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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Ore processing<br />
MOunT iSa, auSTralia<br />
Mount isa mines – the company<br />
Scooptram loader at Mount Isa.<br />
Wholly owned by MIM Holdings,<br />
Mount Isa Mines (MIM) has 2,000<br />
permanent employees at its Mount Isa<br />
<strong>and</strong> Townsville operations, <strong>and</strong> over<br />
Lead-zinc-silver ore from Mount Isa<br />
<strong>and</strong> George Fischer mines is ground to<br />
a fine powder at the Mount Isa facility,<br />
after which a flotation process is used<br />
to separate waste, <strong>and</strong> produce lead-rich<br />
<strong>and</strong> zinc-rich concentrates.<br />
Lead concentrate from Mount Isa<br />
contains 50-60% lead, <strong>and</strong> around 1<br />
kg of silver/t. After smelting to remove<br />
further impurities, blocks of material,<br />
each containing approximately 3,984 kg<br />
of lead <strong>and</strong> 10 kg of silver, are transported<br />
by rail to Townsville for shipment<br />
to MIM’s lead/silver refinery<br />
in Engl<strong>and</strong>. In 2001-2002, lead-zinc<br />
concentrator throughput <strong>and</strong> recovery<br />
increased, <strong>and</strong> there was improved plant<br />
reliability at the lead smelter.<br />
Around 51% zinc concentrate is also<br />
railed to Townsville for refining, or ship-<br />
ment to overseas customers. MIM currently<br />
produces approximately 190,000<br />
t of lead bullion <strong>and</strong> 500,000 t of zinc<br />
concentrate each year.<br />
At the Mount Isa processing facility,<br />
there is a chimneystack at the copper<br />
smelter, built in 1955, which is 155 mhigh,<br />
<strong>and</strong> at the lead smelter the stack,<br />
5,800 employees in other operations<br />
across Australia <strong>and</strong> overseas. In addition<br />
to the Mount Isa complex, MIM<br />
has copper mines at Ernest Henry in<br />
Queensl<strong>and</strong>, <strong>and</strong> a 50% interest in<br />
the Bajo de la Alumbrera project in<br />
Argentina. For lead-zinc-silver,<br />
there is the George Fischer mine (incorporating<br />
the former Hilton mine)<br />
in Queensl<strong>and</strong>, which uses the Mount<br />
Isa <strong>and</strong> Townsville processing facilities,<br />
<strong>and</strong> a majority interest in the<br />
McArthur River mine in Australia’s<br />
Northern Territories. There is a gold<br />
mine at Ravenswood, <strong>and</strong> extensive<br />
coal operations. The latter comprise<br />
built in 1978, is 270 m-high. Copper is<br />
produced electrolytically in the form<br />
of anodes. Each weighs 375 kg <strong>and</strong> is<br />
99.7% pure copper.<br />
expansion plans<br />
In the year ending June, 2002, record<br />
copper smelter production of 233,000 t<br />
of anode was achieved. This was up<br />
from 207,000 t for the previous year.<br />
A recent copper study to improve<br />
reserves <strong>and</strong> efficiencies has resulted in<br />
an increase in reserves to 12 years. This<br />
has led to a planned 40% expansion in<br />
copper production by 2006. A rate of<br />
400,000 t/y for up to 20 years from<br />
Mount Isa <strong>and</strong> MIM’s Ernest Henry<br />
Mine is predicted by MIM.<br />
MIM is planning to exp<strong>and</strong> copper<br />
production by developing the 1900 ore-<br />
body, the Enterprise Mine 3000 <strong>and</strong><br />
3500 orebodies, <strong>and</strong> the surface open<br />
pit mines in <strong>and</strong> around existing orebodies.<br />
The aim for 2003 was to increase<br />
Mount Isa copper production to 245,000<br />
t, improve the recovery rate in the concentrator<br />
following an upgrade, <strong>and</strong><br />
increase plant utilization by improving<br />
maintenance practices. It is estimated<br />
Table: Mount Isa mine life production statistics<br />
Resource Tonnage (million t)<br />
Total lead-zinc ore mined <strong>and</strong> processed 100<br />
Total copper ore mined <strong>and</strong> processed 200<br />
Total copper resource remaining 400<br />
Total lead-zinc resource remaining 200<br />
coking coal at Oaky Creek, steam coal<br />
at Newl<strong>and</strong>s, <strong>and</strong> steaming <strong>and</strong> coking<br />
coal at Collinsville. There is also coal<br />
shipping from Abbot Point <strong>and</strong> Dal-<br />
rymple Bay, <strong>and</strong> a coking plant at<br />
Bowen Basin. All are in Australia.<br />
MIM’s sources of revenue from all<br />
mines are split by products: copper<br />
31%; by-product gold 8%; Ravenswood<br />
mine gold 1%; zinc 18%; lead 8%;<br />
silver 4%; coal 30%.<br />
Markets for Mount Isa’s copper are<br />
Australia (33%), Asia (53%); <strong>and</strong><br />
Europe (14%). <strong>Mining</strong> finance group<br />
Xstrata owns MIM Holdings.<br />
that Mount Isa has over 6 million t of<br />
contained copper still to be mined, more<br />
than has been extracted over the past<br />
60 years.<br />
In more detail, the 2002 reserves <strong>and</strong><br />
resource report gave a total of proved<br />
<strong>and</strong> probable ore reserves of approximately<br />
73 million t at 3.3% copper<br />
(previously 47 million t at 3.6% copper).<br />
The total underground measured, indicated<br />
<strong>and</strong> inferred resources, including<br />
reserves, were approximately 116 million<br />
t at 3.3% copper (previously 88 million t<br />
at 3.7% copper). In addition there were<br />
a total open-cut indicated, inferred resources<br />
of 255 million t at 1.2% copper<br />
(previously an inferred resource of 112<br />
million t at 1.6% copper).<br />
The improved lead-zinc concentrator<br />
performance <strong>and</strong> smelter reliability in<br />
2001-2002 contributed to an increase in<br />
production from 140,000 t to 161,000 t<br />
<strong>and</strong> reduced operating costs. Still, MIM<br />
is planning to reduce off-site realization<br />
costs such as transport <strong>and</strong> smelting,<br />
which represent up to 60% of total production<br />
costs at present.<br />
acknowledgements<br />
Atlas Copco is grateful to the management<br />
of Mount Isa Mines, <strong>and</strong> in<br />
particular to Jim Simpson, General<br />
Manager <strong>Mining</strong>, Lead Zinc, for writing<br />
this article which first appeared in<br />
Underground <strong>Mining</strong> <strong>Methods</strong>, First<br />
Edition.<br />
104 underground mining methods