Rehabilitation & mine closure
We take our responsibility for the environment very seriously. While mining land use is very minimal in NSW, we want the land we do mine to have a long and fruitful life when mining is complete, and there’s no reason why it can’t.
Before mining begins, we work with government authorities to determine the post-mining use of the land and develop a rehabilitation plan. A rehabilitation plan has objectives that are agreed upon by the community and government, and lays out the post-mining use of the land.
For example, on land previously used for agriculture, the aim might be to restore the land to its pre-mining level of productivity. For other land uses, the objective may be to restore the area as close to its original condition as possible. Sometimes the land is completely remodelled to a better condition than before mining, like converting a mined area to a wetland, habitat zone, recreational area or land suitable for urban development.
To minimise our impacts at any given time, we usually start restoring areas of land while the mine is still in operation. We return the land to a safe, stable and self-sustaining condition by filling in voids and reshaping disturbed areas so they’re consistent with the landscape. We create habitats for native plants and animals by planting trees and local seeds, installing nesting boxes, replacing dead trees and controlling weeds and feral animals. We also manage buffer lands or offset sites to improve biodiversity and partner with community groups on conservation initiatives. There are many detailed examples at our World Class Miners site.
Some mining impacts are unavoidable, for example, when we need to clear native vegetation for buildings and infrastructure. Mines establish biodiversity offset areas to counterbalance any losses, often at a ratio as high as ten to one. We also relocate major fauna to nearby habitat areas, and take care to relocate and preserve precious plant species.
The final stage in mining is mine closure and lease relinquishment, when mining equipment is decommissioned and removed and rehabilitation is completed. A mining lease is only relinquished when all legal obligations have been satisfied and the appropriate end land use has been achieved, in line with the rehabilitation plan laid out before mining begins.
Sometimes a mine is temporarily closed, for example, if economic conditions make the mine unviable. At that time, production stops but the site is managed to ensure it stays in a safe and stable condition.
Derelict mines, sometimes called abandoned mines, are a legacy from historical operators before modern mining practices and environmental management and mine rehabilitation regulations were in place as they are today.
These former mine sites were not satisfactorily rehabilitated, but no individual or organisation can be held responsible for their management. Derelict mines can pose potential risks to public safety and the environment.
The NSW Government’s Derelict Mines Program improves derelict mines to reduce these safety and environmental risks. We have a representative on the Derelict Mines Program Steering Committee, and as of 2012, the program is fully funded by mines operating in NSW.
Nowadays we are subject to strict regulations so that all mines are rehabilitated, including security deposits mines lodge with the government to cover the costs of rehabilitation if a company were to fold and couldn’t meet its obligations. This way, the cost of restoring the land is always borne by the mining company, not the NSW government and taxpayers.
The primary consideration when planning a mine void is the long term safety and stability of the site. Once safety has been assured, mines then consider other potential beneficial uses for mine voids so that they can be an ongoing asset to the community.
A soon to be released Upper Hunter Mining Dialogue study of mine voids found that mine pit lakes could provide a range of possible positive contributions to the Upper Hunter long after mining has finished. The recently completed, two-year project has identified potential final uses for the voids which offer a wide variety of opportunities including recreational lakes, wildlife conservation, irrigation, water storage, aquaculture, hydro-electric power generation and more.
Many of the the larger Hunter mines were approved decades ago when issues involving final voids were less of a priority. Modern mining operations now include requirements for progressive rehabilitation as part of the regulatory and approval process, and there is an increasing focus on ensuring any final voids are as small as possible and incorporated into the local landscape.
Regardless of the final land use for voids, there are strict requirements for voids to be rehabilitated to a safe, stable and non-polluting sustainable condition. The NSW Government ensures that this occurs by requiring mines to lodge rehabilitation security deposits that aren’t returned until they are satisfied that those conditions have been met. Over $2 billion is currently held for this purpose.