Land: Mining disturbance
- Authors
- Reviewer
- Key findings
- Indicators and summary of status
- Importance
- Pressure and condition
- Response
Authors
Jan Domagala, Department of Mines and Energy
Ian Wilson, Environmental Protection Agency
Reviewer
David Mulligan, The University of Queensland
Key findings
- The recent increasing world demand for mineral and energy resources has led to a major increase in mineral and energy production in Queensland, as well as an increase in exploration and mining activity, resulting in significant economic growth for the state and benefits to the community. Continued population growth in Queensland has also increased the demand for and production of aggregate resources (construction material), particularly in the south-east and growth areas along the eastern seaboard.
- This increase in mining and quarrying activity has led to an increase in the area disturbed by mining and has the potential to result in adverse environmental impacts and land use conflicts. The Queensland Government is responding to these issues by introducing and enforcing relevant legislation, policies and guidelines to ensure effective rehabilitation of mined areas, as well as planning strategically for the management of mineral and energy resources.
- The mining industry has also been active in adopting and promoting the principles of sustainable development. It is increasingly adopting minimum impact strategies on sites by improving environmental management planning and operational practices, and is supporting a comprehensive mine rehabilitation research program. The industry is also adopting the recommended practice of progressive rehabilitation.
- The Queensland Government continues to be committed to the rehabilitation of abandoned mines through the Abandoned Mine Lands Program; expenditure in the past four years has totalled $14.2 million, almost half of which was spent on the Mount Morgan project.
Indicators and summary of status
The status of the indicators shown below is based on the most recent figures available. Although all of these figures do not cover exactly the same period, they give a good indication of the current conditions (C), pressures (P), responses (R) and trends.
Indicator |
Status of indicator |
Cumulative areas of land disturbed and rehabilitated (C) |
In 2006, the total areas of land disturbed and rehabilitated were about 146 000 hectares and 44 000 hectares, respectively. The current rate of land disturbance is estimated to be 5619 hectares a year, almost 30% higher than in 2002. The rate of rehabilitation is less than half the rate of disturbance, but should increase as new mines mature. [ |
Number of abandoned mine sites (C) |
Although more than 15 000 abandoned mine sites are recorded throughout the state, the number that the state may rehabilitate has yet to be determined, as the criteria for prioritising sites have yet to be finalised. [ |
Production of principal metallic minerals and fuel minerals (P) |
In 2004-05, the production value of metallic minerals was $4.625 billion, and that of fuel minerals was $11.124 billion, increases of 31% and 38%, respectively, on 2003 production. In 2006, royalty returns for mineral and energy resources had increased by 118% since 2003, rising to $1450 million. [ |
Number, location and type of operating mines, quarries and petroleum projects (P) |
Steady increase since 2002, with significant increases in the number of coal mines from 36 in 2005 to 53 in 2006 [ |
Area covered by mining, exploration and petroleum projects (P) |
The area has increased by 58% from |
Rate of rehabilitation of existing mines (R) |
The rate of rehabilitation is less than half the rate of disturbance (43%), but should increase as new mines mature. In 2006, an area of 2429 hectares was rehabilitated. [ |
Rate of rehabilitation of abandoned mines (R) |
The state has maintained its rehabilitation program, 567 sites having been investigated and 240 made safe in Charters Towers, Gympie, Eidsvold, Bluff and Tooliambi from 2003 to 2006. Ongoing monitoring, maintenance and associated contingency works were carried out on 20 rehabilitated project areas across the state. In the past four years, $14.2 million was spent on abandoned mines, almost half being spent on Mount Morgan. Of concern is the lack of funds to deal with the assessment and rehabilitation of major sites. [ |
]
Importance
Queensland 's mining and petroleum industries are a key factor in the state's economic growth. As a result of the recent minerals and energy resources boom, the annual production of minerals and energy resources has contributed $16.022 billion to gross state product. Royalty returns from minerals and energy resources have increased from $666 million in 2003 to $1450 million in 2006. In 2005, the mining and petroleum industries directly employed 24 000 Queenslanders and indirectly generated another 68 000 jobs in the state.
