Sustainability website / Case Studies 2005 / Xstrata coal / Innovation overcomes environmental legacy at Baal Bone

Innovation overcomes environmental legacy at Baal Bone

Overcoming a 55-year-old mining legacy at Baal Bone Mine in the western coalfields of New South Wales has required technical and financial innovation. Baal Bone, one of the oldest mines in the region, has been in operation since the early 1900s. Although it was owned and operated by various operators as an open cut mine from 1947 to 1952, supplying coal to the Balmain Power Station in Sydney, it was not rehabilitated on closure. Underground mining commenced at Baal Bone in 1982.

When Xstrata Coal acquired the operation in 2002, the land was in a degraded condition. As part of the approvals granted to operate Baal Bone mine, Xstrata submitted a plan to rehabilitate the surface mining area and old remnant operations – around 305 hectares – back to an undulating landform supporting native vegetation. This requirement presented two major hurdles:

• how to revegetate a large, inhospitable area devoid of topsoil; and
• how to fund a substantial rehabilitation programme given the limited life of the operation.

Environmental Coordinator Phil English said that against a backdrop of economic and social opportunity, a decision was made to introduce two new open cut operations to extract remnant coal in order to offset a significant portion of the site's rehabilitation liability.

"By developing an open cut, we were effectively introducing plant and equipment to shape and profile historic disturbance while also liberating topsoil, overburden, fill and capping material, essential for rehabilitation. A further upside was the financial stream the open cut provided to address a significant portion of the rehabilitation liability." he said.

"The site itself is quite long, so from an operational point of view, it was strategically more valuable for us to have two open cut operations – one in the north and one in the south. The southern open cut operation will rehabilitate the southern portion of the site. Once that's occurred, the northern open cut will commence and we'll start rehabilitating the northern portion of the site."

The site is located on the western fringe of the Great Dividing Range where topsoil is a scarce resource. The site has investigated the use of 'biosolids' as a soil conditioner and to overcome the topsoil shortage.

The reuse of this traditional waste product for soil conditioning reduces the amount of waste disposed to landfill and will provide a better environment for direct seeding activities.

We use a GPS-tracked helicopter to ensure a broad coverage of native seeds across the rehabilitation zone and minimise any safety exposure of quad bikes working on slopes.

"By GPS mapping we can guarantee that the rehabilitation zone is seeded and documentation is maintained for quality assurance," Phil said.

"Rehabilitation is expected to be completed by the end of 2007. The re-introduction of open cut mining to an underground operation has been highly beneficial for production flexibility and to offset the site's rehabilitation liability." Phil said the project had received the support of the NSW Government.

"The consultation that we ran for the project was invaluable and, without the extremely good support from the underground workforce, the community and the government, we would have had difficulty getting the project off the ground. It has been a lesson in keeping open, two-way communication with all stakeholders in order to achieve the best environmental outcome," Phil said.