Drilling rocks has always been the critical process in mining, quarrying, and tunneling operations. Whether it is an advance made underground, benches drilled at a quarry, or holes drilled to insert rock bolts, all depend upon a single machine working consistently: the hydraulic drifter. In contrast to the earlier pneumatic rock drillers, the hydraulic driller uses high-pressure hydraulic fluid to produce percussive impact force, which results in higher penetration rate, quieter operation, less vibration, and efficient use of energy. Out of the several types of drifters currently employed on drilling rigs and jumbos, the MHD100X, MHD100, and MHD1838HD+ make a representative sample of scaling of drifter design to various types of rocks.
Importance of the Hydraulic Drifter
The drifter
is essentially the business end of a drill rig; that part of the drill which is
attached to the feed arm and strikes the drill rod, imparting its impact energy
to the rod down to the bit. In hydraulic systems, it is done via the impact
energy from a hydraulically driven piston impacting the shank adapter at a very
high frequency and independent rotation. The fact that the percussion and the
rotation are separate actions is what sets the hydraulic drifter apart from
others; the operator can independently control the impact energy, the rotation
and feed rate based on the hardness of the rock, saving on the rod wear and
improving hole straightness.
MHD100 and MHD100X: The Mid-Class
Power Duo
The MHD100
falls into the mid-class of hydraulic drifters, which are used for face
drilling, bolting and general mining production in underground mines and tunnel
developments. Drifters from this weight class are preferred since they achieve
a compromise between having sufficient energy for reliable penetration rates in
medium to hard rocks and being small and light enough to be mounted on
smaller-sized jumbos and single-boom rigs commonly used in narrow vein and
development mines.
In the case
of MHD100X, it is easy to guess what it is – an advanced version of the same
drifter in the same weight class – the "X" in the names of drifters
usually means an improved sealing kit, better wear resistance or advanced
hydraulics that ensure better penetration rate and longevity of the drifter
without increasing its size and shape. For customers who operate the MHD100,
the MHD100X is a logical choice for upgrade, which retains the same mounting
and rod specifications as the previous version, yet offering better drilling
efficiency and durability. Such improvements are very valuable in the mining
industry since the cost of rig modifications is far greater than the cost
difference between the versions of the drifter.
MHD1838HD+: Designed for Heavy Duty
The
MHD1838HD+ is considered one of the heavy duty class drifters, which usually is
designed for high-speed drilling operations in underground metal mines, large
tunnel boring and heavy duty quarries, where the rock mass or holes are tougher
or bigger. The "HD" means heavy duty construction with strengthened
housings, larger bores inside for higher hydraulic flow, and construction parts
that can work with high-frequency impacts without early fatigue. The
"+" usually means a newer version of the machine with some
improvements in durability or flushing/dust handling of the drill steel or
other features that would make rebuild intervals longer.
As the heavy
duty drifters, including 1838HD+, produce more impact energy with each stroke,
they usually work with bigger rigs and higher capacity hydraulic power packs.
In case there are two options – a medium class machine and an HD+ machine, you
have to decide whether you need faster drilling operations or smaller equipment
cost, hoses and pumps size, and heading or bench dimensions.
Selecting the Proper Drifter for the
Application
In reality,
the choice of the appropriate model such as the MHD100, MHD100X, and MHD1838HD+
is determined by a handful of practical considerations:
Hardness and
abrasion resistance of rock – harder rock usually warrants the extra impact
energy that comes with an HD-type drifter.
Compatibility
with rig setup – weight and mounting dimensions of the drifter need to be
compatible with the existing boom and feed assembly.
Hole size
and depth – bigger holes and greater depths require increased capacities.
Production
rate – continuous production drilling requires robust machines designed for
frequent and constant high-frequency operation, whereas sporadic bolting and/or
development operations can be successfully performed using mid-range drifters.
Maintenance
facilities – good in-house maintenance facilities may allow getting additional
efficiency out of higher performance machines.
Conclusion
Although
hydraulic drifters are only a minor physical part of a large drilling rig, they
form the greatest tool that will enable control of the rate of penetration,
durability of rods, and total drilling costs. No matter whether it is a
mid-size class MHD100 or MHD100X to perform normal face and bolting
work, or even a bigger MHD1838HD+ for hard production drilling, it all
comes down to selecting the right size of the drifter for the rock and rig in
question.
