safety on mines
feature
45
06.13
Gary Clench (left) and Trond Skogseth with examples of the
D‑Bolt from Normet.
absorption capacity of a Ø22 D-Bolt has been mea-
sured to be 37 kJ/metre.
Skogseth points out that the D-Bolt – which he
says is priced attractively compared to other dynamic
bolts in the market – can be considered a three-in-one
product. “It can control and dampen rock bursts and
also control squeezing rock areas while, at the same
time, providing high static support, like rebar. There
is no need to combine it with other bolts, as is needed
with other energy bolts. In general, the benefits of the
D-Bolt include reduced downtime from rockfalls and
a lower requirement for rehabilitation bolting. Anoth-
er strong advantage of the system is that installation is
easy – the bolt is installed using standard equipment
and procedures and using the same resins or cements
as would be the case with conventional bolts. Similar
products developed in the past were too complex and
too difficult to install.”
The D-Bolt was officially launched in 2009 with
the first sales being recorded the following year. Says
Skogseth: “DRS, being a start-up with limited re-
sources and reach, decided to initially concentrate on
three key markets – the Scandinavian region and also
Canada and Australia. The thinking was that these
were all safety-conscious markets which would be
most receptive to a safety bolt which costs more than
conventional rebar bolts but which offers huge ben-
efits in return. Sales in all three markets have been
very encouraging – given the natural conservatism of
the mining industry – and purchasers have includ-
ed Xstrata in Canada, BHP Billiton in Australia and
LKAB in Sweden.”
He adds that LKAB is using the D-Bolt at its huge
Kiruna iron ore mine in northern Sweden where it
has just officially opened a new main haulage lev-
el at a depth of 1 365 m. In developing this new
level, large volumes of D-Bolts are being installed
monthly to provide the best possible support in the
dynamic rock conditions and minimise safety risks
at the new depth.
With the D-Bolt now in the Normet fold, Skogseth
says the product is being rolled out worldwide, in-
cluding in South Africa. “We now have the ability to
also attack other markets, and we already deliver to
South America and the US. South Africa is another
very interesting market where we already see a need
for the D-Bolt.” Adds Clench: “We are just starting
to market the D-Bolt locally so there have obviously
been no sales as yet. We are, however, starting to tell
the mines about the product. Given its cost premium
over conventional rock anchors, safety and efficiency
will be what drives demand, which we see coming
from the gold mines, where seismicity is a major is-
sue, and also the platinum mining sector, where ever
increasing mining depths are resulting in more prob-
lematic rock conditions. Initially, we will have to im-
port product but we will look at local manufacture as
soon as the demand justifies it. The D-Bolt makes use
of a very high-specification, low carbon alloy steel,
which could prove difficult to source in South Africa,
but this is something we still have to investigate.”
Currently, the D-Bolt is available in bolt diameters
of 20 mm and 22 mm and in lengths ranging from
1,8 m up to 3 m. Special lengths, however, can be
made, and Normet is also working on new diameters.
Clench stresses that Normet Africa’s primary focus
is on building up a footprint for Normet’s equipment
in Southern Africa. “The local company was only es-
tablished a year ago so we have been very busy since
then marketing Normet’s machines to local mines,”
he states. “We’re happy with the progress we’ve made
and recent orders have included two Spraymec units
for Palabora, a Semmco sprayer for Cullinan, and a
further two Agicars and one Spraymec unit for use
on the Venetia underground project. We’ve also sold
some machines to the Chambishi mine on the Zam-
bian Copperbelt. Clearly, our sales drive provides us
with a perfect platform to also introduce the D-Bolt
to potential customers and we are confident that we
will ultimately become a sig-
nificant player in the safety
bolt market.”
The size of the potential
market in Southern Africa is
difficult to gauge but Normet
in Finland estimates the val-
ue of the global underground
mining market for rockbolts
as being of the order of €1,7
billion annually. It says the
premium bolt market ac-
counts for approximately a
quarter of this total.
Report by Arthur Tassell
D-Bolt and rebar bolt installed (resin not shown).
