Bituminous Coal Mines Research Articles

Industrial fluoride emissions and their spatial characteristics in the Nansi Lake Basin, Eastern China.

Excessive fluoride emissions threaten ecological stability and human health. Previous studies have noted that industrial sources could be significant. However, quantifying industrial fluoride emissions has not been yet reported. In this study, both bottom-up and top-down approaches were used to estimate the fluoride emissions in the Nansi Lake Basin. Global and local spatial autocorrelation were adopted to reveal the spatial agglomeration effects. The fluoride emissions calculated by the bottom-up approach were larger than those calculated by the top-down method. The highest fluoride input mainly occurred in Zoucheng and Mudan. The highest fluoride emissions mainly occurred in Zoucheng and Rencheng using the bottom-up approach. The highest fluoride emissions mainly occurred in Zoucheng and Yanzhou using the top-down approach. Mining and washing of bituminous coal and anthracite (BAW) was the most significant source of fluoride input and emissions. A significant spatial agglomeration effect of fluoride emissions was found. These findings could provide a method for accurate industrial fluoride emission estimation, complement the critical data on the fluoride emissions of main industrial sectors, and provide a scientific basis for tracing fluoride sources.

함북 탄광 광부 강제 취업 문제를 통해 살펴본 1930년대 초 이재민 대책의 문제점

In the 1910s, the Japanese Government-General of Korea not only failed to properly take measures to relieve the disaster victims, but also did not have the will to do so. After experiencing a severe drought in 1919, it began to prepare relief measures. Afterwards, Japan began providing relief to the victims through ‘Direct Relief’ in the form of emergency relief and ‘Indirect Relief’ by mobilizing victims as workers for ‘Disaster Recovery Projects’ and distributing wages to them, and ‘Livelihood Assistance’ through employment support.
 The Japanese government especially invested more money into ‘Indirect Relief’. However, disaster recovery implemented in the name of ‘Indirect Relief’ actually resulted in the enrichment of civil contractors by using the victims as low-wage labor.
 Meanwhile, in the first half of the 1930s, Japanese colonial authorities employed large numbers of victims as miners in bituminous coal mines in the northern region. In fact, the management of mines producing bituminous coal in the 1910s and 1920s was poor. Bituminous coal mines were located in places with inconvenient transportation, so they had the problem of high transportation costs, which made it difficult to make a profit. In order to help Japanese managers who operated bituminous coal mines, the Japanese colonial authorities forced many of the victims to work as low-wage miners at the coal mines.

Urban Air Quality Monitoring in Decarbonization Context; Case Study—Traditional Coal Mining Area, Petroșani, Romania

Humanity is a fossil-fueled civilization with a large influence on the environment. The World Health Organization (WHO) has pointed out that air pollution is now the single biggest environmental threat to human health. The air quality in Petroșani, a traditional mining region from the Jiu Valley bituminous coal basin, Romania, is rarely debated; however, it is not often investigated. In this paper, the main air pollution sources of Petroșani are identified and the performed measurements emphasize the air quality in the area of its transit road. The monitoring program set out the objectives, parameters, and points of the monitoring system, as well as the frequency and duration of the program and other monitoring parameters. The equipment used was provided by the National Institute for Research and Development in Mine Safety and Protection to Explosion from Petroșani, within an institutional partnership with the University of Petroșani. The monitoring of the air quality parameters was conducted from March to July 2020, at six points located on the road that crosses the city. It was thus possible to capture a variety of concentrations of the monitored parameters in different weather conditions to determine the air quality in this area. Based on the variation of the measured values in one of the most important historical Romanian bituminous coal mining basins, the preliminary results suggest a worsening of local air quality parameters in relation to the decarbonization process.

Surface geochemical survey in the vicinity of decommissioned coal mine shafts.

