The coal mines of China Coal Group are mainly located in Pingshuo Minning Area of Shanxi ProviceLinfen of Jinzhong of Shanxi province, Hujierte Mining Area of Ordos of Inner Mongolia, Datun Mining Area of Jiangsu province, Yuheng Mining Area of Yulin of Shaanxi Province, Xinzheng of Henan Province, Xinji Mining Area of Anhui province, Hami Mining Area of Xinjiang Autonomous Region. China Coal Group has more than 70 coal mines with an annual production capacity of 300 million tons, and the controllable resources reserve reaches 60 billion tons. China Coal Group has 38 coal preparation plants with a total washing and preparation capacity of 300 million tons. China Coal Group has a history of more than 30 years in coal and coke import and export and owns a well constructed system of logistics dispatchment centers and distribution networks. Since 2005, the coal trade volume of China Coal Group has been exceeding 100 million tons for 13 consecutive years.
During the 13th Five-Year Plan period, by adhering to the keynotes of scale and intensive development, green and high efficiency, optimizing high quality industry and adjusting inventory, China Coal Group takes great efforts in upgrading the clean and efficient exploration of coal, vigorously promotes the construction of integrated projects of coal, power generation and chemical to enhance the coal production efficiency, to increase the on-site transforming ratio of coal and to highlight the advantage of scale and intensive development. China Coal Group grasps the opportunity of de-capacity policy to deeply participate in the integration of coal resources among state-owned enterprises, actively and steadily promotes enterprises merger and reorganization, reasonably and orderly pushes forward the production reductionand replacement to release the advanced coal production capacity that are under construction in time. By leveraging on elements including the richness of coal resources, market location and environmental capacity, China Coal Group develops the large-scale coal bases in Inner Mongolia-Shaanxi and Shanxi, etc. with differentiation so as to realise the transformation from scale-and-speed-oriented mode to quality-and-efficiency-oriented mode.
Coal production continues to grow globally due to the demand for low cost energy and iron and steel, as well as cement. Coal, based on the current extraction rates, will last about 115years longer than conventional oil and gas reserves, with an estimated 1.1 trillion tonnes of proven coal reserves worldwide. Ten countries are responsible for 90% of the total global coal production. China has been the largest coal producer for the last three decades (with approximately 13% of the world's total reserves), with the United States of America, India, Australia, Indonesia, Russia, South Africa, Kazakhstan, Columbia, and Ukraine being major producers with significant resources (Table 3).
Coal production dates back to the earliest civilizations cited by Aristotle (340) and Agricola (1556) for use in fire combustion during the middle of the fourth century B.C. (Landis & Weaver, 1993). It was thought that the Chinese first commercialized coal production for smelting 20003000 years ago mining coal from the Fu-shun coalfield in Manchuria (Inouye, 1913). Coal replaced wood and charcoal for fuel by the thirteenth century and commercialized for smelting and casting of brass by the seventeenth century in Great Britain (Eavenson, 1939). Coal was exported to other European countries by 1325 as a result of widespread mining with increased coal production from 2.27 to 9.07millionmt during 17001800 (Eavenson, 1939). The Industrial Revolution, confined in Great Britain from 1760 to 1830, increasingly utilized coal to make coke for smelting iron and other metals and to fuel coal-fired steam engine for locomotives (Lindbergh & Provorse, 1977).
Coal was known to fire kilns for native pottery in the southwest United States during the eleventh century (Landis & Weaver, 1993). Immigration of Europeans brought the Industrial Revolution to North America and increased commercialization of coal for use in smelting and space heating in the northeast United States. Coal mining of bituminous and anthracite coals in the central Appalachian Basin occurred in the early 1800 with production of both to as much as 2721mt increasing to 1,814,000mt prior to the American Civil War and reached to about 516,990,000mt by 1913 (Moore, 1922). Dramatic increase of coal production in the United States occurred during the First and Second World Wars after which coal was supplanted by a major shift to oil and gas for energy sources. The rest of the world's reliance of coal resources for energy mimicked that of Great Britain, Europe, and North America. In 1913 prior to the First World War the other countries that relied on coal for energy source were China producing about 13,967,800mt, Australia producing 12,698,000mt, and Russia producing 32,652,000mt (Lesher (1916). In 1989, China has increased coal production by about 67%, Australia by about 14%, and Russia by about 22% (USEIA, 1991). In 2007, the largest coal producers, which account for 75% of global production, in descending order, are China, United States (39% of China production), Australia (37% of United States production), India, South Africa, and Russia (BP, 2012).
