a Rare Selenium Containing Mineral Species by Robert Meyer
Mineral ListMineral list contains entries from the region specified including sub-localities
108 valid minerals. 10 (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. 
Localities in this RegionShow map
- Pinal Co.
- Mammoth District
- St. Anthony deposit
- Mammoth-Saint Anthony Mine (Mammoth-St Anthony Mine; Mammoth Mine; St. Anthony Mine)
- St. Anthony deposit
- Mammoth District
- Pinal Co.