Our long term mine plan involves open cut and underground mining of the Ulan Seam. Open cut mining was suspended to prioritize mining of the underground coal resource. It may recommence to supplement coal resources during the mine life. If it does recommence, it will only be undertaken for approximately 7 to 11 years. Underground mining will continue for the life of the mine. Open cut mining methods utilise a combination of dragline and truck and loader methods. Underground mining activities utilise longwall retreat and continuous mining methods.
Underground mining is undertaken by traditional longwall mining methods. This method targets the highest quality coal by only removing the bottom 3 metres of the Ulan Seam. Primary coal extraction, also known as 'development', is undertaken using continuous miner and shuttle car operation to develop the longwall panels. Secondary coal extraction, utilising longwall mining methods, operates a longwall width of approximately 400 metres. The first 400m wide longwall operation commenced at UCML in 2005, which was the first of its kind in the Southern Hemisphere.
Removing the bottom 3 metres of the Ulan Seam reduces the need to wash the coal; approximately < 30% of run of mine coal from the underground requires washing. All underground coal is conveyed to the surface stockpiles by the coal clearance conveyor system. Underground coal that does not require washing is crushed and conveyed directly to the product stockpiles in preparation for railing offsite. The higher ash coal is trucked to the coal wash plant reclaim stockpile where it is picked up by a reclaimer and conveyed to the coal handling preparation plant (CHPP).
Open cut mining commences with implementing all applicable environmental controls prior to any land clearing activities being carried out. All land clearing activities are undertaken in accordance with our Environmental Management System (EMS) which includes detailed procedures for clearing surface vegetation, flora and fauna management, topsoil stripping and topsoil stockpiling for future reuse. The clearing and disturbance of the land ahead of mining is kept to a minimum.
The salvaged topsoil is either directed to areas undergoing rehabilitation and/or stockpiled for future rehabilitation areas. Direct placement is preferred to minimise soil handling which reduces the impact of soil structure degradation.
Overburden, commonly referred to as the material above the coal seam, is fractured by blasting and then removed by either dragline or excavator and truck operation to expose the Ulan Seam. The coal is then blasted and removed in two strips, above and below a clay band by frontend loader and truck operation. The trucks transport the coal to the in-pit Dump Hopper where it is tipped to a crusher located below.
The crushed coal is then transported by conveyor to the Run of Mine (ROM) stockpile, where it is picked up by a reclaimer and conveyed to the coal handling preparation plant (CHPP). Product coal is stockpiled prior to transport by rail to the east primarily to the Newcastle Port. Coal may also be railed to domestic customers as required.
We operate under Environmental Protection Licence (EPL) 394 which allows for blasting to occur in accordance with a number of strict environmental conditions. Blasting can occur between the hours of 9.00 am to 5.00 pm Eastern Standard Time (EST) Monday to Saturday.
Blasting is restricted during adverse meteorological conditions to minimise potential impacts on private neighbouring residents. Each blast undergoes a detailed design and is monitored in order to maximise the blast efficiency, minimise the dust, fumes, vibration and air blast, and ensure compliance with site specific blasting conditions.