The Bull engines, from their strength and simplicity, give very little trouble, working year after year with astonishing freedom from accident and slight cost of repair.  No attempt is made to economize fuel, which consists mainly of culm, which would otherwise be wasted.  Of late, direct acting steam pumps placed under ground have found much favor with mine operators, on account of their portability and small first cost.  They usually range in size from 8 inch steam and 5 inch water cylinders by 12 inch stroke to 80 inch stream and 14 inch water cylinders by 36 inch stroke.  Great numbers of these pumps are in use all over the United States.

A pumping engine that is remarkable for its size and peculiarities of construction is located at the Lehigh zinc mine, at Friedensburg, Pa.  It was designed by Mr. John West, the company’s engineer, and built by Merrick & Sons, of the Southwark Foundry, Philadelphia.  It is a beam and fly-wheel engine, the steam cylinder being 110 inches in diameter, with a stroke of 10 feet.  There are two beams on the same main center, from the outer end of which a double line of bucket and plunger pumps is operated.  The crank-shaft is underneath the steam cylinder; and there are two fly-wheels, one on each end of said shaft, the crank-pins being fast in the hubs of the same.  There are two connecting rods, which are attached one to each end of an end beam pin 28 inches in diameter.  The main center and crank shafts are also 28 inches in diameter; each of the two plunger holes is 24 inches by 30 inches in section; and all the working parts are in proportion to those heretofore mentioned.

Perhaps no mining district has ever had to contend against greater difficulties in pumping than have faced the engineers of the celebrated Comstock lode, Virginia City, Nev.  The mines are of great depth, in some instances 3,300 feet; and the water is hot, rising to 160 degrees Fahr.  The machinery collected at this location is of great variety and magnitude.  There are many Davey engines, both horizontal and vertical.  The Union and Yellow Jacket shafts have compound fly wheel engines of very great power; the former having a beam, and the latter being horizontal, with cylinders placed side by side, and pistons connected to a massive cross-head, from the ends of which connecting rods lead to crank pins located in the hubs of the fly-wheels, which are overhung upon the ends of the main shaft.  From the center of the cross head, a link runs to the main pump-bob, which operates a double line of 16 inch pumps, 10 foot stroke.  The steam stroke is 12 feet.  Depth of shaft, 3,300 feet.

The pumping machinery used in the iron and copper districts of Michigan usually consists of Cornish plunger pumps, which are operated by geared engines; the latter making from three to sixteen strokes to one of the pumps.