Winning
I
n 1980, Wirtgen rolled out the first prototype of its
surface mining machine, and three years later the
first production machine was sold – the 1900SM,
used for gypsum mining in South Africa. Despite
this, and although the machine has been operating at
open cast sites around the world for over 30 years, the
technology has yet to be adopted in South Africa. In order
to address the potential concerns of South African surface
miners, Wirtgen Sout h Africa arranged to trial one of its
small machines – the 2200SM – at three open cast mines
in Mpumalanga.
Mike Newby, sales consultant: Mineral Technology, gave
us some background on the machine. “The surface miner
is technology adapted from our road milling machines. A
few decades ago Wirtgen decided to see if a road milling
machine – used to mill up road surface for later reuse –
would work in a surface mining application,” he says.
The technology needed to be adapted for mining – the
machines are a lot more robust and are able to cut deeper,
for example, and today Wirtgen has over 500 machines
in use around the world in applications from iron ore to
gypsum. “Despite the proven nature of the technology, in
South Africa, it is still considered a new technology, which
is why we ran trials at a couple of mines last year, to show
off the capabilities and benefits of the machine working in
local conditions,” Newby explains.
“What differentiates the Wirtgen Surface Miner from
other similar machines is the centrally located cutting
drum with tungsten carbide cutting teeth,” explains
Newby. “So as the machine moves forward, the cutting
drum moves into the ground, cuts the material, loads it
onto the intermediate conveyor, which dumps onto the
main discharge conveyor, from where it is ejected, either
onto haul trucks or onto the ground, depending on the
operation. From there, it can be taken directly to the
processing plant. Using the machine has the advantage
of eliminating a number of processes, including drilling,
blasting, loading, hauling and primary crushing, and in
most cases you reduce the need for washing as well.”
The primary consumable for the Wirtgen machine(in
very hard, abrasive material like iron ore or hard
sandstone), along with diesel, water and oil, is the picks
on the cutting drum. To make managing these picks as
easy as possible, Wirtgen came up with the Wirtgen pick
inspector (WPI) system, which uses lasers to measure the
individual wear of each pick to facilitate servicing and
maintenance and make it possible to replace as needed.
The system comprises eight rapid measuring sensors
integrated into the cutting drum compartment of the
surface miner which measures the degree of wear of the
picks in just one minute, avoiding downtime. In coal and
other soft materials, however, wear on picks and the drum
is minimal.
Changing outlooks
Given the South African reluctance to accept the machines
without first-hand experience of their operation under
local conditions, Wirtgen South Africa recently ran a series
QUARRY SA | MAY 2017 _ 17