Morenci Copper Mine Case Study

Morenci is the largest copper mine in North America. Just before Richard started working there, they had set the world record for the highest production open pit mine in the world – 12.4 million tons of material were moved in 24 hours. It is geographically located in eastern Arizona. The mine is run by a company called Phelps Dodge. Approximately 2,000 people work at the mine. (“Morenci Copper Mine”) In the mid 90’s Richard Arstein was working at Caterpillar Proving Grounds, south of Tucson, as a test engineer. People there are only supposed to work for three to five years since it was a unique experience and an experience that they needed more people in the company to have, and he had been there five when an opportunity came up. There was a new exchange program in which Caterpillar and Phelps Dodge would trade employees for a while, and Richard signed up. He …show more content…
They drilled holes 55 feet deep and 12 5/8 inches in diameter in a chevron pattern (like you’d lay out cookies on a cookie sheet). They took samples from each hole at various depths and sent them to the Assay lab for the contents of each to be analyzed. After that, blastmaster, Charlie “Red,” would come and analyze the hole and label it with the amount of ANFO to use. ANFO is a mixture of Ammonium Nitrate and Fuel Oil. It is the same stuff that was used in the Oklahoma City bombing. To put the scale into perspective, about 1500 pounds were used in that event, and at the mine, there was, on average 1800 pounds in each of the approximately 400 holes that would be blasted in a day. That means that about 480 times the amount used in the bombing was used in a day in the mine. (Arstein) Then the ANFO was put into each hole, with a detonator and a booster at the bottom and middle of each hole. Finally, the “stemming” would be put on top, to seal the hole and to put as much of the energy as it could into the surrounding