Modern mining demands rigorous focus on safety, productivity and cost containment, all of which can be driven by breakthrough technologies that are already changing the way miners operate at the coalface, says mining solutions company Strata Worldwide.

The company points out that its proximity detection system (PDS), designed to reduce the risk of accidents involving man and machine, HazardAvert, was verified for its effectiveness on diesel-powered equipment, in June.

“In its efforts to stop or, at the very least, substantially reduce the unacceptably high number of underground fatalities involving moving machinery, the Mineral Resources Department has legislated PDS collision-avoidance technology as a statutory requirement for operations across all commodities,” says Strata Worldwide South Africa president Jonathan Metcalf.

He says the system, which uses a magnetic field, is designed to slow down or stop equipment when a person or vehicle enters a danger zone around moving machinery. At the same time, underground personnel on foot are alerted to impending danger through an audible and visual alarm integrated into their cap lamps.

Metcalf says the system’s uptake has been the greatest in the coal mining sector, “with several industry majors having selected it as the last line of defence in preventing incidents involving a range of electrical equipment, including continuous miners, roof bolters, feeder breakers and shuttle cars”.

The verification of the system’s effectiveness on diesel-powered equipment was a significant milestone for Strata Worldwide, says Metcalf.

He says that, at a customer demonstration of the system in a diesel application, a PDS-equipped load haul dump (LHD) and multi- purpose heavy-duty forklift both came to a complete standstill on entering the signal field emitted by a PDS device.

“The LHD, which was carrying a payload of 16 t, was repeatedly halted at speeds of between 6 km/h and 18.6 km/h, and the forklift at speeds of 6 km/h to 14 km/h,” says Metcalf.

Communications at the Coalface
Strata Worldwide also supplies a WiFi-based communication and tracking system, CommTrac, which delivers reliable interpersonal communication while providing miners with up-to-date knowledge of the exact status of their equipment.

“If mines are to achieve their efficiency and cost objectives, communication is key, whether from surface to underground, or from one underground location to another,” says Metcalf.

He adds that traditional underground telephone and radio systems are cumbersome and, because they rely on cables, they are difficult to install and are also labour intensive to move from one section to another underground.

He says another long-standing problem is that radios have a limited number of channels, which makes having a one-on-one conversation difficult.

CommTrac is entirely wireless and relies on cable-free battery- powered nodes that can be installed when and where they are needed. The system facilitates calls with good voice clarity and two-way text messaging from miner to miner, miner to surface and surface to miner.

In addition, the communication system has a group paging facility and high-speed data access.

“Underground staff can make and take calls and access production information without having to walk or drive to the waiting place where static underground communication systems are traditionally installed,” says Metcalf.

The system’s real-time location tracking application provides vehicle tracking, shaft clearance and miner-in-distress capabilities, using global positioning systemlike tracking that is accurate to within 30 m.

Metcalf says the system is immediately able to determine the number and position of personnel underground in the event of an emergency, so that management and mine rescue teams can reliably determine their last known location. This is achieved through the installation of a lightweight, compact, tracking tag incorporated into the miner’s cap lamp.