Mining_Methods_UnderGround_Mining - Mining and Blasting

MOunT iSa, auSTralia
Mount isa mines continues to
expand
Quadruple ores in
Queensland
Mount Isa Mines, located in northwest
Queensland, having an annual
ore production in excess of
10 million t, constitutes one of the
larger underground mines in the
world. It is wholly owned by MIM
Holdings, and is one of few places
in the world where four minerals
are found in substantial quantities,
and mined in close proximity. The
mine is one of the three largest
producers of lead in the world, is
the fifth largest producer of silver,
the 10th largest producer of zinc,
and is the 19th largest producer of
copper. Another superlative is that
the recently developed Enterprise
copper mine is the deepest mine
in Australia. Atlas Copco equipment
is widely used at the Mount
Isa Mines for production drilling,
raise boring and roof bolting.
geology
The mineral deposits zone at the central
Mount Isa mining complex lie in an approximate
North-South orientation, and
dip towards the West.
Economic copper sulphide mineralization
lies within a brecciated siliceous
and dolomitic rock mass, known
locally as ‘silica-dolomite’, which is
broadly concordant with the surrounding
Urquhart Shale. There are several
copper orebodies. The silica-dolomite
mass which hosts the 1100 and 1900
orebodies has a strike length in excess
of 2.5 km, a maximum width of 530 m,
and a height of more than 400 m. The
recently developed 3000 and 3500 orebodies
lie as deep as 1,800 m. Copper
mineralization is truncated by a basement
fault, bringing altered basic volcanic
rocks (Greenstone) into contact with
the Mount Isa Group sediments. The
dominant sulphide minerals are chalcopyrite,
pyrite and pyrrhotite forming
Mount Isa at sunset.
complex veins and irregular segregations
within the breccia mass.
Mount Isa’s stratiform silver-leadzinc
sulphide mineralization occurs with
pyrite and pyrrhotite in distinct bands
dipping to the west, concordant with
weakly bedded carbonaceous dolomitic
sediments of the Urquhart Shale. The
mineralization is intermittent through a
Boltec 335S at Mount Isa.
stratigraphic interval of over 1 km, but
the major orebodies are restricted to the
upper 650 m. The orebodies occur in
an echelon pattern, interlocking at the
southern and lower sections with the
extremities of the silica-dolomite mass
hosting the copper orebodies.
The position, extent and metal content
of copper and silver-lead-zinc
underground mining methods 99