Cook Mine is in the southern part of the Bowen Basin, and lies on the eastern limb of the Comet Anticline. The strata dips gently, usually <5 degrees to the east, striking slightly east of north.

The upper part of the stratigraphy consists of the Rewan Fm., which is predominantly a grey/green claystone varying in thickness from 80 m to 200 m. The coal bearing Rangal Coal Measures unconformably underlie the Rewan Formation. The upper section of the Rangal Coal Measures consists of four seams interbedded with lithic sandstone, siltstone and carbonaceous claystone strata.

The Rangal Coal Measures contain five main seams (in stratigraphic order from shallowest to deepest): Aries, Castor, Pollux (Argo), Orion and Pisces seams. The main target for underground mining is the Argo seam (4.7 m thick), which is currently being mined.

The depths of the Aries seam (top coal) vary from 110-130 m in the western area to 220-230 m in the eastern area. The thickness of the Aries seam is generally between 1-1.5 m. The Aries Lower Seam (ARL) is not continuous and shows an average thickness of 0.6 m. Where present, it occurs from 1 m to 4 m below the Aries Seam (AR).

The Castor seam is between 10 m and 20 m below the Aries Seam. The Castor average thickness is 2.5-3 m but can locally decrease to 0.5 m or increase to 4 m due to faulting.

Approximately 15 m below the Castor seam is the Argo Rider (AGR). This coaly mudstone band, which generally occurs at the top of the Argo seam, is not continuous and shows an average thickness of 0.5 m.

The Argo seam is the main target of the current mining operations. Argo occurs in the western area where the Pollux and Orion seams coalesce. The Argo average thickness is 4.5 m although it locally decreases to 0.5 m or increases up to 10 m due to faulting. The depth of Argo varies from 150-170 m in the western area to 270-290 m depth in the seam split zone.

Eastward of the Argo split zone, the Pollux and Orion seams occur at depths between 140-220 m and 180-300 m respectively. In Cook North, the Pollux seam is up to 400 m deep. The minimum interburden thickness for seam splitting is 0.3 m, which increases up to 18 m toward the eastern area. The Pollux seam shows an average thickness of 2.7 m and is also considered a mine target in the area between the Argo split line and the Tannyfoil Fault Zone. The Orion Seam shows an average thickness of 1.3 m, which (similar to the Aries and Pisces seams) represent a marginal thickness at large depth for underground mining.

In Cook North the Castor and Pollux seams coalesce to form the Gemini seam (GE). The GE seam shows an average thickness of 5 m and depths from 130-140 m in the northwest to 430 m in the northeast. The seam splitting and coalescing in this area is still not well understood mainly because few boreholes exist and the spacing is largely variable between 300 m and 1,200 m. The forthcoming infill drilling program includes a total of 20 open holes in this area.

The Pisces seam occurs at depths between 170 m to 320 m with a thickness of 1.8 m. The seam includes a stone band which certain area increases to more than 0.3 m thick where the seam splits in two plies (Pisces 1 and Pisces 2), each with an average thickness of 1 m and 0.85 m respectively.

Overburden and interburden sediments generally comprise lithic claystone siltstone, sandstone and carbonaceous shale.

Cook Colliery is a currently operating as a Bord and Pillar mine. Cook Colliery is an underground mine that currently only exploits the Argo Seam. Conventional retreating longwall mining was previously used to mine some of the reserve, with inseam development by continuous miners used to develop longwall panels. After the longwall was inundated with water in 2017, a change to continuous mining only extraction has been adopted. Personnel and equipment access to the underground operation is provided by one main transport drift, with a conveyor also installed in this drift. A second egress is effected by the downcast shaft and associated personnel winder. The mine plan has been developed in conjunction with pillar designs based upon the recommendations of detailed geotechnical studies, updated for performance of actual pillars. All main headings, gateroads, and barrier pillars have been designed to provide the required level of stability at appropriate factors of safety. Reviews of geotechnical designs have been completed. Continuous miner panels have been laid out to maximise resource recovery within the constraints of geological structure. Cook Colliery was added to QCoal’s portfolio following its acquisition from Bounty Mining in 2020. The underground metallurgical mine had been in care and maintenance since December 2019 until its return to operational status in February 2022. Mastermyne were appointed as the Coal Mine Operator (CMO) of the mine site and recommenced coal production in March 2022. The CMO contracted term will see Mastermyne produce circa. 6.3 million tonnes of ROM Coal over six years. The mine site has a long history through both longwall but more predominantly bord pillar mining methods since the 1970’s. Cook Colliery will reconvene its transitioning to place change mining method started prior to QCoal’s acquisition.

Infrastructure on the current lease is concentrated on two main sites – the main mine Infrastructure Area (MIA) and the Coal Handling and Preparation Plant (CHPP). The CHPP includes: - Raw coal unloading area, stockpile facility and associated conveyors - Coal Preparation building - Product stockpiles and associated conveyors - Coarse reject management conveyors and disposal areas - Tailings dams and associated water management dams and pipe networks - Train Load Out (TLO) facility and associated rail track and equipment. The Cook Colliery CHPP consists of ancillary surface conveyors and ROM coal stockpile, provate haula road for ROM coal, coal preparation plant, product stockpiles, a train loader and reject disposal sites. The CHPP modules produce two products – a primary semi hard coking product and a thermal product. The coal produced by Cook Colliery is railed to Gladstone Port for export.