THE CENTURY’S PROGRESS IN MINES AND MINING
By GEO. A. PACKARD,
Metallurgist and Mining Engineer.
When we consider how largely the discovery and exploration of America was due to the search for mines, that the precious metals might be found to replenish the depleted treasuries of European monarchs; and when we note that, as a result of this search, the world’s annual production of gold and silver had increased in the three hundred years following the discovery from $5,508,000, in 1500, to $48,995,000 at the beginning of the nineteenth century, we view with surprise the little progress made during this period in the art of mining.
At the beginning of the present century, we find in use the same general methods that were followed in the time of Columbus. The very first operation—the search for veins—was oftentimes conducted after the manner of the Middle Ages; for in Pryce’s “Mineralogia Cornubiensis,” which seems to have been one of the leading works on mining of the last century, there occurs, among other methods, a lengthy treatise on “How to Discover Mines by the Sole Virtue of the Hazel-tree.” Powder, although it had been invented for centuries, had been so little employed in mining that it was considered merely as a last resort. In a description of mining methods, another work says: “The soft vein is generally dug with the spade and turned out into wooden trays; but the hard veins are knocked out with a gad and a hammer. If the ore is so hard as to be incapable of breaking it in this manner, they usually soften it with fire. But a still more expeditious method is the working with gunpowder. A small quantity of powder does great things this way.”
In 1800 the coal miner was working by the naked light of the tallow dip. Cast-iron rails had been introduced but a few years, and rails of wrought iron, which could be bent to follow the curves of the drifts, were unheard of. The cars were pushed along the levels by boys. Water power, where it could be obtained and applied by means of the overshot wheel, was in general use for pumping, hoisting, and ventilating. But from many a mine the ore was raised by women, who pulled the bucket up “by walking away with the end of the rope” which passed from them over a sheave and thence down the shaft. In places the ore was still carried up the steep inclines to the surface on the backs of women and girls. Ventilation, when not secured by natural means, was obtained by bellows operated by men or mechanically. A mine which had been worked to a depth of one thousand feet was extraordinary. Though steam power, applied in the form of what was known as the atmospheric engine, a device utilizing for suction the vacuum formed by the condensation of steam in a chamber, had been used for years in draining mines, the steam engine, as invented by Watt, had been introduced for hoisting in only a few places. The power was applied to turn a long crank arm, which rotated the drum.
At the beginning of the century the mines of Cornwall, which were the greatest producers in Great Britain, were turning out about 5,000,000 pounds of tin and 10,000,000 pounds of copper a year, while the whole United Kingdom was furnishing only 170,000 tons of iron. South America was the greatest producer of gold and silver, wonderfully rich mines of the latter having been found in Peru and Chile. Humboldt places the production of the whole South American continent for the year 1800 at 691,625 pounds of silver and 9900 pounds of gold.
The United States at that time had practically no mining within its borders. Some small mines of iron, lead, and copper, which had been opened to supply the demands created by the Revolution, were producing spasmodically; but even as late as 1821, William Keating, in an address before the American Philosophical Society, said, “Upon the whole we think we may be warranted in saying that there are as yet no mines in activity in the United States. Coal, in most places, is taken from the surface, or dug from the foot of a hill. The lead mines of Missouri are rich and abundant, but the mining is a mere pilfering of the richest spots.”
In 1801 the Cornish pumping system was introduced. A long rod, extending from the surface to the bottom of the shaft, operates simultaneously a series of pumps placed, one above the other, at intervals of about two hundred and fifty feet. The lowest one lifts the water from the pump and delivers it into a tank from which the next one draws its supply, and this in turn forces it up to a higher tank. With this improved means of drainage mines began to be sunk deeper, a depth of three thousand feet having been reached with this method of pumping. The manufacture of iron pumps, which had begun to replace wooden ones toward the end of the eighteenth century, decreased the amount of repairs necessary on the pumps, and aided in making possible better arrangement of underground work.
It was at about this time, the beginning of the present century, that the method of opening ground by shafts, levels, and raises, which we refer to as “blocking out ore,” began to be more generally adopted, displacing the former mode of following down the ore by a series of irregular, isolated excavations. With it came overhead stoping, in which, after the shaft has been sunk, the level driven and timbered, and a raise made, the miner begins breaking down the ore from over his head, allowing it to run down into chutes. From these it is drawn out into cars pushed along the tracks in the level. The waste is allowed to accumulate on top of the stulls, or timbers, forming the top of the level above referred to, and serves as a platform upon which the miner stands in breaking down more ore.