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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Olympic Dam mine exploration.<br />
wOOMera, SOuTH auSTralia<br />
1999 at a cost of Aus$1,940 million.<br />
They included an automated electric<br />
rail haulage system (based on that at<br />
the LKAB Kiruna mine), a new underground<br />
crusher station, a third haulage<br />
shaft (the Sir Lindsay Clark), a substantial<br />
increase in ventilation capacity, a<br />
new smelter, <strong>and</strong> an enlarged hydrometallurgical<br />
plant. The Sir Lindsay Clark<br />
shaft is fitted with the largest mine winder<br />
in Australia, both in terms of power<br />
(6.5 MW) <strong>and</strong> hoisting capacity (13,765<br />
t/h). These facilities increased the annual<br />
production capacity to 200,000 t<br />
of refined copper, 4,300 t of uranium<br />
oxide, 75,000 oz (2.33 t) of gold <strong>and</strong><br />
850,000 oz (26.44 t) of silver.<br />
Further expansion under the Optimisation<br />
Phase 3 plan in 2003 increased<br />
copper production to 235,000 t/year.<br />
Since 1988, more than 100 km of un-<br />
derground development has taken place<br />
to facilitate the production of more than<br />
17 million t of mined ore. As of Decem-<br />
ber, 2000, ore reserves were predicted<br />
to be 707 million t, with average grading<br />
of 1.7% copper, 0.5 kg/t uranium<br />
oxide, <strong>and</strong> 0.5 gm/t gold.<br />
The mine’s revenue is made up from<br />
sales of copper (75%), uranium (20%)<br />
<strong>and</strong> gold <strong>and</strong> silver (5%). Copper customers<br />
are based in Australia (26%),<br />
Europe (16%), northern Asia (28%) <strong>and</strong><br />
south-east Asia (30%). Uranium is sold<br />
to the United States (54%), Japan (23%),<br />
Europe (22%) <strong>and</strong> Canada (1%).<br />
<strong>Mining</strong> method<br />
A carefully sequenced <strong>and</strong> monitored<br />
method of sublevel open stoping is employed<br />
to extract the ore. This was chosen<br />
chiefly on the basis of: the depth of the<br />
orebody <strong>and</strong> volume of overburden; the<br />
large lateral extent of the orebody; the<br />
geotechnical attributes of the ore (see<br />
above), the host rock <strong>and</strong> barren materials,<br />
as well as their geological distribution;<br />
World ranking of Olympic Dam mine<br />
Metal Resource ranking Production ranking % of world production<br />
Copper No.5 No.17 1.4%<br />
Uranium No.1 No.2 11%<br />
the grade <strong>and</strong> volume of the ore; the<br />
mine’s production requirements.<br />
This type of mining is most suitable<br />
for large ore zones that are characterized<br />
by relatively regular ore-waste<br />
contacts <strong>and</strong> good ground conditions.<br />
At Olympic Dam, the method features<br />
the development of sublevel drives, us-<br />
ually at 30-60 m vertical intervals.<br />
From these sublevels, a 1.4 m-diameter<br />
raise hole is excavated by contracted<br />
raise boring. This extends the whole<br />
vertical extent of the designated stope.<br />
Production blastholes of 89-155 mmdiameter<br />
are then drilled in ringed fans,<br />
or rows parallel to the ore limits. Planning<br />
engineers, in consultation with the<br />
drill-<strong>and</strong>-blast engineer, develop the<br />
patterns using the Datamine Rings soft-<br />
ware package. The normal hole parameters<br />
are 3 m overburden <strong>and</strong> 4 m toe<br />
spacing.<br />
A powder factor of 0.25 kg of explosives<br />
per tonne of ore is generally maintained.<br />
Blasts range in size from about<br />
500 t, when opening an undercut slot, to<br />
250,000 t for the maximum stope ring<br />
firing. There are six to ten blasts/week.<br />
Charging is carried out by two 2-man<br />
crews, working 14 shifts/week. Firing is<br />
110 underground mining methods