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Jan 17, 2024

Mining plants were dependent on steam to stay modern

Apr 2, 2022 Illustration courtesy of savRee Diagram of a basic Blake stone

Apr 2, 2022

Illustration courtesy of savRee Diagram of a basic Blake stone crusher.

As technology advanced from the mid-19th century onward, some newly patented machinery not designed specifically with mining or concentrating in mind, nevertheless, was readily adopted to the mining industry and was eagerly welcomed. One very important such invention — and often overlooked — is the jaw crusher, patented in 1858 by a man named Ely Whitney Blake.

Eli Whitney Blake was a native of Worcester County, Massachusetts, and a nephew of Eli Whitney, inventor of the cotton gin. Blake was an 1816 graduate of Yale, but abandoned advanced study of law when his uncle, Eli, asked for his assistance in organizing and erecting a gun factory in Whitneyville, Connecticut. A talented mechanical engineer, in 1852, Blake was appointed to superintend the macadamizing of the city streets of New Haven, which alerted him to the fact that there was no proper machine for breaking rock. Want of such a machine was one of the causes of production bottlenecks at the Lake Superior copper mines, where rock-breaking was still done by calcining, which Georgius Agricola mentioned in his book "De Re Metallica," first published in 1556. New Haven was using a similar process for its road surfaces.

Blake's solution was to invent what he called, simply, "a machine for crushing stone." Steam-powered, Blake's crusher had a fixed plate and one that pivoted at the top to give it the greatest movement. Rock was fed into the top of the crusher and gradually moved downward toward the discharge outlet at the bottom of the jaws. According to savRee, an engineering website, the V-shaped area between the two jaws is referred to as the crushing chamber. Because the space between the two jaws becomes narrower toward the discharge outlet, the rock is progressively reduced.

Although they greatly increased efficiency, reduced time, saved money and labor, and were used at almost every shaft at which a mine had steam power, they were seldom mentioned in mining company annual reports. Reports generally reported rock hoisted up from the mine, then rock being processed at the stamp mill, but rarely mentioned preliminary crushing. In 1900, Horace J. Stevens, in his book "The Copper Handbook," in reporting of the Calumet and Hecla Mining Company, wrote:

"The shaft-houses at the incline shafts are of uniform pattern. At each the rock is hoisted from the mine to the top of the shaft-house, where it passes through ‘grizzly,’ which allow the finer rock to fall through, the larger masses being reduced in crushers of the jaw type with openings two by three feet." After the preliminary crushing, Horace continued, floor below, was another crusher, 18 x 24 inches, in each shaft-house, Stevens wrote.

The Quincy Mining Company's shaft-rock houses had similar arrangements, according to author and editor Thomas Rickard. In discussing the rockskip being hoisted into the top of the structure from the mine shaft, Rickard wrote:

"When the skip is dumped, the contents fall upon a grizzly, made of fixed cast-iron bars capped by a removable angle-iron, the spaces being 2.5 inches wide. The biggest of the oversize is pushed readily into a low two-wheeled truck, and is then trundled to the rock breaker; this is an expeditious way of moving the pig pieces of rock, and is an advance on the usual manner of pulling across the floor."

Smaller pieces, he wrote, were thrown into the crushers.

As the grizzlies are laid at low angles, he wrote, some of the small pieces of rock came to rest on the bars, which was shoveled into the crushers.

Rickard stated that each of the ‘rock-houses’ was equipped with three Blake-type crushers. The largest had 18 x 24 inch-jaws (the same configuration as that used at C &H), while the two smaller crushers each had jaws set at 13 x 20 inches. Copper masses were placed under a drop hammer weighing 1.5 tons and having a drop of 20 feet.

providing an equivalent of 60-foot tons. Copper, being malleable, would flatten out or change shape after such a blow, knocking adhering rock from the mass.

Stevens, in 1899, wrote that at the No. 3 Baltic Shaft was a "substantial" shaft-rockhouse, framed in wood, sheathed with steel, 88-feet high. It was fitted with two Blake Crushers configured, like those at the Quincy and the C & H, to 18 x 24 inches, driven by an engine "with 16 x 18 inch cylinders."

Stevens also reported that No. 4 shaft had a "temporary plant, with a hoist good for about 1,000 feet, raising a one-ton skip."

In fact, all the shafts were opened with temporary equipment, he wrote, which "are being replaced, as opportunity offers, with permanent buildings and heavy equipment."

Stevens’ selection of the word "temporary," seems to suggest that at the Baltic's five shafts, they were started with portable second-motion gear hoists. Usually, second motion engines turned a single drum.

A second motion gear hoist consisted of two engines, with drum attached by means of drum shaft, receiving its motion by means of a type of gears (double-helical). The brake and reversing gears were operated by hand levers between the two cylinders.

Power, a weekly publication devoted to the generation and transmission of power, stated in its Dec. 28, 1909 volume, that at that time, the largest hoisting engines in the world were located at the Quincy and Tamarack mines, in "the copper country of Michigan." Both hoists were built by the Allis-Chalmers Company in the 1890s. As the publication stated, however, while newer and more powerful steam hoists were subsequently designed and built, electric hoists were also being designed, such as the electric hoist at the coal shipping terminal at Sewall's Point, near Norfolk, Va. which was rated at 1,000 horsepower.

While steam power did indeed revolutionize mining in Michigan's Copper Country, it was not steam alone that triggered the revolution. Innovations and improvements in stamp mill and concentrating called for larger steam engines and the boilers to power them. Jaw crushers, also powered by steam, aided the Michigan mining companies to remain competitive with the newer, open-pit mines in the west. Machine drill, powered by steam-powered air compressors, brought down more rock per shift than hand-drilling, and newer, more efficient steam-powered hoists could raise more rock, faster per day than older, portable hoists. By the turn of the 20th century, the mines in the Lake Superior region were fully equipped to compete with the western mines — as long as the copper content remained rich.

Graham Jaehnig has a BA of Social Science/History from Michigan Technological University, and an MA in English/Creative Nonfiction Writing from Southern New Hampshire University. He is internationally known for his writing on Cornish immigration to the United States mining districts.

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