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Recycling utilization patterns of coal mining waste in China
Resources, Conservation and Recycling 54 (2010) 1331–1340
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Resources, Conservation and Recycling journal homepage: www.elsevier.com/locate/resconrec
Recycling utilization patterns of coal mining waste in China Liu Haibin a , Liu Zhenling b,∗ a b
School of Management, China University of Mining & Technology (Beijing), Beijing 100083, China School of Management, Henan University of Technology, Lian Hua Street, Zhengzhou, Henan 450001, China
a r t i c l e
i n f o
Article history: Received 1 August 2009 Received in revised form 1 May 2010 Accepted 15 May 2010 Keywords: Coal mining waste Comprehensive utilization Recycling economy Industrial chains
a b s t r a c t With the fast development of Chinese economy in recent years, China has become the largest coal production and consumption country in the world. Correspondingly, it has produced large quantities of mining waste including coal gangue, coal sludge, fly-ash, coal mine drainage and coal-bed methane (CBM) that are hazardous to the soil, air, and water. Based on the theory and practice of sustainable development and recycling economy, the paper will discuss and analyze the mining waste management in Jincheng Anthracite Mining Group, Shanxi Province, where they have found the paths to realize the mining waste reusing and recycling in colliery. They had established many green industrial chains in the mining waste treatment: the gangue piles turned into man-made eco-park, gangue used for power generation, fly-ash used in the building material, the coal mining water reused and recycled in closed pipelines, the CBM extracted for home-burning and electricity generation, etc. The coal mining waste has been converted into wealth and played more and more important roles in many fields. The practice indicated that these patterns can be applied in other coal mines. © 2010 Elsevier B.V. All rights reserved.
1. Introduction Coal mining waste has become the primary pollution sources in China. Due to the fast economy development in recent years and the consequently soaring demand for coal to generate electricity, China has become the largest coal producer and consumer in the world. In 2008, China had produced 2716 Mtons raw coal, accounting for approximately 40% of the total production in the world and overtaken the United States as the world’s biggest producer of carbon dioxide. As coal mining waste is part of the raw coal, the more coal production, the more waste to be dealth with. The coal mining waste are coal gangue, coal slime, fly-ash, coal mine drainage, coal-bed methane (CBM). If the waste is disposed improperly, it would threaten the environment and bring about serious pollutions, finally become the constraints to economy development (Skarzynska, 1995; Bell et al., 2000; McKinnon, 2002; Bian and Zhang, 2006). In China, about 95% of total coal production is from underground coal mines. The average production of coal mining wastes is about 15% of coal production, which varies from 10 to 15% with the change of geological and mining conditions. Therefore, it is estimated that the annual production of coal mining wastes is about 315 million tons for underground coal mining since 2007, which accounts for a quarter of the total industrial solid wastes. There are about 4.5
∗ Corresponding author. Tel.: +86 371 6775 6950; fax: +86 371 6775 6390. E-mail address: [email protected] (L. Zhenling). 0921-3449/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.resconrec.2010.05.005
billion tons of coal mining wastes stockpiled at 1700 waste dumps which occupied 15,000 ha lands (Bian et al., 2009). If the gangue is exposed to the air and piled on land, it will produce serious pollutions into the environment. The physical, chemical, or biological changes help it produce spontaneous combustion and pollution leaching (Ma et al., 2008). The hazardous is as follows. • Natural calamity, such as landslide and debris flow due to improperly piled gangue. • Poison releasing, natural weathering and rainwater drenching causing the poisonous into the soil and underground water. • Spontaneous combustion, the poisonous gas emitting into the atmosphere. • Acid rain formation near the gangue mountain. • Noxious substance polluting the groundwater. Coal sludge and fly-ash are another solid industrial waste in coal mine. Coal sludge is produced in the coal washing process, which contains carcinogenic chemicals and toxic heavy metals that are present in coal, such as arsenic, mercury, chromium, cadmium, boron, selenium, and nickel. Although the coal sludge is one of the coal mining wastes, it can be burnt in special condition as it has low calorific value. Coal fly-ash is the leavings after the coal burning in the power plant. The annual production of fly-ash is more than 150 million tons. As it is very small and light, it is very easy to fly with wind. If not scientifically treated, it is easy to pollute the environment of the mining area by polluting the water, atmosphere, soil and occupying land. The traditional treatment may cause:
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Table 1 Chemical composition of the fly-ash and coal gangue.
Flay ash Coal gangue
SiO2
Al2 O3
Fe2 O3
CaO
MgO
Other
Ignition loss
50.6 53.16
27.2 15.53
7.0 7.43
2.8 4.14
1.2 0.97
2.1 –
8.2 16.3
Note: The coal gangue data comes from Jincheng, Shanxi Province. The fly-ash data is the national average. See The High-tech Research Process of Industrial Solid Waste in China in International Workshop on Sustainable Development and Concrete Technology.
• potential toxicant that pollutes the groundwater and soil, • occasionally piles up occupying land and contaminating soil, • contaminating atmospheres in large area contributing to its long-distance transportation that may cause serious regional environmental pollution, • the air-suspended particles, which is much harmful to people’s health. In coal mining process, a large amount of water is required for de-dusting. However, much coal reservation are buried in the semiarid or arid regions where water resource is in highly shortage in many coal mines in China, for example, the Shanxi Province, the West of Neimenggu province. The water mixed with the coal dust, along with the gushing underground water, forms the mine drainage. As estimated by the statistical bureau, the coal mining wastewater sums to about 2.2 billion, averaging 4 m3 water per ton coal production (China and GAoEP, 2002). If untreated, the water combining with heavy metal ions such as iron and mercury ions would definitely pollute the groundwater. Nevertheless, it will waste the cherish water resource. Thus, it is of importance for the coal mine to recycle the mine drainage. The coal-bed methane (CBM) or gas is flammable gas which is accompanied with the coal resource. As it is flammable, it is a kind of valuable and clean energy. However, it is also a killer to the miners and threats to safety production due to its possible explosions underground. In the coal mining production, the general principle for the coal and gas outburst mines is to extract gas before mining. As a kind of greenhouse gas, the effectively utilizing of CBM become important in the recycling economy. It is generally argued that coal mining can have serious adverse environmental and related impacts, including interference with groundwater quantity and quality, land subsidence, impacts on river flows and consequential impact on other land-uses, issues associated with mining wastes disposal, creation of geological hazards, visible and esthetic issues, damage to infrastructure and potential ecological havoc (Skarzynska, 1995; Bell et al., 2000; McKinnon, 2002; Bian and Zhang, 2006). Of these wide range of issues, the disposal of mining wastes itself has received relatively less attention, especially considering the nature of the disposal methods, the opportunities for utilization of the mining wastes and the potential size of their impact on environment if not managed correctly (Szczepanska, 1999). However, the proper treat method for the coal mining waste is welcome for the sustainable development, which can bring about great economic benefits. Therefore, the coal mine wastes have already been one of the major threats to environment and how to scientifically treat has become an urgent problem for coal mines. In recent years, recycling economy has become the focus of the academic study, and with more sophisticated techniques of waste control and use applied into the waste treatment, constructing green industry chains based on recycling economy maybe a solution to the problem. The content of the research is arranged as follows. Section 2 is to review the traditional treatments on the mine wastes. Next section is to introduce the general theory of the recycling economy and the meaning for the coal mine to develop recycling economy. Then, taking the Shanxi Jincheng coal group as example, the recycling
green industrial chains of coal mining wastes are studied. Finally, the conclusion is summarized. 2. Traditional treatments 2.1. Coal gangue Fly-ash and coal gangue are the two main industrial solid waste in China. The chemical compositions (shown in Table 1) were SiO2 , Al2 O3 , Fe2 O3 and some impurities. As the coal gangue is main solid waste for coal mining, one of the most common approaches to waste rock is to stack construction that encapsulate the most pyrite rich rocks in the core of a waste rock stack (Lottermoser, 2003; Williams et al., 2003). For some high carbon coal gangue, it is generally mixed with other coal for mine-mouth power generation, and it has indicated its techno-economic feasibility of mine-mouth power plants (Chugh and Patwardhan, 2004). Mostly, by different processing methods, the reuse of the coal gangue is used as input material for traditional constructing material, e.g. cement, and new building material, such as, calcined products with high coal gangue, non-load-bearing hollow brick, and load bearing hollow brick, and lightweight aggregate that are replace for clay (Xiaoyan and Changsheng, 2007). In addition, coal gangue has been accepted in many places as alternative aggregates in embankment, road, pavement, foundation and building construction, pyrites extraction, zeolites production, etc. (Xiaowang, 2009; Sun and Li, 2008). 2.2. Fly-ash Coal is mainly combusted for electricity generation in power plants, and coal ash is primarily solid waste after burned. Traditionally, the majority of coal ash has been dumped in cone heaps and has the potential to pollute air, soil and water environments and landscapes through dust generation (Xiaojun, 2007; Bian et al., 2009). Although some of them are recycled utilized which is in civil construction materials, there is a limit to the demand for coal ash by construction industries. In Finland, Kikuchi (1999) summarized three ways to treat the coal ash: (1) alkali treatment can transform coal ash to zeolite; (2) potassium silicate fertilizer is produced from coal ash and has a higher receptivity in the soil than that of conventional fertilizers; (3) emission of sulfur dioxide is controlled by flue gas desulfurization using coal ash (Kikuchi, 1999). 2.3. Coal mine water and coal-bed methane There are many problems existed in the treatment of coal mines in China, such as, part wastewater treated adequately, insufficient treatment capacity, improper colliery design, poor quality of treated water, etc. (Ke and Liyun, 2010). Traditionally, the reuse of coal mine water can be divided into four kinds: industrial production (fire extinguishment, dust proof, explosion protection and so on with low quality water), environmental purification (garden forestation, spring, road sprinkle), life living (deeply treated water for drinking, boothing), agricultural water for irrigation (Kurbiel et al., 1996; Dharmappa et al., 2000; Viadero and Tierney, 2003; Lambert et al., 2004).
