Aerial Survey of Open Pits at Lake Asbestos of Quebec
Aerial surveys of the open pits have been conducted regularly at Lake Asbestos of Quebec, Ltd. - a subsidiary of American Smelting and Refining Company - since 1958. Ground controls are supplied by Lake Asbestos, and a topographic map of the pits at a scale of 1 in. to 50 ft., with 2-foot contour intervals, is obtained by aerial photography. The information from the topographic map is then transferred by the Lake Asbestos engineering staff to sections from which the volumes removed are calculated.