2. MACH Energy’s first trainload of coal was delivered to AGL Energy’s Antiene facility in December 2018. Image courtesy of Aurizon.

The Mount Pleasant coal deposit is located in the Hunter Valley region of New South Wales (NSW), Australia. Owned and operated by MACH Energy, the project is developed as a greenfield open-cut mine with a capital investment value of approximately $950m.

The construction at Mount Pleasant began in November 2016 and the mining operations commenced in November 2017. The Mount Pleasant coal mine achieved its first coal production in December 2018.

Australia’s largest rail operator Aurizon signed a long-term contract with MACH Energy to transport up to eight million tonnes per annum (Mtpa) of coal for the company. Aurizon delivered the first coal from the mine to AGL Energy’s Antiene facility.

MACH Energy has been granted approval to produce up to 10.5Mtpa of run-of-mine (ROM) coal until December 2026.

An environmental impact statement (EIS) has been prepared for the Mount Pleasant Optimisation project, which will extend mining operations beyond 2026 through to December 2048. The project involves the mining of additional coal reserves and increases processing capacity up to 21Mtpa.

The Rail Loop Project (Modification 4 for the Mount Pleasant Operation) to modify the existing rail infrastructure located adjacent to the Overton and Wybong Roads was approved by the Department of Planning and Environment in November 2018. The activities related to the project began in October 2020. The project is expected to be completed in 2022.

Location of Mount Pleasant coal deposit

The Mount Pleasant coal deposit is located 4km away from Muswellbrook in the Hunter Valley region of NSW and adjacent to the Bengalla mine resource.

Covering 3,800ha, it is part of the Hunter Coalfield of the Sydney basin.

Geology and mineralisation

Coal deposits at the Mount Pleasant mine are of the late-Permian age and part of the Wittingham Coal Measures, which contain the majority of the coal reserves in the Hunter Valley. The main coal deposits are hosted in the Vane and Jerrys Plains subgroups of the Wittingham Coal Measures.

The lower part of the Jerrys Plains subgroup is 300m-thick and holds the Bowfield, Warkworth, Mount Arthur, Piercefield, Vaux, Broonie and Bayswater seams. The Vane subgroup lies beneath the Jerrys Plains subgroup and is 150m-thick.

The rock types found at these coal seams comprise sandstone, siltstone and coarse-grained sedimentary rock, which occur with subordinate coal and tuffaceous claystone.

Mount Pleasant mine reserves

The Mount Pleasant deposit is estimated to hold 1,423Mt of thermal coal and marketable reserves of 474Mt.

Mining at Mount Pleasant mine

The mining operations at Mount Pleasant mine utilises open-cut mining method from eight seams of the Wittingham Coal Measures, including Warkworth upper seam, Mount Arthur, Piercefield, Vaux, Broonie, Bayswater, Wynn and Edderton.

The mining operations initially focused on the north-western (North pit) and southern (South pit) areas containing the upper and middle seams. The mining operation was performed at a small pit in the Warkworth seam located next to the coal preparation facilities until the permanent mine infrastructure was built.

The overlying rock is fragmented using blasting method and excavated using a dragline comprising electric shovels, hydraulic excavators, and front-end loaders. Coal is transferred and washed at a portable modular plant until the main washery is constructed.

Upon the completion of coal handling and preparation facilities, mining commenced simultaneously at the South pit and the Piercefield pit.

Coal processing at Mount Pleasant

ROM coal is transferred to the coal handling and preparation plant (CHPP) through a hopper. The ROM coal is processed using a combination of density separation and fines flocculation processes.

Coarse reject attained from the washing process is moved to emplacements while fine rejects are moved out and transported to the fines emplacement area located west of the site. Refined coal is stockpiled in the infrastructure area and carried to the rail loop.

Infrastructure at Mount Pleasant mining site

The Rail Loop project for Mount Pleasant involves the construction of the approved rail infrastructure, Hunter River water supply infrastructure and associated power supply relocation, and demolition of old infrastructure.

A rail loading facility with a rail loop extending from Muswellbrook to Ulan Rail line will be constructed. The rail loop will be capable of handling two 9,000t-capacity trains.

The mine will receive water from mine pit inflows and make-up water from the Hunter River, which will be predominantly used in the CHPP for suppression of dust and other ancillary uses.

Other infrastructure at the mine includes a maintenance workshop, coal stockpiles area and an administration building.

Contractors involved

Thiess was awarded a mining contract to carry out complete mining operations at Mount Pleasant until 2021. The scope of the contract also includes mine planning and engineering.

Calibre DRA, a joint venture of G&S Engineering Services and DRA Pacific, was awarded a $149m contract to design and construct the CHPP and the train loadout (TLO) facility.

Whittens was awarded a $22m contract by G&S Engineering Services to perform bulk earthworks at the plant site and construction of roads. The contractual scope further includes construction of a reclaim tunnel, transfer pads and a sizing station.

Hardy Bros was awarded a $44m contract to undertake and commission detailed earthworks for the project.