The increased coal production worldwide through underground mining led to explosions of gas (e.g. methane and carbon dioxide) and coal from the working mine face. Outburst was not a problem when coal was mined from outcrops and shallow shafting in Great Britain and Europe because gas was easily liberated to the atmosphere. As shallow coal resources were slowly exhausted at the end of the eighteenth century and technology was improved to permit construction of deep mines, coalbed gas was recorded in Great Britain, France, and United States. In the early nineteenth and twentieth centuries minor and major outbursts were reported in Australia, Canada, Belgium, China, Germany, Japan, Poland, Russia, and United States (Flores, 1998).
Coal production in the United States is highly concentrated in the Appalachian region. The leading coal-producing states, West Virginia and Kentucky, together accounted for 43% of the value of U.S. coal produced in 1997, as reported by the U.S. Economic Census. Pennsylvania and Virginia together accounted for an additional 17%, bringing the total for the Appalachian region to 61% of the value of U.S. coal production. Wyoming, Colorado, and Alabama together account for another 16%. The leading coal states, West Virginia and Kentucky, are also two of the poorest states in the United States, ranking 50th and 44th, respectively, on median household income in 1999, and 4th and 7th on the proportion of their population who lived in poverty (18% and 16%).
In Appalachian communities where mountaintop removal is under way, residents endure dynamite blasts, falling rock, and dust. Property values decline, and many residents move away. Studies of communities near ordinary surface mining in the United Kingdom indicate that particulate concentrations in air are somewhat elevated in these areas, and children in mining communities make somewhat more visits to their doctors for respiratory symptoms such as wheezing and coughing.
On a global scale, community impacts of coal mining in less developed nations are likely to be more pronounced than in the United States and the United Kingdom, which can afford more stringent regulatory controls. For example, the study of surface mining of coal in the United Kingdom reported mean concentrations of respirable particulates (particulates less than 10 microns in diameter, known as PM10) ranging from 14.4 to 22.3g/m3 (micrograms particulates per cubic meter of air) in nearby communities. A study of surface mining of coal in one of India's major coal fields reported concentrations of respirable particulates of roughly 70g/m3 in nearby residential areas, as well as concentrations of total suspended particulates (i.e., including larger particulates) of 200 to 500g/m3 in these areas.
Coal production and mining activities have negatively impacted our environment and human health resulting thereby in poor quality of air and water, land degradation, loss of flora and fauna, etc. Mine spoils have completely changed the landscape (Gaji et al., 2018; Maiti, 2012). Physicochemical analysis of mine waste and tailings show majorly sandy coarse textures, low content of clay, unfavorable climatic conditions and pH, high soluble salt concentrations, negligible or low nitrogen and phosphorous with less microbial activity. Thus increasing loads of heavy metals (Ag, As, B, Cd, Cu, Cr, Hg, Mn, Ni, Pb, Zn, etc.) in mine soils and their removal are serious issues. Physical remediation methods are generally nonapplicable on these areas as they are only able to treat small contaminated areas. They have high potential for multimetal contaminated sites but cannot be used in large agricultural and mining areas. Chemical remediation methods, on the other hand, are easy to apply, simple, and fast with high public acceptability, but are unsafe and noneco-friendly and have limitations of releasing additional contaminants to the environment. High cost and degrading environment quality have led to search of low-cost, visually benign, environment-friendly clean-up techniques. Phytoremediation is one such safe, eco-friendly, least destructive, and cost-effective remediation technique for large scale clean-ups. Selection and plantation of indigenous hyperaccumulator plant species is essential for colonization, establishment, and cleanup of abandoned mining areas. Efficiency of remediation methods majorly depends upon type of contaminants, extent of pollution, the hyperaccumulator plant used, and edaphic factors such as pH, salinity, heavy-metal toxicity, temperature, humidity, water logging, resistant to drought conditions and others stressors, etc. Success of phytoremediation, however, lies in public acceptance and environmental stability of technology. Allowing native plants to colonize and grow is an attractive option as local and indigenous varieties have lesser requirements of frequent irrigation and pesticide treatments. Moreover, fundamental and field-scale research is still needed before large scale application of phytoremediation technology to address the gap between laboratories to