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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anTOFagaSTa, CHile<br />
Modernization at Sierra Mir<strong>and</strong>a<br />
Computerized<br />
systems<br />
The Sierra Mir<strong>and</strong>a copper mine<br />
in Chile has undergone a complete<br />
transformation over the last year,<br />
as a result of which it is now rated<br />
as one of the most modern mines<br />
in Latin America. Along the way,<br />
the mine has acquired a purposematched<br />
fleet of new generation<br />
Atlas Copco equipment, capable of<br />
high output without the availability<br />
of a high tension underground<br />
electricity supply. To support this<br />
process of modernization, proactive<br />
<strong>and</strong> preventive service <strong>and</strong><br />
maintenance is essential, <strong>and</strong> the<br />
management at Sierra Mir<strong>and</strong>a<br />
know that good aftermarket support<br />
for this type of advanced eq-<br />
uipment is vital in order to achieve<br />
their production goals. It was for<br />
this reason that the mine entrusted<br />
Atlas Copco as a true partner, having<br />
confidence in their reputation<br />
as a serious company with a lot of<br />
experience.<br />
large operation<br />
The Sierra Mir<strong>and</strong>a Mine, located about<br />
60 km northeast of the city of Antofa-<br />
gasta, is one of Chile’s largest underground<br />
mining operations <strong>and</strong> has a history<br />
of using the most modern mining<br />
techniques <strong>and</strong> equipment available.<br />
Sierra Mir<strong>and</strong>a lacks a substantial<br />
power facility, with the exception of<br />
electricity for lighting <strong>and</strong> ventilation,<br />
<strong>and</strong> has no water or air supply lines.<br />
As a result, to mechanize effectively,<br />
all of its underground equipment has<br />
to be self-sufficient. The drill rigs, for<br />
example, are all diesel-hydraulic with<br />
independent water-mist flushing systems.<br />
The mine’s total production is 3.3<br />
million t/y, 1.1 million t of which is<br />
waste rock from development work, <strong>and</strong><br />
the remaining 2.2 million t is copper<br />
ore with an average grade of 0.75%.<br />
The host rock is volcanic <strong>and</strong>esite<br />
<strong>and</strong> the mineral deposit is principally<br />
copper malachite, a combination of<br />
At the controls of a Rocket Boomer L1 C drill rig. Operators at the Sierra<br />
Mir<strong>and</strong>a mine appreciate the benefits of the computerized systems.<br />
copper pitch ore <strong>and</strong> chryssocholla, with<br />
sporadic atacamite.<br />
Three years ago, the mine owner star-<br />
ted the first stage of modernizing the<br />
mine’s operations. This required the<br />
latest generation of equipment in order<br />
to improve the systems for extraction<br />
<strong>and</strong> the mining processes.<br />
atlas Copco fleet<br />
Sierra Mir<strong>and</strong>a is one of the few, <strong>and</strong><br />
possibly the only mine of its size in the<br />
world, that is equipped with dieselhydraulic<br />
machines.<br />
Currently, the mine production drilling<br />
fleet is all Atlas Copco, including<br />
a Simba M6 C, four Rocket Boomer<br />
L1 C drill rigs equipped with the RCS<br />
computerized rig control system, <strong>and</strong> a<br />
Scaletec scaling rig, which is the first of<br />
its kind in Latin America.<br />
In addition, the mine has five Atlas<br />
Copco ROC 460 PC drill rigs, <strong>and</strong><br />
Diamec U6 <strong>and</strong> CT14 exploration rigs,<br />
as well as various mobile compressors.<br />
The production fleet of mobile equipment<br />
comprises four Scooptram<br />
ST1020 remote controlled loaders. A<br />
Scooptram ST2G loader <strong>and</strong> an additional<br />
Simba are also expected to join<br />
the fleet this year.<br />
The owner is investing in the latest<br />
generation of equipment in order to<br />
grow the mine as quicly as possible, <strong>and</strong><br />
the selection of Atlas Copco machines<br />
has provided the exact match for this<br />
requirement.<br />
efficient production<br />
Sierra Mir<strong>and</strong>a has a workforce of about<br />
300, including contractors’ personnel.<br />
The mining method is sub-level stoping,<br />
without backfill. As the orebody is<br />
relatively narrow at 4-10 m-wide it is<br />
necessary to use an extraction method<br />
that is both precise <strong>and</strong> focused.<br />
The deposit is situated near the<br />
surface, which from a geo-mechanical<br />
point of view is favourable, as the support<br />
pillars in the mine are not subjected<br />
to excessive pressure.<br />
Until recently, Atlas Copco ROC 460<br />
truck-mounted drill rigs with short<br />
feeds <strong>and</strong> DTH hammers were used<br />
underground mining methods 97