Methane observed in soil atmosphere above active and abandoned bituminous coal mines has a thermogenic (coalbed) and/or microbial (produced by anaerobic bacteria or resulted from in situ coal biodegradation) origin or it may be a mixture of gases generated from various sources. Identification of the origin of methane may support or refute the thesis on the uncontrolled migration of mine gases in rock formations followed by their emission to the atmosphere at coal extraction sites. Surface geochemical surveys were carried out in the vicinity of the decommissioned mine shafts at the Murcki-Staszic Coal Mine, located in the Upper Silesian Coal Basin (southern Poland). Over a 3-month period, measurements were carried out cyclically at 2 locations. Totally, 43 fixed geochemical probes were installed in the area of the Murcki II "Stanisław" Shaft, in which measurements were carried out in six sessions. Next 29 probes were installed in the area of the Staszic III Shaft, where measurements were taken twice. Each measurement included concentrations of 5 components (methane, non-methane volatile organic compounds, total hydrocarbons, carbon dioxide and oxygen), which provided a total number of 1405 individual analytical determinations. For measurements, portable EcoProbe 5 instrument was used. The stable carbon isotope composition of methane and carbon dioxide was analyzed in selected 10 samples. The isotopic composition of hydrogen in methane was also measured in one sample. The comparative material consisted of eight samples of soil gases and two samples of mine gases, which were used as reference 'soil' gases. The isotopic analyses were conducted using a mass spectrometry method. Based on the results of our analyses, it is stated that both the Murcki II "Stanisław" and the Staszic III shafts were properly decommissioned. The successful sealing of mine shafts prevented mine gases from migration through the shaft into the atmosphere. However, at a single geochemical probe located more than 100m from the former shaft center, methane concentration in soil gases reached over 1vol%. This confirms the general observation that mine gas migrates from coal seams and/or gobs through crushed rocks into the atmosphere. The stable carbon isotope analysis of methane and carbon dioxide as well as stable hydrogen isotope analysis of methane suggest that methane in the soil atmosphere is of thermogenic origin with minor contribution of microbial component.

Comprehensive evaluation of potential coal mine dust emissions in an open-pit coal mine in Northwest China

Coal mining in China is continually increasing, and the associated emitted coal mine dust is of growing environmental and occupational concern. In this study, deposited coal mine dust (DD) was analysed in three different regions of an active, highly-volatile bituminous open-pit coal mine in the Xingjian Province, Northwest of China: coal working fronts, tailings handling sites, and road traffic sites. Samples were analysed for particle size, and geochemical and mineralogical patterns, and then compared with the respirable DD fractions (RDDs, <4 μm) separated from DD samples. Online measurements of ambient air concentrations of particulate matter (PM10 and PM2.5), black carbon (BC) and ultrafine particles (UFP) were performed in the same mine zones where DD was sampled.Furthermore, the RDD samples were subjected to analysis of specific biological response or toxicological indicators (oxidative potential, OP). The results demonstrated: i) large differences in particle size and composition among DD from tailings handling, road traffic and coal working front sites, ii) a strong influence of the DD moisture contents and ash yields on particle size, and, accordingly, on the potential dust emissions, iii) an enrichment of multiple elements (such as Nb, Th, Cr, Sr, Li, As, Pb, Cu, Zr and Ni) in the RDD from coal working fronts compared with their contents in the worked parent coal seams, mostly attributed to mining machinery, tyre and brake wear emissions and to deposition of dust emitted from gangue working zones, iv) low OP values of the RDD emitted from the studied mine, which works a high-quality coal, with OP being influenced by Mn, sulphate and anatase (TiO2) contents, and v) the impact of specific mining operations and mine areas on the levels of air pollutants, such as high PM from tailings handling in the upper parts of the mine or the high UFP levels in the bottom of the mine (due to vehicle and machinery emissions and lower dispersive conditions). The data presented here demonstrate the necessity of extracting the more deeply respirable size fraction of coal mine dusts in future studies on the health effects of these materials because this finer fraction is mineralogically and geochemically different from the parent rocks.