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Due to the uneconomic extraction of the coal-bed methane, it is previously extracted by ventilation gas into air directly without treatment and development which resulted in wasting the resources, greenhouse effect, pneumoconiosis (Tang et al., 2007; Islam and Hayashi, 2008; Hemza et al., 2009; Myers, 2009). Thus, it is necessary to develop the resources and prevent and reduce the mine disasters (Xueyu, 2010).
3. Recycling economy theory and practice in coal mines 3.1. Concept of recycling economy The so-called recycle economy, in essence, is a kind of ecological economy, which requires the ecologic law, instead the traditional mechanism, to guide the economic activities of the human society. Compared to the traditional economy, the great difference of recycling economy lies in the production process, in which the traditional economic chain follows “natural resource → product → pollutant”, one-way flow, linear economy, characterized by high intension exploitation, low level utilization, high emission; while in the recycling economy, the production chain is “resource → products → renewable resources”, a feedback flow, characterized by low intension exploitation, high level utilization, low emission. In the traditional economy, people exploit the natural resources, then manufacture industrial products, and discharge the waste or pollutant into the water, atmosphere and soil. These activity converting resources into waste ceaselessly is primarily the condition so as to achieve a quantitatively economy growth. On the contrast, in recycling economy, the economic activity is environmental friendly and harmonious with the nature. All of the materials and energy should be utilized reasonably and sustainable in order to lower the impact of the economic activities on the natural environment to the smallest extent. How to realize the recycling economy? The “3R” principle and the waste avoidance are two guiding principles applied in practicing the strategic idea of recycle economy. “3Rs” is an acronym which stands for Reduce, Reuse and Recycle. Reduce requires fewer input of raw material and energy in the production process, and this is the most effective of the three Rs and the place to begin. Reusing keeps new resources from being used for a while longer, and old resources from entering the waste stream. Furthermore, reusing requires that the manufactures and packages could be used repeatedly. Moreover, manufacturers are required to extend product life period as long as possible, calling for a boycott of disposable supplies. Recycling is the “R” that has caught on the best, and it requires that the products could be recycled rather than disposed into trash. Taking the idea of recycle economy into consideration, the producers should be responsible for resolving the waste products (Fig. 1).
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3.2. Why do the coal mines need the recycling economy? The major underlying forces that are helping to carry out recycle economy in coal mining areas are: (1) It is favorable for coal mines to realize an overall planning and coordinative development. The recycling economy requires that all industries associated with the coal mining have an overall planning, the industrial and product structure are regulated, the coal exploitation scale and order, the equipment and environment protection have a predestined schemes. This can lead to a coordinate development and maximizing benefits. (2) The limitation and exhaustibility of coal resource determines the comprehensive exploitation and utilization of coal. The middling coal in coal washing, coal sludge and gangue are all low calorific value, but they can be mixed combusted in electricity generation; the coal drainage could be recycled and used for coal washing, daily life and agricultural irrigation; the IGCC (integrated gasification comprehensive circulation) technology brings coal combustion gases to drive the generators and steam turbine generator; the fly-ash of power plant, slag, etc. used for producing construction material, land reclaiming, backfill and so on. (3) Releasing the pressure on the railway transportation and saving the transportation capacity. If the coal mine practice the recycling economy, more coal are converted into electricity transmitted to remote region rather than the raw coal transported. The conversion not only increases the added value of the products, but also reduces the transporting outward amount. The most important is to relieve the contradiction between mining and transportation, which is realistic and practical to be resolved. (4) It is favorable for the sustainable development of coal mining area. The coal mining intensity must be consistent with the coal resource conservation. Under the total output controlling, the recycling economy helps the mines to optimize the industrial and products structure, to make appropriate scale of operation, to improve the utilization efficiency of resources, to make resources advantages turn into the economic advantage. These benefits not only improve the economic benefits of the coal mining enterprise, but also promote the development of other industries. In short, the world has entered an era of diversified energy and chemical materials. Thus, different countries or regions choose practical, feasible coal processing and utilizing technology based on their own needs of energy resources and their economic development level. Development of the recycling has become important solution to the coal mining wastes treatment and energy savings. 3.3. General patterns of recycling economy in coal mine
Fig. 1. The flow of product in recycling economy.
In recent years, the recycle economy theory has been applied into many coal mines in China, where different mines designs different mode in accordance to diverse resource and environmental characteristics. These coal development modes include coalelectricity development, coal-electricity-coke comprehensively development, coal-electricity-high-energy consumption industries, coal-gasification (fluidization) synthetically development, coal-electricity-roads (railway building)-ports, etc. After analyzing the practical activities of recycling economy in different coal mine areas and the relationship between the coal exploitation with its related industries development, we can find that the recycling economy in coal mines should regard the coal mining and coal washing industries as the core of coal mining recycling. The
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Fig. 2. The general mode of recycling economy in coal mines.
development mode should be constructed by carefully selecting the electricity generation, coal transportation, coal coking, and coal-chemical industry, high-energy consumption industry, environmental protection industry. The general mode that the coal mining area develops recycle economy can be expressed as Fig. 2. Fig. 2 shows that the coal mining industrial chain can be extended to downstream industries. Developing recycle economy should pay attention to the resource characteristic of the mining areas, the geographic settings, the regional ecological environment, national macroeconomic environment and relevant policies and so on. Only by optimizing the combinations, a proper developing mode can be selected in the special colliery.
4. Green industrial chains: patterns in Jincheng colliery 4.1. Brief description 4.1.1. Enterprise’s overview Shanxi Jincheng Anthracite Mining Group (JCAMG) is an important coal mining enterprises in China. It is one of the 520 distinguished enterprises in China and one of the 10 leading companies in Shanxi Province, which is the maximum coal production province in China. It is as well one of the important enterprises as an important production base of high-quality anthracite and has registered capital 4052 million Yuan RMB, 25 subsidiaries, 18 branch companies and 18 shareholding companies, more than 50,000 employees. The JCAMG ranks the seventh of “top 100 coal mining enterprises in China” released by China Coal Industry Association. Moreover, it is an important part of Jindong coal base, one of the 13 national planning large-scale coal bases. By the end of 2005, the production capacity approved has reached to 30.60 Mtons/a, the raw coal production to 30.60 Mtons in 2005. The JCAMG has formed a multi-industries production configuration, since the group restructured in 2000. Its production can be divided into four sections, coal mining, railway and port building, coal equipment manufacturing and other non-coal industries.
Based on the present status and prospective market environment, it has chosen three industries, coal and the CBM, coal and electricity generation, coal-chemical industry as primary area in the “Twelfth Five-Year Plan” (2011–2015).
4.1.2. Natural resource (1) Coal resource The JCAMG has a reservation of coal resources at about 54,000 Mtons by the end of 2004. Of which: the geological maintenance reserves of nearly 25,000 Mtons; and predicted resources for nearly 40,000 Mtons, among which, under −1200 m has an amount of 19,961 Mtons, while −1200 m to ∼−1700 m has about 9350 Mtons. Among the geological maintenance reservation of 25,000 Mtons, operating wells and constructing wells takes up reserves to 15,000 Mtons, untapped reserves in the exploration (precisely surveyed reserves) has amount to 58.66 Mtons, prospecting for further investigation of reserves around 618.70 Mtons, the census reserves is 9908.77 Mtons. In the predicted resource, 19961.2 Mtons, of shallower than −1200 m, the operating wells and wells under construction of the JCAMG use 2600 Mtons. The total coal resource of operating wells and wells under construction takes up 9600 Mtons. (2) Water resource Shanxi is located in the North China Plateau, a varied topography and dry climate region. It is extremely shortage in water for this province. The total amount of the annual average water resources is 12.38 billion m3 , the province’s water resources per capita is only 381 m3 , is 1/7 of the national average level, far below the internationally recognized extremely scarce in water bottom line, 500 m3 per capita. In Shanxi Province, there has been continually ultra-intensively, large-scale exploitation of coal resources, which had lead to the severe destruction on the water resource. The water resource in the JCAMG ranks in the middle and upper level among all coal mines in Shanxi Province, but still belongs to dry area. Sooner or later, the water
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resource would become the constraints of the development of the JCAMG. (3) The CBM resource The west colliery of the JCAMG riches in the CBM (gas) resources, in addition, the coal-bed methane is not only high permeability, but also strong in high gas saturation, gas occurrence of high stress, fracture seam, good drawn admissibility. The west colliery of the JCAMG owns totally 13 mining wells that are operating, under construction or in planning. The total mining area has 3728.6 km, Nos. 2 and 3 coal seams of coal resources reserves 25,000 Mtons, No. 3 coal seams CBM reserves of about 600,000 Mm3 , the average ton of the CBM resources is 23.65 m3 . These show a good prospect for future development. Fig. 3. The industrial chains of recycling economy.
4.2. Green industrial chains 4.2.1. Recycling economy patterns In order to reach its great goals, that is to build the colliery of the JCAMG to be the largest anthracite coal base in China, the base of the CBM exploitation and utilization, coal-electricity and coalchemical industries base, the JCAMG stresses on the formation of its core competitiveness and the harmonious development with the environment by taking the recycling economy as its strategy. According to the idea of recycling economy, the industrial chains include two parts. The first one is core chains of recycling economy. It includes the exploitation of coal&CBM, coal washing, coal-electricity, coalchemical industry, mining water, harbors, road and other related industries, in order to continuously improve the Group’s competitiveness. The second one is extended chains. It includes the mining equipment manufacturing, logistics, brick and cement producing, construction and other related industries, constantly enhances the harmonious development of the environment. In the two industrial chains, the waste, gangue, coal water, sludge, fly-ash and the CBM, are not thrown away or discarded discretionarily, but integrated into the whole chains, recycled and
reused, and become the input for other industry. Now, the JCAMG has built a benign interactive development mode combining recycling economy industry chains and ecological environment. The pattern of recycling economy is as shown in Fig. 3. 4.2.2. Coal gangue The comprehensive development and utilization of coal gangue not only can control the sources of pollution, but also can turn the waste into valuable treasure, and get enormous economic benefits. In the colliery of the JCAMG, the comprehensive utilization of coal gangue includes electricity generation, coverage, landfill, and forestation, as shown in Fig. 4. Power generating. Coal gangue used to power generating is an important way to dispose the solid waste, which mainly makes use of calorific value at 3350–6280 kJ/kg of waste rock, using sophisticated technology of the 75 tons/h Circulating Fluidized Bed Boiler, mixed fuel coal gangue with slime for power generation. This technology has solved the difficult problem of different low calorie fuels mixed together. According to statistics, no less than 560,000 tons
Fig. 4. The comprehensive utilization of the coal gangue.
