Advancing tech signaled mine success

It their exploration phases, mining companies began, of course, with locating a prospective copper vein. Once found, the next step was to open the vein to explore its potential wealth. In the Lake Superior copper district, geological forces had determined that copper veins were, in most cases, either vertical or nearly vertical, and once opened, shafts were sunk to follow the same direction and angle of the vein.

In this early stage of exploration, companies employed primitive hoist technology, but it was also the least expensive, and easy to maintain and repair. At the shaft, that technology was a man-powered windlass.

Simple in design, it consisted of a wooden winding drum, or barrel, wound with rope, mounted on an axle. At the other end of the rope was a large, usually wooden, bucket. Men operating the windlass lowered or raised the bucket in the shaft, by winding or unwinding the rope by turning the drum.

Volume XVI of The Colliery Engineer and Metal Miner, for 1896-97, described the system as “the winding drum, or barrel, was generally from six-10 inches in diameter, was supported on a framework platform set over the collar of the shaft. One-inch to 1 1/4-inch diameter hemp rope was used, with several windings around the barrel. A windlass should be manned by two men.”

The publication then issued a stern warning: “Under no circumstances should a single man be allowed to raise or lower another man.”

Windlasses, although inexpensive, had disadvantages and limitations. First, they were slow. Second, they were in the way, being directly over the shaft, but most significantly, the maximum depth from which a windlass could hoist was just 100 feet. The Colliery Engineer stated that in an eight-hour shift, a windlass could not raise more than six tons, and four to five should be expected as normal.

If the mine proved productive, and the windlass reached its limits, it was most often replaced with a horse whim, or a gin. Similar in principle and function to a windlass, whims were just on a larger scale of hoisting technology. Using mathematical formulas, The Colliery Engineer determined that one horse could hoist 15 tons in an eight-hour shift from a recommended depth of 350-400 feet.

The Cliff mine did not even reach that depth with its whim before it ran into production problems. The No.1 Shaft had reached a depth of 246 feet in 1849, and by doing some close figuring based on copper production reports and tonnage hoisted from 1849 and 1850, calculated a drop in production in that time of 83,992 pounds of barrel copper, and an even more dramatic decrease of 367,838 pounds of mass copper raised.

Yet, the mining captain’s and geologic reports indicated no diminish in copper content in the vein. The directors compiled their data, suspected the cause of the production drop, and applied what they thought would remedy the problem.

“…owing chiefly to the want of adequate power for raising the refuse rock and rubble,” stated the company’s 1851 Annual Report, “the mine has not been opened as rapidly as desired. The power employed was an ordinary ‘whim’ propelled by horses.”

To remedy the bottleneck in the mine, the Board of Directors invested $6,000 ($1.8 million in 2016) to erect a steam-powered hoisting plant at the No.1 Shaft, which included the boiler, fixtures, hoist, and necessary buildings. The new hoist became operational in September, 1850.

Unfortunately, beyond stating it was “a steam hoist of great power,” the Annual report offered no details or description, nor do the balance sheets, mentioning only “steam-engine.”

In the Ontonagon District, the Minesota Mine offered little more in its 1859 Annual Report, the first one published by the company. That report stated its inventory only as “three steam-engines, for hoisting from the several shafts,” and went to state, “The three hoisting engines have each a capstan attached.”

That was a very unusual configuration in the Lake Superior copper district, then or later. As steam-powered hoists became standard in the region, they were nearly always outfitted with horizontal winding drums, whereas the Minesota’s report stated its hoists were equipped with capstans, indicating their winding drums were vertical, rather than the standard horizontal.

With both the Cliff and the Minesota, records and archaeological evidence suggest single-flue, Cornish boilers were employed for power, and we’ll talk about them over our Saturday coffee next week.

While the installation of a steam-powered hoist was necessary for increasing the rate of production at the shaft, to many it was also a symbol of success and wealth of the mine.

As demonstrated by the Cliff Mine in 1850, the conversion from horse to steam power, was indeed an expensive leap, one that required extensive thought, hard consideration, thorough studying of mine and production reports, fluctuation of copper prices, and the ability to accurately interpret what the production figures, costs, sales, and dollar-added-value of steam. The Directors were not so much investing current available capital as they were investing in the mine’s future ability to produce.

For us today, looking at those old mid-19th century company reports, we need to remember the difference in economics between then and now. It is easy to think: “$6,000 seems like a cheap enough investment for the time,” but we then need to consider that $6,000 for that time is today’s equivalent to $2 million. For a copper mine on the northwest frontier, of which the only transportation was by water, $2 million was an astronomical sum of money to invest, rather than just distribute it to the shareholders.

It was a statement to anyone who cared to listen that the company was staking its money on the mine’s future, rather than on its current profits. In other words, the early mining companies in the district stated they preferred to turn a slow dime to a fast nickel.