Miner single jacking Bisbee circa 1900
Prior to 1905 the drilling of blast holes in Bisbee was done using hand drilling techniques. This strenuous process made the advance of the underground workings slow and labor intensive. The rates of progress varied on the hardness of the rock and hole direction, vertical being the most difficult.
Single Jacking was the preferred method in Bisbee. This is done
by a single person using a chisel like drill steel hitting it with a hammer rotating the steel ¼ turn then striking it again the process is repeated until the hole is completed. The hammer called a single jack weighs between 3.5-4.5lbs.
Double Jacking ( Double hand)This is done by two people one person holding the drill steel and rotating between strikes and the other hitting the steel with and 8 to 10 pound long handled double jack (sledge hammer) the men would occasionally switch positions to relieve the driller.
Triple Jacking (Three Hand) this is done by two people striking and one person turning the steel.
In all the methods sets of drill steels of graduated lengths and widths are necessary. The short and wider steels are started with, the steels progress to longer and narrower in width as the hole in deepened. Hand steels that have been found underground in Bisbee range from 1 1/4” to ¾” in width. Differences in length of 21/2” to 3” between changes of steel. How the steel is sharpened and shaped depends on the hardness of the rock. Hand steels will have a chisel shaped tip that has the edges is flared out. A common misnomer about the steels is that they were shaped like star drills used in rock quarrying.
Diagram showing different methods of sharpening hand steels
1a is for soft rock and is typical of Bisbee steels. 2b is for harder rock
The bevel is flatter in hard rock and the steel has less of a flare. In softer rock the bevel is steeper and the flare greater. Cleaning of the holes while drilling is critical, the accumulation dust will act as a cushion, softening the effect of the hammer blows. Horizontal holes are keep clean with the use of a copper spoon (drilling spoon)to shovel the cuttings. Down holes use small amounts of water causing the cutting to cling to the steel as mud. The steel is removed every so often and rapped against a rock knocking off the mud. Upward holes cuttings have the benefit of the cutting falling out. Hand drilled holes are easily identified by their triangular shape machine drilled hole are perfectly round.
Drilling rates using various methods and in different rock types
Typically a coal mine tool, augers were an important method of hand drilling, used to drill blast holes in the softer materials like oxides and clays in Bisbee. Several different styles have been found underground the most common are about 4 feet long and have a place where a wooden handle could be fitted.
The auger would be placed against the soft material and rotated with the wooden handle while pressure is applied. An example of a 4 foot auger has a place where it has be hit with a hammer to drive the auger through small area of hard ground.
Two augers have been found that are exceptionally long and with capabilities of drilling larger holes The cutting diameter is the same as with hand steels in case a harder material is encountered the hole is then finished by hand drilling. In 1911 at Oliver mine the ground was so soft, breast augers were used to conserve compressed air.
4’ auger found on 4th level Southwest mine
Bisbee style 4 ½ lb single jack and hand steel
Queen incline in shaft 25ft above B level station
Machine drilling creating perfectly round shaped hole Queen Tunnel main drift
Annie Larkin 2010, pers. comm., 8 March
Arizona Republican December 28, 1905
A treatise on metal mining vol 3 1899, Burr printing house New York, section 38 pp. 55-56
Benton-Cohen, Katherine 2009,Borderline Americans: racial division and labor in the Arizona borderlands, Harvard university press, p96
Bisbee Daily Review July 5th 1902
Bisbee Daily Review July 5th 1903
Bisbee Daily Review June 27th 1903
Bisbee Daily Review June 29th 1913
Colliery Engineer February 1907 Vol 27 p291
Compressed Air Magazine May 1918 Vol XXIII No.5 p8766
Graeme, R ‘ Bisbee Arizona” Mineralogical Record Sept- Oct 1981 Vol 25 p 274
Horace Jared Stevens, Walter Harvey Weed, 1911, The Copper Handbook, Vol 10
Mines and Minerals, February, 1907 Vol XXVII, No.7
Mining & scientific press, July 19, 1913 p.108
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The Arizona Republican, September 4, 1903
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Richard Graeme IV 2010, pers. comm., 8 February
Richard Graeme III 2010, pers. comm., 2 February
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University Missourian October 28 1908