TECHNOLOGY
and more environmental constraints can make blasting
uneconomical or undesirable.
Compared to other mechanical excavation methods
(such as excavators with hydraulic rock breakers or
rippers), the Tesmec Rock Hawg is the more cost-effective
solution (provided that the job site extension is not too
small and that it is sufficiently flat).
The productivity of a single Tesmec Rock Hawg can
be more than three times that of an excavator of the
same weight (or up to 15 times a 25-ton class excavator),
equipped with hydraulic rock breaker, and a few Rock
Hawg units can replace an entire fleet of excavators.
Rock Hawg machines are relatively small-sized
machines, engineered with the scope of crushing rock,
thanks to the special drum attachment with carbide
digging tools and the high engine power that allows a very
high hourly output per single unit.
The high capacity of Rock Hawg machines reduce to
one the number of units simultaneously working on the
proposed job sites. Excavating with one single machine
increases efficiency, safety, and costs for manoeuvring
and servicing.
Rock Hawg produces small and quite uniform material
with a tight particle size. Excavation and crushing are
carried out in one single phase, and this always allows
avoiding primary crushing and more efficient settings on
secondary and tertiary crushing systems. In large part, the
size fractions obtained are a function of how the rock is
laid into the ground (rock strength, rock brittleness, and
rock mass fracture degree).
The ‘reverse’ cutting mode of the Rock Hawg allows
some degree of control of the grain size of excavated
material, both in terms of oversized blocks (larger than
6” or 15cm) and sand/fines generation, allowing some
variation in the size fractions obtained during cutting.
Since all the excavated material passes under the drum and
the tooth penetration reduces with depth, the shallower
the cut, the bigger the size of the excavated material.
Conversely, smaller-sized particles can be achieved by
increasing the digging depth and reducing the advance
speed of the machine. Having this small-sized material
produced in a uniform configuration allows the material
to be handled much more efficiently than the product
achieved in excavation with drill and blast or rock
breakers. This means savings for reduced wear and tear on
truck bodies and loader buckets.
What are the benefits of the Rock Hawg?
There are many advantages to using the Tesmec Rock
Hawg technology. Rock Hawg machines can excavate
vertical side walls, thanks to the drum being wider than
the tracks and it being supported in the centre. Moreover,
the rear-mounted drum also allows for the excavation
of square corners. This means that the excavated pit in
many cases will not need any further finishing by other
excavation means.
The shock and vibration from Rock Hawg excavation
are negligible and therefore, the danger zone becomes a
non-issue. Rock Hawg machines generally produce low
amounts of dust. In case the requested level of dispersed
dust must be strictly limited, the Rock Hawg machine
QUARRY SA | JULY/AUGUST 2018 _ 17