Download or read book Under-ice Mining Techniques written by John F. Abel and published by . This book was released on 1961 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methods of excavating in the Greenland Ice Cap, and the planning required, equipment employed, and problems encountered are described individually for each of 5 operating seasons (1955-1959), and relative cost evaluations of the different methods are given. Three basic methods were used: hand-picking and manual haulage; explosives and manual haulage (drill-blast-muck cycle); and mechanized mining and haulage. Manual methods, which are of low capacity and limited to widths under 12 ft, are justified only when small openings are required, and in remote, inaccessible regions. The drill-blast-muck cycle of mining has a slightly higher capacity than manual methods, but requires power to operate the drills and to ventilate after blasting. Explosives can be used for room spans not exceeding 12 ft; when greater spans are excavated by blasting, the resulting roof is unstable. The machine method using mechanized coal mining equipment has the highest capacity and the lowest unit cost. Openings with roof spans in excess of 36 ft have been made with coal mining machines without dangerous roof conditions developing.