| Deposit ID | 10039684 |
|---|---|
| MRDS ID | M050650 |
| Record type | Deposit |
| Current site name | El Tiro Open Pit Mine |
| Alternate or previous names | Red Rock Group, Silver Bell Mine |
| Geographic coordinates: | -111.53764, 32.41622 (WGS84) |
|---|
Political divisions (FIPS codes)
Pima(county)
Arizona(state)
United States(country)
North America(continent)
Land(continent)
USGS map quadrangles
Silver Bell West(quadrangle 1:24,000 scale)
Silver Bell Mountains(quadrangle 1:100,000 scale)
Tucson(quadrangle 1:250,000 scale)
Hydrologic units (watersheds)
Aguirre Valley(hydrologic unit)
Santa Cruz(hydrologic accounting unit)
Middle Gila(hydrologic subregion)
Lower Colorado(hydrologic region)
| Country | State | County |
|---|---|---|
| United States | Arizona | Pima |
| Meridian | Township | Range | Section | Fraction | State |
|---|---|---|---|---|---|
| Gila and Salt River | 011S;012S | 008E;008E | 33;04 | SW4 (33); NW4 (04) | Arizona |
| Commodity | Importance |
|---|---|
| Copper | Primary |
| Molybdenum | Secondary |
| Silver | Secondary |
| Lead | Secondary |
| Gold | Secondary |
| Materials | Type of material |
|---|---|
| Chalcocite | Ore |
| Chalcopyrite | Ore |
| Cuprite | Ore |
| Limonite | Ore |
| Molybdenite | Ore |
| Pyrite | Ore |
| Result | TYPICAL ORE IS ALTERED ROCK & SULFIDES IN A RATIO OF ABOUT 10:1 |
|---|
| Model code | 53 |
|---|---|
| USGS model code | 17 |
| Deposit model name | Porphyry Cu |
| Mark3 model number | 4 |
| Host or associated | Associated | ||
|---|---|---|---|
| Rock type | Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Dacite | ||
| Rock type qualifier | dacite porphyry and an extensive mass of coarse grained alaskite | ||
| |||
| Host or associated | Host | ||
|---|---|---|---|
| Rock type | Plutonic Rock > Granitoid > Quartz Monzonite | ||
| Rock unit name | El Tiro and Imperial stocks | ||
| |||
| (1) | -111.53764, 32.41622 |
|---|
| Type of structure | Local |
|---|---|
| Structure description | Sheared Limestone, Parallel Fissures In Dacite Porphyry |
| General form | TABULAR |
|---|---|
| Thickness | 91.44M |
| Length | 670.56M |
| Width | 396.24M |
| Depth to top | 30.48M |
| Operation type | Underground |
|---|---|
| Development status | Past Producer |
| Commodity type | Metallic |
| Deposit size | Large |
| Significant | No |
| Year of first production | 1954 |
| District name | Silver Bell District |
|---|
| Ownership category | Unknown |
|---|
| Type | Operator |
|---|---|
| Owner | Asarco (American Smelting And Refining Co.) |
| Year | 1931 | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Period | Pre-1931 | |||||||||||||||||||||
| Material | ORE | |||||||||||||||||||||
| Accuracy | Estimate | |||||||||||||||||||||
| Description | Cp_Grade: ^5% Cu, 0.2 Oz Ag/T, Minor Au & Pb | |||||||||||||||||||||
| ||||||||||||||||||||||
| Agency | Database name | Acronym | Record ID | Notes |
|---|---|---|---|---|
| USGS | Mineral Resources Data System | MRDS | M050650 | |
| USGS | Mineral Resources Data System | MRDS | M030549 |
Richard and Courtright, 1966, Porph-Cu Volume Abm.
Browne, Q. J. and Miller, M. A., 2002, Use of geologic parameters for development of low-grade copper reserves, Silver Bell Mine, Arizona; In Society of Mining Engineers Annual Meeting and Exhibit, 2002, Technical Program, Society of Mining Engineers, p. 68.
Long, K.R., 1995, Production and reserves of Cordilleran (Alaska to Chile) porphyry copper deposits; in Pierce, F.W. and Bolm, J.G., eds., Porphyry Copper Deposits of the American Cordillera, Arizona Geological Society, Digest 20, p. 35-68.
Graybeal F T 1983 - Geology of the El Tiro area: in Titley S R 1983 Advances in Geology of the Porphyry Copper Deposits, Southwestern North America University of Arizona Press, Tucson pp 487-505
Kerr, 1951, Gsa Bull 62, P. 451-480.
Lopez J A, Titley S R 1995 - Outcrop and capping characteristics of the supergene sulfide enrichment at North Silver Bell, Pima County, Arizona: in Pierce F W, Bolm J G (Eds), Porphyry Copper Deposits of the American Cordillera Arizona Geol. Soc. Digest 20 pp 424-435
Hardwick, 1963, USBM Ic 8153.
Richard K, Courtright J H 1966 - Structure and mineralization at Silver Bell, Arizona: in Titley S R, Hicks C L 1966 Geology of the Porphyry Copper Deposits, Southwestern North America University of Arizona Press, Tucson pp 157-163
Cook S S and Porter T M, 2005 - The Geologic History of Oxidation and Supergene Enrichment in the Porphyry Copper Deposits of Southwestern North America, in Porter T M, (Ed), Super Porphyry Copper and Gold Deposits: A Global Perspective, v1 pp 207-242
Keith, 1974, Abm Bull 189, P. 143.
Galey, 1979, Soc Econ Geol, Porphyry Cu Field Conf, 18 P.
The Porter GeoConsultancy webpage for Silver Bell contains a description of the geology at El Tiro. Accessed on 8/12/2010.
http://www.portergeo.com.au/
Cimri
S B Keith Ariz Bur Mines Bull 189 1974 P 143
| Subject category | Comment text |
|---|---|
| Deposit | Ore In Thin Quartz Sulfide Veinlets That Form A Disseminated Deposit In Aggregate. Large Size Refers To Silver Bell Property; Underground El Tiro Operations Prior To 1931 Were Small. |
| Type | Date | Name | Affiliation | Comment |
|---|---|---|---|---|
| Reporter | 01-MAR-83 | Peterson, Jocelyn A. | U.S. Geological Survey | |
| Reporter | 04-NOV-83 | ADMR | U.S. Bureau of Mines |
Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.
MRDS records operators as of each record's last update (≤ 2019). Some of the operators listed here have since changed hands or dissolved:
Curated by qvyshift.com from publicly-reported M&A activity (SEC filings, press releases, USGS Mineral Yearbooks). Not authoritative — verify against primary sources before relying on it. The MSHA panel above is the current authoritative source for actively-permitted mines.
These are landing pages for further research — the state agencies don't currently expose per-mine deep links.