Emissions from underground coal fires extend the already well-known adverse health impacts of coal extraction and combustion. The extraction, storage, transportation, and utilization of coal that produces fugitive dust pose a significant risk to human and animal health, and the environment. Emissions from coal-fired power plants, and residential coal use, may expose individuals to hazardous air pollutants including mercury, sulfur dioxide, nitrogen oxides (NO x ), toxic heavy metals (e.g. As, Pb), radioactive elements (e.g. uranium, radium, and thorium), and volatile organic compounds. One aspect of coal combustion has been largely neglected, that is the threat of uncontrolled coal fires. The thousands of naturally occurring or anthropogenic-induced uncontrolled coal fires worldwide are a major environmental insult to the air, soil, and water and a major threat to the health of those unfortunate enough to work or live in the vicinity. Some have persisted for decades or even centuries, constantly spewing hazardous material into the environment. Medical geology, the study of the impacts of natural materials on human health, can help by identifying and analyzing the toxic emissions as well as the health effects from collaboration with biomedical and public health researchers.

Activities associated with mining and fuel extraction may present a range of potential health risks for nearby communities. The environmental legacy of mining and fuel extraction is extensive, with millions of active and abandoned mines globally. Evaluation of community risks from mineral and fuel extraction is often a complex task, given the variety of products produced, multiple potential exposure contexts, routes of contact, and health impacts. Adverse health outcomes that may arise from mineral-related processes include release of toxicants such as metals, metalloids, and mineral dusts, and indirect effects such as the increased potential of vectorborne disease. The ongoing processing and end-use of minerals also produce gas emissions (such as carbon dioxide and sulfur dioxide), often on a large scale. Polycyclic aromatic hydrocarbons (PAHs) are substances of particular concern arising from conventional crude oil and coal extraction, oil sands/shales wastes, and tailings water, and are classified as either proven or suspected carcinogens. The geotechnical and structural aspects of mine sites must also be considered, including the risk of major hazardous events such as release of tailings dam contents. Indirect or delayed effects of mineral and fuel extraction include those that act to affect community health through contamination or disruption of water supplies and food sources (e.g., crops). As with many industries, the balance between risks and benefits of mining must be carefully calibrated.

The geochemistry of the REE (La, Ce, Sm, Eu, Tb, Yb, and Lu) is reviewed with supporting data from coals of North Asia. The 7189 samples from North Asia included in this study represent all coal ranks (lignites, subbituminous coals, bituminous coals and anthracites) as well as coals formed under different geotectonic regimes and in different sedimentary conditions. These coals are characterized by higher contents of the REE as compared to the coal Clarke. The distribution characteristics and accumulations of the REE have been studied in several coal deposits and basins. Within some basins with the near-background average contents of the REE isolated coal beds enriched in lanthanides have been observed. In coal basins and deposits the relative enrichment in the lanthanides are observed in the fields or zones adjacent to the source area of the terrigenous material. Accumulation of high REE contents in coal deposits can be attributed to the presence of rocks in the source area containing high concentrations of REE and also alkaline or acidic volcanic ash contemporaneous with the peat accumulation in the basin. Transformation of volcanic ashes under the aggressive hydro-environment of a peat bog results in the mobilization and redeposition of the REE adjacent to the altered volcanic ashes (tonsteins) with the formation of high concentrations of REE in the coal beds. The formation of the REE anomalies may also be related to hydrothermal processes. The modes of occurrence of the REE change during the coalification process. Brown coals with a low degree of coalification are dominated by the organic modes of occurrence of the REE, whereas in hard coals and anthracites authigenic mineral forms dominate.

Coal is one of the most complex and challenging natural materials to analyze and understand. Unlike most rocks that consist predominantly of crystalline mineral grains, coal is largely an assemblage of amorphous, degraded plant remains metamorphosed to various degrees and intermixed with a generous sprinkling of minute syngenetic, diagenetic, epigenetic, and detrital mineral grains, and containing within its structure various amounts of water, oils, and gases. This chapter tries to make geochemical sense of this wonderfully complex and important resource.

