... Report on the building and ornamental stones of Canada, vol. I-V (1912)
Parks, W. A. (William Arthur), 1868-1936, Canada. Mines Branch · Ottawa : Government printing bureau · leaf 108
to 1,000 lbs., and are capable of sinking to depths of from4 feet to over 30 feet. The price likewise varies greatly, but good drills costfrom less than $200 up to $500 according to size and efficiency. Thedrills used maybe single bitted but the cutting face is usually made either+ or X shaped. As…
Building stones
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