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of gangue is burnt in gangue power plants every year, equivalent to 80,000 tons of standard coal. As for the gangue unsuitable for power generating, the utilization of coal gangue includes coverage, forestation and landfill. How to cover the gangue? Usually, the gangue unfit for burning is piled up near the mouth of the coal well and forms a coal gangue mountain as the gangue dumps higher and higher. Coverage it to put the loess or mud onto the waste rock mountain so as to reduce the ventilation (the oxygen), prevent from the spontaneous combustion and its expansion, prepare for field building up and afforesting. After the coverage with the soil on the gangue mountain, the next step is to create the condition for the afforesting by consolidating the land, such as tamping surrounded the mountain, step-style preparation. Then, by improving the environment for plant growth or being reclaimed in accordance with site conditions, the plants, such as the locust tree, hippophae, Rosa, etc. can be planted that can keep the soil from erosion and gangue from spontaneous burning. After afforesting, the atmosphere pollution, dust, poisonous materials, can be avoided effectively, the atmosphere and water quality can be improved dramatically. Landfill can be divided into two methods as the conventional landfill and sanitary landfill. Conventional landfill method is to fill gangue directly in the pond, lake, ditch or low-lying areas collapsed on the site and waste not to make any deal. This discharge is very simple and cheap, but easy to pollute the environment caused by the secondary pollution. Sanitary landfill is the world’s most commonly used in solid waste treatment technology. It is on the site scientifically selected, to use the necessary protective means and reasonable landfill structure, try to mitigate and eliminate the solid waste pollution on the environment. Sanitary landfill can effectively control the leaching of water diffusion; reduce the pollution on groundwater, plant trees and grass, restore the ecological environment at the top layer of impermeable or reclamation. In the colliery of the JCAMG, the comprehensive utilization of the coal gangue has made great positive impacts. Suppose that every 1000 m3 of coal gangue takes up 40 m2 , the total gangue discarded by the coal mines, more than 500,000 m3 annually in the JCAMG, would occupy more than 2 ha new land, which would be a heavy burden for the mines. Through the analysis on the chemical, sulfur, harmful trace, radioactivity and leaching, etc., they are confirmed that these indexes do not exceed the national standard and the gangue can be used to reclamation and fill land. Coal mining subsidence area gradually expanded, with an average depth of 4.3 m collapsed, the biggest sinking depth of 8 m. Therefore, they combine the solid waste emission with the subsidence area reclamation governance in the practice. On the one hand, they has bought the relevant machinery and equipments, take out the topsoil in the subsiding area, dump the gangue into the subsiding area, refilling the soil or loess with the gangue, compacting layer by layer, covering the cultivating soil on the top layer. This approach can enhance the density of filling waste, reduce wastewater permeability and water content in the gangues, so as to prevent the leaching of heavy metals and other harmful substances leaking into the groundwater. At present, land subsidence has control over 2000 acres, 6000 acres are being implemented under the governance and planning treatment. On the other hand, the refilling areas are tidied through filling by layers, roller compacted, and their bearing capacity of the weight of building is improved. As a result, the base is so solid that it can be industrial construction land for developing non-coal industries. The chemical plants, construction and installation company, flyash brick factory, Liquefied Petroleum Gas (LPG) station, training base and so on are built one by one in these refilling area. A large number of surplus staff is re-employed in these companies. In addition, they also implement an eco-environmental reengineering that is to reclamation the land using coal gangue, village reconstruction in the subsidence area. The results indicate that by the end
of 2007, more than 3 million tons coal gangue disappeared, about 70 ha land emerged. The total investment was 34.8 million Yuan RMB, the planned 490 families had moved back to the area, each household with a construction area of 160–200 m2 , courtyard area of 70–100 m2 . This project was identified as one of the top 10 Technological Demonstration Projects of Sustainable Development in Shanxi Province. As for the coal gangue mountain left over in initial stage of the well construction, they also invested great number money in dealing with from the governance, greening and making landscape. In the early gangue mountain, the ring road was built, pavilion with ancient style founded, more than 20 species of bush planted, the corner of the subside area was transformed into a man-made lake, covering 14,670 m2 , a pavilion and bridge built inside the lake, fish in water, willow on the lakeside, a garden of 8000 m2 and a leisure fitness plaza entertainment of 16,000 m2 . The colliery district has become a beautiful landscape matched together with mountain and trees, flowers, the environment elegant beautiful scenery, so that the waste rock pile into an ecological park, creating significant environmental protection, land reclamation, economic and social benefits. Just like conservative estimates of profitability indicate potential to provide a return on investment in the range of 20–25%. A 40% return on investment is projected if the Coal Industrial Park includes production and captive use of process steam (Chugh and Patwardhan, 2004). 4.2.3. Coal sludge and fly-ash Coal sludge or slime is the tailed coal after mechanical dewatering of coal in the coal washing process. It can flow with the water, but air-dried quickly to ash and fly with the wind. As discussed above, if the coal sludge cant treat properly, it would pollution and waste the resources, thus it has been a hot “potato” in the waste comprehensive utilization. In the Jincheng colliery, it has found the path to reduce the waste and turn it into resource. Taking the Chengzhuang coal mine as example, it has produced about 180,000 tons sludge every year. The mine has built a slime burning power plant that can convert the slime into electrical energy, burning the coal sludge 180,000 tons per year, and generating 180 million kWh, earning profit 40 million Yuan RMB annually. The project not only effectively supplement power supply for coal mine, creating significant economic benefits, but also make full use of waste heat of power generation to supply the mine office and staff conducted a focus on residential heating, heating up an area of 1,000,000 m2 , equivalent to 10 large-scale heating boiler room, eliminating the heating boiler soot pollution, annual savings of more than 10 million tons of coal-fired heating boilers and 100 million operation and maintenance costs. This waste treatment solves the problem of the slime storage, sale, transport, erosion, pollution and other problems and set up a good example for the slime utilization. The coal after burnt in the boiler will become the soot emitted into the air and fly-ash left in the hearth. Before the recycling economy implemented, the ash was transported outside subside area by cars. Because the fly-ash is small, light, easy to disperse with the wind, it can cause a certain amount of pollution. In order to treat the waste scientifically, the Jincheng colliery launched a project of flyash replacing the loess defending and extinguishing fire grouting underground. The fly-ash is easy to dehydrate and pile up, which overcome the defects of loess in mud flow impedance, difficulty in piled up. After the fly-ash slurry infused into the loose body, it can soon dehydrate and pile up, blocking the hole, which bring about great benefits, saving the soil resource, get high-quality fireproofing materials. In addition, the fly-ash is added into the cement and other solidifying material using in the lane reconstruction in the well, which is solid, stable, labor-and-time-saving, cost-saving and improve the ability in fireproofing.
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There is another way to utilize the fly-ash, which is to add into material producing the colored brick. In order to reduce the pollution of the fly-ash to the maximum extent, the Jincheng colliery launched a project of blocks molding colored brick. The project produced more than 500,000 colored bricks annually, achieved revenues of 1.5 million Yuan, 300,000 Yuan of profits, and created more than 20 jobs. The colored bricks can be used in the road surface beautifying, landscaping, building architecture, which ended the history of brick making only with the clay. Supposing that every colored brick replacing 1.5 kg clay, the project could save the clay more than 10,000 tons which not only beautify the environment, save the fund, but also improve economic efficiency, save the valuable land resources.
Fig. 5. The comprehensive utilization of the fly-ash.
Fig. 6. The reuse and recycle of the coal mining water.
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Fig. 7. The comprehensive extraction and utilization CBM.
