This cost pressure has also
impacted longwall equipment sales,
according to Dr Uli Lange, Deputy
Director of Sales at Eickhoff. “From
our perspective as a supplier of
premium coal cutting equipment, one
of the biggest challenges the longwall
mining industry has had to face has
been the massive decrease in
commodity prices,” Lange said. This
has resulted in “longwall operators
being put under massive pressure to
reduce costs; hence less sales volumes
at OEMs for longwall equipment.”
At the mines, this means that
operators are looking to extend the life
of existing equipment. This can lead to
reduced productivity, said Haughey, as
older equipment significantly increases
the likelihood of equipment
breakdown – with the consequent
growth in maintenance requirements.
Older equipment can also lead to
increased dust generation – either from
worn bits or poorly-maintained dust
suppression systems – an important
issue as regulators around the world
are imposing stricter limits on the
amount of dust to which miners can be
exposed.
To counter this, some mines are
looking to automation to help boost
the amount of coal they can cut using
existing equipment. “Operators intend
to increase production with their
existing equipment in order to balance
out low revenues resulting from low
coal prices,” explained Lange. “This
can be achieved by means of
automation while cutting at less gaps
in production flow, hence higher
average cutting rates. Automated
systems usually do not allow for
production records over one shift;
however, in the long run, such systems
guarantee higher average production
rates per month and year.”
Away from the economic
challenges, geology is also becoming
more difficult, according to
Dr John Stankus, President of
Keystone Mining Services, a Jennmar
affiliate, with deeper overburden,
weak geology and increased horizontal
stresses all requiring more difficult and
expensive roof control.
Haughey agreed: “Due to the
depletion of ‘good seams’, mine
operators are now forced to mine
lower‑quality coal seams that include
more rock – or to mine large amounts
of reject material to get to the coal
seam.” This again increases the
amount of dust – as well as noise –
produced during mining, adding to
health and safety challenges, as well as
increasing the time required to mine
the desired amount of coal and
wearing the cutting tools more quickly
(again a source of dust).
New technologies for
new challenges
To meet these new challenges, mines
are turning to technology to maintain
productivity and ensure their
personnel work in safety. Automation
is the buzzword here – but it is not the
only development that is helping to
make longwall mines safer places to
work in.
“New roof control products are
being developed to deal with more
difficult ground conditions: e.g.
higher-capacity cable bolts, pumpable
cribs for roof-to-floor support,
easy-to-operate steel props and
cuttable non-metallic rib control
products,” said Stankus. “Additional
advancements have been made in
computer modelling technology and
methods that provide improved and
more accurate determination of stress
conditions that affect roof control.”
And in terms of the equipment,
“underground coal mining machinery
will probably become more and more
intelligent in order to avoid unsafe
interaction and to cope with
negligence of human beings in close
proximity,” predicted Lange. “It is
essential to have reliable sensor
technology onboard that gathers a lot
of information from the environment
around the equipment in order to
support various kinds of jobs at the
coal face.”
“Data gathering, storing and
analysis is crucial for further
development of automated by safe
systems,” Lange continued. These
systems can also provide information
on the condition of the components,
supporting predictive maintenance
rather than risking hazardous
breakdowns while in operation.
Sensor technology was also
highlighted by Haughey: “Advanced
sensor technologies, along with the
latest cameras, coupled with
high‑speed date communications, are
enabling mine operators to move mine
personnel away from the face and to
monitor longwall operations from a
distance.”
Meanwhile, before a miner even
enters the mine, technology – in the
form of computer or simulator-based
training – can help operators to learn
safe operating and maintenance
procedures without putting
themselves and colleagues at risk
underground, added Lange.
The search for the
Holy Grail: longwall
automation
Ultimately, however, the increased use
of technology will be used to reduce
the number of miners underground
through the use of automation. And a
fully-automated longwall system is an
achievable goal, according to all three
interviewees.
There is, however, always likely to
be a need to have people underground,
as Lange explained: “A
fully‑automated longwall face seems
to be a realistic aim, when speaking
only about production. Nevertheless, it
seems very unlikely that maintenance
and repair services will be able to be
conducted without personnel. When
breakdowns occur, quick reaction
times are essential for operating
companies. From today’s point of
view, only mine personnel can
guarantee those quick reaction times.”
“We expect that there will always
be a need to send mine personnel
underground to perform normal
maintenance tasks associated with
longwall equipment (e.g. changing
bits, checking and replenishing oil
and chain maintenance) and to deal
with exceptions (e.g. geological
changes, high methane gas readings
and water infiltration)” concurred
Haughey.
Health and safety
improvements
So what is on offer now to improve
health and safety in longwall mines?
20
|
World Coal
|
July 2015
