The Challenge

NLT partnered with MMG Ltd. to outfit their Dugald River mine in Queensland, Australia with a solution to remotely monitor and control paste-fill operations underground. The system required the ability to monitor instrument readings and record data from six separate levels, while providing the ability to control and adjust the flow of paste through the pipes as required. The instrumentation included pressure sensors, flow metres, valve controllers, and video equipment. To ensure the paste-fill facility located on the surface operated optimally and safely, the control system required a mix of I/O connectivity, including analogue signals (4-20mA), industrial communications (over ModbusTCP), and valve control.

The NLT solution

NLT designed, manufactured, supplied, and deployed a distributed system with an N-Connex backbone to enable the paste-fill application. The solution, which was distributed over 6 levels down to the 290 level, included:

  • NLT Fiber back-bone
  • NLT N-Connex network infrastructure
  • NLT Control Modules
  • IP Camera solutions
  • Custom hardware (NLT Control Lite & Dump Valve Controller)

The system allows underground sensors and IP camera signals to be observed anywhere on the network and real-time management of both surface and underground control equipment. Powered by N-Connex The N-Connex system is ruggedized and fit-for-purpose. Designed with miners in mind, it is built for harsh environments and protected from water ingress with an IP67 rating. The system is designed for fast deployment in mines and enables distributed connectivity underground through Ethernet, Wi-Fi, and Powerover-Ethernet (PoE).

About Paste Fill

Paste-fill is a method used to fill underground voids where ore has been extracted. It can be used to provide working platforms, stabilize ground, and dispose of waste rock. The paste is a dense non-draining slurry with toothpaste consistency that is pumped through pipes underground to the target region. The method provides economic, environmental, and engineering design benefits to a mining operation.

Benefits to MMG

The implementation of the system enabled MMG to avoid costly control systems integration by simplifying the design and realizing the following benefits:

  • Local instrumentation minimized the need to run costly instrumentation wire over long distances
  • Compared to a PLC, the NLT Control Lite is smaller, lighter, and generates less heat, enabling it to be mounted near the instruments
  • The system requires minimal configuration and in-house expertise
  • The PoE features of the NLT N-Connex solution eliminates the need for additional power wiring.
  • Overall the NLT solution was simpler and less expensive to develop and deploy than other comparable solutions.
  • The system has enabled streamlined and efficient execution of paste-fill operations.
  • The system is fully implemented over the N-Connex network which provides a high-speed gigabit, redundant fibre and Ethernet solution.
  • The NLT solution reduced the capital cost for the project by over $50,000 compared to alternative approaches.