In order to assess the potential impact of the geological environment on the health of the population of the Slovak Republic, the geological environment was divided into eight major units: Paleozoic, Crystalline, Carbonatic Mesozoic and basal Paleogene, Carbonatic-silicate Mesozoic and Paleogene, Paleogene Flysch, Neovolcanics, Neogene and Quaternary sediments. Based on these geological units, the databases of environmental indicators (chemical elements/parameters in groundwater and soils) and health indicators (concerning health status and demographic development of the population) were compiled. The geological environment of the Neogene volcanics (andesites and basalts) has been clearly documented as having the least favourable impact on the health of Slovak population, while Paleogene Flysch geological environment (sandstones, shales, claystones) has the most favourable impact. The most significant differences between these two geological environments were observed, especially for the following health indicators: SMRI6364 (cerebral infarction and strokes) more than 70 %, SMRK (digestive system) 55 %, REI (circulatory system) and REE (endocrine and metabolic system) almost 40 % and REC (malignant neoplasms) more than 30 %. These results can likely be associated with deficit contents of Ca and Mg in groundwater from the Neogene volcanics that are only about half the level of Ca and Mg in groundwater of the Paleogene sediments.

null

The current paper presents the concentration, distribution, and modes of occurrence of trace elements of 13 coals from south Brazil. The samples were collected in the state of Santa Catarina. Chemical analyses and the high ash yields indicate that all studied coals are rich in mineral matter, with SiO2 and Al2O3 dominating as determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Quartz is the main mineral species and is associated with minor levels of feldspars, kaolinite, hematite, and iron-rich carbonates. The contents of trace elements, including As, Pb, Cd, Ni, Cr, Mn, Be, V, U, Zn, Li, Cu, Tl, and Ni, in coals were determined. A comparison of ranges and means of elemental concentrations in Santa Catarina, Brazil, and world coals shows that the ranges of most elements in Santa Catarina coal are very close to the usual worldwide concentration ranges in coal.

To study the effectiveness of washing in removal of arsenic and sulfur from coals with different ranges of arsenic concentration, coal was divided into three groups on the basis of arsenic content: 0–5.5 mg/kg, 5.5 mg/kg–8.00 mg/kg, and over 8.00 mg/kg. The result shows that the arsenic in coals with higher arsenic content occurs mainly in an inorganic state and can be relatively easily removed. Arsenic removal is very difficult and less complete when the arsenic content is lower than 5.5 mg/kg because most of this arsenic is in an organic state. There is no relationship between washing rate of total sulfur and arsenic content, but the relationship between the washing rate of total sulfur and percent of organic sulfur is very strong.

Three hundred and six coal samples were taken from main coal mines of twenty-six provinces, autonomous regions, and municipalities in China, according to the resource distribution and coal-forming periods as well as the coal ranks and coal yields. Nitrogen was determined by using the Kjeldahl method at U.S. Geological Survey (USGS), which exhibit a normal frequency distribution. The nitrogen contents of over 90% Chinese coal vary from 0.52% to 1.41% and the average nitrogen content is recommended to be 0.98%. Nitrogen in coal exists primarily in organic form. There is a slight positive relationship between nitrogen content and coal ranking.

In 1999, the USGS initiated the National Coal Quality Inventory (NaCQI) project to address a need for quality information on coals that will be mined during the next 20-30 years. At the time this project was initiated, the publicly available USGS coal quality data was based on samples primarily collected and analyzed between 1973 and 1985. The primary objective of NaCQI was to create a database containing comprehensive, accurate and accessible chemical information on the quality of mined and prepared United States coals and their combustion byproducts. This objective was to be accomplished through maintaining the existing publicly available coal quality database, expanding the database through the acquisition of new samples from priority areas, and analysis of the samples using updated coal analytical chemistry procedures. Priorities for sampling include those areas where future sources of compliance coal are federally owned. This project was a cooperative effort between the U.S. Geological Survey (USGS), State geological surveys, universities, coal burning utilities, and the coal mining industry. Funding support came from the Electric Power Research Institute (EPRI) and the U.S. Department of Energy (DOE).

