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Remote Sensing Techniques for Detecting Self-Heated Hot Spots on Coal Waste Dumps in Upper Silesia, Poland
Abstract
The use of the NDVI, NDSI, and NDSII indices and thermal maps, combined with Landsat TM, ETM+, ASTER, and Sentinel 2 images, can help to identify and localize self-heating sites in coal-waste dumps. Nighttime images can show hot spots with high intensity as in the Makoszowy dump, for example. The advantages of the methods described here are that the satellite images used are freely available, and that they localize the hot spots by drawing information from large areas. Though the method does not require it, field temperature measurements provide a useful validation. However, several disadvantages are apparent; for example, snow-cover or nighttime images are not always available due to atmospheric disturbances and technical problems with the Landsat ETM+. The distribution and amount of snow can significantly influence the perceived location of hot spots. Furthermore, self-heating sites of small spatial extent are often difficult to detect as they are too small in relation to the pixel size of the thermal data. Finally, the detection of hot spots with low thermal intensity in shallow locations, and those on steep slopes, can be problematic, due to the limitations of the thermal sensor. As these types of hot spots commonly provide smooth values, attempts to distinguish these anomalies from the surrounding pixel values, and solar effects, can give misleading results.
The method has potential for monitoring coal-waste dumps in USCB, and wherever similar self-heating problems exist. In the future, drones with thermal infrared cameras will likely replace the more expensive aircraft and alleviate detector sensitivity problems.
... On the selected Polish dumps the ongoing self-heating was well documented e.g. Misz-Kennan and Fabiańska (2011), Nádudvari (2014), Fabiańska et al. (2019), Kruszewski et al. (2018) and Nádudvari et al. (2018Nádudvari et al. ( , 2021Nádudvari et al. ( , 2021b) therefore these researches were provided good insight about the state of self-heating, pollution levelsespecially heavy metals e.g. Hg, Pb or organic pollutants: benzene, phenols, PAHs. ...
... These dumps stand out above the landscape, towering over the surrounding settlements. Regardless of the differences and similarities between the two basins, the self-heating phenomenon was detected in both regions, and its impact on the natural environment and society was determined (Panov et al., 1999;Fabiańska et al., 2019;Nádudvari et al., 2018Nádudvari et al., , 2020aNádudvari et al., , 2021bAbramowicz et al., 2021). ...
... That can indicate low thermal activity, which is usually visible on Landsat thermal map with a 2-3°C difference between pixel max (hot spot)-pixel min (cold, snow-covered surface with no thermal activity). Hot spots with lower thermal activity or their extensions smaller than the TIRS satellite sensor capabilities making difficult to detect such hot surfaces (Nádudvari and Ciesielczuk, 2018;Nádudvari et al., 2021a). ...
The self-heating of coal waste dumps is considered as a serious environmental issue, wherever active or inactive coal mining has been present. This issue is introduced from two active coal mining regions from Poland (Upper Silesian Coal Basin) and Ukraine (Donetsk Coal Basin) based on mineralogy, organic petrography and geochemistry, and remote sensing techniques. Thermally affected coal wastes reveal changes recorded by organic and mineral matter. Irregular cracks and fissures appear within and at the edges of organic matter particles, which are oxidised, devolatilised and plasticised. Mineral phases underwent oxidation, dehydration, structure rebuilding and recrystallisation. Highest temperatures generated during the fire cause melting and paralava formation. During self-heating, some chalcophile elements like Hg (mostly present as HgS), Pb, Zn can be enriched and released, or different organic pollutants like phenols (originated from vitrinite particles), different PAHs with alkyl substitutes, chlorinated PAHs, or sulphur heterocycles are formed. The introduced remote sensing techniques helped to localise and monitor hot spots with different temperature ranges. Applying SWIR bands of Landsat hot spots from extremely burning dumps in Ukraine were successfully localised, however, only night-time scenes with SWIR can be used. The sun’s disturbing effects should be considered as an influential factor for both thermal imaging camera or satellite images. Thermal cameras can reveal the most detailed signs of low to high temperature anomalies with different cracks and line shapes.
... Therefore, any disregard for the manner of the impact of solar radiation on the surface can lead to significant distortion of thermal information from a surface. Even partial sunshine significantly disturbs the temperature values obtained (Zhang and Kuenzer 2007;Nádudvari 2014;Usamentiaga et al. 2014;Nádudvari and Ciesielczuk 2018). ...
