Mining_Methods_UnderGround_Mining - Mining and Blasting
Mining_Methods_UnderGround_Mining - Mining and Blasting
Mining_Methods_UnderGround_Mining - Mining and Blasting
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to the hanging wall. The fill used on<br />
site includes uncrushed underground<br />
development rock spoil, heavy media<br />
reject from the process plant, or hydraulic<br />
s<strong>and</strong> fill from the surface.<br />
The potential hazards of loading out<br />
from within an open stope have been<br />
tackled by technical development. With<br />
the benching method, teleremote production<br />
loading was also brought in.<br />
With this system, employing CCTV<br />
cameras on the front <strong>and</strong> back of the<br />
LHD, operators can now h<strong>and</strong>le up to<br />
three units by remote control from one<br />
location. This is an air-conditioned<br />
cabin, which may be up to 1 km away.<br />
The system saves time spent on a job,<br />
increases operator safety, <strong>and</strong> gives operators<br />
more control.<br />
The technology was practically ahead<br />
of its time when introduced, because<br />
it is still current. It was a step towards<br />
the development of today’s equipment<br />
with built-in navigational systems.<br />
Benching has increased productivity,<br />
improved safety, reduced costs <strong>and</strong><br />
provides better utilization of equipment.<br />
The extensive mine workings at Mount<br />
Isa incorporate a total length of under-<br />
ground openings including road-ways,<br />
19A<br />
17D<br />
18E<br />
19/L<br />
Huge savings in drilling consumables<br />
Atlas Copco Secoroc workshop at Mount Isa Mines.<br />
An alliance between MIM <strong>and</strong> Atlas<br />
Copco Secoroc has resulted in a reduc-<br />
tion of annual bit consumption from<br />
28,000 to just 11,000, with no changes<br />
in tonnages. For more than 15 years,<br />
Secoroc had held a supply-only con-<br />
tract for drilling consumables with<br />
MIM. When taking over the role of<br />
General Manager, they reviewed the<br />
contract <strong>and</strong> found a throw-away cul-<br />
ture that, if turned around, had the<br />
16B<br />
18B<br />
19C<br />
Tailor made stope design at Mount Isa copper mine.<br />
orepasses <strong>and</strong> shafts, of approximately<br />
975 km. The workings produce 10 mil-<br />
lion t/year. Most mines have at least one<br />
particular form of technical challenge,<br />
<strong>and</strong> at Mount Isa it is heat, due to the<br />
great working depths. The virgin rock<br />
temperatures are around 60 degrees C.<br />
MOunT iSa, auSTralia<br />
However, with proper ventilation the<br />
mine’s wet-bulb temperature is below<br />
23 degrees C. The Mount Isa ventilation<br />
system is one of the largest of its kind<br />
in the world, <strong>and</strong> includes bulk coolers<br />
on the surface to cool the air before it<br />
goes underground.<br />
underground mining methods 103<br />
19C<br />
18E<br />
potential to markedly save costs <strong>and</strong><br />
improve safety. The original consuma-<br />
bles contract was not providing enough<br />
information to the supplier. This reali-<br />
zation was instrumental in changing<br />
the contract from supply only, to full<br />
service <strong>and</strong> supply. MIM is a very large<br />
<strong>and</strong> busy company, making the focus<br />
on drilling consumables difficult.<br />
MIM undertook the task of generating<br />
information <strong>and</strong> sharing it with<br />
Secoroc, to release the mutual benefits<br />
of reduced costs for the client <strong>and</strong><br />
contract extensions for the supplier.<br />
To foster continuous improvement,<br />
quarterly meetings were implemented<br />
to discuss the provision of service<br />
– prompt reporting of loss, product<br />
training <strong>and</strong> product development.<br />
Both parties agree on what has <strong>and</strong><br />
what hasn’t been done, focusing on<br />
the objectives. As a result, Secoroc is<br />
able to provide the most suitable <strong>and</strong><br />
16B<br />
19/L<br />
Current practice in stope design<br />
Match stope outline with grade contour.<br />
Consider existing development horizontal<br />
& vertical (inaccessible).<br />
Design additional development as required<br />
for stope extraction.<br />
Use rock mechanics principles (pillars,<br />
exposure dimensions).<br />
Location & quality of faults & fill masses<br />
(delay exposure).<br />
Extraction options<br />
Simplify stope extraction sequence.<br />
Minimize remote mucking.<br />
Delay exposing faults <strong>and</strong> fill masses.<br />
Effective ventilation circuits.<br />
Safety considerations & hazard ID.<br />
Design -> Monitor operating<br />
cost-efficient products for MIM operations,<br />
resulting in fewer bits for the<br />
same tonnages. MIM <strong>and</strong> Secoroc are<br />
now really pushing the idea of reusing<br />
material <strong>and</strong> focusing on wastage. Bit<br />
resharpening, rod straightening <strong>and</strong><br />
rod clearing have been introduced with<br />
the resharpening ratio for development<br />
bits now averaging 1.5 times.<br />
Consumable care is an area where<br />
the jumbo operators can improve the<br />
life of consumables <strong>and</strong> cost per metre,<br />
<strong>and</strong> Secoroc is required to take a lead<br />
in education in the use of its products.<br />
The companies are working towards<br />
agreeing on <strong>and</strong> setting expectations<br />
about scaling st<strong>and</strong>ards, <strong>and</strong> procedures<br />
to reduce damage.<br />
The initial supply <strong>and</strong> service contract<br />
ran for one year <strong>and</strong> has since<br />
been extended for three years on a performance-based<br />
rolling contract, with<br />
three monthly performance reviews.