Colorado Fuel and Iron Company opened the Allen Mine in western Las Animas County in 1951 and named it for Charles Allen Jr., who had assumed control of the company in the mid-1940s. Considered one of the most modern mechanized coal operations in the nation, it employed an average of 500 people. Workers and coal moved in and out by rope hoists and rectangular vehicles called slope cars, while coal brought to the surface was loaded onto train cars of the company's Colorado & Wyoming Railroad and shipped to Pueblo for steelmaking and other commercial uses. A dinky engine, a small locomotive or diesel engine, hauled equipment, supplies, and materials around the site. The mine supplied coal to the steelworks in Pueblo until 1983, when changing technology, rising international competition, stricter environmental laws, and the shift of steelmaking furnaces to electric power brought the end of CF&I's mining operations.