Report on the building and ornamental stones of Canada (1912)
Parks, William A. (William Arthur), 1868-1936, Canada. Mines Branch (1901-1936) · Ottawa : Dept. of Mines, Mines Branch · leaf 158
suiface, aftei IxMug divestedof debris and soil, is at once attacked by channe ling machines and th(> (excava-tion carried down vertically \ to S feet. The opening is then enlargedby directing the channels outwaids on all foui sides at an angle of about 25° 99 from the vertical. This is…
Building stones · Geology, Economic · Stone industry and trade
Internet Archive · University of Toronto, Robarts Library · Public Domain Mark 1.0. Free to use for anything.