Besides the above ways of fly-ash utilization, there are other ways to reuse the waste: filling it in the mined-out area, grouting separated strata zone in overburden in wells, surface subsidence mitigation, producing aluminum with the high-aluminum fly-ash (Fig. 5). 4.2.4. Coal mining water Due to the shortage of water in Jincheng colliery, it is of importance to reuse the coal mining drainage in wells, life sewage in living area, sewage in hospitals and coal washing water. The coal mining drainage can be reused in life and industrial production after treated and the life sewage be used to garden irrigation, supplementary water in the coal washing plant and the power plants. Taking the Chengzhuang coal mine as example, they invested 4.38 million Yuan RMB to construct a coal mining drainage treatment stations in 2003. Then, invested 7 million Yuan to reconstruct the stations and enhance the coal mining water treatment capacities in 2006. Now, the treated water is used in recycle cooling water in the self-supporting power plant, supplementary water for the coal washing plant, fire protection water, and underground well production water, which recycle the wastewater and reuse the relatively valuable water resource, saving the water resource more than 2 million cubic meters every year. To further conserve water and reduce the consumption of underground fresh water, they also invested 5.3 million Yuan in 2007 to improve the water treatment capacity that can reuse all the waste mining water underground and implementation of zero emission. At the same time, they reconstruct the water resource establishment including green spraying, irrigation water and man-made lakes, such as landscape ornamental water attractions, reusing all the remaining mining water. A great amount of money initially spending on the water resource exploitation and well fresh water lifting is saved, directly economic benefit over 1.4 million Yuan RMB. In order to improve the life sewage treatment capacity in colliery, the Chengzhuang mine invested 8.5 million Yuan to build a sewage treatment plants handling 10,000 m3 wastewater per day. The life sewage is treated through coagulation-sedimentation processes, the technology selection reasonable; after depth treatment, the water quality meets the “National Integrated Wastewater Discharge Standard” level standard, reducing pollutants (COD) emissions near 400 tons every year. As for the hospital wastewater, they built a hospital wastewater treatment station with capacity of 100 m3 that “swallowed up” 80 wastewater drained daily by hospital and “digest” it into clear water meeting the “South–North Water
Diversion in Shanxi Province along the water pollutant discharge standards” The black water outflow from the coal washing plants is a hard problem to deal with for the colliery. They constructed a coal sludge water filtration plant that can recycle all the black water in closed circulation pipes. Meanwhile, the slime can be retrieved and provided to the self-supporting power plant for electricity generation or sold externally. The treatment stopped the out-drainage into the farmland causing the pollution to the living environment and river valley of surrounding area, created significant economic, environment and social benefits (Fig. 6). 4.2.5. Coal-bed methane The coal-bed methane (CBM) is gas that is company with the coal berried underground. The CBM is not only a waste gas in coal mining, but also a valuable natural resource. Extracted the CBM before mining and utilized in industrial production or living burning is conforming to the requirement of the recycling economy. Jincheng colliery has established a base of the comprehensive utilization of the CBM, which sets up a good example for other coal mines. At present, its CBM extraction wells group have become the largest scale in China, the CBM compression and liquefaction capacity is the largest in Asia. The CBM has been widely used many industries, such as civil usage, industrial production, power generating, car fuel, etc. The recycling economy industrial chains mode is shown as Fig. 7. (1) Extraction overview In Jincheng colliery, the principle for the CBM extraction is “extracting firstly on the ground, combining with the extraction underground”. The ground extraction is to establish the CBM wells in the coal fields before coal mine well and the underground extraction is to gather the CBM by the 1000 m digger in module type. In the “Twelve Five-year” period (2011–2015), the JCAMG plans to construct 2000 the CBM extraction wells at Fanzhuang, Zhenzhuang, Shizhuang and Dongda four mines and layout the extraction modules, forming the ground and underground extraction. In the process of the extraction, the large-diameter, high-volume pipes, large-diameter holes, high negative pressure extraction apparatus were used, totally six mobile CBM pumps gathering 60–70 m3 /min was equipped with in the gassy outburst mines in 2007, which solved the problem of the local outburst sites in mines. By the end of 2007, the JCAMG had exploited annually the CBM 0.8 billion m3 and
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Table 2 The CBM resources in Jincheng coal mines (unit: 109 m3 ). Regions
Subtotal
Xieli Panji, Gugou Zhangji Guqiao Panbei, Zhuji Zhangou Shangyao Xinji Total
1096.04 1311.2 257.4 471.3 531.41 560.1 1232.46 467.77 5928.25
−1000 m and above
−1000 to ∼−1500 m
64.5 276.61 127.37 230.31 173.45 375.4
732.44 885.6 130.17 241.42 359.96 184.85
158.07 1395.61
309.7 2842.41
Under −1500 m 299.05 158.72
1232.46
established a CBM driving power plant, Shihe plant, an Asia’s largest CBM power plant (Table 2). (2) The CBM utilization The CBM utilization mainly include three ways: provide to the surrounding cities and provinces for living, input into the “West–East” gas pipeline to the east, local power generation. There are additionally other technical schedules. Wind emission coal-bed methane (gas) reduction technique. As wind emission gas concentration is generally less than 1%, it is difficult to achieve stable combustion oxidation, only when the ambient temperature maintained at 1000 ◦ C or above oxidation can be effectively broken down into carbon dioxide and water. There are two solutions, one is to keep the temperature above 1000 ◦ C, and another is to burn at relatively low temperature combustion oxidation stability by using the catalysts to reduce the activation energy of the methane. By collecting the carbon dioxide combusted by the wind emission gas, it can be converted into dry ice or compressed for sale, which also can achieve social and economic benefits. At present, the gas flow of air for combustion technologies and reactor technology can reduce the wind emission gas emitted directly to the atmosphere, which has good application prospects. Low concentration gas purification technology. As for the low concentration gas, the general technology is to purify and convert it into high concentration gas because the latter can be used in many industrial fields. The purified gas not only can be used as vehicle fuel, supplying for the Jincheng, ChangZhi, Linfen, Yuncheng and Taiyuan and other cities, but also be taken as one of the gas resource bases for the “West–East” gas pipelines. Furthermore, the gas can be liquefied and transported long distance to remote area. In addition, the CBM is also a high-quality raw chemical material for synthetic methanol, synthetic ammonia and acetylene. It can produce the carbon black applied to tire rubber industry, plastics production, printing ink, battery, alloy, smelting, and so on. In a word, they have found the paths to both ensure the safety production and promote the economy growth of the company through large scale extraction and comprehensive utilization. 5. Conclusion and recommendations Through the above research, it can be found that coal mining waste is serious threaten to the environment and urgent problem to be solved for the government in China. The case study indicates that the JCAMG has set up a good example for the coal mines. Based on the recycling economy theory, the coal mining waste industrial chains of comprehensive utilization is the effective solution for the coal mining industrial waste. The scientific management mode in the Jincheng colliery not only saves the natural resource, reduces or avoids the environment pollution, but also turns the waste into wealth, creates great social and economic benefits. It is worth of studying and learning for other mines.
1690.23
Meanwhile, the utilization pattern of coal mining waste has the comprehensiveness and the diffusion quality, in which the resources and material recycling patterns deserved learning.
Acknowledgements The authors would like to thank the National Natural Science Foundation of China (Grant No. 70773111) and the Ph.D. Programs Foundation of Ministry of Education of China (No. 109032) for their financial support. We are also grateful for the helpful comments provided by two anonymous reviewers.
References Bell F, Stacey T, et al. Mining subsidence and its effect on the environment: some differing examples. Environmental Geology 2000;40:135–52. Bian Z, Dong J, et al. The impact of disposal and treatment of coal mining wastes on environment and farmland. Environmental Geology 2009;58(3):625–34. Bian Z, Zhang Y. Land use changes in Xuzhou coal mining are. Acta Geopraphica Sinica 2006;61:349–58 (in Chinese). China and GAoEP. Environmental quality standards for surface water, GB3838-2002; 2002. Chugh YP, Patwardhan A. Mine-mouth power and process steam generation using fine coal waste fuel. Resources, Conservation and Recycling 2004;40(3): 225–43. Dharmappa HB, Wingrove K, et al. Wastewater and stormwater minimisation in a coal mine. Journal of Cleaner Production 2000;8(1):23–34. Hemza P, Sivek M, et al. Factors influencing the methane content of coal beds of the Czech part of the Upper Silesian Coal Basin, Czech Republic. International Journal of Coal Geology 2009;79(1–2):29–39. Islam MR, Hayashi D. Geology and coal bed methane resource potential of the Gondwana Barapukuria Coal Basin, Dinajpur, Bangladesh. International Journal of Coal Geology 2008;75(3):127–43. Ke C, Liyun R. Research on comprehensive utilization of coal mine water in Shendong coal mining area. Shanxi Architecture 2010;36(2):208–12. Kikuchi R. Application of coal ash to environmental improvement: transformation into zeolite, potassium fertilizer, and FGD absorbent. Resources, Conservation and Recycling 1999;27(4):333–46. Kurbiel J, Balcerzak W, et al. Selection of the best desalination technology for highly saline drainage water from coal mines in southern Poland. Desalination 1996;106(1–3):415–8. Lambert DC, McDonough KM, et al. Long-term changes in quality of discharge water from abandoned underground coal mines in Uniontown Syncline, Fayette County, PA, USA. Water Research 2004;38(2):277–88. Lottermoser B. Mine wastes: characterization, treatment and environmental impacts. Berlin, Heidelberg, New York: Springer; 2003. Ma C, Li X, et al. Settlement behavior of coal mine waste in different surrounding rock conditions. Journal of Central South University of Technology (English Edition) 2008;15(3):350–5. McKinnon E. The environmental effects of mining waste disposal at Lihir Gold Mine, Papua New Guinea. Journal of Rural Remote Environmental Health 2002;1:40–50. Myers T. Groundwater management and coal bed methane development in the Powder River Basin of Montana. Journal of Hydrology 2009;368(1–4): 178–93. Skarzynska K. Reuse of coal mining wastes in civil engineering – Part 2: utilization of minestone. Waste Management 1995;15:83–126. Sun X, Li X. New technology of waste-filling replacement mining on strip coal pillar. Meitan Xuebao/Journal of the China Coal Society 2008;33(3):259–63. Szczepanska J. Distribution and environmental impact of coal-mining wastes in Upper Silesia, Poland. Environmental Geology 1999;38(3):249–58. Tang S, Wang Y, et al. A comprehensive appraisal on the characteristics of coal-bed methane reservoir in Turpan-Hami Basin. Journal of China University of Mining and Technology 2007;17(4):521–5, 545.
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Viadero RC, Tierney AE. Use of treated mine water for rainbow trout (Oncorhynchus mykiss) culture—a preliminary assessment. Aquacultural Engineering 2003;29(1–2):43–56. Williams D, Jeffery J, et al. A review of the acid rock drainage potential and hydrological implications of selectively-placed waste rock at a gold mine in NSW. In: 6th ICARD, Australia; 2003. Xiaojun H. Environmental damage and new uses technology of fly-ash. GuangDongHuaGong 2007;34(5):77–9 (in Chinese).
Xiaowang X. The reusage and recycle of coal gangue. Environmental Science and Technology 2009;22(1):121–5. Xiaoyan Y, Changsheng J. Comprehensive utilization of the coal gangue. Coal Technology 2007;26(10):108–10. Xueyu J. Current comprehensive utilization and ProsPeet of coalbed methane in Jincheng Coal Mining Area. China Coalbed Methane 2010;5(2):23–7.