land, i.e., researches under controlled conditions and real-time field studies where plant species grow in polluted environment. Several plant species are reported to accumulate metals higher than toxic level such as Agrostis castellana (for As and Fe), C. ladanifer (for Cr and W), D. purpurea (for Sb, W, and Zn), H. lanatus (for As, Cu, and Fe), Pinus pinaster (for As, W, and Zn), Solanum nigrum (for Zn), serpentine plant species Alyssum serpyllifolium (for Cr and Ni), and Plantago radicata (for Ni). The future prospects in phytomanagement of mine waste sites therefore require more knowledge about native hyperaccumulator plants, their growth requirements for decontamination of land and restoring ecosystem services and maintaining quality of life. Further studies about plant communities, biogeochemical cycles and functional ecosystem characteristics are important for ecosystem integrity and resilience. There are risks of pollen and seed movement associated with phytoremediation that require assessment of options such as discing, harvesting, and on-site processing to reduce the likelihood of movement and contamination. However, in most cases risks related to application of phytoremediation are relatively small compared to the risks of doing nothing. As phytoremediation industry is compliance driven, it must include assessment of economic and technical barriers along with regulatory regulations to determine success of phytotechnology in mining areas. The challenge yet lies in solving the pollution transfer in food web, time required and financial risk assessment for complete remediation of contaminated areas, lack of knowledge regarding risk management during crop choices as hyperaccumulator and emissions that may be generated during processing and conversion into bioenergy, the establishment of hyperaccumulator seed bank for the expansion of phytomining studies in various ecological zones, improving the mechanization of phytoremediation to reduce overall cost. The opportunities that are also worth mentioning include crops for metal enrichment, transgenic varieties of plants and bacteria to increase phytodegradation of contaminants and bioenergy production through phytoremediation. More work in these areas in the near future is needed to establish phytoremediation for metal ions at the global level.
Africa's coal production and consumption are concentrated heavily in South Africa. In 1999, South Africa produced 248 million short tons of coal, with 70% of it going to domestic markets and the remainder to the export market . South Africa is a major coal exporter but is experiencing competition from South America and Australia, as these countries are building more production capacity . South Africa is the world's largest producer of coal-based synthetic liquid fuels. In 1999, about 17% of the coal consumed in South Africa, on a Btu basis, was used to produce coal liquids, which in turn accounted for more than 25% of all liquid fuels consumed in South Africa . Coal consumption is projected to increase by 35 million short tons by 2020, primarily to meet increased demand for electricity. Some of this increase is expected outside of South Africa in Kenya, Nigeria, Tanzania, and Morocco.
World coal production increased by 3.1% in 2017 after falling for 3years The trend changed in 2017 with a total production of 7549Mt as per IEA Key Statistics 2018. Coal is made up of thermal coal, coking coal, and lignite, and the data for the last 3years are tabulated in Table2.2. About 75% of the total coal produced is steam coal.
The People's Republic of China is the world's leading coal producer since 1985, and in 2017, China produced 3.376109t (3.376billion tonnes) of coal, which is roughly 45% of the total coal production in the world. The second and third top producers are India and the United States. Production in the United States increased by 6.3% compared with 2016 levels. The top 10 coal producers and the respective quantities are shown in Fig.2.3. Out of major producers of coal, Indonesia tops the list of net exporters by exporting almost 80% of their production. Australia, once the top exporter, is the second largest exporter with a significant portion (76%) of coal exported. Despite being the top producers of coal, China and India continue to be the top net importers of coal, with 263 and 207Mt of net imports to China and India, respectively .
Coal is mainly used for the electricity generation and commercial heatingin 2016, this took up 65.3% of the primary coal usage globally. Other sectors of usage for coal include iron and steel production, cement manufacturing, and as a feedstock for liquid fuel. In OECD countries, the coal share for electricity and commercial heating increase to 82.4%. Coking coal is an essential element in blast furnace steel production. Non-OECD countries account for 82.9% of the total coking coal consumption. Fig.2.4 shows the country rankings for the coal-fired power generation for 2016. China tops the list with 4242TWh with almost 60% of the coal demand in China used for power generation.
