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