Historic Zinc Smelter Engine Preserved

Although now one of Oklahoma’s best-kept secrets, the engine that once contributed up to 10 percent of annual zinc production worldwide lives on in Pawnee, Oklahoma. The Blackwell Zinc Co. smelter, once one of the world’s largest, operated in Blackwell, Oklahoma, from 1916 to 1974. The number of tractor and automotive carburetors and other parts cast from zinc and zinc alloys that might have originated in that facility is mindboggling.

Many collectors today think of Allis-Chalmers as a tractor manufacturer, but in the late 19th and early 20th centuries, Allis-Chalmers specialized in production of small- to medium-size plants, generally supplied turnkey to the customer. Allis-Chalmers equipped the Blackwell smelter with two Corliss steam engines, each direct-connected to its own 350kw alternator. The engines were designed to run at 150rpm. At that speed, the alternator produces 60 hertz 3-phase AC current at 480 volts per phase. Two water-tube natural gas-fired boilers were provided by Babcock & Wilcox.

After the plant closed in 1974, Pawnee resident Kenneth Kelley led a group of volunteers in an effort to save one of the plant’s two Allis-Chalmers Corliss steam engines from destruction. Volunteers dismantled the engine and moved it to Pawnee. Volunteers also saved the exciter engine used to provide field current for the two alternators and the steam-powered Worthington fire pump from the smelter. Today, the club’s Corliss engine is listed on the National Register of Historic Places.

Though far from the largest industrial engine ever built, the Blackwell engine is nonetheless a good-size engine by every measure. It weighs 110 tons (its 12-foot diameter flywheel alone weighs 10 tons). The cylinder bore is 20 inches in diameter and the piston stroke is 36 inches. The foundations are replicas of the originals made from the 1914 blueprints provided by Allis-Chalmers in the 1970s. The foundations (made from poured concrete) extend 7 feet below the engine. FC