the copper country strike of 1913–1914 was a major strike affecting all copper mines in the copper country of michigan.the strike, organized by the western federation of miners, was the first unionized strike within the copper country.it was called to achieve goals of shorter work days, higher wages, union recognition, and to maintain family mining groups.
the united states is a net exporter of copper ore and copper concentrate. in 2015, out of 1.25 million metric tons of recoverable copper metal extracted from mines, 320,000 tons of copper were exported in the form of ore and concentrate, to be smelted and refined elsewhere.
within the first year of operation, the pit extracted 17,000 tons of ore per day at a grade of 0.75% copper. ultimately, about 1,000,000,000 tons of material were mined from the berkeley pit. copper was the principal metal produced, although other metals were also extracted, including silver and gold .
kennecott utah copper llc kuc , a division of rio tinto group, is a mining, smelting, and refining company. its corporate headquarters are located in south jordan , utah , usa. kennecott operates the bingham canyon mine , one of the largest open-pit copper mines in the world in bingham canyon , salt lake county , utah.
exploration activities between 1952 and 1960 expanded the mount isa ore reserves from 9.9 million tons of lead-zinc-silver ore to 25.6 million tons, and from 3.8 million tons of copper ore to 24.2 million tons.
molybdenum is mined as a principal ore and is also recovered as a byproduct of copper and tungsten mining. the world's production of molybdenum was 250,000 tonnes in 2011, the largest producers being china 94,000 t , the united states 64,000 t , chile 38,000 t , peru 18,000 t and mexico 12,000 t . the total reserves are estimated at 10 .
in 1973, a new copper concentrator, known as the 'no. 4 concentrator' was commissioned to treat the copper ore at a rate of six million t/y of ore containing 3% copper and 55–60% silica and the old no. 1 concentrator was shut down, and a new fluidized-bed roaster was installed in the copper smelter to replace the multiple hearth roasters .
native copper is an uncombined form of copper that occurs as a natural mineral.copper is one of the few metallic elements to occur in native form, although it most commonly occurs in oxidized states and mixed with other elements. native copper was an important ore of copper in historic times and was used by pre-historic peoples.. native copper occurs rarely as isometric cubic and octahedral .