Mining_Methods_UnderGround_Mining - Mining and Blasting

JelSˇ aVa, SlOVakia
Graphitic slate
Magnesite
Dolomite
Bench-like dolomite
Diabase
Ochre
Geological section of Dúbrava Massif (Industrial Minerals).
some ore is located between access levels,
some is distant from the core facili-
ties, and some occurs as layers too thin
for overhand stoping. Extraction technology
for all these various sources
will require new drilling, loading and
hauling equipment.
Although the new mining level is be-
low the rail haulage, and ore will probably
be delivered directly to the primary
crusher, SMZ expects the rail system to
remain in use for another 10 years.
grade improvement
Secoroc equipment supplied through
ISOP is used for the Atlas Copco rigs
at Jelšava. Despite the very abrasive
nature of the magnesite, bit life ranges
from 600 m to 1,500 m. The three
Rocket Boomers use 51 mm bits, and
the Simba H357 drills with 64-65 mm
bits. The mine does 80% of its blasting
with ANFO, and uses plastic explosive
for wet holes.
Of the annual mine production of
1.2 million t, around 1.16 million t is
magnesite, and concentrate output is
approximately 700,000 t. Back in 2001,
chamber and pillar mining supplied
430,000 t, overhand stoping 705,000
t and development 28,000 t. By 2002,
70% of drill/blast production came
from overhand stoping with the Rocket
Boomers, 20% from pneumatic drilling
in chamber and pillar sections, and 10%
from pillar recovery with the Simba
H357. The improvement in average
grade achieved by the more selective overhand
stoping with hydraulic drills has
increased the output of clinker, despite
lower gross output.
atlas Copco
representation
Atlas Copco has a Customer Center in
Prague, serving the Czech Republic and
adjacent countries. In 1992 ISOP, based
at Zvolen in the centre of the country,
was appointed as its sole distributor in
Slovakia. The Rocket Boomer 282
provided for trials in 1998 was the first
two boom hydraulic rig supplied to
a Slovakian mine, and the Rocket
Boomer M2 C was also a first.
Including the units at SMZ, ISOP
presently supports nine Atlas Copco
underground drill rigs in mines. Other
customers include Siderit, which has
two Boomer H104 drill rigs and several
Atlas Copco hydraulic breakers working
at its iron-manganese ore mine at
Nižná Slaná, not far from Jelšava. ISOP
modified these Boomer H104 rigs at
the workshop in Zvolen so they could
work as longhole drilling rigs. Siderit
delivers ore to the US Steel plant in
Košice, and to the Novy Huta works at
Ostrava in the Czech Republic.
There are also six Atlas Copco surface
drilling rigs in the country, five of
which are DTH machines and the sixth
a Coprod-fitted hydraulic rig. This latter
machine yields 500,000 t/y limestone
for supply to US Steel Košice.
acknowledgements
Atlas Copco is grateful to the management
of SMZ for its assistance with the
production of this article.
72 underground mining methods