Contents lists available at ScienceDirect
Resources, Conservation and Recycling journal homepage: www.elsevier.com/locate/resconrec
Recycling utilization patterns of coal mining waste in China Liu Haibin a , Liu Zhenling b,∗ a b
School of Management, China University of Mining & Technology (Beijing), Beijing 100083, China School of Management, Henan University of Technology, Lian Hua Street, Zhengzhou, Henan 450001, China
a r t i c l e
i n f o
Article history: Received 1 August 2009 Received in revised form 1 May 2010 Accepted 15 May 2010 Keywords: Coal mining waste Comprehensive utilization Recycling economy Industrial chains
a b s t r a c t With the fast development of Chinese economy in recent years, China has become the largest coal production and consumption country in the world. Correspondingly, it has produced large quantities of mining waste including coal gangue, coal sludge, fly-ash, coal mine drainage and coal-bed methane (CBM) that are hazardous to the soil, air, and water. Based on the theory and practice of sustainable development and recycling economy, the paper will discuss and analyze the mining waste management in Jincheng Anthracite Mining Group, Shanxi Province, where they have found the paths to realize the mining waste reusing and recycling in colliery. They had established many green industrial chains in the mining waste treatment: the gangue piles turned into man-made eco-park, gangue used for power generation, fly-ash used in the building material, the coal mining water reused and recycled in closed pipelines, the CBM extracted for home-burning and electricity generation, etc. The coal mining waste has been converted into wealth and played more and more important roles in many fields. The practice indicated that these patterns can be applied in other coal mines. © 2010 Elsevier B.V. All rights reserved.
1. Introduction Coal mining waste has become the primary pollution sources in China. Due to the fast economy development in recent years and the consequently soaring demand for coal to generate electricity, China has become the largest coal producer and consumer in the world. In 2008, China had produced 2716 Mtons raw coal, accounting for approximately 40% of the total production in the world and overtaken the United States as the world’s biggest producer of carbon dioxide. As coal mining waste is part of the raw coal, the more coal production, the more waste to be dealth with. The coal mining waste are coal gangue, coal slime, fly-ash, coal mine drainage, coal-bed methane (CBM). If the waste is disposed improperly, it would threaten the environment and bring about serious pollutions, finally become the constraints to economy development (Skarzynska, 1995; Bell et al., 2000; McKinnon, 2002; Bian and Zhang, 2006). In China, about 95% of total coal production is from underground coal mines. The average production of coal mining wastes is about 15% of coal production, which varies from 10 to 15% with the change of geological and mining conditions. Therefore, it is estimated that the annual production of coal mining wastes is about 315 million tons for underground coal mining since 2007, which accounts for a quarter of the total industrial solid wastes. There are about 4.5
∗ Corresponding author. Tel.: +86 371 6775 6950; fax: +86 371 6775 6390. E-mail address: [email protected] (L. Zhenling). 0921-3449/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.resconrec.2010.05.005
billion tons of coal mining wastes stockpiled at 1700 waste dumps which occupied 15,000 ha lands (Bian et al., 2009). If the gangue is exposed to the air and piled on land, it will produce serious pollutions into the environment. The physical, chemical, or biological changes help it produce spontaneous combustion and pollution leaching (Ma et al., 2008). The hazardous is as follows. • Natural calamity, such as landslide and debris flow due to improperly piled gangue. • Poison releasing, natural weathering and rainwater drenching causing the poisonous into the soil and underground water. • Spontaneous combustion, the poisonous gas emitting into the atmosphere. • Acid rain formation near the gangue mountain. • Noxious substance polluting the groundwater. Coal sludge and fly-ash are another solid industrial waste in coal mine. Coal sludge is produced in the coal washing process, which contains carcinogenic chemicals and toxic heavy metals that are present in coal, such as arsenic, mercury, chromium, cadmium, boron, selenium, and nickel. Although the coal sludge is one of the coal mining wastes, it can be burnt in special condition as it has low calorific value. Coal fly-ash is the leavings after the coal burning in the power plant. The annual production of fly-ash is more than 150 million tons. As it is very small and light, it is very easy to fly with wind. If not scientifically treated, it is easy to pollute the environment of the mining area by polluting the water, atmosphere, soil and occupying land. The traditional treatment may cause:
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Table 1 Chemical composition of the fly-ash and coal gangue.
Flay ash Coal gangue
SiO2
Al2 O3
Fe2 O3
CaO
MgO
Other
Ignition loss
50.6 53.16
27.2 15.53
7.0 7.43
2.8 4.14
1.2 0.97
2.1 –
8.2 16.3
Note: The coal gangue data comes from Jincheng, Shanxi Province. The fly-ash data is the national average. See The High-tech Research Process of Industrial Solid Waste in China in International Workshop on Sustainable Development and Concrete Technology.
• potential toxicant that pollutes the groundwater and soil, • occasionally piles up occupying land and contaminating soil, • contaminating atmospheres in large area contributing to its long-distance transportation that may cause serious regional environmental pollution, • the air-suspended particles, which is much harmful to people’s health. In coal mining process, a large amount of water is required for de-dusting. However, much coal reservation are buried in the semiarid or arid regions where water resource is in highly shortage in many coal mines in China, for example, the Shanxi Province, the West of Neimenggu province. The water mixed with the coal dust, along with the gushing underground water, forms the mine drainage. As estimated by the statistical bureau, the coal mining wastewater sums to about 2.2 billion, averaging 4 m3 water per ton coal production (China and GAoEP, 2002). If untreated, the water combining with heavy metal ions such as iron and mercury ions would definitely pollute the groundwater. Nevertheless, it will waste the cherish water resource. Thus, it is of importance for the coal mine to recycle the mine drainage. The coal-bed methane (CBM) or gas is flammable gas which is accompanied with the coal resource. As it is flammable, it is a kind of valuable and clean energy. However, it is also a killer to the miners and threats to safety production due to its possible explosions underground. In the coal mining production, the general principle for the coal and gas outburst mines is to extract gas before mining. As a kind of greenhouse gas, the effectively utilizing of CBM become important in the recycling economy. It is generally argued that coal mining can have serious adverse environmental and related impacts, including interference with groundwater quantity and quality, land subsidence, impacts on river flows and consequential impact on other land-uses, issues associated with mining wastes disposal, creation of geological hazards, visible and esthetic issues, damage to infrastructure and potential ecological havoc (Skarzynska, 1995; Bell et al., 2000; McKinnon, 2002; Bian and Zhang, 2006). Of these wide range of issues, the disposal of mining wastes itself has received relatively less attention, especially considering the nature of the disposal methods, the opportunities for utilization of the mining wastes and the potential size of their impact on environment if not managed correctly (Szczepanska, 1999). However, the proper treat method for the coal mining waste is welcome for the sustainable development, which can bring about great economic benefits. Therefore, the coal mine wastes have already been one of the major threats to environment and how to scientifically treat has become an urgent problem for coal mines. In recent years, recycling economy has become the focus of the academic study, and with more sophisticated techniques of waste control and use applied into the waste treatment, constructing green industry chains based on recycling economy maybe a solution to the problem. The content of the research is arranged as follows. Section 2 is to review the traditional treatments on the mine wastes. Next section is to introduce the general theory of the recycling economy and the meaning for the coal mine to develop recycling economy. Then, taking the Shanxi Jincheng coal group as example, the recycling
green industrial chains of coal mining wastes are studied. Finally, the conclusion is summarized. 2. Traditional treatments 2.1. Coal gangue Fly-ash and coal gangue are the two main industrial solid waste in China. The chemical compositions (shown in Table 1) were SiO2 , Al2 O3 , Fe2 O3 and some impurities. As the coal gangue is main solid waste for coal mining, one of the most common approaches to waste rock is to stack construction that encapsulate the most pyrite rich rocks in the core of a waste rock stack (Lottermoser, 2003; Williams et al., 2003). For some high carbon coal gangue, it is generally mixed with other coal for mine-mouth power generation, and it has indicated its techno-economic feasibility of mine-mouth power plants (Chugh and Patwardhan, 2004). Mostly, by different processing methods, the reuse of the coal gangue is used as input material for traditional constructing material, e.g. cement, and new building material, such as, calcined products with high coal gangue, non-load-bearing hollow brick, and load bearing hollow brick, and lightweight aggregate that are replace for clay (Xiaoyan and Changsheng, 2007). In addition, coal gangue has been accepted in many places as alternative aggregates in embankment, road, pavement, foundation and building construction, pyrites extraction, zeolites production, etc. (Xiaowang, 2009; Sun and Li, 2008). 2.2. Fly-ash Coal is mainly combusted for electricity generation in power plants, and coal ash is primarily solid waste after burned. Traditionally, the majority of coal ash has been dumped in cone heaps and has the potential to pollute air, soil and water environments and landscapes through dust generation (Xiaojun, 2007; Bian et al., 2009). Although some of them are recycled utilized which is in civil construction materials, there is a limit to the demand for coal ash by construction industries. In Finland, Kikuchi (1999) summarized three ways to treat the coal ash: (1) alkali treatment can transform coal ash to zeolite; (2) potassium silicate fertilizer is produced from coal ash and has a higher receptivity in the soil than that of conventional fertilizers; (3) emission of sulfur dioxide is controlled by flue gas desulfurization using coal ash (Kikuchi, 1999). 2.3. Coal mine water and coal-bed methane There are many problems existed in the treatment of coal mines in China, such as, part wastewater treated adequately, insufficient treatment capacity, improper colliery design, poor quality of treated water, etc. (Ke and Liyun, 2010). Traditionally, the reuse of coal mine water can be divided into four kinds: industrial production (fire extinguishment, dust proof, explosion protection and so on with low quality water), environmental purification (garden forestation, spring, road sprinkle), life living (deeply treated water for drinking, boothing), agricultural water for irrigation (Kurbiel et al., 1996; Dharmappa et al., 2000; Viadero and Tierney, 2003; Lambert et al., 2004).
