Removing personnel from underground loading operations at Mandalay Resources’ Costerfield gold-antimony mine in Victoria, Australia, through RCT’s ControlMaster® Teleremote and Guidance Automation, has led to time and cost savings, as well as maintenance and safety benefits, according to a recent case study from the automation specialist.

Costerfield produces ore via a single portal underground mine with narrow vein mining carried out to extract vertical veins of ore. The mine produces up to 80,000 gold-antimony-equivalent ounces per year in a concentrate comprising around 54% antimony and 60 g/t gold.

The nature of narrow vein mining dictates that ore drives are quite thin to reduce the amount of waste material that is captured, with Costerfield’s drilling and blasting program designed to maximise ore recovery by throwing the ore towards the draw point. Historically, however, the site could only recover 75% of the ore, according to RCT, due to the remaining ore sitting in the stope void out of reach of the underground LHD as manually operated loaders could not exceed the stope brow.

Looking to increase productivity, Mandalay investigated implementing a loader that could be managed remotely to extract additional ore and to safeguard equipment operators from hazardous situations at the mine face. This led to it, in 2015, engaging RCT to implement its ControlMaster Teleremote and Guidance Automation product on a Sandvik LH203 LHD.

The automated loader enabled Mandalay Resources to retrieve significant amounts of ore that were previously unreachable, RCT said.

In recent years RCT has increased the autonomous fleet at Costerfield by commissioning ControlMaster Teleremote and Guidance Automation on a second Sandvik LH203 as well as a Sandvik LH151D.

The machines are managed from Fibre Optic Control Stations at secure locations in the underground mine protected by Laser Guard Containment Units as well as stations on the mine’s surface.

Jayson Guzzo, Major Projects and Innovation Manager – Costerfield, Mandalay Resources, said removing operators from the machine is the “best outcome” as it eliminates their exposure from one of the highest risk jobs, which is working at a stope brow.

“The small loaders we use are very rigid which has the potential for repetitive strain injuries,” he said. “They also have open cabs and, in this environment, dust, machine exhaust and debris can be an added safety concern.”

In mid-2019, Mandalay made the decision to implement a digital mine communications network to accommodate future technological growth.

Guzzo said: “Given that we are a narrow vein operation we may have to access ore a significant distance from the mine access point so we are looking at going to a digital platform so we can run a fibre backbone and autonomously operate machines over a vast distance.

“In a traditional mine, you might spend a whole week bogging a single stope before moving, but at Costerfield we might bog three or four headings in one shift, so the number of sites that we have to have set up at any one time are multiple, hence a digital system will significantly speed up the process of commissioning new drives.”

Mandalay has reported that ControlMaster Guidance Automation enabled them to carry out bogging and firing operations simultaneously, saving them substantial time which was previously spent clearing personnel to a safe distance, RCT said.

Guzzo said the solution has enabled the company to reduce shift changeover time by two thirds – which is a significant cost saving – and the site has also experienced less unplanned machine downtime.

“At Costerfield, the drives are roughly 2 m wide so Guidance Automation keeps the machines off the walls and stops them bouncing around the tunnels, so the damage to the machines is a lot less and results in significantly reduced unplanned maintenance time,” he said.

Guzzo concluded: “Relocating operators from the cab of our loaders to safer environments on the mine’s surface is essential and being able to continue bogging during firing as well as significantly reducing shift changeover time is critical to improving site productivity.

“Plant automation is definitely the way of the future in the mining industry and RCT are the leaders in that area, which is why they are our preferred supplier with this equipment.”