Mining_Methods_UnderGround_Mining - Mining and Blasting

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