The proximity detection system (PDS) from Booyco Electronics, brings the mine in line with the latest mine safety regulations.
According to the mine’s underground engineer, Petrus Vilakazi, Sudor Coal recently completed the implementation of the system; a process that started in March 2016 and was rolled out across all three of the mine’s sections over a period of about one year.
“In terms of the new safety legislation, we initially presented our implementation plan for a collision-avoidance system (CAS) to the Principal Inspector at the Department of Mineral Resources,” says Vilakazi, “and this year we were able to report back to say the system was in place.”
Official statistics show that transport-related incidents remain a leading cause of fatalities in South African mines, alongside incidents caused by fall-of-ground.
PDS is a key part of the sector’s strategy to work towards the goal of zero harm, an approach that has succeeded in reducing deaths in mining by 5% to a record low of 73 in 2016; injuries also fell 15% last year.
PDS allows for interventions where a potentially dangerous situation exists between a pedestrian and a machine.
The system includes a sensing device, to detect the presence of a pedestrian or other vehicle in a working area, and an audible and visual alarm to alert both the equipment operator and pedestrians as they enter danger zones. It can also help locate people and machinery if there is an emergency underground.
Legislation requires that any PDS system employed must be ‘fit for purpose’ in order to comply.
Sudor Coal has been operating since 2004, and mines the Number 4 Seam – lying at about 60 m below surface – in all three sections at Weltevreden.
The first stage of implementing the Booyco PDS system was the installation of over 200 buzzers and flash units on one section, over a period of about four months.
The transmitters were installed on the continuous miner, the shuttle car and the roof bolter in each section.
“Commissioning of the PDS was done in two phases: in the cold-commissioning phase, the system creates a warning – with a flashing light and buzzer – to warn the machine operator and pedestrian of their proximity to each other,” says Vilakazi.
“Hot-commissioning then follows, where the system’s intervention was operationalised. The movement of the machine will firstly be retarded if there is no response to the warning; then, if there is still no action, the system brings the machine to a stand-still.”
An important aspect of the system is its report generating capability, giving mine management quick and detailed insight into interferences and stoppages that occur underground.
Initially, the report data can also be analysed to allow the mine to choose the appropriate detection zone option to achieve the optimal level of detection and retardation.
While the round or oval shape of the CWS 800-configuration is not adjustable, the CWS 900-configuration allows the danger zones to be cut to as little as a metre from the side of the machine.
“Being a bord-and-pillar mine, we chose the 900-field option for the devices on our equipment in the inbye zone – the hazardous zone within 180 m of the coalface,” says Vilakazi.
“This option reduces the interference picked up by the machine from the side-wall, while at the same time still detecting pedestrians at a safe distance to the front and rear of the machine – the most dangerous areas.”
PDS devices on the moving equipment in the outbye area – such as tractors and conveyors – use the 800-field option, as the operating space is not as constricted.
He says it was important to communicate the rationale for the system clearly with the underground employees, to ensure that everyone understood why it was necessary and how it would improve safety.
“Anything new takes some getting used to, but it was not long before the system was well accepted by all stakeholders and it now works smoothly with no impact on production levels,” he says.
“Employees also realised that the company had invested substantially in this system so that they could work more safely, and they have bought into the implementation process.”
Started in 2009, the Weltevreden operation is also preparing to mine the Number 2 Seam and an 8° decline shaft is being prepared to access this level from the 4 Seam to increase the mine’s lifespan.
The mine supplies all its production to Eskom for power station use.
Vilakazi points out that the system also makes a valuable contribution to safety by encouraging discipline at the workface.
“If a pedestrian is in the wrong place or is too close to a machine, thereby causing it to stop, the operator is inconvenienced and can report the incident,” he says.
“Management can also pick up every incident of interference in our reports, and can take it up with the persons involved if necessary.”
According to Booyco Electronics MD Anton Lourens, the company’s PDS has gained a reputation for helping mines protect their people – their most important asset.
It was developed as part of the Booyco Electronics Asset Management System (BEAMS), which provides underground and surface mining operations with a web-based reporting application and robust database to optimise mine safety and ensure compliance to legislation.
Lourens says the PDS transfers information between users via Booyco Electronics’ Human Machine Interface (HMI) – designed and developed in-house. System communication is exchanged with operators using icons, making it easy to understand.
Having secured a strong position in the PDS field, Booyco Electronics is replicating this success in surface applications with its PDS which is able to enhance vehicle and operator safety in surface mining operations.
All images: Booyco Electronics