The greening of open-pit coal mines
14 December 2012
Open-pit mines are often the poster children for environmentally unfriendly coal production, with deep scars across landscapes.
But just like high-efficiency, low-emissions coal-fired power plants can reduce the climate change impact of using coal, the forthcoming IEA Medium-Term Coal Market Report shows that the right policies can mitigate the impact on the landscape of open-pit coal mines.
In the past, the declared objective of environmental mining works was to restore the mined landscape to its original shape and use after the completion of mining. But companies, regulatory authorities and social groups have realised that no matter what the technical and financial resources invested, the amount of coal removed make it virtually impossible to return a mined area to its original state.
Instead, companies now are leveraging the economic and technical capacity of the mining operation to upgrade the affected land and surroundings at very low additional costs, creating new and possibly more useful space for nearby communities even if the landscape is not returned to the previous state.
A company can use its powerful operating equipment not just to develop the open pit but also to simultaneously shape the affected land. Timing the machinery’s work with the grooming in mind significantly reduces the additional cost to operations, allowing the company to leave behind attractive and useful land without having much impact on profitability.
But the key is that the company must develop its plan before mining starts, as the shaping of the land affects operations.
An example of an open-pit coal mine that was repurposed with environmental concerns in mind at not great cost was ENDESA’s As Pontes mine in Spain, which produced 261 million tonnes of brown coal from 1976 to 2008, displacing 697 million cubic metres of earth in the process. As detailed in an unpublished paper by Miguel Colomo, former Director of Mining at Endesa, reclamation efforts both during and after the mining left the region with a forest on a 1 150-hectare hill, with roads and drainage that facilitate hunting, tourism, livestock farming and forestry. The void created by the mining was turned into a 1 200-hectare lake that can be used not just for tourism but also energy generation and as a water supply for other industries.
In another example, Peabody in 2010 completed a coal-mine restoration project in the remote northern steppes of Mongolia, transforming the former open-cut Ereen Mine into a pastureland for local livestock and building a new community designed for the region’s climate. According to the company, the restored land is four times as productive as adjacent native grazing land, and it includes a source for drinking water that previously was hard to come by there. The project involved more than 60 people, including Peabody environmental scientists and engineers plus local engineers, workers and representatives of the Mongolian Agricultural University and the Mongolian Forage Seed Producers Association.
In New South Wales, Australia, Xstrata Coal reported that it is rehabilitating sections of the Ravensworth State Forest for the closure of the Mount Owen mine, intending to leave behind a native woodland five times larger than the forested area on the site before the mining began. University of Newcastle specialists are co-operating with the company to restore native plant and animal life in the area, which will cover 1 774 hectares.
Open-pit mines will not disappear soon, any more than coal usage will. From the US West to Mozambique, companies are using open-pit mining as a low-cost way to recover the world’s fastest-growing energy source. At 28% of total primary energy consumption, coal is second only to oil as a fuel. But while other policies can address impacts such as noise and dust produced during the mining, Medium-Term Coal Market Report 2012 highlights how the right environmental, operational and management approach exists to leave behind a useful and scenic, if not original, landscape after the mining, at limited cost to the operator.