... That is perfectly seen in the diagram (Fig. 3) for the Makoszowy dump, where coal waste excavation started in early 2000 and thermal activity stopped by about 2007. By 2013, all coal waste had been removed from Makoszowy dump (Nádudvari and Ciesielczuk 2018). A similar tendency is visible on a representative dump (Fig. 3-Ukrainian dump) from the Donetsk Coal Basin for the 2001-2003 timespan, where self-heating progressed from the initial/weak stage to the advanced stage in 1987-1994. ...
... That makes the detection of hot spots with low intensity or situated in a deeper part of a dump Classification of fires in coal waste dumps based on Landsat, Aster thermal bands and thermal… complicated (Figs. 4 and 5). When hot spots occur at shallow depths or with low thermal activity and a limited extent, cold air temperatures can overcome the self-heating and any thermal response by the TIR sensor is diminished (Nádudvari and Ciesielczuk 2018). Therefore, on the drone TIR reacts in the same way. ...
A self-heating intensity index (SHII) based on the highest (pixel max.) and lowest (pixel min.) values taken from satellite thermal maps of burning coal waste dumps are proposed. The index enables the classification of such fires in Ukrainian-and Polish coal waste dumps. Both in Ukraine and in Poland, varying thermal intensities during 1985-2019 are revealed, using the SHII and following thermal intensity threshold values, namely, extreme thermal activity ([ 7), advanced (3-7), moderate (3-1.5), initial (1.5-1), no activity (\ 1). The SHII shows decreasing thermal activity in the selected Ukrainian coal waste dumps during 2017-2019. It aids in reconstructing the thermal history of the dumps. Analysis of satellite images revealed a large number of burning coal waste dumps in the Donetsk Coal Basin (Ukraine) with high thermal activity. Such burning likely reflects large amounts of organic matter and sulphides in the dumped material subjected to self-heating and self-burning processes, lack of compaction of the coal waste and/or high methane contents. Comparison of SHII values calculated from satellite-and drone thermal-camera images were compared to show that SHII from drone thermal images have much higher values than those from satellite images; the former have better resolution. Thus, SHII from Landsat-and drone images should be used separately in dump heating studies.
... Four samples of ~1-1.5 kg for microbiological analysis were collected, wrapped in aluminum foil, immediately transported to the Institute of Biology, Biotechnology and Environmental Protection (University of Silesia, Katowice), and stored at 4 o C until further processing. Previous reports detailed the thermal activity, formation of different organic pollutants, and emissions of toxic gases from these dumps (Tabor, 2002;Misz-Kennan et al., 2013;Nádudvari, 2014;Nádudvari and Fabiańska, 2016;Nádudvari and Ciesielczuk, 2018;Kruszewski et al., 2018Kruszewski et al., , 2020 Fig. 1. The location of the self-heating coal waste dumps was studied. ...
... Such temperatures are easily attained during such self-heating ( Á . Nádudvari et al. Nádudvari and Ciesielczuk, 2018;Nádudvari et al., 2020). HgS is readily adsorbed chemically on FeS 2 (100) and FeS 2 (110) surfaces. ...
This study aims to provide numerous environmental research approaches to understand the formation of mineral and organic mercury compounds in self-heating coal waste dumps of the Upper Silesian Coal Basin (USCB). The results are combined with environmental and health risk assessments. The mineralogy comprised accessory minerals in the fine fraction of thermally affected waste, i.e., Hg sulfides, most likely cinnabar or metacinnabar. Moreover, other metals, e.g., Pb, Zn and Cu, were found as sulfide forms. Apart from Hg, the ICP-ES/MS data confirmed the high content of Mn, Zn, Pb, Hg, Cr and Ba in these wastes. The high concentration of available Hg resulted in elevated MeHg concentrations in the dumps. There were no correlations or trends between MeHg concentrations and elemental Hg, TS, TOC, and pH. Furthermore, we did not detect microbial genes responsible for Hg methylation. The organic compounds identified in waste and emitted gases, such as organic acids, or free methyl radicals, common in such burn environments, could be responsible for the formation of MeHg. The concentration levels of gases, e.g., benzene, formaldehyde, NH3, emitted by the vents, reached or surpassed acceptable levels numerous times. The potential ecological and human health risks of these dumps were moderate to very high due to the significant influence of the high Hg concentrations.
... On the northern side, hot spots fall below the satellite sensitivity limits. A hot spot at the top of the highest cone in the Czerwionka-Leszczyny dump has been waning since the early 1985s (Nádudvari 2014;Nádudvari and Ciesielczuk 2018). Self-heating has also occurred on the eastern side (Fig. 1b). ...
