We had a great day touring Butte Montana, especially looking into the history of copper mining there. But first we toured the old “Uptown” area. consisting of many square blocks. The older buildings, some of Victorian architecture, were made of brick, often of several stories. Most of the commercial buildings housed businesses; few were empty. The phrase “Richest Hill on Earth apparently is a nickname for Butte. It was the largest city in Montana until about 1960.
Snow capped mountains were readily seen from “uptown”.
The headframe for this old underground copper mine on a hill above the city proclaims “Mile High” and “Mile Deep” The mine yard is at 5280 ft elevation and the workings go down 5280 feet from there.
Many underground mines close to each other were converted to open pit mining beginning in 1955. The original Bradshaw pit went down 1800 ft. by 1982, when the dewatering pumps were turned off. Water from two aquifers have been filling the pit since. The water now is about 1000 ft. deep. It is so laden with metals in solution that it is a Superfund site. The deeper more dense water is being mined for copper. The water is pumped to a structure, left in contact with scrap iron, and copper precipitates on the iron. The water is pumped back into the pit. The copper concentrate is removed from the scrap iron, and the iron goes back into the cycle to capture more copper. The process yields about 20,000 pounds of copper every month!
To the far right of the picture is the Montana Resources’ current open pit operation using conventional methods. The minerals recovered are copper and molybdenum, with small amounts of silver and gold.
Wider view of the open pit walls. There was no convenient observation point to look down into the pit.
Old “Euc” mine truck displayed is much smaller that mine trucks currently being used.
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