Spotlight Feature Articles MINE SAFETY - Page 2

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 A 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