Dose-response relationship between different respirable coal dust exposures and pneumoconiosis risk

Objective: To investigate the dose-response relationship between the cumulative dust exposures to anthracite, bituminous coal, and lignite and the cumulative prevalence rates of pneumoconiosis due to the exposures, respectively and provide a basis for scientific development of occupational health standards. Methods: Investigation on the exposure to coal dust and pneumoconiosis prevalence was conducted in 9 state-owned coal mines. The cumulative anthracite, bituminous coal, and lignite dust exposure specific cumulative prevalence rates of pneumoconiosis were calculated by life table method, respectively. The linear regression equations were used to control the unilateral interval to obtain the exposure concentration limits of the respirable coal dust, respectively. Results: A total of 21 000 coal miners in the 9 coal mines were included in the study. The detection rates of pneumoconiosis in coal miners in anthracite, bituminous coal and lignite mines were 11.27%, 21.32%, and 6.00%. The average lengths of exposure to coal dust at pneumoconiosis onset were 20.12 years, 22.88 years, and 25.21 years, respectively and the dose-response relationships between the cumulative respirable coal dust exposure and the cumulative prevalence rates were all linear regression equations, which are y=5.788x-16.043 (R(2)=0.949), y=5.679x-16.837 (R(2)=0.904), and y=6.465x-19.573 (R(2)=0.944), respectively. Supposing that the safety coefficient is 1.2, when the cumulative prevalence rate of pneumoconiosis after 30 years of exposure to dust is not higher than 1%, the exposure concentration limits of the three types of respirable coal dust are 1.7, 2.3, and 3.9 mg/m(3), respectively. Conclusions: The results of this study shows that the detection rate of pneumoconiosis, the average length of exposure to coal dust at pneumoconiosis onset, and the exposure concentration limits of the respirable coal dust varied with coal types. In the case of the same cumulative level of coal dust exposure, the lower the coal volatiles is (i.e. the higher the carbon content is), the higher the cumulative prevalence rate of pneumoconiosis is (anthracite>bituminous coal>lignite). It is suggested to develop national occupational health standards of coal dust exposure according to the grades of coal.

High Specific Activity of Radium Isotopes in Baryte from the Czech Part of the Upper Silesian Basin—An Example of Spontaneous Mine Water Treatment

Radium-bearing barytes (radiobarytes) have been known since the beginning of the 20th century. They are mainly found as precipitates of low-temperature hydrothermal solutions. In anthropogenic environments, they frequently occur as crusts on oil industry equipment used for borehole extraction, in leachates from uranium mill tailings, and as a by-product of phosphoric acid manufacturing. Recently, we recognized Ra-rich baryte as a precipitate in the water drainage system of a bituminous coal mine in the Czech part of the Upper Silesian Basin. The precipitate is a relatively pure baryte, with the empirical formula (Ba0.934Sr0.058Ca0.051Mg0.003)Σ1.046S0.985O4.000. The mean specific activity of 226Ra was investigated by the two-sample method and it equals 39.62(22) Bq/g, a level that exceeds known natural occurrences. The values for 228Ra and 224Ra are 23.39(26) Bq/g and 11.03(25) Bq/g. The radium content in the baryte is 1.071 ng/g. It is clear that the Ra-rich baryte results from the mixing of two different mine waters—brines rich in Ba, Sr, and isotopes 226Ra and 228Ra and waters that are affected by sulfide weathering in mine works. When this mixing occurs in surface watercourses, it could present a serious problem due to the half-life of 226Ra, which is 1600 years. If such mixing spontaneously happens in a mine, then the environmental risks will be much lower and will be, to a great, extent eliminated after the closure of the mine.

