The Kestrel longwall mine, in Queensland’s Bowen Basin, has undergone multiple strategic reviews for life-of-mine and five-year planning requirements. A computer model, developed by GHD, consultants in management, engineering and environment, has helped the mine establish long-term inventory strategies and costings.
Developed primarily for planning underground conveyor systems and associated power supply and distribution systems, the software can also model mining equipment requirements.
An underground services inventory requirement and expenditure model can be automatically generated using standard underground mine layouts, mining equipment capacities and mining schedules. The model can then be used continuously during a mine’s operation to assess the impacts of, and plan for variations in mine layout, mining schedule or preferred equipment.
Conveyor power demands and drive configurations are calculated, inventory quantities for all service equipment items are determined, and conveyor installations and inventory purchases scheduled. The system maintains minimum inventory levels, forecasts maximum inventory levels and produces total expenditure requirements for each year and any other periods specified.
“Mines often find themselves carrying excessive inventories,” said GHD project manager Andrew Napier. “Modelling this way is very effective for developing inventory minimisation strategies.
“Strategies commonly evaluated include those for temporary gateroad use; mains development conveyor systems; equipment commonality; drive unit size maximisation; multiple-use ‘smart’ substations; multiple cables versus single cables for high-power demand equipment; and the use of contractor-supplied or second-hand equipment.”
GHD said modelling can also be used to assess the impact of development rates or project approval timing for mines expanding or moving into new underground areas.
“Expenditure levels and timing are automatically adjusted if the development rate or approval timing affects the ability to reuse the existing area’s equipment. There is provision to assess the impact of varying rates of inventory attrition, due to operating wear or damage during retrieval.”
Napier stressed that the expenditure requirements themselves should never be the sole criteria for conveyor inventory selection.
“Experience with underground mining operations must determine which inventory combinations will be modelled,” Napier said.
According to GHD the main benefits are:
- provision of an effective underground services strategy
- generation of budget expenditure forecasts
- determination of the effects of mine layout or schedule options on expenditure and inventory requirements
- identification of conveyor equipment configurations and drive power capacity requirements
- minimisation of underground services inventory levels
