By Chen Anming
Vice Head, Ventilation and Fire Prevention Department
Yanzhou Coal Mining Co., Ltd.
Vice Head, Geological Survey Department
Yanzhou Coal Mining Co., Ltd.
Yancoal Australia (Yancoal), a coal mining company that operates exclusively in Australia, but is majority-owned by the Chinese company Yanzhou Coal Mining Co. Ltd., produces thermal and metallurgical coal from its seven mines, most of which are opencast, located in some of the Australia’s richest coal reserves in New South Wales and Queensland (see Figure 1). The company also manages an opencast mine in Western Australia’s Collie Coal Basin south of Perth and an open cut mine in Queensland’s Surat Basin on behalf of Yanzhou. Yancoal also has access to key port and rail infrastructure, including shareholdings or allocated capacity in major coal terminals. Much of the 32.5 million tonnes of coal mined by Yancoal in 2014 was exported to South Korea and Japan, with a relatively minor amount being exported to China.
YANCOAL’S COMMITMENT TO RECLAMATION
As Yancoal has become a major coal producer in Australia, the company has worked extensively to ensure that it meets Australia’s stringent environmental regulations, including those that relate to mine reclamation.
In Australia, coal is mined primarily in Queensland, New South Wales, and Victoria. In fiscal year 2013–14, 431 million tonnes of coal were mined, most of it in opencast mines, of which 375 tonnes were exported.1 The Australian landmass is generally relatively barren with a thin layer of topsoil, especially in mining areas. Moreover, the country’s plant and animal species are relatively unique, making it critically important to protect the ecology around mining areas. Thus, timely and successful reclamation is necessary to ensure that the environmental impact of mining activities is minimized. Today about 80% of land disturbed for mining in Australia has been reclaimed and the country is a global leader in the field.
The ultimate goal of Yancoal’s reclamation programs are in line with those of other mining companies in Australia: to establish stable, compatible landforms on mined areas, revegetated with native species. This allows the original plant and animal communities to become re-established and aims to leave a positive legacy for future generations—such as recreation areas, aquaculture options, or, in many cases, a nature reserve.
RECLAMATION THAT BEGINS PRIOR TO MINING
An important aspect of best practices of mine reclamation in Australia is working with various levels of government throughout the entire process: from before mining begins, during mining, and throughout the full reclamation process.2
After the exploration rights are issued for the mine, a detailed mining operations plan is created. This plan includes forecasting land disturbance, a draft land reclamation plan, and projection of reclamation costs. Projected costs are verified through feedback from the local community stakeholders and experts.
Mining companies must hire independent reclamation experts to determine the extent of the land that will be disturbed and subsequently survey the topography, soil, animals, plants, historical artifacts, water drainage, etc., to fully assess the potential impact of the mining project. From this, a management plan is drawn up and a specialized survey research report is compiled.
After the report is finalized and the mining company obtains the proper permissions to mine, a security deposit must be paid by the mining company prior to any actual excavation. This is a relatively common practice in many countries that ensures funds are available for reclamation, even in a case where a mining company becomes fiscally insolvent or for some other reason there are delays in the reclamation process.
CASE STUDY: RECLAMATION OF YANCOAL’S ASHTON COAL MINE
Yancoal works to protect the delicate Australian ecosystem through a multi-step reclamation process, including the initial clearing out of animals and plants, plant storage, topsoil collection, mining operations, surface reshaping, water drainage design, gypsum scattering, deep plowing, rocks removal, topsoil addition, and vegetation restoration. This process has been implemented at the company’s opencast mines, including the Ashton coal mine. Like many opencast mines, Ashton works through the reclamation steps in one part of the mine even as coal is being actively mined elsewhere.
Relocation of Animals and Plants
Before mining begins in any area of the Ashton mine, plants and animals are relocated. This process requires authorization from the state environmental department. Per regulations and rules, environmental and ecological experts complete an inspection and assessment of the area within 12 months prior to the commencement of mining. To minimize the disturbance and improve the chance of successful reclamation using original species, trees that do not host animal habitats are the first to be cleared. Trees that may have animal habitats are kept for longer and are then only cleared under the instruction of experts and are saved for reclamation.
