History of Mining: The evolution of shaft sinking systems in the western world and the improvement in sinking rates (Part 2 of 7) – by C. Graham and V. Evans (CIM Magazine – September/October 2007)


Shaft Sinking from 1600 to 1800 – The Industrial Revolution

It was during this period of time that the first mining schools were opened in North America and the first technical societies for mining were formed. The first School of Mines in the United States was opened in 1864 at Columbia University in New York. In Canada, McGill University opened a mining engineering program in 1871. This was followed by the University of Toronto in 1892, and Queen’s University in 1893.

Also helping to spread the expertise involved in shaft sinking were the mining technical institutes. In Canada, the first of these to be formed was “The Gold Miners Club of Nova Scotia” in 1887. This organization was reorganized the following year as “The Gold Miners Association of Nova Scotia.” A number of other provinces also set up provincial mining associations in the 1890s. In 1898 the Canadian Mining Institute was formed.

One of the early improvements to shaft sinking techniques during this period was the introduction of horse whims for the removal of material from the shaft bottom. This development occurred in the late 17th and early 18th centuries. A well-designed horse whim could remove material from the shaft bottom many times faster than windlasses operated by manpower.

The second improvement to take place during this period was the replacement of fire setting with drilling and blasting. It took three centuries after gunpowder became known in Europe before some resourceful miner, probably in the late 1500s, thought to stuff some into the cracks in rocks, ignite it, and let chemistry do the work. Eventually, miners realized that if, instead of relying on natural cracks, they used an iron tool to make a deep hole with a small outer opening that could be plugged to confine the combustion gases, they could break even more rock.

It is thought that the first use of blasting with black powder in mines was in Hungary in 1627. For various reasons, such as high cost, lack of suitable drilling tools, and fear of roof collapse, the use of black powder in mining and shaft sinking did not spread rapidly, although it was generally widely accepted by 1700.

One man swinging a four-pound hammer and holding his own drill rod was called single jacking. A two-man team was called double jacking. One man would swing a hammer that might have a nine pound head while his partner held the drill rod and rotated it in the hole. In average rock, one man might drill eight inches in an hour, while a two-man crew might make two feet. On average, it might take 40 to 60 holes, 1 to 11/2 inches in diameter, to be able to blast away enough rock to advance an eight foot by six foot shaft two feet.

Drilling these 120 feet of holes might use up to 400 pieces of sharpened steel and require the better part of a week. Sometimes a third man was added, also with an eight or nine pound hammer, to further increase the drilling speed. For almost 250 years, this method of drilling blastholes was improved upon only in the composition of drill steels and the manner of tempering them.

Black powder was an extremely dangerous blasting medium. It had to be ignited either by flame or intense heat. The original fuse systems were thin lines of the powder itself or crude fuses made of straw, goose quills, paper, or other combustible material combined with sprinklings of powder. Burning speed of this type of fuse was extremely unreliable.

The first reference to blasting in America is contained in a committee report on the purchase of the Simsbury Connecticut copper mine for conversion into Newgate Prison in 1773. This report stated “by blasting rocks they had prepared a well-finished lodging room about 15 feet by 12 in the caverns and had secured the west shaft of the mine with a large door.”

For the rest of this article, click here: http://www.cim.org/en/Publications-and-Technical-Resources/Publications/CIM-Magazine/September-October-2007/history/history-of-mining.aspx