Mining_Methods_UnderGround_Mining - Mining and Blasting

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