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Due to the uneconomic extraction of the coal-bed methane, it is previously extracted by ventilation gas into air directly without treatment and development which resulted in wasting the resources, greenhouse effect, pneumoconiosis (Tang et al., 2007; Islam and Hayashi, 2008; Hemza et al., 2009; Myers, 2009). Thus, it is necessary to develop the resources and prevent and reduce the mine disasters (Xueyu, 2010).
3. Recycling economy theory and practice in coal mines 3.1. Concept of recycling economy The so-called recycle economy, in essence, is a kind of ecological economy, which requires the ecologic law, instead the traditional mechanism, to guide the economic activities of the human society. Compared to the traditional economy, the great difference of recycling economy lies in the production process, in which the traditional economic chain follows “natural resource → product → pollutant”, one-way flow, linear economy, characterized by high intension exploitation, low level utilization, high emission; while in the recycling economy, the production chain is “resource → products → renewable resources”, a feedback flow, characterized by low intension exploitation, high level utilization, low emission. In the traditional economy, people exploit the natural resources, then manufacture industrial products, and discharge the waste or pollutant into the water, atmosphere and soil. These activity converting resources into waste ceaselessly is primarily the condition so as to achieve a quantitatively economy growth. On the contrast, in recycling economy, the economic activity is environmental friendly and harmonious with the nature. All of the materials and energy should be utilized reasonably and sustainable in order to lower the impact of the economic activities on the natural environment to the smallest extent. How to realize the recycling economy? The “3R” principle and the waste avoidance are two guiding principles applied in practicing the strategic idea of recycle economy. “3Rs” is an acronym which stands for Reduce, Reuse and Recycle. Reduce requires fewer input of raw material and energy in the production process, and this is the most effective of the three Rs and the place to begin. Reusing keeps new resources from being used for a while longer, and old resources from entering the waste stream. Furthermore, reusing requires that the manufactures and packages could be used repeatedly. Moreover, manufacturers are required to extend product life period as long as possible, calling for a boycott of disposable supplies. Recycling is the “R” that has caught on the best, and it requires that the products could be recycled rather than disposed into trash. Taking the idea of recycle economy into consideration, the producers should be responsible for resolving the waste products (Fig. 1).
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3.2. Why do the coal mines need the recycling economy? The major underlying forces that are helping to carry out recycle economy in coal mining areas are: (1) It is favorable for coal mines to realize an overall planning and coordinative development. The recycling economy requires that all industries associated with the coal mining have an overall planning, the industrial and product structure are regulated, the coal exploitation scale and order, the equipment and environment protection have a predestined schemes. This can lead to a coordinate development and maximizing benefits. (2) The limitation and exhaustibility of coal resource determines the comprehensive exploitation and utilization of coal. The middling coal in coal washing, coal sludge and gangue are all low calorific value, but they can be mixed combusted in electricity generation; the coal drainage could be recycled and used for coal washing, daily life and agricultural irrigation; the IGCC (integrated gasification comprehensive circulation) technology brings coal combustion gases to drive the generators and steam turbine generator; the fly-ash of power plant, slag, etc. used for producing construction material, land reclaiming, backfill and so on. (3) Releasing the pressure on the railway transportation and saving the transportation capacity. If the coal mine practice the recycling economy, more coal are converted into electricity transmitted to remote region rather than the raw coal transported. The conversion not only increases the added value of the products, but also reduces the transporting outward amount. The most important is to relieve the contradiction between mining and transportation, which is realistic and practical to be resolved. (4) It is favorable for the sustainable development of coal mining area. The coal mining intensity must be consistent with the coal resource conservation. Under the total output controlling, the recycling economy helps the mines to optimize the industrial and products structure, to make appropriate scale of operation, to improve the utilization efficiency of resources, to make resources advantages turn into the economic advantage. These benefits not only improve the economic benefits of the coal mining enterprise, but also promote the development of other industries. In short, the world has entered an era of diversified energy and chemical materials. Thus, different countries or regions choose practical, feasible coal processing and utilizing technology based on their own needs of energy resources and their economic development level. Development of the recycling has become important solution to the coal mining wastes treatment and energy savings. 3.3. General patterns of recycling economy in coal mine
Fig. 1. The flow of product in recycling economy.
In recent years, the recycle economy theory has been applied into many coal mines in China, where different mines designs different mode in accordance to diverse resource and environmental characteristics. These coal development modes include coalelectricity development, coal-electricity-coke comprehensively development, coal-electricity-high-energy consumption industries, coal-gasification (fluidization) synthetically development, coal-electricity-roads (railway building)-ports, etc. After analyzing the practical activities of recycling economy in different coal mine areas and the relationship between the coal exploitation with its related industries development, we can find that the recycling economy in coal mines should regard the coal mining and coal washing industries as the core of coal mining recycling. The
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Fig. 2. The general mode of recycling economy in coal mines.
development mode should be constructed by carefully selecting the electricity generation, coal transportation, coal coking, and coal-chemical industry, high-energy consumption industry, environmental protection industry. The general mode that the coal mining area develops recycle economy can be expressed as Fig. 2. Fig. 2 shows that the coal mining industrial chain can be extended to downstream industries. Developing recycle economy should pay attention to the resource characteristic of the mining areas, the geographic settings, the regional ecological environment, national macroeconomic environment and relevant policies and so on. Only by optimizing the combinations, a proper developing mode can be selected in the special colliery.
4. Green industrial chains: patterns in Jincheng colliery 4.1. Brief description 4.1.1. Enterprise’s overview Shanxi Jincheng Anthracite Mining Group (JCAMG) is an important coal mining enterprises in China. It is one of the 520 distinguished enterprises in China and one of the 10 leading companies in Shanxi Province, which is the maximum coal production province in China. It is as well one of the important enterprises as an important production base of high-quality anthracite and has registered capital 4052 million Yuan RMB, 25 subsidiaries, 18 branch companies and 18 shareholding companies, more than 50,000 employees. The JCAMG ranks the seventh of “top 100 coal mining enterprises in China” released by China Coal Industry Association. Moreover, it is an important part of Jindong coal base, one of the 13 national planning large-scale coal bases. By the end of 2005, the production capacity approved has reached to 30.60 Mtons/a, the raw coal production to 30.60 Mtons in 2005. The JCAMG has formed a multi-industries production configuration, since the group restructured in 2000. Its production can be divided into four sections, coal mining, railway and port building, coal equipment manufacturing and other non-coal industries.
Based on the present status and prospective market environment, it has chosen three industries, coal and the CBM, coal and electricity generation, coal-chemical industry as primary area in the “Twelfth Five-Year Plan” (2011–2015).
4.1.2. Natural resource (1) Coal resource The JCAMG has a reservation of coal resources at about 54,000 Mtons by the end of 2004. Of which: the geological maintenance reserves of nearly 25,000 Mtons; and predicted resources for nearly 40,000 Mtons, among which, under −1200 m has an amount of 19,961 Mtons, while −1200 m to ∼−1700 m has about 9350 Mtons. Among the geological maintenance reservation of 25,000 Mtons, operating wells and constructing wells takes up reserves to 15,000 Mtons, untapped reserves in the exploration (precisely surveyed reserves) has amount to 58.66 Mtons, prospecting for further investigation of reserves around 618.70 Mtons, the census reserves is 9908.77 Mtons. In the predicted resource, 19961.2 Mtons, of shallower than −1200 m, the operating wells and wells under construction of the JCAMG use 2600 Mtons. The total coal resource of operating wells and wells under construction takes up 9600 Mtons. (2) Water resource Shanxi is located in the North China Plateau, a varied topography and dry climate region. It is extremely shortage in water for this province. The total amount of the annual average water resources is 12.38 billion m3 , the province’s water resources per capita is only 381 m3 , is 1/7 of the national average level, far below the internationally recognized extremely scarce in water bottom line, 500 m3 per capita. In Shanxi Province, there has been continually ultra-intensively, large-scale exploitation of coal resources, which had lead to the severe destruction on the water resource. The water resource in the JCAMG ranks in the middle and upper level among all coal mines in Shanxi Province, but still belongs to dry area. Sooner or later, the water
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resource would become the constraints of the development of the JCAMG. (3) The CBM resource The west colliery of the JCAMG riches in the CBM (gas) resources, in addition, the coal-bed methane is not only high permeability, but also strong in high gas saturation, gas occurrence of high stress, fracture seam, good drawn admissibility. The west colliery of the JCAMG owns totally 13 mining wells that are operating, under construction or in planning. The total mining area has 3728.6 km, Nos. 2 and 3 coal seams of coal resources reserves 25,000 Mtons, No. 3 coal seams CBM reserves of about 600,000 Mm3 , the average ton of the CBM resources is 23.65 m3 . These show a good prospect for future development. Fig. 3. The industrial chains of recycling economy.
4.2. Green industrial chains 4.2.1. Recycling economy patterns In order to reach its great goals, that is to build the colliery of the JCAMG to be the largest anthracite coal base in China, the base of the CBM exploitation and utilization, coal-electricity and coalchemical industries base, the JCAMG stresses on the formation of its core competitiveness and the harmonious development with the environment by taking the recycling economy as its strategy. According to the idea of recycling economy, the industrial chains include two parts. The first one is core chains of recycling economy. It includes the exploitation of coal&CBM, coal washing, coal-electricity, coalchemical industry, mining water, harbors, road and other related industries, in order to continuously improve the Group’s competitiveness. The second one is extended chains. It includes the mining equipment manufacturing, logistics, brick and cement producing, construction and other related industries, constantly enhances the harmonious development of the environment. In the two industrial chains, the waste, gangue, coal water, sludge, fly-ash and the CBM, are not thrown away or discarded discretionarily, but integrated into the whole chains, recycled and
reused, and become the input for other industry. Now, the JCAMG has built a benign interactive development mode combining recycling economy industry chains and ecological environment. The pattern of recycling economy is as shown in Fig. 3. 4.2.2. Coal gangue The comprehensive development and utilization of coal gangue not only can control the sources of pollution, but also can turn the waste into valuable treasure, and get enormous economic benefits. In the colliery of the JCAMG, the comprehensive utilization of coal gangue includes electricity generation, coverage, landfill, and forestation, as shown in Fig. 4. Power generating. Coal gangue used to power generating is an important way to dispose the solid waste, which mainly makes use of calorific value at 3350–6280 kJ/kg of waste rock, using sophisticated technology of the 75 tons/h Circulating Fluidized Bed Boiler, mixed fuel coal gangue with slime for power generation. This technology has solved the difficult problem of different low calorie fuels mixed together. According to statistics, no less than 560,000 tons
Fig. 4. The comprehensive utilization of the coal gangue.