Burning Bridges: Senator Rush Dew Holt and the Guffey Coal Acts of 1935 and 1937

Burning Bridges: Senator Rush Dew Holt and the Guffey Coal Acts of 1935 and 1937 C. Lloyd Tomlinson The legislative session was drawing to a close on the evening of June 20, 1936, the day after Rush Dew Holt’s thirty-first birthday. The United States Senate was ready to vote on a replacement bill for the Guffey-Snyder Act, a law intended to stabilize the bituminous coal industry. The Supreme Court overturned the 1935 law barely a month before with its decision in Carter v. Carter Coal Company. The court ruled that local wages and hours did not fall within the federal government’s powers to regulate interstate commerce, thereby rendering the law null and void. The Senate worked hastily to churn out a replacement and essentially stripped the labor protections from the new bill. The amended legislation had the support of the majority of the Senate as well as the president of the United Mine Workers of America (UMW), John L. Lewis. The new bill was almost guaranteed to pass.1 Holt, the “Boy Senator” from West Virginia, had other plans. The junior senator took the floor and declared that he would spend his unlimited time reading from Aesop’s Fables. In addition to reading Aesop, Holt attacked Lewis for siding with the coal companies over the miners, lambasted West Virginia’s senior senator Matthew Neely for ignoring the miners in their state, and ripped into the Works Progress Administration for acting as a tool of political patronage. By the time he concluded his filibuster and the Senate adjourned, it was 11:55 p.m., and the bill was dead.2 The filibuster left an undeniable impact on Holt’s image and political career. Rush Holt Jr., in the inaugural lecture named for his father, notes that the senator “became a man without a party” that some viewed as “fearlessly honest, while others perceived him as quixotic, unreliable, and ungrateful to those who had supported him.”3 Through the remainder of his term, Holt grew increasingly isolated. The results of the 1940 primary election ensured that Holt would not return to the Senate for the next term.4 While the filibuster remains an excellent piece of political theater, as well as the defining moment of Holt’s Senate career, it merely scratches the surface of his fight against legislation that he believed did not help working [End Page 29] West Virginians. The 1936 filibuster began Holt’s shift toward becoming more critical of the New Deal. It also created a deep personal and political rivalry with Senator Joseph Guffey of Pennsylvania, who cosponsored the legislation, as well as Senator Matthew Neely of West Virginia. After the filibuster, their feud played out in the public sphere: political rallies, the press, and the airwaves all served as battlegrounds. Holt also managed to make enemies of John L. Lewis and UMW District 17 president Van W. Bittner. Though Holt found himself a pariah by the end of the decade, he nevertheless remained convinced that he was fighting for the best interests of coal miners throughout West Virginia. Rush Holt has been covered by a handful of historians to date. Jerry Bruce Thomas takes a sharply critical view of Holt, pointing out his attempts to use New Deal programs as a form of political patronage to get a job for his brother, Matthew, and his persona as a reckless maverick who “took any sort of disagreement on issues as a personal attack and tended to respond in kind.”5 A doctoral dissertation by William Coffey remains the most thorough study of Holt’s life and career to date. It functions as a fairly evenhanded biographical treatment, though it does not examine his career past 1942.6 In 2011, Rush Holt Jr. delivered the inaugural Rush D. Holt lecture, which focused on the filibuster and its immediate consequences.7 The filibuster figures prominently in each of these works, revealing its importance in West Virginia and American politics, as well as its impact on the bituminous coal industry. Bituminous coal mining had been a “sick industry” for decades before the passage of the Guffey Act. It was an industry bloated by excessive competition...

Rule of Law in Labor Relations, 1898-1940

The paper examines changes in labor regulation between 1898 and 1940 in the context of issues related to rule of law in two areas. 1) Many see the 1905 Lochner Supreme Court decision on men’s hours laws as the beginning of 30 years in which labor regulation was stymied by the doctrine of “freedom of contract.” Seeing close votes and substantial turnover of judges on the Supreme Court, the de facto situation was more complex as some states maintained their laws or passed new ones. 2) Labor disputes led to some of the greatest threats to rule of law. To limit descents into violence, states passed arbitration laws, pro-union laws, and anti-union laws. Uncertainty about the rules led to a sharp rise in strikes and violence after World War I and again when Congress and the states sought to establish the rules for collective bargaining between 1932 and 1937. A panel analysis of the impact of state laws in bituminous coal mining from 1902 to 1941 shows that the arbitration and pro-union laws were associated with less violence during periods of uncertainty. During several periods state pro-union laws were associated with more strikes and state anti-union laws with fewer strikes.

