Technical Summary Report, NRRI/TSR-2011/01, May 2011. Natural Resources Research Institute, University of Minnesota Duluth, 5013 Miller Trunk Highway, Duluth, MN 55811This summary report compares capital
and operating costs associated with
hypothetical underground and surface
mining operations located on Minnesota’s
Western Mesabi Iron Range. Spreadsheet
cost models developed by the author are
used for generating the comparative cost
data.* The models are based in part on
underground and surface mine cost
information provided in InfoMine USA, Inc.
Mining Cost Service. Model output is
intended to provide only an approximation
of capital and operating costs associated
with both underground and surface mining,
and should be viewed accordingly. “Ore” is
considered to be restricted to sub-members
Lower Cherty 4 and Lower Cherty 3 (LC-4
and LC-3). Note that the stripping ratio
increases from about 4:1 to 6:1
approximately one mile to the south of the
Biwabik Iron Formation’s southern subcrop
extent. Currently, the stripping ratio at active Minnesota iron ore (taconite) surface mining operations is at about 1:1. Based on the Biwabik Iron Formation’s overall dip of 5-10° to the south in the area of interest, for every mile that mining progresses down-dip, the depth to ore increases by about 700 feet. Therefore, the ore zone (LC-4 and LC-3) of
any mine developed more than one mile to
the south of historic iron ore mining activity will be more than 1,000 feet below ground surface.Natural Resources Research Institute, University of Minnesota Duluth, 5013 Miller Trunk Highway, Duluth, MN 5581