Magma Mine (Magma Superior Mine; Irene claim; Hub claim; Pomeroy; Superior Division; Silver Queen; Monarch claim; Magma Copper Mine; Broken Hill; Apex), Superior, Pioneer District, Pinal Mts, Pinal Co., Arizona, USA
|Latitude & Longitude (WGS84):||33° 18' 11'' North , 111° 5' 58'' West|
|Latitude & Longitude (decimal):||33.30306,-111.09944|
|Other regions containing this locality:||Sonoran Desert, North America|
|Köppen climate type:||BSh : Hot semi-arid (steppe) climate|
A former underground Cu-Mo-Au-Ag-Pb-Zn-Mn-As-Bi-Cd mine located in all of sec. 35, T1S, R12E (Superior 7.5 minute topo map), on the N side of Superior, on private property. Discovered by Charles C. Mason in 1874. Produced 1880 to 1981. Originally called the Silver Queen (1875-1909). Magma Copper Company began operating it in 1910 with minor production until 1911, when ownership passed to the Lake Superior and Arizona Mining Co. Previously owned by Newmont Mining. This mine was idle in recent years but was being explored through drilling early this year (2002) by new owners. This is a deep mine that is extrordinarily hot. Also known as / designated: Amalgamated Gold, Silver and Copper Co. property; Patneted claim MS340, MS 350, MS 2930a, MS 3144 and MS 4152; and the Magma King Manganese Mining Co. property. Claims extend into secs. 23-27, 29, 34-36, and into T2S, R12E, T1S, R13E, and T2S, R13E. The workings are located in secs. 35, 36, 25 and 26. Main shafts in the NE¼, sec. 35, and the NW¼ sec. 36. Magma Copper Co. has state leases in secs. 4, 5, 8 & 9, T2S, R13E.
The orebodies are replacements within the Magma and Koerner fault zones of the east-west system. Those of the Magma vein constitute by far the greater proportion of the tonnage extracted or developed. The ore consists of distinct shoots or bodies. The ore bodies dip 70-80N, at 1493.52 meters thick, 121.92 meters dept-to-top, 4900 meters depth-to-bottom, 152.4 meters wide, and 2651.76 meters long. Ore control was faults and fractures, mainly E-W-trending, associated with crushed fault fillings. Also Devonian (Martin) Limestone replacement on the eastern extremity.
The main or largest orebody has been developed laterally between the Main fault and No. 4 shaft and vertically from the 400 to below the 4600 level as measured below the collar of No. 1 shaft or 5,800 feet down the pitch. In the vicinity of the 1200 level at 4,600 coordinate, the ore consists of sphalerite and a little galena, with only traces of copper. Between the 1300 and 1400 levels it changes abruptly into a bornite-rich ore with little or no zinc and lead. In levels above the schist the width of the main orebody ranges from 5 to 40 feet. Where the vein is wide, the ore generally occurs as two or more rich stringers separated by poorer vein material.
The West orebody is a faulted segment, possibly of the Magma vein, west of the Main fault and east of the Concentrator fault. This vein segment strikes alomost east and dips steeply north. The West orebody averaged about 15 feet in width and 7% in Cu content together with subordinate zinc and lead.
The East orebodies or "zinc stopes" lie east of zero crosscut. These bodies are not continuous, and none of the known oreshoots persists for more than several hundred feet. In general sphalerite predominates above the 2550 level, and chalcopyrite below.
The Koerner vein orebody is similar to the Main orebody but smaller. Mineralogically, its ore is indistinguishable from that of the Main orebody on the same levels. Local serpentinization & uralitization, sericitization.
A dike of quartz monzonite porphyry occurs within the Magma fault zone from the surface to the 1200 level, and in many places deeper it forms either the orth or south wall of the vein. The dike was not sufficiently mineralized to constitute ore.
Diabase was the most favorable host rock for ore deposition in the Main oreshoot.
Practically all of the zinc orebodies have quartzite or limestone for one wall. Replacement bodies in limestone are limited chiefly to the zinc-copper area. Here the "Lake Superior and Arizona" zone, in Martin limestone about 20 feet stratigraphically above the Troy quartzite, has been replaced by ore of good grade for a thickness of 30-50 feet and a width ranging up to 30 feet.
In the Pinal schist, the zone of faulting and mineralization in the Magma vein is considerably wider than in the upper levels and commonly contains horses of relatively unbroken, unmineralizaed wall rock. Its walls are less distinct, in many places indefinite, and perhaps more than 100 feet apart. Orebodies here tend to be lenticular both horizontally and vertically. Where both walls are in schist, the mineable vein forms two branches.
The outcrop of the Magma vein has been so leached that gossan is generally lacking.
Host rock units include Pinal Schist, Dripping Springs Quartzite, Apache Group-Mescal Limestone, Martin Limestone and Apache Basalt. Alteration includes serpentinization and uralitization and sericitization.
Workings include 8 shafts. This is the deepest mine in the state. There are 36 levels, with levels every 100 feet in the upper 2000 feet, and then every 200 feet apart down to 4800 feet. Workings diminish in thickness to the east, and are mainly between the 3000 foot and 4000 foot levels. The length of workings is estimated.
Mineral ListMineral list contains entries from the region specified including sub-localities
57 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
|Olenekian - Ediacaran|
247.2 - 635 Ma
|Paleozoic sedimentary rocks|
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.