Global projects and exploration
“The planned method of re-entry will be made
safe through the use of controls, in line with
mining standards around the world,” Little
says. He adds that it is an extraordinarily
complex undertaking and that the government
had the benefit of advice from some of the best
in the world in their field.
Three feasible options were considered,
namely single entry using the existing drift
design; drilling a second tunnel at the end of
the drift, closer to the mine workings; and
drilling a large borehole part way down the
drift for both ventilation and emergency egress.
Little has chosen to execute the single-entry
approach, as recommended by the agency as
a safe and appropriate re-entry method. The
New Zealand Police has also been engaged
to provide their service in examining the drift
tunnel through to the roof fall area.
Major works for the re-entry is scheduled
to go under way around February this year.
“The people of New Zealand can rest assured
that this re-entry plan is achievable. It is now
our intention to get this job done and try and
find out why those 29 men went to work on
19 November 2010, and never came home,”
Little adds.
The material is loaded onto RopeCon by
a feeder conveyor and unloaded at the
unloading station via a housed-in chute. The
system transports 2 100 tons of limestone
and marl every hour to cover the demand for
the cement production.
RopeCon is developed by the Austrian
ropeway manufacturer Doppelmayr. It offers the
benefits of a belt conveyor as well as those of a
cable car by successfully combining what is best
in both technologies. The system is currently
in use for a variety of material transport
applications. It essentially consists of a cross-
reinforced continuous flat belt with corrugated
side walls, which is driven and deflected by a
drum in the head or tail station. The belt is fixed
to axles arranged at regular intervals, which
support the belt. Running wheels are fitted to
either end of the axles. These run on track ropes
with fixed anchoring and guide the belt. The
three track rope pairs form the line structure for
the system and are elevated off the ground on
tower structures. The system therefore requires
only a minimum of space on the ground and is
ideally suited for difficult terrain and to cross
obstacles of all kinds.
Guatemala
[12] MINING MIRROR FEBRUARY 2019
Cementos Progreso has installed a system called RopeCon to transport material over a distance of about
1.6km, with a vertical rise of almost 200m.
The countryside around the village of
San Juan Sacatepéquez in south-eastern
Guatemala is hilly and forested. Cementos
Progreso had been planning to build a new
cement plant there for some time. Among
other things, the project required a solution to
transport limestone and marl from the crusher
to the processing plant. Cementos Progreso
opted for RopeCon as a means to cover the
distance of about 1.6km and the vertical rise
of almost 200m.
The San Gabriel cement plant is located
approximately 35km north-west of Guatemala
City. There the Guatemalan company Cementos
Progreso produces more than 2.2 million tons
of cement every year for the local market. The
limestone needed for the process is mined in
a quarry located about 200m lower than the
cement plant. The terrain between the crusher in
the quarry and the plant is hilly and wooded and
stretches over a distance of at least 1.6km.
By using RopeCon to transport the
limestone between the crusher and the
processing plant, Cementos Progreso is able to
cross that terrain in a straight line despite the
difficult topographical situation. This means
that a gradient of 22 degrees is reached where
the terrain is steepest. Because the RopeCon
belt is fitted with axles with running wheels
at regular intervals, no additional cleats were
required to tackle that gradient.
The system requires no more than four
towers over its entire length. Thanks to the
long rope spans between the towers, the
amount of space required on the ground
can be reduced to a minimum. The need to
interfere with vegetation remains limited to
a small number of points and the track does
not represent an insurmountable obstacle for
wildlife or humans.
Transport solution flattens the
earth
The gradient at its steepest is about 22 degrees.
Canada
Mine reaps electric rewards
Canadian mining company Goldcorp is set
to replace all its diesel mobile equipment at
the Borden Project with electric vehicles.
According to the company, the move
will enable it to derive health and safety,
environmental, and economic benefits.
Borden, which is 200km west of Goldcorp’s
Porcupine mine, is in the feasibility phase and
is expected to start production before the end
of 2019. It will be Canada’s first all-electric
underground mine, which has been backed
by the Government of Canada with USD5-
million of funding.
The shift will reduce 70% of carbon footprint
compared with conventional technologies. It
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