FGX air-vibrating separators for cleaning steam coal – functional and economical parameters

FGX Dry Separators are a construction developed at the turn of the 20th century. It was created in China as a combination of a vertical jet air classifier and a vibration screen with a tapered channel. This structure has been modified (Figure 1). These separators proved to be very effective in deshaling of excavated coal. They are designed to remove as many grains of stone as possible. For this reason, separation is carried out in the thickness range above 2.0 g/cm3. The article describes the structure of dry separator as well as the principle of its operation. The factors influencing the enrichment efficiency and the separation accuracy of feed parameters have also been listed here. Moreover, the technical parameters of the separator which are subject to regulation and influence the course of the separation process have been discussed. Synthetic information on economic efficiency has been provided. The possibilities of application of FGX separators in the systems of existing enrichment plants or as independent processing plants have been presented. There are currently three FGX separators working in Poland. In the Institute of Mechanised Construction and Rock Mining in the Katowice Branch, the bituminous coal of some mines is tested on an installation with a capacity of up to 10 Mg/h. The results of the research confirm the possibility of implementing FGX separators in the bituminous coal mining in Poland. Two separators, with a capacity of about 30 Mg/h, improve the parameters of imported coal intended for individual customers; they are owned by private companies. More than 2000 FGX separators in more than a dozen countries are in operation in the world. They are effective and are referred to as ‘21st century technology’.

Estimation of Wage–Risk Differentials Without Wages

Utilizing the duality properties of a production/profit function, this article estimates the risk premium received by Pennsylvania bituminous coal miners in 1915, without recourse to any information related to wages. A Cobb-Douglas coal production function is fitted to data for 694 mining establishments. Miners received modest risk compensation, expressed as the value of a statistical life (VSL), of US$6,020 for fatal injuries and US$3,550 for nonfatal accidents. Converted to current price and wage levels, the death risk VSL is roughly US$400,000—far below modern multi-million dollar life values for workplace risk. JEL Classifications: II0, JI7, J28, LII, L72

CYCLE TIME SEGMENTS OF ELECTRIC ROPE SHOVELS- A CASE STUDY

Monitored cycle times and cycle time segments of three 35 m3 electric rope shovels are given and discussed from a bituminous coal mine in Kuzbass Coal Basin in Siberia, based on daily monitoring reports of a four days period in May 2015. Furthermore, the results of a 45 m3 shovel operating in Northern Europe; and the results of 12 m3 and 15 m3 electric rope shovels surveyed by other researchers operating at Turkish coal mines are also given. Parameters like cycle times, cycle time segments, dig times, dig time over cycle time ratios and process rates are given and depicted, interpreted and discussed.

Distribution of methane and carbon dioxide concentrations in the near-surface zone, genetic implications, and evaluation of gas flux around abandoned shafts in the Jastrzębie-Pszczyna area (southern part of the Upper Silesian Coal Basin, Poland)

