4
in a way that they follow the crest automatically while still
preserving the minimum burden (Figure 4).
Regardless of whether the design basis is an automatic
or traditional method, a unique digital record of the design
pattern and the blast site is of prime importance for getting
reproducible conditions. A collaborative loop is created
for quantifying the results of a blast, changing the design,
quantifying the next blast, and comparing it with the previ-
ous result. This repeated application and objective compari-
son allow successively to improve blasts, both economically
and from a safety aspect.
OPTIMIZED BURDEN FACE AND
VOLUME DETERMINATION
Operations general volumes of interest for production
schedule purposes include:
Volume of the muck pile (Flight to be performed
before and after digging the muck pile) and
The corresponding bank volume (Flight to be done
before the blast and can generate volumes).
Volumes are determined directly from 3D models
using BlastMetrix. The prerequisite is that they share a
common coordinate system (NAD83 state plane). The dif-
ference between the 3D models then reflects the volumet-
ric change. Another point is taking the images for the 3D
models at the right time. For example, all material from a
previous shot is already removed and an unobstructed view
of the bench face is possible. Figure 5 shows 3D modeled
volume measurements for the pattern yield. The obtained
bank volume is approx. 34,500 tons (31,300 metric tons)
(14,500 yd3 or 11,000 m3). On the other side, it showcases
the bank volume that results from comparing 3D models of
the bench face pre- and post- blast.
Muckpile Volumes
As part of CRH America’s best practices, Pike gathered the
volume from the 3D modeled volumes rather than the typi-
cal blast volume calculator provided by the blasting con-
tractor (ISEE Blasters Handbook, 18th Edition, 2020).
Blast Volume 27
Burden Spacing
Face Height No. of Holes
#
##
=
e o
(1)
The volume calculated from 3D model is highly accu-
rate providing us with more accurate KPIs, including the
powder factor and blast cost per ton.
FRAGMENTATION ANALYSIS
The fragmentation analysis was performed using
BlastMetrix, transforming the images into a 3D distribu-
tion of the expected fragmentation. The entire muck pile
was modeled, Figure 6 and Figure 7 show the resultant
3D models after particle detection and distribution curve.
Particles are colored according to their size, highlighting
Figure 4. Minimum burden for the entire highwall face
(optimized) looking towards the east. Legend. Green-10 feet
(3 meters), Red 9 feet (2.7 meters), and Blue 11 feet
(3.3 meters)
Figure 5. Volume calculated in the BlastMetrix with the
designed pattern
Figure 6. 3D fragmentation model built using BlastMetrix
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