00000nam 2200000za 4500 9.865039 CaOODSP 20221107161713 cr ||||||||||| 181121s1976 onc #ot f|0| 0 eng d 0660005786 CaOODSP eng eng fre n-cn--- M38-13/76-29E-PDF M38-13/76-29 Welwood, R. J. R. Mining technology in 1974 [electronic resource] / R. J. R. Welwood. [Ottawa] : Energy, Mines and Resources Canada, 1976. iii, 36 p. : figures. CANMET report ; 76-29E Cover title. "September 1976." Includes bibliographic references. "The tonnage of metallic ore mined underground in Canada decreased slightly to 64.4 million tons in 1974 from 65.5 million tons in 1973, a decrease of 1.7%. An increase of less than 1% in surface-mined ore brought the total from surface operations to 239.7 million tons, i.e. approximately 79% of the total metallic ore mined in Canada. In the non-metallic mines, there was a 10.6% increase from underground, largely owing to increased production of potash. A minor increase occurred in surface-mined non-metallic ores. During 1974, approximately 40% of the metallic underground ore was mined by cut and fill methods or variations, followed by open stoping with about 36%. The tons mined by other underground methods were slightly reduced. Sharp rises in underground mining costs are noted for 1974. This trend is expected to continue at a high rate in 1975. Surface mining costs in general showed only slight increases"--Summary, p. i. Includes summary in French. gccst Mining technology Canada. Energy, Mines and Resources Canada. CANMET report ; 76-29E. (CaOODSP)9.852792 PDF 978 KB https://publications.gc.ca/collections/collection_2018/rncan-nrcan/m38-13/M38-13-76-29-eng.pdf