Page:Popular Science Monthly Volume 36.djvu/545

Rh out and the asbestus, separated from the containing rock, is "cobbed"—i.e., separated by hammering from adhering foreign matter. This "cobbing" is a comparatively easy matter in the case of the finer quality, as it usually separates readily from the gangue, but in the lower grades much difficulty is experienced in separating the fibrous matter from the non-fibrous. At best there is great waste. Much of the asbestus is in thin or narrow veins, and is wasted, as by the present mode of operating it does not pay to separate this from the serpentine. A machine that will enable these narrow veins to be utilized is a desideratum.

When "cobbed" the asbestus is graded according to purity, color, and length of fiber into three grades and bagged for shipment. The finest quality or "firsts" finds ready sale at prices ranging from $80 to $110 per ton; "seconds" fetch from $50 to $70 per ton; while "thirds" may be valued at $13 to $15 per ton. In good mines the yield of asbestus is from three to five per cent of the rock quarried, and the cost of mining may be put down at $25 to $30 per ton. Returns obtained by the Geological Survey of Canada show that, for the year 1888, Canada's output was 4,404 tons, valued at the mines at $255,000, and this the output of nine different mines. Over three fourths of the whole was shipped to the United States; small quantities going to Great Britain, Germany, France, Belgium, and Italy, and being used in domestic manufacturing.

Judging from the results obtained in the mines now worked, and the indications in other parts of the serpentine belt, it may be safely said that the asbestus deposits of Canada are well-nigh inexhaustible. There is every prospect that the industry will rapidly expand, as capitalists are turning attention to it, the work hitherto done "proving conclusively that mining for asbestus, when properly conducted, shows a more steady return for the money invested, with less elements of risk, than mining for any other known mineral."

Upon its non-conducting power and its ability to resist high temperature depend the many varied uses of the mineral. First and most important are its applications in connection with the steam engine and boiler. For packing pistons, flange joints, hot-air joints, cylinder-heads, and similar purposes, asbestus has proved itself invaluable, and for these purposes it is spun into yarn or wicking or rope, or made into mill-board. A large quantity is manufactured into a kind of felt, either alone or, in some cases, along with other fibrous material. Much of this asbestus felt is used as a non-conducting covering for steam-pipes. It is made into sections to fit any size of pipe, and into rolls and sheets for large surfaces. It is in use on the war-ships of the United States Navy, and has there and elsewhere been demonstrated to be