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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zinkgruVan, Sweden<br />
Ergonomically-designed cab on the Simba M4 C drill rig.<br />
was mined in late-1998, the quality of<br />
the hanging was found to be worse than<br />
expected, with cave-ins, high waste rock<br />
dilution, <strong>and</strong> difficult backfilling.<br />
Burkl<strong>and</strong> stopes<br />
Earlier, a study of the new copper orebody<br />
had recommended that longhole<br />
open stoping <strong>and</strong> paste backfill should<br />
be used when the width of the copper<br />
mineralization reaches up to 40 m. The<br />
results of this study were adapted to<br />
the Burkl<strong>and</strong> orebody, where the 450<br />
section was converted to longhole open<br />
stoping with primary <strong>and</strong> secondary<br />
stopes. The first two primary stopes<br />
were mined out by October, 2000.<br />
When the primary stopes are extracted,<br />
they are paste filled. The secondary stope,<br />
Stope drilling <strong>and</strong> cable bolting. Stoping sequence.<br />
45 m<br />
Ore outline<br />
Cable bolts<br />
Cor/slot<br />
Rib<br />
pillar<br />
Rib<br />
pillar<br />
50 m<br />
A<br />
Plan view of typical bottom drawpoint level<br />
Vertical section through stope looking east<br />
A<br />
Rib<br />
pillar<br />
10 m<br />
Drill level<br />
(for below)<br />
Development level<br />
(for above)<br />
Drawpoint level<br />
(shown in plan view)<br />
lying between two paste filled stopes,<br />
can then be mined out <strong>and</strong> filled with<br />
waste rock, or paste fill with a low cement<br />
content.<br />
The stope design in the upper levels<br />
in Burkl<strong>and</strong> was chosen to facilitate the<br />
change from sub-level open stoping to<br />
longhole open stoping. The levels were<br />
already arranged in 100 m sequences,<br />
so the height of the stopes became 37 m.<br />
Stope width was designed to be about<br />
half the room length used for sublevel<br />
open stoping. The primary stopes were<br />
designed to be 20 m-long, with the secondary<br />
stopes 25 m-long.<br />
The stope hanging walls are cable<br />
reinforced from the ore drive on the<br />
extraction level, <strong>and</strong> on the upper sub-<br />
level, using 15.7 mm cables with maxi-<br />
mum tensile strength of 265 KN. The<br />
crosscuts are cable reinforced <strong>and</strong> shotcreted<br />
to secure the footwall brow.<br />
Mine-wide, four longhole rigs are<br />
used for production <strong>and</strong> cable drilling.<br />
Stopes are drilled downwards from the<br />
orebody drives, <strong>and</strong> from the crosscuts<br />
in the top sub-level. The benches are<br />
opened on a 600-1,200 mm-diameter<br />
raise bored hole, with an opening slot<br />
along the hanging wall. <strong>Blasting</strong> is se-<br />
quential, <strong>and</strong> rock is loaded from the<br />
extraction level below. The transition to<br />
Robbins opening slots<br />
54 underground mining methods<br />
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