Butte Montana Mining History
It was so successful that the GBP block caving development was limited to the work completed by 1958. The Berkeley Pit became the major mine in Butte, feeding the new Weed Concentrator 30,000 tons a day by 1963, devouring three neighborhoods in the process. The last caving was done in 1963 through the Kelley shaft, the last one sunk in Butte.