Fifty coal samples (28 anthracite and 22 lignites) were collected from both main and small coal mines in DPR Korea prioritized by resource distribution and coal production. The concentrations of 61 elements in 50 coal samples were determined by several multielement and element-specific techniques, including inductively coupled plasma atomic emission spectrometry (ICP-AES), and inductively coupled plasma mass spectrometry (ICP-MS), ion chromatogram (IC), cold-vapor atomic absorption spectrometry (CV-AAS), and hydride generation atomic absorption spectrometry (HGAAS). The ranges, arithmetic means and geometric means of concentrations of these elements are presented. A comparison with crustal abundances (Clarke values) shows that some potentially hazardous elements in the coals of DPR Korea are highly enriched Li, B, S, Cl, Zn, As, Se, Cd, Sn, Sb, W, Te, Hg, Ag, Pb, and La, Ce, Dy, Tm, Ge, Mo, Cs, Tl, Bi, Th and U are moderately enriched. A comparison of ranges and means of elemental concentrations in DPR Korea, Chinese, and world coals shows the ranges of most elements in DPR Korea coals are very close to the ranges of world coals. Arithmetic means of most elements in DPR Korea coals are close to that of American coals. Most elements arithmetic means are higher in Jurassic and Paleogene coals than coals of other ages. In DPR Korea coals, only seven elements in early Permian coals are higher than other periods: Li, Zn, Se, Cd, Hg, Pb, and Bi. Only five elements B, As, Sr, Mo, W in Neogene coals have arithmetic means higher than others. SiO2 and Al2O3 in ashes are more than 70% except six samples. The correlation between ash yields and major elements from high to low is in the order of Si>Al>Ti>K>Mg>Fe>Na>Ca>P>S. Most elements have high positive correlation with ash (r>0.5) and show high inorganic affinity.

Based on the analysis of 15 raw coals and washed coals collected from Southwestern, the washing rate of arsenic, sulfur and ash from raw coals was studied. The average washing rate of arsenic in raw coal is 38%. Arsenic of raw coals is mainly associated with pyrite and sulfide. However, arsenic of some raw coals is mainly or wholly associated with organic matter and mineral enwrapped by organic matter. It is difficult to remove such part of arsenic and it will enrich in the washed coals. The results show that there is a little relationship between occurrence mode of arsenic associated with organic sulfur and rank of coal, but it is complicated with age of coal-bearing strata.

National and international policy makers and industry require accurate information on coal, including coal quality data, to make informed decisions regarding international import needs and export opportunities, foreign policy, technology transfer policies, foreign investment prospects, environmental and health assessments, and byproduct use and disposal issues. Unfortunately, the information needed is generally proprietary and does not exist in the public domain. The U.S. Geological Survey (USGS), in conjunction with partners in about 60 countries, is developing a digital compilation of worldwide coal quality. The World Coal Quality Inventory (WoCQI) will contain coal quality information for samples obtained from major coal beds in countries having significant coal production, as well as from many countries producing smaller volumes of coal, with an emphasis on coals currently being burned. The information that will be incorporated includes, but is not limited to, proximate and ultimate analyses; sulfur-form data; major, minor, and trace element analysis; and semi-quantitative analyses of minerals, modes of occurrence, and petrography. The coal quality information will eventually be linked to a Geographic Information System (GIS) that shows the coal basins and sample locations along with geologic, land use, transportation, industrial, and cultural information. The WoCQI will be accessible on the USGS web page and new data added periodically. This multi-national collaboration is developing global coal quality data that contain a broad array of technologic, economic, and environmental parameters, which should help to ensure the efficient and environmentally compatible use of global coal resources in the 21st century.

Nationwide sampling program is designed according to the resources distribution and coal-forming periods as well as coal rank and yield of coal in China, and 305 coal samples were collected from 26 provinces, municipalities and autonomous regions. Fluorine in coal is determined by pyrohydrolysis / fluoride-ion selective electrode method. Fluorine in coals is mainly of an inorganic nature. Coal rank has no effect on fluorine content. The influence of a factor, such as geological age, on fluorine contents might be concealed by other factors, more research should be done to discern it. The distribution of fluorine in each province, municipality and autonomous region's coals is studied, and the fluorine source in coal-burning endemic fluorosis areas should be estimated over again. The contents of fluorine in Chinese coals show logarithm normal distribution, and 90% of values ranged from 47mg/kg to 347mg/kg, the average fluorine content in Chinese coals was designated as the geometric mean, 136mg/kg. Fluorine in Chinese coals is within the world coal's range.