... The frequency and intensity of self-heating varies greatly within the USCB. The area most affected by heating is the southwestern part of the basin, i.e., the Rybnik area where almost all coal-waste dumps were or are self-heating ( Fig. 1b; Misz-Kennan et al. 2013;Nádudvari 2014;Nádudvari and Ciesielczuk 2018). There, self-heating temperatures can be extremely high, e.g., 1300°C in the Szarlota dump in Rydułtowy. ...
Many temporary and permanent reservoirs of water occur on or near coal-waste dumps in the Lower- and Upper Silesian Coal Basins (Poland). Little or nothing is known of the degree to which their water chemistry might reflect (i) reservoir type, i.e., whether permanent or temporary, (ii) level of coal-waste thermal activity, i.e., whether inactive or self-heating or burnt-out or (iii) region, i.e., whether the dumps are in Upper- or Lower Silesia. To provide some answers, concentrations of selected ions (NH 4 ⁺ , HCO 3 ⁻ , F ⁻ , Cl ⁻ , Br ⁻ , NO 2 ⁻ , NO 3 ⁻ , PO 4 ³⁻ ,SO 4 ²⁻ ) were determined by ion chromatography and of nineteen elements (Al, B, Ba, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, P, Pb, S, Si, Sr, Zn) by inductively coupled plasma mass spectrometry (ICP-MS). The data allow a number of the following observations. When permanent reservoirs are considered, there is a clear relationship between concentrations of ions and major and trace elements and dump thermal activity. The highest concentrations occur where the thermal activity is high as inorganic components are transformed into more water-soluble forms. As dump thermal activity shows a regional pattern, it follows also that elemental and ion concentrations in the dump waters show significant regional differences. In temporary reservoirs, concentrations of ions and major and trace elements are much lower and any correlations between components less significant than in the permanent reservoirs; these reservoirs exist for too short a time for any balance between coal waste- and water components to be established.
... Five coal-waste dumps were selected where self-heating continues at various levels of activity ( Fig. 1). At the Czerwionka-Leszczyny dump (Fig. 1), a thermal activity that has continued for more than 30-40 years is decreasing today (see Nádudvari, 2014;Nádudvari and Ciesielczuk, 2018). On the Rybnik-Rymer dump, where self-heating also lasted 30-40 years, the dump's eastern slope is covered by concrete panels through cracks in which bitumen seeps. ...
... The Anna dump holds waste from the "Anna" Coal Mine (Fig. 1). Long-lasting heating in this dump is characterized today by odorous gases, sulphur, bitumen, and salammoniac crusts (Misz-Kennan et al., 2013;Nádudvari, 2014;Nádudvari and Ciesielczuk, 2018). In the Czarny Las dump in Ruda Ś ląska, self-heating started in 1995 and spread and migrated towards the north-east over the years. ...
This study provides potential insight between self-heating coal-waste dumps and related environmental pollution in southern Poland. Samples collected from dumps in the Upper Silesian Coal Basin were used to quantify released contents of organic- and inorganic pollutants, i.e., polycyclic aromatic hydrocarbons (PAHs) and trace elements (Pb, Cd, Cr, Cu, Zn, Ni, Hg, As). Elevated Hg concentrations (~100-1078 mg/kg) and Pb (~600-2000 mg/kg) attest to the evaporation of these metals from deeper parts of the dumps. The acidic pH levels (3.0 – 4.5) may help to mobilize these elements. Pearson’s correlation coefficients for samples analyzed by AAS and ICP-MS indicate a similar origin for Cd, Zn, and As. Mostly 2- and 3-ring PAHs, especially anthracene in burnt soil, dominate in the samples. Chlorinated PAHs, thiophenol, pyridines, quinolines (and derivatives) in thermally-altered samples, and waste containing pyrolytic bitumen indicate coking conditions. The high levels of Hg, Pb, and Cd, and chlorinated PAHs and nitrogen heterocycles formed or enriched during self-heating in these dumps should be deemed a significant environmental hazard. Calculating the lifetime cancer risks due to PAHs and heavy metals accumulations in the dumps are substantial, and access to these dumps should be prohibited.
... Among samples collected during routine visits, we found hematite of spherulitic or botryoidal shape at three locations, namely, coal-waste dumps in Radlin, and Czerwionka in the south-western part of the Upper Silesian Coal Basin and, in the north-western part, the Wełnowiec dump (e.g., Misz-Kennan et al., 2013;Kruszewski, 2013;Fabiańska et al., 2013Fabiańska et al., , 2017Nádudvari and Ciesielczuk, 2018;Pierwoła et al., 2018;Fig. 1). ...