At the Ashton mine, the plants cleared without any animal habitats can be saved or mulched, based on the recommendations of ecology experts. Those plants that provide animal habitats are transported to other locations where they can continue to grow until they are needed for reclamation. Keeping original plants and reusing them to the greatest extent possible offers the added benefit of improving soil fertility.
Topsoil Collection and Storage
As Australia has a relatively thin layer of topsoil, its protection and use during reclamation is quite important. Thus, Yancoal collects topsoil prior to the commencement of mining. Ideally, the collected topsoil is used immediately in an ongoing reclamation effort nearby. Otherwise, it is stored and used when its original home undergoes reclamation. If the topsoil is not used immediately, it is protected by planting grass on its surface, which prevents water loss and erosion, and protects important microorganisms.
Refill and Ground Surface Reshaping
Once mining is complete in a specific area at Ashton mine, active reclamation begins, even as other parts of the mine are in operation. The first step is to refill the ground with gangue and reshape the surface, according to the specifications set in the original mining permits and determined based on the original terrain.
Ensuring proper water drainage is achieved on reclaimed land at Ashton is particularly important and has been designed with the local topography in mind. Stones are used in water drainage ditches to prevent water loss and soil erosion or ponding.
Gypsum can improve soil’s physicochemical structure, increase its stickiness, and thus reduce soil erosion. For these reasons, gypsum is regularly used by Yancoal in its reclamation efforts. It is scattered on the surface of the gangue after refill, and at the same time, suitably added to the topsoil as needed based on soil tests. As a general practice to prevent repeated disturbance to the reclaimed soil, Yancoal mixes the gypsum with the topsoil at the storage area, before it is used at the reclamation site.
Deep Plowing and Removal of Rocks
To prevent compaction, Yancoal deep plows the backfill (i.e., 0.6-m depth). By applying the process of deep plowing, Yancoal is able to remove rocks larger than 200 mm in diameter from the topsoil. Notably, this is a specific requirement set by the New South Wales Department of Mining under which the Ashton mine operates.
Yancoal structures the terrain and at least 100 mm of topsoil is added. Subsequently, the ground is leveled off, and at the same time, plant fragments, gypsum, lime, or compost are added to the soil based on the original soil conditions to improve it and help the original ecology recover more rapidly.
During reclamation Yancoal reintroduces the original landforms and vegetation to the mining site to the greatest degree possible, working to equal or even boost ecological productivity compared to the original state. However, vegetation restoration is a gradual process as plants must be allowed to take root and grow. As land is reclaimed at Ashton mine, grass is usually first to be planted, season permitting. After a turf is formed, shrubs or trees are then planted.
At Ashton and its other mines, Yancoal monitors the progress of reclamation, which can continue for decades, including the state of the plants, animals, soil, and water drainage. Ensuring the success of plant species requires monitoring plant diversity, density, rate of coverage, height, and grass varieties and growth condition. Animal activities are also monitored, including the species type, populations, and successful breeding sites. Monitoring the soil includes regular analysis of its quality and thickness, while water drainage monitoring requires inspections monthly and after major rainfalls.
Protecting Australia’s ecosystem while carrying out mining is a practice that has been successfully demonstrated by coal producers in the country for years. Yancoal is proud to become a part of this legacy and is working to contribute to the responsible operation of the country’s coal industry.
- Australia Office of the Chief Economist. (2015, September). Resources and energy quarterly, pp. 44, 56.
- Zhou, D. & Li, W. (2015). Analysis of Australian mining development environment access mechanism. World Nonferrous Metals, 3.
The content in Cornerstone does not necessarily reflect the views of the World Coal Association or its members.
Receive e-mail alerts when the new issue comes online!
Click here to opt-in or opt-out.