In 2005 the production of aggregate resources, used for constructing roads, ports, airports, bridges, railways, factories, hospitals, schools and homes, was 41.9 million tonnes. Most of this material came from 203 sites that each produce more than 5000 tonnes a year. Because aggregate is a high-volume, low-cost commodity, it needs to be sourced and processed as close as possible to the communities that use it.
An obvious consequence of the recent increase in mining and exploration activity is an increase in the area of mining disturbance. Although this increase has occurred at widely dispersed locations, there can be significant local environmental impacts and land use conflicts.
The Environmental Protection Agency (EPA) administers the environmental regulatory regime for mining and quarrying under the Environmental Protection Act 1994 (EP Act). Regulation of petroleum and gas activities was transferred to this Act in 2005.
Abandoned mine sites are recognised as major safety and environmental issues in Queensland. Although most of the 15 000 abandoned sites are small, there are a number of large, complex sites with major environmental issues, such as Mount Morgan. Several of the large sites will cost the state tens of millions dollars to rehabilitate. This rehabilitation work is undertaken by the Abandoned Mine Lands Program (AMLP) through the Department of Mines and Energy (DME).
Pressure and condition
As mining and exploration are key factors in Queensland's economic growth, the government will continue to promote and facilitate the industry in the state. The recent resources boom has seen an increase in the total area covered by exploration and mining tenements for minerals and petroleum in Queensland from 41.7 million hectares in 2003 to 65.9 million hectares in 2006.
Pressures
The area disturbed by mining and exploration activities represents 0.08% of the total area of Queensland and the nature and impacts of the disturbance are quite variable. Of the 65.9 million hectares held under exploration and mining tenements in the state, 59.6 million hectares are held under exploration permits where exploration activities have minimal impact on the environment. The environmental impact of production activities over the 2.4 million hectares held under petroleum leases is also minimal and generally confined to small areas such as drill sites and production facilities. Of the 2.5 million hectares held under petroleum pipeline licences, only a small area is affected by the pipeline easements.
The greatest potential for environmental harm is within the 1.5 million hectares held under mining leases and licences. Mines here include open-cut and underground mines. Process wastes, particularly tailings and acid rock drainage from metalliferous mines, can cause significant contamination of waterways. Open-cut mines, particularly the large-scale open-cut coal mines, disturb relatively large areas of land and have the potential to degrade the land and aquifers, and contaminate waterways.
Continued population growth in Queensland has increased the demand for aggregate resources (construction material), particularly in the south-east and growth areas along the eastern seaboard. The resulting increase in quarrying activity is also increasing the potential for adverse environmental impacts and land use conflicts.
Most abandoned mines are in remote areas. With the increasing population and popularity of four-wheel-drive vehicles, however, visitation to these sites has increased. The Queensland Government is committed to actively managing the rehabilitation of abandoned mines to ensure the safety of the community and environment.
Condition and trends
The areas of land that had been disturbed and rehabilitated by current mining activities before April 2006 were approximately 146 000 hectares and 44 000 hectares, respectively (Table 4.4). Land has been considered as rehabilitated if it has been recontoured to its final landform, irrespective of whether the post-mining vegetation has been established on the landform. Table 4.4 does not include statistics relating to disturbance or rehabilitation on mining tenements that had been surrendered or cancelled, or disturbance or rehabilitation from petroleum activities or quarries.
The area disturbed by mining increased significantly during the period 2002-06. The extent of the increase is not readily obtained as the 2002 data were derived from a survey which did not cover all mines operating at the time and the 2006 data are based on predictions of disturbance contained in plans of operations for mines. The current annual rate of mine disturbance, 5619 hectares, is almost 30% higher than the annual rate in the period from 1999 to 2002. Most of the increase has resulted from the opening of more than 20 new coal mines and increased production from many existing coal mines. The rate of rehabilitation has risen slightly since 2002 but has not kept up with the increased rate of disturbance. The widening gap is strongly influenced by the coal mining industry's focus on expanding existing mines and opening new mines and the delay before any of these newly disturbed areas will be available for rehabilitation.
