As the mines in the Lake Superior copper district reached further into the earth, the cost of shaft-sinking, drifting and stoping increased. In mines with lower grade ores, such as the Quincy and the Atlantic, reducing the increasing cost of mining could mean, not only the difference between remaining competitive, but also the difference between profiting and shutting down. Mining company reports and other historical documents demonstrate that as the mines went deeper, the rock became “harder,” or more dense, requiring longer drilling time and increased amounts of black powder. The companies had begun looking to machine rock drills, both steam-powered and air-powered.
In running trials on various pneumatic drills of different manufacture, many mines found that the early Burleigh rock drills were too large, too cumbersome and too unreliable to be worth investing money into. At other mines, they were simply made to work.
Publications like the Engineering and Mining Journal gave high praise to machine drills, particularly the Burleigh. The Sept. 30, 1876, edition of the Engineering and Mining Journal, Vol. 22 heaped high praise on the Burleigh drill for its work on Hell’s Gate in New York Harbor.
Previous to 1872, the Journal stated, the drilling was done by hand, but subsequently, almost all drilling was done with the Burleigh Rock Drills and the Rand Drill, which was also spoken of in flattering terms by the officers in charge. The average progress of the work for 12 months, by six Burleigh drills as 235 lineal feet of heading per month. Each shift of eight hours drill on average, 30 feet of holes with each machine. The cost of drilling with the Burleigh Drill, the journal continued, was found to be, on an average, 36 to 37 cents per foot, this including repairs, etc. Hand drilling cost about 95 cents per foot.
In 1879, the Atlantic Mining Company invested in a Rand air compressor and five drills were purchased to run inside the 1,000-foot deep mine. According to the Annual Report of the Commissioner of Mineral Statistics of the State of Michigan for 1880, each drill was run by a team of six men and stoped 60 fathoms per month. William Tonkin, the mine’s agent, reported that the new drills reduced the cost of drilling to $10 from $17 with hand-drilling.
The report did state, though, that in 1871, the Quincy Mining Company ran trials with steam-powered drills, but during that year, they were proved too unwieldy for general work and were abandoned, except for special work. By 1878, however, the company had found an air-powered drill that met their requirements.The air compressing machinery was increased, enabling the mine to operate five more additional Rand drills than before.
By 1880, the Osceola Mine had two compressors, running 15 Rand drills with four men and two boys to each drill. John Daniels, agent of the Osceola, stated that he found a savings of 40 percent in stoping using the machine drills and 20 percent in drifting over hand drilling. At the Calumet and Hecla Mine, in 1880, there were 62 Rand drills at use in the Calumet and the Hecla branches.
To the north, at the Allouez Mine, in 1878, the mine had been running three Burleigh drills and in 1880, the company was running trials with a single Rand drill. Mining Engineering professor, Thomas Eggleston, in his book, Copper Mining on Lake Superior, published in 1878, wrote that there three Burleighs at use in the Allouez with six men on each.
On the amygdaloid lode, said Eggleston, three men easily made three holes of two to two and a half feet in an eight-hour shift, in moderately hard rock. On the conglomerate lode, that was not possible, because of the hardness of the rock and when practical, either Burleigh or Winchester drills were used.
“In the year 1879, the Calumet & Hecla Company, after a careful trial of the new drills, decided to introduce them throughout the mine as rapidly as they could be obtained,” the Calumet and Hecla Mining Company’s Semi-Centennial Edition of the 1916 publication of the Keweenaw Miner, stated, “and an air compressing plant be erected to supply them with motive power.”
The publication stated that at around the same time, high-explosives, or the nitro-glycerin powder was also introduced. The results of the two new technologies, used in conjunction, were more than apparent — except at the Allouez Mine, where black powder remained the primary blasting agent.
“The miners do not like dynamite, nor any other modern explosives,” Eggleston wrote, “as they say the air after a shot gives them a headache.” The blasting, he added, was conducted at the end of a shift as much as possible, to give the air time to clear out before the next shift began.
The C & H 1916 publication boasted: “The growth of legitimate mining in the copper district has been constant from its first beginnings to the present time. The primitive camps, huts and log cabins have long since, at the older mines, given place to the well-built towns, with dwellings containing all the comforts and often the luxuries of modern civilization. The stores and shops are hardly excelled by those in our larger cities. The public schools are of the best, from primary to high. The churches, embracing those of all denominations, are well housed, well equipped and well supported.”
With the conversion from hand-drilling to pneumatic rock drills, and using high-explosives instead of black powder, the cost of sinking, drifting and stoping per foot and per fathom was slashed by one-half, a savings of at least $200,000, the publication claimed.
“A few years later this saving over hand labor amounted to a half a million dollars per annum,” the publication boasted, “and at present, with its largely increased production, I am confident that $2,000,000 would not misrepresent the annual savings by underground machinery at the mine alone.”
The adoption of machine drills would take time — it did take time. But in the long run, the huge monetary investment required to purchase, erect compressors, boilers, air lines, and the purchase of the drills, along with the struggles to find high-explosives miners felt comfortable using, kept the larger producing mines profitable, at least for the foreseeable future.