Mining in focus
carbon footprint — and which can
also be improved to result in less
CO₂ emissions. Research shows that
for every cubic metre of rock mined,
about 4kg of CO₂ is produced by the
explosives, 5kg of CO₂ by the process
of loading and hauling, and 27kg of
CO₂ by crushing and milling — a total
of some 36kg.
An important negative result of a
bad blast is difficult digging conditions:
loaders will struggle to dig where the
required fragmentation has not been
achieved, for instance. This means the
machines will burn more diesel and
emit more CO₂ .
Coarser fragmentation will also lead
to less-efficient functioning of the
crushers and the mill, which will in turn
consume more electricity — also a major
greenhouse gas contributor.
By blasting badly, a mine will
effectively be losing ore. So, despite
creating all these extra greenhouse gases,
there is even less ore to show for it. The
result is that more mining is necessary to
reach the targeted production levels.
Therefore, there is plenty of scope for
mines to reduce their carbon footprint by
improving their blasting performance. It
has been shown that throw blasting can
cut greenhouse gas emissions by 1–2%,
and improved fragmentation can achieve
even larger reductions of about 6%. Even
greater potential lies in reducing ore
losses, with efficient ore-waste separation
capable of reducing greenhouse gas
output by between 5% and 25%.
As mining companies are required
to report more thoroughly and
systematically on their triple-bottom
line — including the environmental
impact — they should pay greater
attention to their blasting practices.
They may be pleasantly surprised
by what can be achieved in terms of
both reducing greenhouse gases and
improving mining efficiencies. b
About the author
Tony Rorke is technical director at
blasting specialist BME.