in 1913, the minerals separation paid for a test plant for the inspiration copper company at miami, arizona. built under the san francisco office director, edward nutter, it proved a success. inspiration engineer l. d. ricketts ripped out a gravity concentration mill and replaced it with the minerals separation process, the first major use of the process at an american copper mine. a major holder of inspiration stock were men who controlled the great anaconda mine of butte. they immediately followed the inspiration success to build a minerals separation licensed plant at butte, in 1915-1916, a major statement about the final acceptance of the minerals separation patented process.