Tyrone Mine, Tyrone Area, Burro Mountains Mining District, Grant County, New Mexico, USAi

Regional Level Types
Tyrone Mine	Mine (Active)
Tyrone Area	Area
Burro Mountains Mining District	Mining District
Grant County	County
New Mexico	State
USA	Country

Mining began circa 600AD by native Americans for turquoise. Underground mining began in the 1860's with open pit operations starting in 1968.

Porphyry copper deposits are low-grade (<0.8%) disseminated deposits of copper found in and around small intrusive bodies composed of porhyritic diorite, granodiorite, monzonite or quartz monzonite. Primary chalcopyrite is non-economic and required supergene enrichment to chalcocite and covellite to form economic deposits.

An open pit mine in a porphyry copper deposit. Located just SW of Silver City, NM. Mined from the Main, San Salvador, Gettysburg and Copper Mountain pits. Owned by Phelps Dodge Corp. & Burro Chief Copper Co. (1985).
This mine has removed several other old underground mines in the area and covered others with the dumps.

The Open Pits at the Tyrone Mine Facility include the Main, West Main, Valencia, Gettysburg, Copper Mountain, South Rim, Savanna and San Salvador Hill pits.
Previously mined and now partially or completely backfilled pits include the San Salvador Hill, Virginia Racket, West Racket, East Main, Gettysburg Entry, BA-O, and Upper Main. Of the existing open pits at the mine, the Main, West Main, Valencia, Savanna, and Gettysburg Pits are contiguous.
Includes A Number of Older Underground Mines: Gettysburg, Copper Gulf, Rocket, Niagra, Mowhawk, Sampson, McKinley, St. Louis, Boston, Virginia, Klondike, Valencia, Emerald

Structure: Five Northeast Trending Zones Of Closely Spaced Fractures Are Also Zones Of Higher Grade Ore. Deposit Bounded To Nw By Nne Burro Chief Fault And To S By Ew Racket Virginia Fault.

Alteration: Alteration Products: Sericite, Quartz, Chlorite, Epidote, Kaolinite. Erratic Argillic Alteration. Pervasive Quartz-Sericite Alteration. Peripheral Propylitic Alteration With Chloritized Biotite, Feldspar Altered To Montmorillonite, And Addition Of Pyrite. Silicification Along Contact Between Eeo Porphyry And Prec Granite.

Tectonics: Continental Magmatic Arc

Commodity: Presence of torbernite suspected due to radioactivity recorded in some drill holes.

Deposit: Deposits occur in a highly fractured disseminated copper porphyry stock. Numerous fracture fillings and veinlets were mined underground prior to open pit operations. Protore consists of quartz-sericite-pyrite-chalcopyrite stockwork veinlets with very little bornite and grades of 0.05 to 0.15% cu. Multiple stages of primary copper veinlets are hosted by prec granite, cret andesite, and four stages of eeo quartz monzonite porphyry. The chalcocite enrichment blanket, up to 500 ft thick, had grades of 0.8 to 1.0% cu. Chalcocite replaces pyrite and chalcopyrite. Enrichment blanket is overlain by a hemetitic leached capping up to 500 ft thick. Oxide ore in leached blanket in copper mountain pit consists of chrysocolla-malachite-azurite veinlets, coatings, and rare disseminations grading 0.06 to 0.60% cu. Secondary enrichment occured at 45 ma (eeo). About 350 million st of 0.2 to 0.4% cu protore was enriched to about 0.8% cu. Enriched blanket was subsequently offset by nne trending faults. Additional concentration of chalcocite occured along these nne trendings faults and fractures at 19.5 ma (emio). These formed tabular bodies of chalcocite ore averaging 2 to 3% cu of which at least 20 were partly mined out by old underground workings. All mineralization cut by unrelated mio? fluorite veins.

Deposit type: Porphyry Cu-Mo

Development: Work, later merging to form the savannah copper co. (2577 ac) which was acquired by phelps dodge in 1916. In 1906 briggs oliver development co optioned the burro chief group from thomas parker, was suceeded by the tyrone copper co. And then the chemung copper co. (953 ac) which was acquired by phelps dodge in 1912. Having consolidated control of the major chalcocite vein properties, phelps dodge developed a 1400 tpd mine and mill from 1913 to 1916 and operated the mine from 1916 to 1921. Leach operations, producing cement copper continued to 1928 when leach plant was dismantled. Intermittent development and production by company and leasers ceased in 1949. From 1949 to 1958. Phelps dodge delineated the supergene enrichment blanket orebody by drilling 720 churn drill holes on 200 ft centers over an area 8400 ft east-west by 9400 ft north-south for a total footage of 434,000 ft to a maximum of 1000 ft depth. During that time phelps dodge acquired property of the azure mining co. Turquoise mined by native americans. John e. Coleman located first copper and turquoise claims in 1869. St. Louis claim located 1879 by james bullard, john swisshelm, and j.w. Fleming then sold to val verde copper co. Oxide surface ores, smelted in a 5o tpd reverbatory furnace located in dead man gulch, were quickly exhausted. A 500 ft shaft cut the tabular st. Louis chalcocite orebody. About the same time the alessandro copper co. Attempted to leach oxide ores from claims 3 miles east of the st. Louis and another smelter at oak grove ran for a short time. The val verde copper co. Was subsequently absorbed into the southwestern copper co. Which later acquired the sampson and other properties. In 1901 the burro mountain copper co. Took over the southwestern copper co. And built the leopold mill. The burro mountain property (1000 ac) was optioned by phelps dodge in 1904 and acquired in 1906. Around 1905 the comanche mining and smelting co. And copper gulf development co. Began and the american gem and turquoise co. Stripping began may 1, 1967, mill operations began in 1969, and leach operations began in 1972. Mill operated continuously until february, 1992 when reserves of mill ore were exhausted. Mill subsequently dismantled except for one 15,000 tpd section retained for treatment of mill ore which may become available during mining of recently delineated leach ores. A sx/e W plant of 14,000 tpd capacity was installed in 1984. A fourth expansion in 1992 brought capacity to 70,000 tpd. Additional drilling from 1991 continues to delineate more leach ore reserves.

Rock formation(s): Tyrone Stock;Stage I Porphyry;Stage Ii Porphyry;Stage Iii Breccia;Stage Iv Porphyry

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Link to USGS MRDS:	10012285

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