The primary objectives in blasting taconite are to produce broken rock that
permits optimum digging and shovel loading rates with minimum secondary breakage
and eliminates primary crusher delays. Since at least 1990, much of the blasting
research by explosives companies, academics, and mining companies has been
directed toward determining the downstream benefits of increased blast energy,
particularly on crushing and coarse grinding. Several papers have been published that
attempt to quantify the cost benefits. However, so many variables are involved that
most benefits are only indicated or estimated.
A report entitled "Effects of Blasting on Milling," by C. M. Lownds and D. A.
Bocca of Viking Explosives & Supply, Inc., and K. Nielsen, Professor, Department of
Geology and Mineral Resources Engineering, Norwegian University of Science and
Technology, was presented at the 1997 Duluth, Minnesota, SME Annual Meeting. It
describes a rather simple method of explosively loading taconite samples and of
evaluating the explosive effects on grindability.1
" The small-scale explosive tests were
conducted on taconite rock pieces collected from the back of a muckpile instead of on
diamond drill core or sawed and drilled cubes, as described in previous work.2
testwork described in the following report was proposed as a continuation of the tests
on rock fragments to examine more extensively the effects of small-scale explosive
tests on rock weakening.
University of Minnesota Duluth, Natural Resources Research Institute, 5013 Miller Trunk Highway, Duluth, MN 55811-1442; Coleraine Minerals Research Laboratory, One Gayley Avenue, Box 188, Coleraine, MN 55722
Niles, H. B; Bacca, D. A.
Weakending of Taconite in Small Scale Explosive Tests.
University of Minnesota Duluth.
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