The old St. Nicholas Coal Breaker was at one time the largest and most productive coal breaker in the world; divided into two separate halves that could be run independently—each producing 12,500 tons of coal per day, the plant producing 25,000 tons of coal per day when running at full capacity. It had a single-hopper dumper building feeding its conveyor with two dumping bays. The left or west side of the building accommodated coal hopper cars with bottom dump doors or dump truck loads; the right and east track was a rotary dumper, capable of holding down and rotating two forty-foot hoppers on its dumper tracks.
Constructed on a site less than half a mile away in 1972, the new St. Nicholas coal operation is a modern coal processing plant, a successor system to the breakers that once towered as much as twelve stories above the local terrain. Built tightly into the hillside, the new plant still towers about seven stories over the shipping lot where various grades of anthracite fill semi-dump trucks for transport. Unlike the old St. Nicholas breaker, the newer plant ships mostly by truck, and its rail-loading operations utilize a shuttle line of trucks successively shuttling coal loads from the loading yard, down the drive and across the street to a dump-to-railcar building, then looping back when loading a large consist of railroad hopper cars.
As of January 2015, demolition has officially begun on the old breaker and support buildings in Mahonoy City.