The objective of this paper is to evaluate the possible migration of coal-bed methane and carbon dioxide to the earth's surface in a selected areas from the southern part of the Upper Silesian Coal Basin (USCB) and resulted hazards produced by near-surface gas migration, referred to the geological setting and the origin of these gases. The surface geochemical survey was run over the areas of both the operating and the abandoned bituminous coal mines, including the remediated shafts and the regional tectonic dislocations: the Bzie-Czechowice and the Jawiszowice fault zones. The survey included a total of 453 soil gas samples collected at a depth of about 1.2 m and along 7 horizontal profiles as well as in the vicinities of remediated shafts. All collected gas samples were chromatographically analysed for methane and carbon dioxide concentrations. Selected samples showing increased concentrations of methane and/or carbon dioxide were analysed also for stable carbon isotopes of these gases. Additionally, gas emission was measured at 5 sites selected due to the increased concentrations of the gases.The maximum detected concentrations of methane and carbon dioxide in soil gas samples were 52.8 and 17.4 vol%, respectively. The closure of high methane-emitting bituminous coal mines in the USCB, including the termination of mine ventilation, caused the increase of average methane concentrations in the near-surface zone. Vast anomalies of both gases can be the effects of migration from secondary accumulations of “free” methane present in the elevated parts of Carboniferous formation capped by Miocene claystones and mudstones. Methane originated from primary accumulations located beneath the degassing zone and migrated along fault zones. However, carbon dioxide migrated from both the primary and the secondary accumulations, and, sometimes, it originated also from secondary oxidation of methane. The methane recovery captured with degassing wells run in the area of the abandoned “Morcinek” Mine disturbed the naturaly, vertically migrating methane towards the earth's surface and caused the local decrease of average methane concentrations in soil gas collected along the D-D' sampling line. It was additionally confirmed by relatively high methane concentrations (over 50 vol%) detected in samples collected from the wells degassing the shafts I, II and III of the closed “Morcinek” Mine. The methane is of microbial origin and migrated from secondary accumulation located within the Carboniferous (Pennsylvanian) coal-bearing strata. In the regional tectonic zone of the Bzie-Czechowice Fault, over 4 times higher average carbon dioxide concentrations were detected, in comparison with those analysed in the Jawiszowice Fault Zone. Carbon dioxide was of microbial origin, migrating from a secondary accumulation.Relatively low values of both the methane and carbon dioxide emissions were noticed at sampling sites, where elevated concentrations of both gases were encountered previously in the near-surface zone. This suggests that gases may accumulate in the near-surface zone as a result of long-term, and relatively slow migration from the depth. Hence, and in this case the potential gas hazard caused by uncontrolled and fast inflow of methane and carbon dioxide to a basements of buildings is insignificant.

A Profit Function Approach to Wage–Risk Differentials

A variable profit function is used in a novel way to estimate wage–risk premiums in Ohio bituminous coal mining. Unlike the dominant hedonic method, the profit function does not assume equilibrium and allows inferences about the marginal opportunity cost of accidents to mining companies. The profit function risk premium, expressed as a value of a statistical life (VSL), is $12,000 (in 1915 prices), and is below published estimates covering this period. The hedonic method is also used and yields a very similar VSL, a robustness check. It is also shown that the use of piece rate–based wages of coal loaders (the main group of miners) yields more plausible hedonic estimates than the fixed daily wage of “inside” miners typically employed.

Biogenic Methane Cycling in a Laboratory Model of an Abandoned Bituminous Coal Mine

ABSTRACTMicrobial communities in decommissioned coal mines have the potential to promote methane generation. Here, two 1 m x 10 cm diameter column bioreactors designed to mimic an abandoned coal mine were monitored for a year, with zones of methanogenesis in the bottom, saturated waters and aerobic coal degradation and methane oxidation at the top. The resilience of aerobic methanotrophs to survive periods with low methane and oxygen conditions suggests methanotrophs may be useful in decreasing atmospheric methane fugitive emissions from decommissioned mines. When biogenic methane production from coal did occur, the rate was slow, ≤ 0.073 nmol CH4/g coal/day.

Differential distribution of metals in tree tissues growing on reclaimed coal mine overburden dumps, Jharia coal field (India).