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of gangue is burnt in gangue power plants every year, equivalent to 80,000 tons of standard coal. As for the gangue unsuitable for power generating, the utilization of coal gangue includes coverage, forestation and landfill. How to cover the gangue? Usually, the gangue unfit for burning is piled up near the mouth of the coal well and forms a coal gangue mountain as the gangue dumps higher and higher. Coverage it to put the loess or mud onto the waste rock mountain so as to reduce the ventilation (the oxygen), prevent from the spontaneous combustion and its expansion, prepare for field building up and afforesting. After the coverage with the soil on the gangue mountain, the next step is to create the condition for the afforesting by consolidating the land, such as tamping surrounded the mountain, step-style preparation. Then, by improving the environment for plant growth or being reclaimed in accordance with site conditions, the plants, such as the locust tree, hippophae, Rosa, etc. can be planted that can keep the soil from erosion and gangue from spontaneous burning. After afforesting, the atmosphere pollution, dust, poisonous materials, can be avoided effectively, the atmosphere and water quality can be improved dramatically. Landfill can be divided into two methods as the conventional landfill and sanitary landfill. Conventional landfill method is to fill gangue directly in the pond, lake, ditch or low-lying areas collapsed on the site and waste not to make any deal. This discharge is very simple and cheap, but easy to pollute the environment caused by the secondary pollution. Sanitary landfill is the world’s most commonly used in solid waste treatment technology. It is on the site scientifically selected, to use the necessary protective means and reasonable landfill structure, try to mitigate and eliminate the solid waste pollution on the environment. Sanitary landfill can effectively control the leaching of water diffusion; reduce the pollution on groundwater, plant trees and grass, restore the ecological environment at the top layer of impermeable or reclamation. In the colliery of the JCAMG, the comprehensive utilization of the coal gangue has made great positive impacts. Suppose that every 1000 m3 of coal gangue takes up 40 m2 , the total gangue discarded by the coal mines, more than 500,000 m3 annually in the JCAMG, would occupy more than 2 ha new land, which would be a heavy burden for the mines. Through the analysis on the chemical, sulfur, harmful trace, radioactivity and leaching, etc., they are confirmed that these indexes do not exceed the national standard and the gangue can be used to reclamation and fill land. Coal mining subsidence area gradually expanded, with an average depth of 4.3 m collapsed, the biggest sinking depth of 8 m. Therefore, they combine the solid waste emission with the subsidence area reclamation governance in the practice. On the one hand, they has bought the relevant machinery and equipments, take out the topsoil in the subsiding area, dump the gangue into the subsiding area, refilling the soil or loess with the gangue, compacting layer by layer, covering the cultivating soil on the top layer. This approach can enhance the density of filling waste, reduce wastewater permeability and water content in the gangues, so as to prevent the leaching of heavy metals and other harmful substances leaking into the groundwater. At present, land subsidence has control over 2000 acres, 6000 acres are being implemented under the governance and planning treatment. On the other hand, the refilling areas are tidied through filling by layers, roller compacted, and their bearing capacity of the weight of building is improved. As a result, the base is so solid that it can be industrial construction land for developing non-coal industries. The chemical plants, construction and installation company, flyash brick factory, Liquefied Petroleum Gas (LPG) station, training base and so on are built one by one in these refilling area. A large number of surplus staff is re-employed in these companies. In addition, they also implement an eco-environmental reengineering that is to reclamation the land using coal gangue, village reconstruction in the subsidence area. The results indicate that by the end
of 2007, more than 3 million tons coal gangue disappeared, about 70 ha land emerged. The total investment was 34.8 million Yuan RMB, the planned 490 families had moved back to the area, each household with a construction area of 160–200 m2 , courtyard area of 70–100 m2 . This project was identified as one of the top 10 Technological Demonstration Projects of Sustainable Development in Shanxi Province. As for the coal gangue mountain left over in initial stage of the well construction, they also invested great number money in dealing with from the governance, greening and making landscape. In the early gangue mountain, the ring road was built, pavilion with ancient style founded, more than 20 species of bush planted, the corner of the subside area was transformed into a man-made lake, covering 14,670 m2 , a pavilion and bridge built inside the lake, fish in water, willow on the lakeside, a garden of 8000 m2 and a leisure fitness plaza entertainment of 16,000 m2 . The colliery district has become a beautiful landscape matched together with mountain and trees, flowers, the environment elegant beautiful scenery, so that the waste rock pile into an ecological park, creating significant environmental protection, land reclamation, economic and social benefits. Just like conservative estimates of profitability indicate potential to provide a return on investment in the range of 20–25%. A 40% return on investment is projected if the Coal Industrial Park includes production and captive use of process steam (Chugh and Patwardhan, 2004). 4.2.3. Coal sludge and fly-ash Coal sludge or slime is the tailed coal after mechanical dewatering of coal in the coal washing process. It can flow with the water, but air-dried quickly to ash and fly with the wind. As discussed above, if the coal sludge cant treat properly, it would pollution and waste the resources, thus it has been a hot “potato” in the waste comprehensive utilization. In the Jincheng colliery, it has found the path to reduce the waste and turn it into resource. Taking the Chengzhuang coal mine as example, it has produced about 180,000 tons sludge every year. The mine has built a slime burning power plant that can convert the slime into electrical energy, burning the coal sludge 180,000 tons per year, and generating 180 million kWh, earning profit 40 million Yuan RMB annually. The project not only effectively supplement power supply for coal mine, creating significant economic benefits, but also make full use of waste heat of power generation to supply the mine office and staff conducted a focus on residential heating, heating up an area of 1,000,000 m2 , equivalent to 10 large-scale heating boiler room, eliminating the heating boiler soot pollution, annual savings of more than 10 million tons of coal-fired heating boilers and 100 million operation and maintenance costs. This waste treatment solves the problem of the slime storage, sale, transport, erosion, pollution and other problems and set up a good example for the slime utilization. The coal after burnt in the boiler will become the soot emitted into the air and fly-ash left in the hearth. Before the recycling economy implemented, the ash was transported outside subside area by cars. Because the fly-ash is small, light, easy to disperse with the wind, it can cause a certain amount of pollution. In order to treat the waste scientifically, the Jincheng colliery launched a project of flyash replacing the loess defending and extinguishing fire grouting underground. The fly-ash is easy to dehydrate and pile up, which overcome the defects of loess in mud flow impedance, difficulty in piled up. After the fly-ash slurry infused into the loose body, it can soon dehydrate and pile up, blocking the hole, which bring about great benefits, saving the soil resource, get high-quality fireproofing materials. In addition, the fly-ash is added into the cement and other solidifying material using in the lane reconstruction in the well, which is solid, stable, labor-and-time-saving, cost-saving and improve the ability in fireproofing.
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There is another way to utilize the fly-ash, which is to add into material producing the colored brick. In order to reduce the pollution of the fly-ash to the maximum extent, the Jincheng colliery launched a project of blocks molding colored brick. The project produced more than 500,000 colored bricks annually, achieved revenues of 1.5 million Yuan, 300,000 Yuan of profits, and created more than 20 jobs. The colored bricks can be used in the road surface beautifying, landscaping, building architecture, which ended the history of brick making only with the clay. Supposing that every colored brick replacing 1.5 kg clay, the project could save the clay more than 10,000 tons which not only beautify the environment, save the fund, but also improve economic efficiency, save the valuable land resources.
Fig. 5. The comprehensive utilization of the fly-ash.
Fig. 6. The reuse and recycle of the coal mining water.
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Fig. 7. The comprehensive extraction and utilization CBM.
