21 May 2021

Modern rehabilitation of the Melville legacy coal mining site

Locals around a historical mining site are benefiting from improved local ambience and land amenity, as Whitehaven reaches a milestone in the rehabilitation of the former Melville open cut area. As part of a plan to rehabilitate the area compatible with the surrounding landscape and landuse, the original Melville underground entry and north open-cut void are now filled and covered with vegetation.

 

Covering about 34.4 hectares, the Melville site sits within the original Black Jack Colliery, an open-cut and underground coal mine about 7km south of Gunnedah that began operation in the 1890s. Typically coal from this area was used to power local rail, and production declined with the conversion from steam to diesel locomotion.

Mining ceased at the Melville area in 1989, by which time the mining lease had been held by multiple companies. Formal mine closure from the then Department of Mines was never granted. In 2005 Whitehaven acquired the mining lease for the area as part of the purchase of Namoi Mining, and took on responsibility for rehabilitation of the disused site.

The Melville site includes a former underground mine entry and a legacy open-cut void that had been backfilled with coal discarded from the nearby Gunnedah Colliery coal processing plant and Whitehaven’s nearby Gunnedah Coal Handling and Processing Plant.

Importantly, the site is at the base of the prominent Black Jack Hill and is highly visible from nearby roads and residences.

The first part of the rehabilitation process involved developing a mine closure plan, also known as the rehabilitation plan, which is reviewed and approved by the NSW Resources Regulator. To develop the plan, Whitehaven worked with neighbouring landholders to ensure the area would have a final landform and land use suitable to the local context, which in this case is grazing land integrated with the surrounding farm land and Black Jack Hill.

The rehabilitation plan also outlines how Whitehaven plans to meet the detailed closure criteria required by the NSW Government, including through activities such as removing infrastructure, testing for contaminated materials, as well as filling the void and shaping the land.

Specialised software was used to develop a final landform design that is safe, stable and blends into the surrounding land. Innovative drainage design was required to manage clean water runoff from Black Jack Hill so it returned to the natural catchment. This was done by extending the natural drainage from Black Jack Hill through the Melville rehabilitated void using rock drains integrated into the final landform.

The area was reshaped then capped with about one metre of soil and rock. It was then covered with a 0.2m layer of topsoil fertilised with locally-sourced composted manure, and seeded to a native grass community. A cover crop of oats was also used to provide initial soil stability and allow the native grasses time to become established.

“We’ve been working closely with local contractors and landholders to complete this rehabilitation project and ensure the final landform and land use meets the expectations of our community and achieves both regulatory and stakeholder requirements,” said Daryl Robinson, Whitehaven’s Closed Mines and Rehabilitation Manager.

Steve Campbell leases land near the Melville site and says it has been terrific to see the rehabilitation take place.

“The shape of the site is now virtually the same as before mining took place, and in time there will be trees on the site as well. The comments of people that traverse the Wandobah Rd asking what was happening has been extensive. From the time the oats were sown and the hill became a sea of green, right through till the oats hayed off, people have been asking what’s been happening at the site – and it has been a pleasure to be able to tell them what a fantastic job has been done,” said Mr Campbell.

“Mining has occurred in this area for more than a hundred years, and over that time regulations around mine closure and rehabilitation have become significantly stricter, to the benefit of the environment and community. We’re pleased to be able to use modern technology to help make this historical mine site functional again for another land use,” added Mr Robinson.

Whitehaven’s team is currently monitoring and maintaining the area as the grassland develops. It is expected to take two to three years before grazing can recommence and 5 to 10 years to achieve final mine closure.

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