Mining companies are digging deeper than ever to maximize output, what starts as an open-pit mine often extends underground. “As mines get deeper, extraction of valuable ore becomes more costly,” said Derek Meloche, manager of business development, Variant Mining Technologies. “In addition, safeguarding personnel from underground hazards is a critical concern.” Located in the Sudbury basin in Ontario, Canada, Variant Mining Technologies specialize in solutions for underground hard rock mining. The company works to solve one of the industry’s biggest challenges – moving material underground safely and efficiently.
Block Caving Challenges
Transporting ore underground presents significant challenges, depending on the excavation method used. In block caving, a large section of rock is undercut. The ore then collapses – or “caves” – gradually under its own weight. The resulting rubble funnels through a series of vertical ore passes at various levels in the mine. A chute system is located at the bottom of each ore pass. “The chute is a device that allows ore to be transferred safely to the haulage vehicles,” Meloche explained. “It controls the flow so haulage equipment can be loaded quickly and safely.” Trucks collect the material from a chute at the haulage level and transport it to conveyance systems, which bring the ore to a centralized crusher and/or to the surface.
Safety First
We are focused on creating a productive mining environment that mitigates and eliminates risk – and is an attractive place to work. Traditionally, underground ore chute systems have been viewed as steel fabrications, with very limited control. However, Variant brings control technology to the forefront to help make equipment safer, more efficient, and more reliable.
A Two-Fold Control Solution
Successful operation of the ore loading system depends on the coordinated control of the ore chutes and haulage vehicles. Variant is charged with supplying the ore chutes – and a safety control system that meets functional safety requirements. To achieve a functionally safe system, in this case a system that meets SIL 3 ratings, the design considered the process that encompasses the bin, chutes and trucks. The control system is built on platform Featuring, designs that eliminate hazards, safety-rated controllers, and HMI interfaces. The system is designed with a controller and HMI in each chute and aboard each truck. For fail-safe communication, the integrated system uses safety-rated protocols running on an Ethernet wireless network.
Enabling Smart Technology
To optimize the system, Variant incorporated several technologies that are not new in other industries but new to underground mining. For example, the vehicle detection system in the chute loading area detects a truck’s presence and position – while RFID technology determines the vehicle model and type. “This technology allows operators in the truck cabs to control the chutes in a safer manner,” Meloche said. “The chute will not operate unless a haulage truck is present and in the correct position. Jeeps or other vehicle types cannot trigger operation.” The system also includes fallen object protection. A gate at the end of the chute contains any loose rocks from the previous load to help safeguard approaching vehicles and personnel. “And our system monitors the ore bins associated with each chute to make sure they don’t run empty,” Meloche said. “We keep material in the bins at all times to serve as a buffer – so ore falling 150 feet doesn’t come out of the chute like a rocket.”
Exceeding Expectations
Our Team of Certified Machine Safety Experts CMSE™ design ore handling systems that improve operator safety while optimizing mine throughput. Variant anticipates the system will enable significantly better traffic control and equipment utilization than other systems on the market. “Overall, mining companies are most concerned about safety – and productivity,” said Meloche. “Our safety-rated SIL 3 system is designed to improve both.” This truck loading control system is currently patent pending.
