DRGW 5515 and 3 other SD50's have just begun loading at the Pittsburgh & Midway mine near Oak Creek, Colorado. This mine is now inactive and everything in this photo, except the rails, has been removed. Scanned from a color print.
The EMD SD (special duty) series are a strong and reliable kind of locomotive which still serve America's rails today. They have proved themselves reliable by clocking in several million miles of freight service over several decades.