Modern Mining April 2016

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44 MODERN MININGApril 2016
EQUIPMENT
Stemming is a key element in the
‘drill and blast’ mining technique.
In stemming, material such as fine
gravel or aggregate is placed on top
of explosives in drill holes. When the
explosives are detonated, the stemming locks
in the expanding gases and keeps the forces in
the borehole until rock begins to break.
The stemming truck’s duties are to fill blast
holes on a mine site into which the liquid mix-
ture of ammonium nitrate and fuel oil explosive
charges has already been inserted. The holes
are typically located at 5 m intervals in the area
to be broken up.
The stemming trucks available from Scania
South Africa are the result of a partnership it
has with Cobra Petro Projects. An initial truck
Stemming trucks from Scania
can cut open-pit mining costs
A completed Scania
stemming truck ready for
delivery.
Becky Smith, Scania South
Africa’s GMMining.
A crucial part of the open-pit mining cycle is the blasting process and any
equipment that can make this activity more efficient is highly prized by the
mining industry. Stemming trucks are one class of product that can contribute
to making blasting procedures faster and more efficient and Scania South Africa
can now offer customers what it believes is one of the most efficient trucks of this
type on the market. The stemming truck forms part of Scania’s extensive range of
mining trucks.
was manufactured and introduced to the South
African market two years ago. One of South
Africa’s most well established mining groups
saw it and arranged a demonstration review.
The truck impressed the company to the extent
that it purchased the demo model. Within a
few months two other units were purchased.
The units are manufactured under licence to
Ausroad, an Australian company which orig-
inally developed them for a mining client in
Western Australia.
According to Becky Smith, Scania South
Africa’s GM Mining, it is not uncommon in the
South African mining industry to see the stem-
ming function being performed by front-end
loaders, which she says is not only inefficient
but also tends to give inconsistent blasting
results. In addition, backfill
material either consists of aggre-
gate that needs to be transported
to the blast site or of the rock dis-
placed through the drilling of the
blast hole. This means that the
material is not graded and spe-
cific to the requirements of the
blast – which affects efficiency.
“This new stemming truck
technology makes it easy to
ensure that the correct amount
of precisely sized aggregate is
delivered into the blast holes in
an efficient manner,” Smith says.
Benefits of using the stem-
ming truck include operational
safety (one truck and operator)
versus several smaller vehicles;
being able to access hard-to-
reach blast areas with an 8 m
boom conveyor (170 degrees);
and significantly decreasing the