Besides the above ways of fly-ash utilization, there are other ways to reuse the waste: filling it in the mined-out area, grouting separated strata zone in overburden in wells, surface subsidence mitigation, producing aluminum with the high-aluminum fly-ash (Fig. 5). 4.2.4. Coal mining water Due to the shortage of water in Jincheng colliery, it is of importance to reuse the coal mining drainage in wells, life sewage in living area, sewage in hospitals and coal washing water. The coal mining drainage can be reused in life and industrial production after treated and the life sewage be used to garden irrigation, supplementary water in the coal washing plant and the power plants. Taking the Chengzhuang coal mine as example, they invested 4.38 million Yuan RMB to construct a coal mining drainage treatment stations in 2003. Then, invested 7 million Yuan to reconstruct the stations and enhance the coal mining water treatment capacities in 2006. Now, the treated water is used in recycle cooling water in the self-supporting power plant, supplementary water for the coal washing plant, fire protection water, and underground well production water, which recycle the wastewater and reuse the relatively valuable water resource, saving the water resource more than 2 million cubic meters every year. To further conserve water and reduce the consumption of underground fresh water, they also invested 5.3 million Yuan in 2007 to improve the water treatment capacity that can reuse all the waste mining water underground and implementation of zero emission. At the same time, they reconstruct the water resource establishment including green spraying, irrigation water and man-made lakes, such as landscape ornamental water attractions, reusing all the remaining mining water. A great amount of money initially spending on the water resource exploitation and well fresh water lifting is saved, directly economic benefit over 1.4 million Yuan RMB. In order to improve the life sewage treatment capacity in colliery, the Chengzhuang mine invested 8.5 million Yuan to build a sewage treatment plants handling 10,000 m3 wastewater per day. The life sewage is treated through coagulation-sedimentation processes, the technology selection reasonable; after depth treatment, the water quality meets the “National Integrated Wastewater Discharge Standard” level standard, reducing pollutants (COD) emissions near 400 tons every year. As for the hospital wastewater, they built a hospital wastewater treatment station with capacity of 100 m3 that “swallowed up” 80 wastewater drained daily by hospital and “digest” it into clear water meeting the “South–North Water
Diversion in Shanxi Province along the water pollutant discharge standards” The black water outflow from the coal washing plants is a hard problem to deal with for the colliery. They constructed a coal sludge water filtration plant that can recycle all the black water in closed circulation pipes. Meanwhile, the slime can be retrieved and provided to the self-supporting power plant for electricity generation or sold externally. The treatment stopped the out-drainage into the farmland causing the pollution to the living environment and river valley of surrounding area, created significant economic, environment and social benefits (Fig. 6). 4.2.5. Coal-bed methane The coal-bed methane (CBM) is gas that is company with the coal berried underground. The CBM is not only a waste gas in coal mining, but also a valuable natural resource. Extracted the CBM before mining and utilized in industrial production or living burning is conforming to the requirement of the recycling economy. Jincheng colliery has established a base of the comprehensive utilization of the CBM, which sets up a good example for other coal mines. At present, its CBM extraction wells group have become the largest scale in China, the CBM compression and liquefaction capacity is the largest in Asia. The CBM has been widely used many industries, such as civil usage, industrial production, power generating, car fuel, etc. The recycling economy industrial chains mode is shown as Fig. 7. (1) Extraction overview In Jincheng colliery, the principle for the CBM extraction is “extracting firstly on the ground, combining with the extraction underground”. The ground extraction is to establish the CBM wells in the coal fields before coal mine well and the underground extraction is to gather the CBM by the 1000 m digger in module type. In the “Twelve Five-year” period (2011–2015), the JCAMG plans to construct 2000 the CBM extraction wells at Fanzhuang, Zhenzhuang, Shizhuang and Dongda four mines and layout the extraction modules, forming the ground and underground extraction. In the process of the extraction, the large-diameter, high-volume pipes, large-diameter holes, high negative pressure extraction apparatus were used, totally six mobile CBM pumps gathering 60–70 m3 /min was equipped with in the gassy outburst mines in 2007, which solved the problem of the local outburst sites in mines. By the end of 2007, the JCAMG had exploited annually the CBM 0.8 billion m3 and
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Table 2 The CBM resources in Jincheng coal mines (unit: 109 m3 ). Regions
Subtotal
Xieli Panji, Gugou Zhangji Guqiao Panbei, Zhuji Zhangou Shangyao Xinji Total
1096.04 1311.2 257.4 471.3 531.41 560.1 1232.46 467.77 5928.25
−1000 m and above
−1000 to ∼−1500 m
64.5 276.61 127.37 230.31 173.45 375.4
732.44 885.6 130.17 241.42 359.96 184.85
158.07 1395.61
309.7 2842.41
Under −1500 m 299.05 158.72
1232.46
established a CBM driving power plant, Shihe plant, an Asia’s largest CBM power plant (Table 2). (2) The CBM utilization The CBM utilization mainly include three ways: provide to the surrounding cities and provinces for living, input into the “West–East” gas pipeline to the east, local power generation. There are additionally other technical schedules. Wind emission coal-bed methane (gas) reduction technique. As wind emission gas concentration is generally less than 1%, it is difficult to achieve stable combustion oxidation, only when the ambient temperature maintained at 1000 ◦ C or above oxidation can be effectively broken down into carbon dioxide and water. There are two solutions, one is to keep the temperature above 1000 ◦ C, and another is to burn at relatively low temperature combustion oxidation stability by using the catalysts to reduce the activation energy of the methane. By collecting the carbon dioxide combusted by the wind emission gas, it can be converted into dry ice or compressed for sale, which also can achieve social and economic benefits. At present, the gas flow of air for combustion technologies and reactor technology can reduce the wind emission gas emitted directly to the atmosphere, which has good application prospects. Low concentration gas purification technology. As for the low concentration gas, the general technology is to purify and convert it into high concentration gas because the latter can be used in many industrial fields. The purified gas not only can be used as vehicle fuel, supplying for the Jincheng, ChangZhi, Linfen, Yuncheng and Taiyuan and other cities, but also be taken as one of the gas resource bases for the “West–East” gas pipelines. Furthermore, the gas can be liquefied and transported long distance to remote area. In addition, the CBM is also a high-quality raw chemical material for synthetic methanol, synthetic ammonia and acetylene. It can produce the carbon black applied to tire rubber industry, plastics production, printing ink, battery, alloy, smelting, and so on. In a word, they have found the paths to both ensure the safety production and promote the economy growth of the company through large scale extraction and comprehensive utilization. 5. Conclusion and recommendations Through the above research, it can be found that coal mining waste is serious threaten to the environment and urgent problem to be solved for the government in China. The case study indicates that the JCAMG has set up a good example for the coal mines. Based on the recycling economy theory, the coal mining waste industrial chains of comprehensive utilization is the effective solution for the coal mining industrial waste. The scientific management mode in the Jincheng colliery not only saves the natural resource, reduces or avoids the environment pollution, but also turns the waste into wealth, creates great social and economic benefits. It is worth of studying and learning for other mines.
1690.23
Meanwhile, the utilization pattern of coal mining waste has the comprehensiveness and the diffusion quality, in which the resources and material recycling patterns deserved learning.
Acknowledgements The authors would like to thank the National Natural Science Foundation of China (Grant No. 70773111) and the Ph.D. Programs Foundation of Ministry of Education of China (No. 109032) for their financial support. We are also grateful for the helpful comments provided by two anonymous reviewers.
References Bell F, Stacey T, et al. Mining subsidence and its effect on the environment: some differing examples. Environmental Geology 2000;40:135–52. Bian Z, Dong J, et al. The impact of disposal and treatment of coal mining wastes on environment and farmland. Environmental Geology 2009;58(3):625–34. Bian Z, Zhang Y. Land use changes in Xuzhou coal mining are. Acta Geopraphica Sinica 2006;61:349–58 (in Chinese). China and GAoEP. Environmental quality standards for surface water, GB3838-2002; 2002. Chugh YP, Patwardhan A. Mine-mouth power and process steam generation using fine coal waste fuel. Resources, Conservation and Recycling 2004;40(3): 225–43. Dharmappa HB, Wingrove K, et al. Wastewater and stormwater minimisation in a coal mine. Journal of Cleaner Production 2000;8(1):23–34. Hemza P, Sivek M, et al. Factors influencing the methane content of coal beds of the Czech part of the Upper Silesian Coal Basin, Czech Republic. International Journal of Coal Geology 2009;79(1–2):29–39. Islam MR, Hayashi D. Geology and coal bed methane resource potential of the Gondwana Barapukuria Coal Basin, Dinajpur, Bangladesh. International Journal of Coal Geology 2008;75(3):127–43. Ke C, Liyun R. Research on comprehensive utilization of coal mine water in Shendong coal mining area. Shanxi Architecture 2010;36(2):208–12. Kikuchi R. Application of coal ash to environmental improvement: transformation into zeolite, potassium fertilizer, and FGD absorbent. Resources, Conservation and Recycling 1999;27(4):333–46. Kurbiel J, Balcerzak W, et al. Selection of the best desalination technology for highly saline drainage water from coal mines in southern Poland. Desalination 1996;106(1–3):415–8. Lambert DC, McDonough KM, et al. Long-term changes in quality of discharge water from abandoned underground coal mines in Uniontown Syncline, Fayette County, PA, USA. Water Research 2004;38(2):277–88. Lottermoser B. Mine wastes: characterization, treatment and environmental impacts. Berlin, Heidelberg, New York: Springer; 2003. Ma C, Li X, et al. Settlement behavior of coal mine waste in different surrounding rock conditions. Journal of Central South University of Technology (English Edition) 2008;15(3):350–5. McKinnon E. The environmental effects of mining waste disposal at Lihir Gold Mine, Papua New Guinea. Journal of Rural Remote Environmental Health 2002;1:40–50. Myers T. Groundwater management and coal bed methane development in the Powder River Basin of Montana. Journal of Hydrology 2009;368(1–4): 178–93. Skarzynska K. Reuse of coal mining wastes in civil engineering – Part 2: utilization of minestone. Waste Management 1995;15:83–126. Sun X, Li X. New technology of waste-filling replacement mining on strip coal pillar. Meitan Xuebao/Journal of the China Coal Society 2008;33(3):259–63. Szczepanska J. Distribution and environmental impact of coal-mining wastes in Upper Silesia, Poland. Environmental Geology 1999;38(3):249–58. Tang S, Wang Y, et al. A comprehensive appraisal on the characteristics of coal-bed methane reservoir in Turpan-Hami Basin. Journal of China University of Mining and Technology 2007;17(4):521–5, 545.
1340
L. Haibin, L. Zhenling / Resources, Conservation and Recycling 54 (2010) 1331–1340
Viadero RC, Tierney AE. Use of treated mine water for rainbow trout (Oncorhynchus mykiss) culture—a preliminary assessment. Aquacultural Engineering 2003;29(1–2):43–56. Williams D, Jeffery J, et al. A review of the acid rock drainage potential and hydrological implications of selectively-placed waste rock at a gold mine in NSW. In: 6th ICARD, Australia; 2003. Xiaojun H. Environmental damage and new uses technology of fly-ash. GuangDongHuaGong 2007;34(5):77–9 (in Chinese).
Xiaowang X. The reusage and recycle of coal gangue. Environmental Science and Technology 2009;22(1):121–5. Xiaoyan Y, Changsheng J. Comprehensive utilization of the coal gangue. Coal Technology 2007;26(10):108–10. Xueyu J. Current comprehensive utilization and ProsPeet of coalbed methane in Jincheng Coal Mining Area. China Coalbed Methane 2010;5(2):23–7.