The generation of coal seam gas (CSG) is increasing in the southern part of the state. The CSG is liberated from coal beds when water is pumped from the coal seams. This water is commonly saline and the traditional method of disposal is via surface evaporation ponds. Increasingly, the water is being used in coal mining and other commercial operations or is being treated for other beneficial uses.
As the number of abandoned mines that are rehabilitated increases, demand on existing resources to monitor and maintain the sites will increase correspondingly.
Response
Regulatory response
The Petroleum and Gas (Production and Safety) Act 2004 (Qld) and the Petroleum and Other Legislation Amendment Act 2004 (Qld) commenced on 31 December 2004 and March 2005, respectively. These Acts introduced a comprehensive regulatory regime for the upstream petroleum and pipeline industries in Queensland and provide a modern regime for land access and safety associated with the production, transport and use of petroleum. The legislation also incorporated the regulation of exploration for and production of coal seam gas. Amendments were made to the EP Act to accommodate the changes in the petroleum and gas legislation. These amendments commenced on 1 January 2005.
In January 2006, the EP Act was amended to provide for certification of progressive rehabilitation of land disturbed by mining and petroleum activities. No applications for certification had been received by May 2007.
The EP Act requires applicants for environmental authorities for mining, petroleum and extractive resource quarrying activities to propose the rehabilitation outcomes, indicators and standards for their projects; these are used as the basis of rehabilitation conditions in the environmental authority. However, if the activities will have only low environmental impacts, the applicants are required to certify that they will comply with standard environmental conditions in a relevant code of environmental compliance. To help the industry propose rehabilitation outcomes, indicators and standards, in May 2006 the EPA published Guideline 18-Rehabilitation requirements for mining projects.
The Geothermal Exploration Act 2004 (Qld) commenced in March 2005 to provide the necessary legislative framework to enable geothermal exploration in Queensland.
The Department of Mines and Energy has continued to develop State Planning Policy 2/07 for the Protection of Extractive Resources, which is a tool for strategic planning in land use decision making to manage the land use conflicts often associated with aggregate quarries and urban development.
The Department of Mines and Energy has also developed a policy on the management of abandoned mines, Abandoned Mine Lands Program (AMLP).
Table 4.4 Summary of plan of operations data
Mineral |
Number of opera-tions |
Total disturb-ance April 2006 (ha) |
Total rehabilit-ation April 2006 (ha) |
Net disturb-ance April 2006 (ha) |
Annual disturb-ance 2006 (ha) |
Annual rehabilit-ation 2006 |
Bauxite |
2 |
14 700 |
7 600 |
7 100 |
200 |
350 |
Bentonite |
3 |
423 |
247 |
176 |
2 |
6 |
Building stone |
26 |
97 |
27 |
70 |
7 |
2 |
Clay |
16 |
436 |
29 |
407 |
15 |
5 |
Coal |
53 |
95 619 |
26 705 |
68 914 |
5 019 |
1 831 |
Cobalt |
1 |
1 |
0 |
1 |
0 |
0 |
Copper |
40 |
8 664 |
1 245 |
7 419 |
0 |
0 |
Diatomite |
2 |
16 |
10 |
6 |
0 |
2 |
Dolomite |
4 |
18 |
11 |
7 |
2 |
0 |
Garnet |
1 |
2 |
1 |
1 |
0 |
0 |
Gems |
5 |
110 |
0 |
110 |
0 |
0 |
Gold |
174 |
5 702 |
2 712 |
2 990 |
3 |
2 |
Gypsum |
5 |
22 |
4 |
18 |
4 |
2 |
Kaolin |
2 |
70 |
1 |
69 |
0 |
0 |
Lead |
1 |
343 |
3 |
340 |
0 |
1 |
Limestone |
21 |
608 |
204 |
404 |
3 |
0 |
Magnesite |
1 |
1 960 |
1 675 |
285 |
20 |
15 |
Mineral sands |
3 |
4 337 |
2 195 |
2 142 |
190 |
150 |
Nickel |
3 |
39 |
3 |
36 |
0 |
0 |
Oil shale |
1 |
193 |
139 |
54 |
0 |
0 |
Opal |
69 |
261 |
211 |
50 |
20 |
25 |
Peat |
2 |
5 |
0 |
5 |
0 |
0 |
Phosphate |
1 |
720 |
0 |
720 |
70 |
0 |
Salt |
1 |
8 213 |
0 |
8 213 |
0 |
0 |
Sapphire |
29 |
243 |
204 |
29 |
14 |
14 |
Silica |
12 |
688 |
231 |
457 |
26 |
23 |
Tantalite |
1 |
1 |
0 |
1 |
0 |
