THE UEBERROTH ZINC MINE, PENNSYLVANIA, AND ITS MASSIVE “CORNISH” ENGINE (1872-76)

On the SE outskirts of Allentown, PA, beside the flooded open pit that marks the site of the Lehigh Zinc Company’s Ueberroth Mine, stands the house of the largest stationary steam engine built in North America. The Bethlehem-based company (1860-1911) owed its existence to the 1853 discovery of rich zinc ore in the dolomitic limestones of Friedenville’s Saucon Valley. But the mines were notoriously wet and, at Ueberroth, a series of increasingly larger pumps were erected to cope with this problem. In 1869, the company’s engineer, Cornishman John West, was asked to design an engine capable of pumping 12,000 gals/min from a depth of 300 ft. His engine, a condensing, double-acting rotative beam engine weighing 675 tons, was unique, but proved to be as successful as it was gargantuan. With a 110-inch cylinder and two latticework beams, the engine worked pump rods in the shaft and a pair of huge flywheels inside the engine house. It was built at Merrick & Sons Southwark Foundry in Philadelphia, although much of the casting was subcontracted to Lazell, Perkins & Co. of Bridgewater, MA, and the pumps, boilers and mountings were manufactured by I.P. Morris & Co. of Philadelphia. Erected by Cornishman Simeon Noell, the engine was set to work on January 19, 1872, and was run continuously until October 28, 1876, when the mine was allowed to flood. West is thought to have called his engine “The President” in honor of President Grant who had been invited to officiate at its dedication, but failed to arrive.

The engine house, built of Potsdam Sandstone, is three stories high with the first floor at the elevation of the air pumps and condenser, the second floor near the top of the cylinder, and the third at the level of the beams. The north wall, which supported the beams, is 9 ft thick with slots for the two flywheels; the rear (south) wall contains the cylinder opening, above which is the steam inlet and recesses for the two spring beams; and two square stacks that served the engine’s 16 boilers occupy the rear corners. The boilers were housed in an adjoining building to the rear. The house plan is dominated by a central masonry platform, to which the engine was anchored, with large pits on either side for the flywheels and cranks. As a record of West’s extraordinary engine and a rare example of the use of beam engines in North America, the house is a prime candidate for preservation.