UNDERGROUND DRILLING
designed to provide clients with a unit that can
complete a site's production drilling requirements
as a regular Simba 157, then with a shift
changeover it can be used to drill diamond core for
grade control. To do this a LM50 diamond drill was
fitted to a Simba H157. All of the top hammer
control system has been left in place and the
diamond drill control system has been fitted in
parallel. This multipurpose rig was designed with
small scale mines in mind - mines that don’t have
enough production drilling to fully utilise a rig and
yet where good grade control is essential. This rig
can also be used as a stand-alone diamond drill
capable of holes up to 120 m in length.
Upwards directional core drilling
Devico recently participated in a drilling program
for a future cable shaft, controlling the deviation
in an upwards directed hole drilled from
underground. The hole was started at an angle
pointing 60 degrees upwards and was to be
drilled to 250 m. It would be enlarged later on it,
making it necessary to avoid large or rapid
directional changes that could conflict with the
reaming equipment. Frequent surveying was
important to measure and detect any natural
deviation at an early stage. The normal DeviShot
magnetic multishot system was used for all the
surveying. A full hole core barrel was used in
order to minimise the deviation, however, the
natural deviation was still strong enough to
deviate the hole away from the intended path.
The full hole core barrel was then replaced with
the DeviDrill and a short section of directional
drilling completed bringing the hole back to the
correct path. A limited dogleg intensity setting
was used in order to reduce the turn rate from
the normal dogleg of 9 to a dogleg of 5.
The pressure conditions in an up-hole are very
different compared to a more typical down-hole
as water needs to be pushed up the drill string in
order to reach the drill bit. As the DeviDrill
orientation system relies on building a system
Devico technology controlling deviation in an
upwards directed hole drilled from underground
pressure of up to 20 bar it was necessary to
increase the pump pressure slightly in order to
compensate for the hydrostatic pressure needed
to reach the bit. This was done without any
issues, and two directional corrections
completed successfully. The hole broke through
at surface after 250 m of drilling, ending 80 cm
from the target point, well within the accuracy
requirement of 1.5 m. IM
Brunner & Lay
Mining
g & Construction Tools
American made and Family owned since 1882
PAVING BREAKERS
DEMOLITION TOOLS
ROCK DRILLING
American Made! Quality, Performance,
Value and Reliability, since 1882.
1510 N Old Missouri Rd, Springdale AR 72764
ph 479 756-0880 fx 479 756-5366
Call (800) 872-6899 or visit BrunnerLay.com