HIGH PROFILE
mechanised pipe changing has become available
for V-30 slot raising. This reduces the number of
units operated in the production drift at the same
time as the storage capacity of a pipe changer is
up to 40 m.
Mines are constantly seeking possibilities for
improving hole accuracy, to minimising ore loss
and dilution and to improve rock fragmentation at
the bottom of the stopes. At the end of the day,
accuracy is a function of the measures you
implement and your drill operator’s abilities. The
following factors are important to consider in this
process:
n Drilling equipment that fulfil the requirements
of the mining method and drill plans
n The use of large size rock tools compared to
the hole diameter drilled
n Correct alignment of holes and good drill
stability during drilling
n Drilling parameter settings which are optimised
to hole and rock conditions
n Implementing drill operator KPI's based on
accuracy rather than metres
Hole alignment is a key element in controlling
hole accuracy. Most longhole drills utilise laser
point-based carrier positioning at the fans, after
which one of the fan pivot points (position in the
drift) is shown to the unit (by moving the boom
rotation centre to the position). With the
introduction of the 400i-class longhole drills bit
navigation will become available for added
accuracy in hole alignment. The Drill Plan
Visualizer can be used in creating drill plans
suitable for upload on the drill’s control system,
and in retrieving the as-drilled data back for
reporting and visualisation.
To have each hole aligned within the specified
system accuracy and on the correct collaring point
requires careful use of the instruments,
continuously and well-maintained machine and a
drill operator who is motivated to align all holes
accurately, so that accuracy can be achieved on
each hole.
Sandvik’s offering framework for
digitalised longhole drilling
Sandvik’s product offering is designed to meet the
industry requirements in the following way:
n Autonomous equipment and features: the units
are fitted with onboard autonomous features,
smart rock tools and control systems for
remote to autonomous operations, supporting
the operator or fully taking over manual tasks
n The equipment is connected: transfer,
collection, reporting and visualisation of as-
drilled data and data on fleet health and status
is continuous, assisting in remote and real-time
support for planning and monitoring across
sites
n Tools for analytics and process optimisation:
solutions based on processed data from
equipment, rock tools, customers’ systems,
environment, predictive insights and real-time
analytics are available to improve operator and
asset performance
Bestselling longhole drills
For drilling long, large diameter and accurate
production holes the boom and the boom support
of a longhole drill must ensure absolute stability
during drilling; for this reason, the leading mining
contractors prefer products with horseshoe type
boom support and a telescopic boom. The
telescopic boom allows pivot points to be set on a
line, which helps in planning the drilling pattern
and in matching the plan with the stope plan and
orebody.
Sandvik’s DL421 is the most popular longhole
drill in the market in mass mining, in 4 x 4 m or
larger cross sections, providing a proven track
record in drilling capacity, hole accuracy and
productivity; with the introduction of bit
changer complete fans can be drilled in
automation.
The number of units fitted with onboard air
supply for air mist drilling is increasing.
Experience has shown that penetration rates are
10-15% higher compared to water flushing;
cuttings mix with air-to-water mist and in many
cases also stabilise the walls of the hole. The
minimum uphole velocity is 15-25 m/s and this
determines the capacity of the air compressor for
different hole/rod diameter combinations. IM
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Working alongside you, we help yo
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dsiunderground.c
com
JULY 2019 | International Mining 29