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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7 m<br />
9 m<br />
gerMany/SOuTH kOrea<br />
Pillar<br />
Vertical benching of bottom parts<br />
Principle mining method at Yongjeung.<br />
Pillar<br />
that over 5.5 million t will eventually<br />
be mined. Average chemical analysis of<br />
the limestone bed is CaO 54.4%, SiO 2<br />
0.78%, MgO 0.53%, Al 2O 3 0.03%, <strong>and</strong><br />
Fe 2O 3 0.17%.<br />
Around 25,000 t/month of limestone<br />
is produced for markets that include<br />
companies operating plants for the<br />
manufacture of desulphurization products,<br />
quicklime, calcium carbonate <strong>and</strong><br />
chicken feed.<br />
The limestone bed is mined in three<br />
steps, starting with 15 m-wide x 7 mhigh<br />
room <strong>and</strong> pillar, followed by a 9 m<br />
bench. A Rocket Boomer L1C-DH diesel<br />
powered drill rig is the main production<br />
machine in the room <strong>and</strong> pillar faces,<br />
© Atlas Copco Rock Drills AB, 2000<br />
drilling 4 m-long x 51 mm-diameter<br />
holes. Generally, 50 holes are drilled in<br />
each face, <strong>and</strong> three faces are drilled in<br />
each 8 h shift. This affords a capacity<br />
of 3,000 t/day or 70,000 t/month. When<br />
drilling, the rig’s diesel engine operates<br />
for around 1 min/drilled metre, consuming<br />
0.31 litres of fuel. Returns from<br />
rig consumables are: rods 975 m; bits<br />
750 m; shanks 3,900 m; <strong>and</strong> sleeves<br />
1,950 m.<br />
An Atlas Copco ROC D5 crawler rig<br />
is used for downhole drilling of the<br />
bottom bench. This rig has a long folding<br />
boom which allows the operators to<br />
drill at a comfortable 5.5 m from the<br />
edge of the crater, a major improvement<br />
over the previous pneumatic rigs, which<br />
needed to be within 2 m of the edge.<br />
Conclusions<br />
Where there is no suitable electricity<br />
supply to the mining areas to power an<br />
electro-hydraulic rig, as at Auersmacher<br />
<strong>and</strong> Yongjeung, diesel-driven hydraulic<br />
rigs offer a means of upgrading mining<br />
efficiency without excessive capital<br />
expenditure. At these mines, drilling<br />
rates doubled with the introduction<br />
of the Rocket Boomer L1C-DH, <strong>and</strong><br />
round depths increased significantly.<br />
These machines, equipped with water<br />
tanks <strong>and</strong> water mist flushing, operate<br />
efficiently despite the absence of mains<br />
supplies of water <strong>and</strong> electricity. They<br />
are also adaptable, performing on both<br />
production <strong>and</strong> development, <strong>and</strong> h<strong>and</strong>ling<br />
rockbolt <strong>and</strong> ancillary drilling.<br />
Production <strong>and</strong> efficiency gains have<br />
been recorded wherever the Rocket<br />
Boomer L1C-DH has been introduced,<br />
making it a boon to mines where every<br />
penny counts.<br />
acknowledgements<br />
Atlas Copco is grateful to the managements<br />
at Auersmacher, Heidelberg,<br />
TKDZ <strong>and</strong> Yongjeung for their inputs<br />
to this article <strong>and</strong> for permission to<br />
publish.<br />
Rocket Boomer L1 C-DH on demonstration at Yongjeung limestone mine. Atlas Copco ROC D5 drilling the bench at Yongjeung.<br />
128 underground mining methods