Opencast bituminous coal mining invariably generates huge amount of metal-polluted waste rocks (stored as overburden (OB) dumps) and reclaimed by planting fast growing hardy tree species which accumulate metals in their tissues. In the present study, reclaimed OB dumps located in Jharia coal field (Jharkhand, India) were selected to assess the accumulation of selected metals (Pb, Zn, Mn, Cu and Co) in tissues (leaf, stem bark, stem wood, root bark and root wood) of two commonly planted tree species (Acacia auriculiformis A.Cunn. ex Benth. and Melia azedarach L.). In reclaimed mine soil (RMS), the concentrations of pseudo-total and available metals (DTPA-extractable) were found 182-498 and 196-1877% higher, respectively, than control soil (CS). The positive Spearman's correlation coefficients between pseudo-total concentration of Pb and Cu (r = 0.717; p < 0.05), Pb and Co (r = 0.650; p < 0.05), Zn and Mn (0.359), Cu and Co (r = 0.896; p < 0.01) suggested similar sources for Pb-Cu-Co and Mn-Zn. Among the five tree tissues considered, Pb selectively accumulated in root bark, stem bark and leaves; Zn and Mn in leaves; and Cu in root wood and stem wood. These results suggested metal accumulation to be "tissue-specific". The biological indices (BCF, TFleaf, TFstem bark and TFstem wood) indicated variation in metal uptake potential of different tree tissues. The study indicated that A. auriculiformis could be employed for Mn phytoextraction (BCF, TFleaf, TFstem bark and TFstem wood > 1). The applicability of both the trees in Cu phytostabilization (BCF > 1; TFleaf, TFstem bark and TFstem wood < 1) was suggested. The study enhanced knowledge about the selection of tree species for the phytoremediation of coal mine OB dumps and specific tree tissues for monitoring metal pollution.

Shrinking of cities in the Czech Republic and its reflection on society: Case study of Karviná City

The shrinking of cities is a process that accompanies cities in post-conjunctural changes, when they are entering a phase of economic decline and the decline in population connected with it. The Ostrava-Karvina area is one of the economically problematic regions in the Czech Republic nowadays but it used to be ranked as one of the economic heartlands in the period of socialism. The region, dependent on bituminous coal mining and heavy industry, gradually began to decline after the year 1989 and one of the consequences is a significant decline in its population. This paper deals with identification of the causes and consequences of shrinking cities explained through the example of the town of Karvina through an analysis of quantitative data, questionnaire surveys, and semi-structured interviews. The questionnaire survey revealed that the main reason causing the departure of young and educated citizens is the lack of work opportunities. High unemployment and thus the presence of many socially disadvantaged people causes the atmosphere in the city to deteriorate, and this is accompanied by social problems, such as ageing of the population or criminality. Lack of safety of citizens and a bad environment are other reasons why young people leave the city. The decreasing number of citizens closes the vicious circle by leading to a lower demand for services, closing of shops and other services and increasing numbers of empty houses and flats. Another essential part of the paper is the question of possible measures by the local authority leading to the elimination of these undesirable phenomena, but also the belief in the necessity of help from the government.

Geotouristic attractions of the Ostrava part of the Upper Silesian Basin: geological and environmental sites

Abstract In the Ostrava part of the Upper Silesian Basin there are many geotouristic sites connected with the underground mining of Carboniferous bituminous coal. Text is focused on those related to the geology of the Basin and environmental issues connected to coal mining. Of great intrest are outcrops of Mississippian sediments of the paralic Ostrava Formation, as well as two most important museums with permanent geological exhibitions. Some interesting geological features conncted to younger periods of Quarternary glaciation are also mentioned. Two types of publicly accessible sites related to the environmental burdens (burning coal heaps, saline mine water drainage system) are also described.

Evidence of methane and carbon dioxide migration to the near surface zone in the area of the abandoned coal mines in Wałbrzych District (Lower Silesian Coal Basin, SW Poland) based on periodical changes of molecular and isotopic compositions

