The borefield region is located within the Gunnedah Basin, which predominantly comprises Permian Age metasediments and volcanics and is overlain by Quaternary alluvial deposits within the valleys. The Permian metasediments in the region include the Maules Creek Formation which outcrop further to the east of the Boggabri Volcanics and are mined for coal at Boggabri, Tarrawonga and Maules Creek mines. The volcanic units belong to the Boggabri Volcanics and include basalt, trachyte and rhyolite flows and pyroclastics. In the borefield region the Boggabri Volcanics form the basement rock underlying the alluvium and bordering the alluvial plain.

The alluvial deposits in the proposed borefield area are associated with the Namoi River and the lower reaches of ‘Nagero’ and Bollol Creeks. The thickness of alluvium has been recorded exceeding 125 m deep in places but may typically be between 25 to 75m thick. Within alluvial creek embayments bordered by the volcanics, such as along Bollol Creek and ‘Nagero’ Creek the alluvial pile may be up to 30m deep.

The alluvial sediments are recognised as belonging to two formations, although they are not always distinguishable. The uppermost Narrabri Formation predominantly consists of clay with minor sands and gravels. Underlying the Narrabri Formation is the Gunnadah Formation which typically comprises gravel and sand with minor clay beds. The geological logs from registered bores in the alluvium and from the Boggabri test production bores discriminate an upper 8 – 25 m largely consisting of clay which is floodplain sediments deposited in low energy environment, and possibly the Narrabri Formation. The sand and gravel layers are likely to be channel deposits along the meandering river systems and commonly are clayey and silty in composition and poorly sorted. Gravel clasts are typically sub-angular to subrounded and are probably derived from volcanics and metasediments in the local region. Interlayed clay – silt layers are low energy floodplain sediments.

Boggabri Coal Mine (BCM) is an open cut coal mine located 15 km north-east of the township of Boggabri and extracts coal resources down to the Merriown coal seam using a truck and excavator method.

During the current Mining Operations Plan (MOP) term (from the date of approval until 31 December 2024), mining and transport operations at the BCM will remain relatively constant. The production rate over this period is expected to remain at full production (between 7.3 and 7.9 Mtpa product coal). In early 2015, the rail spur commenced operation, transporting product coal directly from the MIA. This has removed the need for haulage of product coal between the mine and the BCT on the private haul road. The CHPP also commenced operation in 2015, which has enabled further processing of ROM coal required for the mine to reach the full production rate.

Mining activity during the MOP term will involve a continuation of extraction within the A, C and E Pits. The development will continue in an eastern direction completing A Pit whilst also progressing in a northerly direction into C Pit and easterly direction into E Pit. Mining will continue along 100 metre wide mining strips for the duration of the MOP term. Backfilling will continue progressively to
the south.

Coal will be mined from six seams during the MOP term; the Teston, Thornfield, Braymont, Bollol Creek, Jeralong and basal Merriown.

Truck and excavator operations will continue to be undertaken to handle a ROM coal product which will be transported by truck to the onsite coal processing and rail transport facilities. A number of inpit ROM stockpile areas will also be utilised within the active mining areas to provide temporary storage of ROM coal prior to processing and rail transport. The Project Approval permits the use of a dragline, although there are no immediate plans to utilise such plant.

Out-of-pit dumping will continue on the western and southern overburden emplacement areas to a maximum RL of 395 m. The A and C Pit will continue to be progressively backfilled to the south.

Initially, coal was mined and transported to the ROM crushing facility located in the south western corner of CL368, crushed and blended (without further beneficiation) to produce an export quality steaming coal and a product suitable for pulverised coal injection applications. Product coal was then hauled 17 km via a bitumen sealed private coal haul road to the BCT facility for loading and rail transport to the Port of Newcastle.

Coal Handling and Preparation Plant (CHPP) comprises a 1500 tonne per hour capacity bypass crusher and a 500 tonne per hour capacity Coal Processing Plant (CPP) feed crusher. Product coal is transferred to the product stockpile utilising two slewing and luffing stackers. Product coal is then loaded onto trains via valves to a reclaim tunnel and TLO facility. The reclaim valves feed a conveyor with approximately 5,000 t of coal per hour. A section of the product stockpile is also utilised as a temporary storage area, to allow for coal stacking and r ........