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90
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World Coal
|
August 2015
dimensio
Ian Bell, Motion Metrics
International Corp., Canada,
explains the use of 3D image-based
fragmentation analysis in a study
on the effects of reducing powder
factor, while maintaining loading
and hauling rates.
C
omminution – the reduction in the size
of solid rock particles – accounts for
approximately 53% of mine site energy
consumption and results in significant
production costs.
1
Efficient drilling and blasting has a
direct impact on comminution energy consumption
and, as a result, considerable cost savings can be
attained by optimising the size of the blasted material.
This optimisation involves many factors, including
the efficiency and reliability of hauling and loading
operations, in addition to the efficiency of mechanical
crushing.
Fragmentation analysis is commonly used to
quantitatively determine blast results. This analysis
provides a distribution of rock sizes found in the
blasted material. With this information, blast
engineers can evaluate the effects of modifying key
blast parameters, such as powder ratios, hole-size and
hole-spacing. A common method for determining
material fragmentation is to use sieves of different
sizes. By measuring the amount of rock that passes
through each sieve, a distribution can be found.
Although this method provides accurate results, it is
time consuming and not reasonable to perform on a
regular basis. A new and modern approach is to use
image‑based fragmentation analysis. Images of
blasted material are captured and software algorithms
are applied to determine the rock sizes within the
image.
A recent study from an opencast coal mine in
British Columbia, Canada, found that powder factor
reduction of 11% was achievable through blast
optimisation.
2
This study evaluated the effects of
reducing powder factor, while attempting to maintain
New