Coal will continue to be a major energy supplier for the world for at least the next two to three decades. However, increased competition from other fuel resources, shift to cleaner energy, and climate change mitigation plans are the challenges for the coal sector. Different steps for sustainable use of coal include improvement of the coal quality, deployment of higher efficiency and lower emission technologies, and investment in CO2 capture and storage.
National coal production was increased from surface mines in shallow Tertiary coal resources compared early production from deep underground mines in Gondwana Coal Measures. As of 2008, there are 559 active coal mines with underground mines accounting for 337 and surface mines accounting 186, and 36 mixed underground and surface mines (USEPA, 2010). Eighty four percent of the coal production comes from the surface mines. About 61% of these coal mines are very gassy emitting at a rate of >0.01 to >10m3/t. Singh et al. (1999) reported that 40% of the coal mine disaster in India from 1908 to 1995 is caused by coalbed gas outbursts causing 839 fatalities. Coal Mining is reported to be contributing to about 9% of total coalbed gas emission of India (Pande, 1996), which have increased more than three times from 1995 to 2010.
Coalbed gas or CMM emissions from Indian coal mines increased from 763MMm3 in 1990 to 1.6Bcm in 2010 (USEPA, 2010). Although the Indian government has demonstrated the commercial feasibility of recovery and utilization of CMM, no commercial production of coalmine gas is in place. Another potential source of coalbed gas is from AMM. The best potential for CMM recovery is before, during, and after mining with the later recovery from AMM. Five percent of abandoned coal mines in India are considered gassy (USEPA, 2010). Recovered CMM may be used to generate local power for electricity (with a maximum capacity of 500kW), as well as being used in 50-ton mine dump trucks, powered by converted bifuel engines (UNDP, 2009).
USEPA (2010) reported that for the first time for India, prospective operators are being offered active coal mining blocks to extract and utilize CMM. India's Coal Mine Planning and Design Institute recently issued a notice inviting tenders for five CMM blocks held by Coal India Limited. The blocks are located in the Jharia and East-Bokaro coalfields in northern India (Figure 9.29). The objective of the CMM projects is to drain gassy coal beds below the coal currently mined using predrainage technology of gas recovery. Original rules prohibited coal owners from extracting CMM released during mining operations. However, the Coal and Petroleum Ministries have agreed to allow coal owners (e.g. Coal India) to explore CMM. However, the Petroleum Ministry must approve commercialization of the coalbed gas by coal owners. The offering of the CMM projects will bring India's coalmine gas resources to market in an environmentally beneficial manner (USEPA, 2011).
Due to coal production and combustion, rising concentrations of carbon dioxide and other greenhouse gases in the atmosphere are contributing to increased global temperatures and climate changes. Additionally the production, transmission, storage, and distribution of coal further emit carbon dioxide, which leads to the trapping of heat in the Earths atmosphere. In the US, coal power plants account for a third of US carbon dioxide emissions (MIT, 2009). Higher carbon dioxide emissions can have a significant long-term effect on the environment and human populations including: increase of precipitation and flooding in storm-affected areas, more intense hurricanes in warm sea surfaces, increases in heat waves, and rise in sea level due to polar ice cap melting. Vast amounts of this greenhouse gas also threaten to acidify oceans, destroying plankton life that forms the bottom link of the food chain and affecting shell formation of aquatic organisms (Holzman, 2008).
One possible solution to the rise in carbon dioxide emissions is a new system whereby carbon dioxide produced by burning coal is subsequently captured and sequestered, in a process known as carbon capture and storage (CCS). Large volumes of the gas can then be stored in natural facilities such as depleted oil and gas fields (Drake, 2009). Other options to reduce carbon dioxide are also available in the form of alternative fuel sources and more efficient emission controls.
The gargantuan coal production program has propelled the growth of the Indian economy. This has been further accelerated by the reformed policy matters related to (Solomon, 2015): deregulation, attracting foreign investment, cutting subsidies, stimulating competition, reduction of red tape and bureaucracy and the eradication of corruption. Coal is considered as the linchpin for Indias rise to burgeoning economic progress. The coal industry is controlled by the public sector: CIL, which is the worlds largest coal company. CIL, in its strategic reforms, is inviting the private sector to boost its performance. Indias coal-fired electricity generation capacity is forecast to almost double over the next decade, with most of the increment coming from clean coal (Solomon, 2015).