The objective of this paper is to determine the reasons, origin and character of periodical changes of methane and carbon dioxide concentrations in the near-surface zone as well as emission of these gases to atmosphere after closing bituminous coal and anthracite mines in the former Wałbrzych Coal District (SW Poland). The measurements were performed during the period including the active impact of “water piston effect” on the migration of a coal-bearing gases as well as the period of stabilization of water table of the Pennsylvanian aquifer. In the years 1997–2005, 20 sampling sessions were completed during which 3210 soil gas samples were collected at a depth of about 1.2m and along 4 measurement lines located in the Gorce and the Sobięcin depressions. Maximum methane and carbon dioxide concentrations measured in soil gas samples reached 32.4 and 15.7vol%, respectively. Isotopic study shows that coal-bed gases, recent microbial methane, and multigenetic carbon dioxide from degassing of ground-waters of the Upper Pennsylvanian aquifer occur within the near-surface zone of the Wałbrzych Coal District. Within the Serpukhovian Wałbrzych and Upper Bashkirian-Moscovian Žacleř coal-bearing formations three genetic types of coal-bed gases occur: Variscan thermogenic (methane, higher gaseous hydrocarbons and carbon dioxide), endogenic (abiogenic) carbon dioxide and “late” (Late Cretaceous) and recent microbial methane and carbon dioxide. Changes of mean concentrations of methane and carbon dioxide in the near-surface zone recorded during years of studies demonstrated the influence of “water piston effect”, which drives migration of coalbed gases towards the earth surface. In both the Gorce and the Sobięcin depressions, gas migrates with various intensity. Generally, the lower methane emission measured in the years 2004–2005, and compared with the period 1999–2000, resulted from the stabilization of groundwater table whereas higher carbon dioxide emission confirms the degassing of shallow groundwaters. Anomalous concentrations of methane and carbon dioxide were related to numerous faults and fracture systems cutting the steeply dipping Upper Mississippian and Pennsylvanian coal-bearing formations, and to the outcrops of these rocks. However, in the near-surface zone, multiproportional mixing of coal-bed gases, recent microbial methane and carbon dioxide is observed. Periodical changes of stable carbon isotope composition of methane and carbon dioxide of near-surface zone in particular sessions are caused by the time-related change of location of water table of Pennsylvanian aquifer in the complicated structure of the Gorce and Sobięcin depressions. Persistently anomalous concentrations of methane and carbon dioxide in the near surface zone, still observed after several-years-long stabilization of groundwater table, seem to indicate a continuous supply of coalbed gases to the near-surface zone through pervious dislocations. Such an interpretation is confirmed by the extreme value of methane emission detected at a particular sampling site after the cessation of the “water piston” effect. It was presumably caused by the secondary intensification of gas flux from deep sources, triggered by neotectonic movements in the study area.

A trend analysis of the incidence of occupational diseases in Chongqing, China, from 2006 to 2014

Objective: To investigate the incidence of occupational diseases in Chongqing, China, from 2006 to 2014, and to analyze the harm, features, and trend of occupational diseases in Chongqing. Methods: The data of new cases of occupational diseases from 2006 to 2014 were collected, and the patients with a confirmed diagnosis of occupational diseases were selected as study subjects to analyze the incidence of occupational diseases in Chongqing. Results: There were 17499 cases of occupational diseases in total in Chongqing from 2006 to 2014. Among these patients, 17124 (97.86%) were male, most of whom (95.40%) had occupational pneumoconiosis, and 375 (2.14%) were female, most of whom (72.80%) had occupational chemical poisoning. There were 16400 cases (93.72%) of occupational pneumoconiosis in total, mainly coal workers' pneumoconiosis (55.87%) and silicosis (43.02%) , and the main industries involved were coal mining and washing, railway transport equipment manufacturing, and mining and washing of bituminous coal and anthracite. There were 724 cases of occupational poisoning in total; there were 281 cases of acute occupational poisoning, mainly gas poisoning (39.86%) and carbon monoxide poisoning (33.10%) ; there were 443 cases of chronic occupational poisoning, mainly poisoning caused by benzene (47.63%) , mercury and its inorganic compounds (32.74%) , and lead and its inorganic compounds (9.03%) . Conclusion: Occupational diseases in Chongqing are mainly occupational pneumoconiosis, and occupational health supervision should be enhanced in the industries of coal mining and washing and railway transport equipment manufacturing to protect workers' health.