ShovelMetrics system has not been
installed. Another example would be a
blasting contractor or supplier that
needs a fragmentation analysis
solution to demonstrate the quality of
its solution to a customer.
As mines search for portable
solutions, Motion Metrics International
has introduced its PortaMetrics™
image-based fragmentation
technology. This portable tablet
integrates three high-resolution digital
cameras into a rugged industrial
package. A glove friendly touch screen
display, with onboard processing
makes this device capable of capturing
and processing images in any
environment. Operators can quickly
capture images of a blast and view the
results immediately, without making a
trip back to the office. Integrated GPS
ensures that captured images can be
quickly associated to specific blasts.
The PortaMetrics solution offers a
key advantage over other portable
solutions. Making use of three
cameras, the device is able to
determine the distance to any point in
the image. This 3D point cloud
eliminates the need to manually add a
scaling factor, saving time and making
the process safer. Falling rock from
exposed bench faces presents a real
danger to personnel. Rather than
requiring the operator to get very close
to the bench to place and remove the
scaling object, they can stand 5 – 20 m
away when capturing images.
Not only does this 3D camera offer
convenience for the operator, it can
also improve the accuracy of the size
estimation. An evaluation of the 3D
point accuracy compared with
traditional scaling methods was
completed.
3
In this evaluation, it was
found that by using a full 3D point
cloud, error up to 15% can be removed
from the size estimation. This error
was found to be random; one image
might have 15% overestimation, while
another image might underestimate
sizes by 15%. Given the importance of
having consistent size estimation data
between blasts, it is critical to remove
this error.
Another aspect of the PortaMetrics
device is its potential to be used as a
versatile mine measurement tool.
Although the primary focus of the
device has been on high-quality
fragmentation analysis, the rich 3D
data can be used for other critical
measurements in the mine. In addition
to the device’s current slope measuring
capabilities, Motion Metrics has
additional valuable developments
planned. For example, the 3D point
clouds generated by the software can
be used for bench face profiling and
stockpile volume measurement.
Conclusion
Blast optimisation is a critical process
in any mining operation. Poorly
optimised blasts have increased costs
due to higher than necessary powder
factor or reduced hauling and loading
efficiency. An essential tool in blast
optimisation is image-based
fragmentation analysis. This powerful
metric provides needed feedback to
blast engineers, allowing them not
only to validate the accuracy of their
blast simulations but also to provide a
good indication of digability. A
reduction of 5.7 million kg of
explosives – corresponding to over
CAN$10 million in savings – was
found at one coal mine in British
Columbia, Canada.
4
The ShovelMetrics
and PortaMetrics solutions provide
convenience and accuracy in the field
of image‑based fragmentation analysis.
Through use of these systems, a
comprehensive fragmentation analysis
for every blast is achievable, opening
the door for significant optimisation
and ultimately improving the bottom
line.
References
1. BAUER, F. ‘Blast Optimization
Through Long Term Fragmentation
Analysis’
Journal of Explosives Engineers
(September/October 2015) pp 6 – 15.
2. According to the Coalition for
Eco‑Efficient Comminution (CEE) See:
/
3. SAMETI, B., BELL, I., AZMIN, A.,
KO, D. and TAFAZOLI, S., ‘Benchface
and Quarry fragmentation Analysis:
3D Imaging vs. Scaling References’,
presentation given at the 41
st
Annual
Conference on Explosives and Blasting
Technique (1 – 4 Februrary 2015).
4. Based on a rate of CAN$0.87/lb.
See: ’Orica Australian National Price
List – Mining Services.‘ Available
at:
services.com/uploads/Aus%20
Pricelist/July%201%202014/Orica_
AustralianPriceList_1July2014v2.pdf
PortaMetrics™ uses 3D imaging techniques to provide fragmentation analysis and
slope estimation.
Example image from a PortaMetrics
™
device with rock segmentation.
August 2015
|
World Coal
|
93
