Mining Methods
| Within the opencut mine, Ensham utilizes a large pre-strip fleet and draglines to remove overburden. Ensham currently has four draglines: a Marion 8050 dragline with a 48 cubic metre bucket, a P&H9020 dragline with a 88 cubic metre bucket, a Bucyrus Eirie dragline with a 30 cubic metre bucket and a Bucyrus 8750 with a 110 cubic metre bucket. Most of the overburden is drilled and blasted prior to excavating. |
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Ensham Resources is delighted with the performance
of the second biggest dragline in the world, which
it has commissioned at its central Queensland mine.
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Once exposed, the coal is removed by
loader or excavator and hauled by trucks
to a coal processing and stockpiling
area. Coal is crushed to a top size of
50mm and stockpiled on one of 4
stockpile pads.
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The mine’s coal handling
facility has a design capacity
of 1,400tph and comprises: |
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A
600 tonne capacity receival
hopper. |
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A
primary double rolls crusher to
size coal to a topsize of
125-150mm. |
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A
screen to remove the -50mm
material thereby minimising
unnecessary crushing and
degradation of the coal |
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A
secondary double rolls crusher
to reduce the remaining +50mm
material to a 50 x 0mm size |
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The product coal sized at 50 x
0mm is conveyed either directly
to stockpiling or is redirected
to the sizing station where it
can be screened to meet specific
requirements |
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The oversize and undersize
fractions from the screen plant
may then be conveyored to
different stockpiles |
The screening plant has been
installed to provide sized coal for
specialised markets. Screens are
interchangeable 3.0m x 8.5m heavy duty
vibrating "banana" screens with a
guaranteed screen efficiency of 95% and
with a design feed rate capable of
1,400tph.
Stockpiling at the mine is via overhead
tripper and there is capacity to
comfortably stockpile 350,000 tonnes
with the capability to blend, if
necessary, from each of three separate
live stockpiles. Coal is reclaimed via
an underground conveyor, a similar
system to that used at RGTCT, Gladstone.
All crushing, stockpiling, blending, and
train loading activities are computer
controlled.
The mine commenced operation
in late 1993 and since that time
production has steadily increased as
equipment availability and market
conditions allowed. Production, railings
and sales for each calendar year since
the commencement of mining have been as
follows:
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COAL MINED |
COAL RAILED |
SALES |
|
1993 |
360,000
tonnes |
324,000
tonnes |
273,000
tonnes |
| 1994 |
1,104,000
tonnes |
1,038,000
tonnes |
1,007,000
tonnes |
| 1995 |
1,940,000
tonnes |
1,870,000
tonnes |
1,841,000
tonnes |
| 1996 |
1,713,000
tonnes |
1,711,000
tonnes |
1,710,000
tonnes |
| 1997 |
2,795,000
tonnes |
2,671,000
tonnes |
2,640,000
tonnes |
| 1998 |
2,774,000
tonnes |
2,685,000
tonnes |
2,513,000
tonnes |
| 1999 |
3,955,000
tonnes |
3,535,000
tonnes |
3,357,000
tonnes |
| 2000 |
4,404,000
tonnes |
5,135,000
tonnes |
5,597,000
tonnes |
| 2001 |
5,546,000
tonnes |
5,510,000
tonnes |
5,239,000
tonnes |
| 2002 |
5,308,000
tonnes |
5,389,000
tonnes |
5,397,000
tonnes |
| 2003 |
6,485,000
tonnes |
6,358,000
tonnes |
6,606,000
tonnes |
| 2004 |
8,088,000 tonnes |
8,204,000
tonnes |
8,017,000
tonnes |
|
2005 |
8,870,000 tonnes |
8,367,000
tonnes |
8,312,000
tonnes |
|
2006 |
7,701,000 tonnes |
7,935,000
tonnes |
8,092,000
tonnes |
|
2007 |
8,011,000 tonnes |
7,880,000
tonnes |
8,125,000
tonnes |
|
2008 |
4,928,000 tonnes |
5,055,000
tonnes |
5,245,000
tonnes |
|
2009 |
7,584,000 tonnes |
7,660,000
tonnes |
7,732,000
tonnes |
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