MINE SAFETY
Reacting in real time
With mining companies continuing to move towards a ‘zero
harm’ culture, equipment and solution providers have to
devise new ways to protect workers and machines in open-pit
and underground mines without denting productivity. Dan
Gleeson looks at some of the avenues they are going down
s operational mining environments have
increased in complexity with the adoption
of new technologies aimed at improving
productivity, the need to know where personnel
and equipment are in real time has grown in
importance.
Miners – as they introduce teleremote and
automated equipment into the fleet mix – must
ensure manned equipment and their own
personnel are protected from potential incidents
on site. To do this, they need to use the most
accurate personnel and vehicle detection
systems possible.
These systems then need to be put through
their paces so operators can learn to trust them.
Tom Michaud, Chief Technology Officer of
Strata Worldwide, has been through this
process with many mining customers on the
way to helping the company install over 1,500
HazardAvert ® proximity detection systems
(PDS). He knows user acceptance is inextricably
tied to the accuracy of the system and the PDS’
ability to stop operations only in the event of an
imminent accident.
He explained: “A big issue I fight with is:
what is the acceptable level of ‘false positives’
before the operator gets frustrated and puts
some tape over the speaker?
“That’s what we have seen on sites. If
operators get frustrated with the PDS, they tape
it and damage it just so it stops bothering them.
They just don’t trust it.”
PDS or vehicle detection systems (VDS) are
typically engineered to, first, warn operators of
an impending hazard through an audible alarm
and, if the potential for an accident persists,
enforce a stop through a communicated braking
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International Mining | OCTOBER 2019
command.
The ability to gain operator trust varies from
site to site depending on the region, type of
operation, type of device required to be worn
and worker demographic.
The mine managers, themselves, are also
wary of asking workers to try out new VDS or
PDS solutions. While nothing is more important
than safety, the additional time it takes to
inspect, analyse and reset these systems after a
warning or enforced stop has a negative impact
on production. Therefore, there can be a strong
correlation between the number of ‘false
positives’ these machines produce and the
ability of a mine to reach its production targets.
Regional regulatory requirements
In recent years, these mine managers have had
some difficult decisions to make as regulators
have acted to enforce a minimum baseline of
proximity detection in mining operations.
In February 2015, the government of South
Africa amended its Mine Health and Safety Act,
implementing regulations related to mine
machinery and equipment that means PDS must
be installed on all mobile equipment on mines.
Similarly, the US’ Mine Safety and Health
Administration (MSHA) requires operators of
underground coal mines to equip “place-
changing continuous mining machines” with
PDS.
This means mines have to get on-board with
these new safety requirements.
Knowing where a person is, while important,
has been deemed not enough to reliably
prevent costly and potentially fatal situations in
mining.
indurad’s iProximity Solution: iRTT digital CAN
Bus linked antenna units on LHD vehicle
This fact is pushing the industry and
regulators from simple PDS (level 7) to collision
avoidance systems (CAS, level 9), with the
Australia-based Earth Moving Equipment Safety
Round Table (EMESRT) leading the charge.
Only last month, the organisation published
version two of its Vehicle Interaction System
Performance Requirement 5A (PR-5A) as part of
this push. While version one was developed
with more of a designer perspective of what the
systems needed to provide, version two adds a
defined level 7, 8 and 9 user case into the mix,
allowing a balance between user and designer’s
needs, EMESRT said.
EMESRT said: “The objective is to prevent a
person or equipment (machine or vehicle)
causing a potential unwanted event (PUE) in the
following four PUE categories resulting in injury
or equipment damage:
n “Equipment to person;
n “Equipment to equipment;
n “Equipment to environment; and
n “Loss of control of equipment.”
The legislation might not yet be in place to
enforce the type of Level 9 CAS EMESRT is
currently talking about, but there is clearly an
expectation it will follow in the near-term, with
several PDS vendors already adopting this in
certain applications.
This includes indurad with its iProximity CAS,
which has been successfully tested in Level 9
CAS tests with two OEM LHDs in South Africa
recently.
Based on the company’s iRTT
(RadioTransponderTag) technology, iProximity
uses three physically independent radio
channels and four signal processing methods:
time difference of arrival (TDOA), time of flight
(TOF), received signal strength (RSS) and
phasor measurement units (PMU). Particularly,
the PMU method sets indurad’s solution apart
from its peers, according to the company. “It’s
developed for precise phase measurements and
backed by more than a decade of indurad’s
experience on building high performance radar
sensors,” the company said.
Dr Reik Winkel, CEO of indurad, sees PDS and
CAS as bridging technologies: "Looking back,
the industry started with low-cost ultrasonic
beepers. Then, we saw the transition to PDS.
Now, the industry is heading to CAS – to safely
stop the machine.”
The company has designed and used the iRTT
technology already with fully automated
underground LHDs and surface articulated
dump trucks, he added – showing it is ‘future-
proofed’ for the autonomous mine of the future.
The iRTT technology is also used as the