Sampled outcrops of Permian coal seams of the Bainmedart Coal Measures in the Lambert Graben, eastern Antarctica, have been analysed for their proximates, ultimates, ash constituents and trace elements. A similar series of samples has been analysed for their principle maceral and microlithotype components and vitrinite reflectance. The coals are sub-bituminous to high volatile bituminous in rank; maturity increases markedly in southern exposures around Radok Lake where the oldest part of the succession is exposed and some strata have been intruded by mafic dykes and ultramafic sills. The coal ash is mostly silica and aluminium oxides, indicating that the mineral ash component is mostly quartz and various clay minerals. The ratio of silica to aluminium oxides appears to increase in an upward stratigraphic direction. The coal macerals include a relatively high liptinite content (mainly sporinite) that is significantly higher than for typical Gondwana coals. Greater degrees of weathering within the floodbasin/peat mire environments associated with climatic drying towards the end of the Permian might account for both preferential sporopollenin preservation and increased silica:aluminium oxide ratios up-section. Correlation of the coal maceral components to adjacent peninsula India coals indicates the closest comparative coals of similar age and rank occur within the Godavari Basin, rather then the Mahanadi Basin, which is traditionally interpreted to have been contiguous with the Lambert Graben before Gondwanan breakup. The petrological characteristics suggest that either previous interpretations of Palaeozoic basin alignments between Antarctica and India are incorrect, or that environmental settings and post-Permian burial histories of these basins were strongly independent of their tectonic juxtaposition. A permineralized peat bed within the succession reveals that the coals predominantly comprise wood- and leaf-rich debris derived from low-diversity forest-mire communities dominated by glossopterid and noeggerathiopsid gymnosperms.

The U.S. Geological Survey (USGS) and the Turkish General Directorate of Mineral Research and Exploration (Maden Tetkik ve Arama Genel Müdürlügü, MTA) are working together to provide a better understanding of the chemical properties of Turkish coals from major Turkish lignite producing areas.The coals in Turkey are generally low rank (lignite or subbituminous) formed in several different depositional environments at different geologic times and have differing chemical properties. Eocene coals are limited to northern Turkey; Oligocene coals, found in the Thrace Basins of northwestern Turkey, are intercalated with marine sediments; Miocene coals are generally located in Western Turkey. The coal deposits, which have limnic characteristics, have relatively abundant reserves. Pliocene–Pleistocene coals are found in the eastern part of Turkey. Most of these coals have low calorific values, high moisture, and high ash contents.Analysis of 143 coal channel samples (most are lignite and subbituminous in rank, but a few are bituminous and one is anthracitic in rank) has been completed for up to 54 elements and other coal properties using a variety of analytical techniques, including inductively coupled plasma emission and mass spectrometry, instrumental neutron activation analysis, and various single element techniques and ASTM standard procedures. Many of these coals have elemental concentrations similar to U.S. lignites found in the Gulf Coast and Fort Union regions. However, maximum or mean concentrations of B, Cr, Cs, Ni, As, Br, Sb, Cs, and U in Turkey are higher than the corresponding maximum or mean values found in either the Fort Union or Gulf Coast regions.

Uncontrolled release of pollutants from burning coal beds and waste banks presents potential environmental and human health hazards. On a global scale, the emissions of large volumes of greenhouse gases from burning coal beds may contribute to climate change that alters ecosystems and patterns of disease occurrence. On regional and local scales, the emissions from burning coal beds and waste banks of acidic gases, particulates, organic compounds, and trace elements can contribute to a range of respiratory and other human health problems. Although there are few published reports of health problems caused by these emissions, the potential for problems can be significant. In India, large numbers of people have been displaced from their homes because of health problems caused by emissions from burning coal beds. Volatile elements such as arsenic, fluorine, mercury, and selenium are commonly enriched in coal deposits. Burning coal beds can volatilize these elements, which then can be inhaled, or adsorbed on crops and foods, taken up by livestock or bioaccumulated in birds and fish. Some of these elements can condense on dust particles that can be inhaled or ingested. In addition, selenium, arsenic, lead, tin, bismuth, fluorine, and other elements condense where the hot gaseous emissions come in contact with ambient air, forming mats of concentrated efflorescent minerals on the surface of the ground. These mats can be leached by rainwater and washed into local water bodies providing other potential routes of exposure. Although there are little data linking burning coal beds and waste banks to known health problems, a possibly analogous situation exists in rural China where mineralized coal burned in a residential environment has caused widespread and severe health problems such as fluorosis and arseniasis.