In addition to the power sector, there is substantial demand growth for coal in the iron and steel industry, cement manufacturing and others. Along with population growth, the use of coal can boost industrial development and help create a new economy making India a leading economy globally. Coal is the fuel of choice because of its reliability, affordability and availability. The growing implementation of clean coal technologies will also accelerate the use of coal as the primary source of electric power, leading to economic development, social progress and a higher quality of life: the economic miracles of the 21st century (Clemente and Clemente, 2013).
Majority of global coal production comes from underground mining which is done by two methods: (1) room and pillar and (2) longwall mining. As shallow coal seams are mined out and mining reaches greater depths, longwall mining becomes the preferred method of mining. In United States, more than 50% of all underground mined coal is mined by the longwall method. The trend for panel sizes and mining equipment in the coal industry is to continue to go upward pushing production capacities and productivity to higher levels. Another reason for increasing the longwall panel size is that development sections cannot keep up with the rate of longwall advance. Increasing the width of the longwall panel slows down the rate of advance. Today it is quite realistic to plan longwall panels in mildly gassy coal seams that are 1500ft wide and 15,000ft long containing nearly 5 to 7million tons of raw coal. Such large longwall panels offer many benefits as follows:
Were active in the whole value chain, from exploration and development to mining, concentration, pelletising, rail transport and port operations. With operations that span Europe, the Americas, Africa and Asia, we aim to optimise our portfolio so we can deliver results at any point in the economic cycle, and to manage our assets to the highest standards. We are equally driven to mine responsibly and sustainably, minimising the impact of mining on the natural environment, and working closely with local communities to build skills and social infrastructure to ensure long-term development.
We have a geographically diversified portfolio of 14 operating units in Brazil, Bosnia, Canada, Kazakhstan, Liberia, Mexico, Ukraine and United States that in 2019 produced 57.1 million tonnes of iron ore and 5.5 million tonnes of coking coal. Our main products include iron ore lump, fines, concentrate pellets and sinter feed, and coking coal, thermal coal and pulverised coal injection (PCI) coal.
Mining has impacts on land, communities and natural habitats. We want these impacts to be positive. Our goal is to ensure that our mining operations leave a sustainable, social, environmental and economic legacy.
Technology has huge potential to make mining more efficient and reduce its environmental impact. From drone technology to digitisation, our operations around the world are constantly finding new ways to mine better.
We are specifically focussing on Potential Serious Injury and Fatality events (PSIF) detailed analysis and root cause reviews, risk assessment and courageous leadership. Permeating all levels of the mining business, courageous leadership is about creating an environment in which people are valued above all other priorities, in which there is a conviction that zero injuries can be achieved, and employees bring a positive attitude to work. Its about managing our own behaviours to eliminate risks, accepting that safety is everyones responsibility and having the courage to make positive change.
Coalbed methane (CBM) drainage in underground coal mining is of significance to guarantee mining process safety and bring valuable environmental benefits, as the drainage could help to eliminate methane-related accidents, reduce greenhouse gas (GHG) emissions and provide a source of clean energy. Due to the manifold benefits, extensive investigations have been conducted on methane emissions and drainage methods. However, few review studies have been reported in analysing and summarizing those previous investigations. Therefore, in this paper, a broad review on CBM emissions and drainage methods is conducted. First, the methane emissions in underground coal mines are reviewed, including methane generation, storage and migration characteristics, emission sources, emission estimation, and the factors influencing emissions such as coal properties, geological conditions and mining-process parameters. Then, based on the borehole trajectory, three methane drainage methods for reducing methane emissions are categorized: surface to inseam (SIS) methane drainage, underground to inseam (UIS) methane drainage and cross-measure borehole methane drainage. Each drainage method is analysed from perspectives of borehole design and application function. Particularly, the popular UIS drainage borehole design and sealing for preventing ventilation air leakage are emphasized. Finally, summary and conclusions on previous works are provided. Outcomes of this review work are expected to provide relevant researchers and mining engineers with effective contents on methane emissions and drainage methods in underground coal mines. Based on the site-specific methane conditions in their coalmines, mining engineers could determine the most appropriate methane-drainage methods to increase the drainage efficiency and reduce methane emissions for a safer and more efficient mining process.