The major geological units present at the mine comprise the Rangal Coal Measures and the underlying Burngrove Formation, both of the Late Permian Blackwater Group. The Rangal Coal Measures, which are the upper-most Permian unit present in the Bowen Basin, are the focus of coal exploration within this region. The Burngrove Formation also contains coal seams but these are not typically of economic interest, due to their banded nature and high raw ash content.

The mine extracts three target seams (Aries, Pollux and Orion) in the Rangal coal measures at depths starting from approximately 35 metres (western side). The structural geology is characterized by steep dip and thrust faulting typically experienced in other coal mines such as Yarrabee and Jellinbah. The main characteristic of the mine are the reverse faults of the Jellinbah Thrust Belt. The westerly dipping faults range from large regional faults with displacements of up to 100 m to smaller local faults with displacements generally up to 10 m. The tertiary blanket that covers the Rangal Coal Measures ranges from 20m – 40m across the deposit. Multiple cross sections and long sections were created and for each the seam correlation and the geological interpretation was reviewed from first principles.

The coal bearing formations of interest within the project area are held within the Blackwater Group, an upper Permian package of generally uniform sandstones, mud, and siltstones, tuffaceous lithotypes an ........

A margin ranking process based on a combination of contractor truck/excavator open cut mining methods. There appears to be adequate room for all required spoil dumps and on-site infrastructure.

The Bluff opencut mine will be developed using excavators and rear dump trucks. Initially waste material will be hauled to external spoil dumps until in pit dumping can be established. Coal will be hauled to a ROM stockpile where it will be transported to nearby Cook Colliery, via road trains. Margin ranking and pit optimisation has been based upon a contractor operation.

Coal production at Bluff mine is expected to ramp up to a steady state ROM target of 80,000t to 100,000t per month, representing an annualised production rate of between 1Mtpa and 1.2Mtpa ROM over four to six years to supply the global steel industry.

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