0 |
Tin |
19 |
626 |
5 |
621 |
0 |
1 |
Uranium |
1 |
5 |
1 |
4 |
0 |
0 |
Zeolite |
2 |
3 |
3 |
0 |
0 |
0 |
Zinc |
2 |
2 299 |
75 |
2 224 |
24 |
0 |
Total |
503 |
146 424 |
43 541 |
102 873 |
5 619 |
2 429 |
Source: EPA
Industry responses
During the recent rapid expansion of the coal mining industry in Queensland, the industry also increased its rehabilitation effort. However, the increased rehabilitation has not kept pace with the increased disturbance. The operator of only one coal mine has indicated that the mine is considering an application for progressive certification of rehabilitation in the near future. Several gold mines have ceased production and are working towards surrender.
The Minerals Council of Australia (MCA) published Enduring Value in 2004 to provide guidance to the Australian mining industry on implementing the ten principles of sustainable development adopted the previous year by the International Council on Mining and Metals (ICMM). The MCA has also collaborated with the Commonwealth Department of Industry, Tourism and Resources to produce a series of booklets, Leading Practice Sustainable Development Program for the Mining Industry , to revise the Best Practice Environmental Management in Mining series which the Commonwealth Environment Protection Agency produced in the 1990s. Staff from several Queensland mines have assisted in the production of these booklets.
The industry has continued to fund research projects in rehabilitation, biodiversity and water management issues for mining in general. There have also been significant environmental research projects focusing on specific mines and related work on developing environmental management systems for mines. The result is continuous improvement in the environmental performance of the industry. Despite the efforts of the industry, the environmental authority holders of four mines have been prosecuted for unlawful release of a contaminant or failure to comply with conditions of environmental authorities and the environmental authority holders of several mines have been required to conduct environmental evaluations.
Abandoned Mine Lands Program
Major Abandoned Mine Lands Program (AMLP) projects since 2003 include the installation of a lime dosing water treatment plant to treat contaminated open-cut pit water from the former Mount Morgan mine site, as well as capping of the waste rock dump and revegetation at Horn Island.
DME has continued its shaft capping program, 567 sites having been investigated and 240 shafts made safe at Charters Towers, Gympie, Eidsvold, Bluff and Tooliambi since 2003. Ongoing monitoring and maintenance and associated contingency works have been done on project areas including Mount Morgan, Horn Island, Charters Towers, Croydon, Herberton, Irvinebank, Mount Oxide, Mary Kathleen, Dittmer, Kamerunga, Palmer River, Maureen Uranium, Belyando, Bluff, Sarina, Gympie, Ipswich, Aldershot, Agricola, Jibbinbar, Kilkivan, Burgowan, Pratten, Leyburn, Sundown, Duck Creek and Sheep Station Creek.
All known abandoned mines in each region have been prioritised by a first pass geographic information system (GIS) site prioritisation model developed as part of the AMLP. A data management system, which incorporates a risk assessment module, is being developed to manage abandoned mines throughout the state.
Priority sites are progressively being inspected and assessed for rehabilitation programs throughout the state.
Underground coal mine plans have been digitised and georeferenced to accurately locate undermined areas where urban and industrial development may encroach on the old workings.
DME has collaborated with The University of Queensland and James Cook University on projects at Mount Morgan and Horn Island and in the Stanthorpe area.
Most AMLP projects involve significant effort in consultation with various local stakeholders, including local government authorities, the mining industry, heritage groups and regional natural resource management groups.
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Last reviewed 16 May 2011
Last updated 4 September 2007