Why dig the Pit?

Why dig the Pit?. . We needed copper! America's Industrial Revolution, the Age of Electricity, and the Information Revolution wouldn't have happened without it. Copper is a superb conductor of electricity. Every house, every car, every electronic gizmo from refrigerators to iPods needs copper wiring. We all depend on copper., The Lure of Copper , Underground mining targeted high-grade ore (rock containing a high concentration of metal). But as demand for copper rose through the 20th century and as new tecnologies made it possible to extract copper from low-grade ore at a profit-low-grade ore became a desirable resource. Some of the hills surrounding the underground mines contained low-grade ore. Open-pit mining went after low-grade ore. Open-pit mining methods maximized copper recovery., The Stockpile: Waste rock-rock that contains little or no copper - was piled into man-made hills called "stockpiles." The No. 7 Stockpile can be seen far to the left of the pit, beyond Bisbee. Nowadays, even tiny traces of copper may be valuable. Copper can still be extracted from the stockpile by means of a chemical process called leaching., Timeline: , 1908 - Ford Motor Company introduces Model T (demand for copper rises) , 1911 - Willis Carrier introduces air conditioning (demand rises) , 1912 - Arizona becomes a state , 1917 - United States enters world war one (demand rises) Blasting starts on Sacramento , 1921 - Production begins at Sacramento Pit , 1929 - New York Stock Market Crash (demand falls) Sacramento Pit ceases operations , 1941 - United States enters world war two (demand rises) , 1946 - Price controls on copper removed (prices rise) , 1950 - United States enters Korean conflict (demand rises) Development of Lavender Pit begins , 1954 - Production begins at Lavender Pit , 1956 - Copper export restrictions removed (prices rise) , 1965 - Dollar devalued by Johnson Administration , 1970 - National Air Quality Control Act signed , 1971 - Nixon severs US dollar from international gold standard , 1974 - US economy in recession (demand falls) Lavender Pit ceases operations , 1975 - First personal computers (demand rises) , 1989 - Cochise Project mineral deposit sampling begins , 2006 - Environmental remediation of Bisbee's historic mining district begins , 2008 - US economy in recession (demand falls), Goodbye - and Welcome Back? , By the mid-1970s Bisbee's mines had run out of desirable ore. Mining operations were shut down. Could mining in Bisbee start up again? It might if demand skyrockets (driving up the price of copper) and technology improves (making production cheaper). Then the VERY low-grade copper in Bisbee's hills could attract mining companies once more.