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008170816s1974    oncd    os   f000 0 eng d
040 |aCaOODSP|beng
041 |aeng|bfre
043 |an-cn---
0861 |aM34-20/188E-PDF|zM34-20/188
1001 |aDubnie, Amil.
24510|aMining technology - statistics 1972 and 1973 developments |h[electronic resource] / |cAmil Dubnie, Mining Research Centre.
260 |aOttawa : |bInformation Canada, |c1974.
300 |aiv, 29, [2] p. : |bchart
4901 |aTechnical bulletin ; |vTB 188
500 |aCover title.
500 |a"May, 1974."
500 |aDigitized edition from print [produced by Natural Resources Canada].
520 |a“The tonnage of metallic ore mined underground in Canada decreased in 1972 while a corresponding increase took place in the tonnage mined from surface bringing the latter to 72% of the total. In the non-metallic less coal mine category, tonnages showed only a minor increase. In coal mines, the tonnage derived from surface increased, reaching 79% of the total for the group. During 1972, about 37% of underground metallic ore was mined by the cut-and-fill method or variations, followed by open stoping at 31%. The general trend of underground mining costs is up, while productivity has not shown a comparable rise. Costs and productivity in surface mines are holding approximately at previous levels. Promising advances in underground mining during 1973 were the use of a "roadheader" for mining without drilling and blasting under certain conditions, and the application of large-diameter holes to open stoping"--Summary, p. i.
546 |aIncludes summary in French.
69207|2gccst|aMining industry
69207|2gccst|aStatistics
7101 |aCanada. |bNatural Resources Canada.
7101 |aCanada. |bMines Branch.
830#0|aTechnical bulletin (Canada. Dept. of Energy, Mines and Resources. Mines Branch)|vTB 188|w(CaOODSP)9.834857
85640|qPDF|s1.52 MB|uhttps://publications.gc.ca/collections/collection_2017/rncan-nrcan/M34-20/M34-20-188-eng.pdf
986 |a300067