Illawarra Coal detailed the move from Area 3 at its Appin longwall mine to the new Area 7, also known as Appin West, for Australian Longwall Magazine.
Longwall equipment and teams had been working in Area 3 to overcome a production shortfall while Illawarra Coal designed new longwall layouts to run along the Nepean River, to allow for a more acceptable extension to mining in Area 7. During this time, the company decided not to mine directly beneath the river on environmental grounds.
The changeout from Area 3 to Area 7 began in October 2007, relocating the longwall equipment eight kilometres to Longwall 701.
The financial repercussions of such a large move were recently reported, with the miner noting in half-yearly results recently released that “longwall discontinuity” at Appin was a factor behind its higher operating costs for the half-year period.
To keep those costs down, and mitigate any safety risk to its workers, Illawarra Coal had to operate to an exacting plan to a strict timeline.
Prior to the longwall being moved, Illawarra Coal’s general manager, sustainable development and external affairs, John Brannon said several major clearance surveys were undertaken, leading to a number of excavations around intersections to allow the equipment to turn corners.
Roadways also had to be enlarged to provide the height to fit the equipment through.
Additional load-haul dumps were hired to accommodate the increased transport distance and complexity.
“The whole changeover was project managed and ran to a tight schedule with some specialist engineers brought in to assist,” Brannon said.
To keep the longwall changeout costs down, Illawarra Coal employed various strategies.
To begin with, the company had to thoroughly plan the project and schedule the changeout with the balance of the mine’s operations. Every stage of the longwall changeout was risk assessed.
Brannon said regular updates between longwall teams and the rest of the mine were necessary, particularly when managing the interaction of the longwall equipment and other operational activities, and maintaining the rest of the operation.
Appin also opted to layout much of its capital expenditure for the project on a new longwall as equipment was old and outdated and the face widths between the two areas were considerably different at 255m and 318m.
Appin’s new longwall equipment consists of the Joy 7LS2 shearer, 181 1000-tonne shields, two 980-kilowatt armoured face conveyor drives, a 1000mm panline with an 800mm web and a Matilda-style beam stage loader.
While development crews were driving roadways in Area 7, Illawarra Coal completed a mini-build of the new longwall prior to installation in Area 3, where it was first used.
As part of a contingency plan, the company also received approval for an application to mine panel 409. Illawarra Coal now plans to start the panel after the current longwall 702 in Appin West is complete, while development of Longwall 703 continues.
Overall, Illawarra Coal’s decision to change the mine layout for Area 7, to avoid surface structures, had other costs besides those associated with logistics, new equipment and production, as the company estimates the mine effectively sterilised 12 million tonnes of coal.
At the Longwall conference at Cypress Lakes last year, BHP Billiton Illawarra vice-president of operations Jim Middleton told delegates the coal industry needed to be progressive and proactive in addressing environmental issues and being part of the community.
He held up Appin’s sister mine, Dendrobium, as an example of where the company had changed its mining plan to protect a river it had originally planned to mine beneath. Middleton said the company was not forced into the position, but instead opted to change the project plan to be “part of the community”
Appin is initially targeting 3.5Mt per annum from Area 7, with a long-term plan to increase production to 4.5Mtpa. The mine life is more than 20 years.
Continued mining at Area 7 has secured employment for up to 400 people, while state-government impact assessments confirmed mining of Area 3 did not affect waterflow or Sydney Water’s catchment water quality.