... In case of Marcel dump the intensive fire was well documented by Nádudvari (2014) and Nádudvari and Ciesielczuk (2018) based on thermal images, where the hot spot in 1993-2011 occurred (N-SE: 300-600 m; W-E: 300-450 m direction) compared to 2013, 2017, 2021 years where hot spots occurred with smaller size (N-SE: 100-300 m; W-E: 150-200 m) and it seems to have disappeared by . However, in 1999, 2001, and 2011, the hot spots were visible as more intense. ...
... In case of Marcel dump the intensive fire was well documented by Nádudvari (2014) and Nádudvari and Ciesielczuk (2018) based on thermal images, where the hot spot in 1993-2011 occurred (N-SE: 300-600 m; W-E: 300-450 m direction) compared to 2013, 2017, 2021 years where hot spots occurred with smaller size (N-SE: 100-300 m; W-E: 150-200 m) and it seems to have disappeared by . However, in 1999, 2001, and 2011, the hot spots were visible as more intense. ...
... On the northern side, hot spots fall below the satellite sensitivity limits. In the Czerwionka-Leszczyny dump, the hot spot at the top of the highest cone has been waning since the early 1985s (Nádudvari 2014;Nádudvari and Ciesielczuk 2018). The eastern side has also undergone self-heating ( Fig. 1b). ...
Many temporary- and permanent reservoirs of water occur on or near coal-waste dumps in the Lower- and Upper Silesian Coal Basins (Poland). Little or nothing is known of the degree to which their water chemistry might reflect (a) reservoir type, i.e., whether permanent or temporary, (b) level of coal-waste thermal activity, i.e., whether inactive or self-heating or burnt-out or (c) region, i.e., whether the dumps are in Upper- or Lower Silesia. To provide some answers, concentrations of selected ions (NH4+, HCO3-, F-, Cl-, Br-, NO2-, NO3-, PO43-,SO42-) were determined by ion chromatography and of nineteen elements (Al, B, Ba, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, P, Pb, S, Si, Sr, Zn) by inductively coupled plasma mass spectrometry (ICP-MS). The data allow a number of the following observations. When permanent reservoirs are considered, there is a clear relationship between concentrations of ions and major- and trace elements and dump thermal activity. The highest concentrations occur where the thermal activity is high as inorganic components are transformed into more water-soluble forms. As dump thermal activity shows a regional pattern, it follows also that elemental- and ion concentrations in the dump waters show significant regional differences. In temporary reservoirs, concentrations of ions and major- and trace elements are much lower and any correlations between components less significant than in the permanent reservoirs; these reservoirs exist for too short a time for any balance between coal waste- and water components to be established.
... The Wełnowiec dump is the only exception where the timespan of coal waste dumping was relatively short and occurred in the 1990s of the past century. Detailed descriptions of the history of the dumps and their thermal activity, and the sampling sites, have been published previously (Lewińska-Preis et al., 2020;Fabiańska et al., 2013bFabiańska et al., , 2018Nádudvari, 2014;Nádudvari and Ciesielczuk, 2018). The locations of the coal waste dumps and their thermal activity are illustrated in Fig. 1. ...
Organic phases in the waters of permanent- and temporary reservoirs located on and near coal-waste dumps in Upper- and Lower Silesia, Poland, include recent compounds of biogenic origin, geochemical compounds (biomarkers), dissolved products of coal-waste self-heating, and anthropogenic markers. Due to their adverse environmental- and health effects, the concentration levels of two compound groups were assessed, namely, polycyclic aromatic hydrocarbons (PAHs) and organic phosphates (OPEs). Their occurrence depends on whether sampling sites were thermally active or not. The predominant source of organic compounds in coal-waste dump water at thermally active sites is organic matter from coal waste. Products of self-heating dissolved in water include phenolic compounds, light ketones, organic acids, and PAHs showing the highest concentrations. OPEs are present only at thermally active sites where firefighting operations had taken place recently. These most probably derived from pump lubricants and/or the diesel engines of heavy-duty equipment such as excavators and bulldozers as no fire retardants were used. Biomarker- and PAHs ratios indicative of air particulate contamination prevail at sites where any thermal activity had ceased long ago. Traffic emission from nearby settlements seems to be the main source of organic compounds at such sites as the biomarkers indicate a crude-oil related source.
... On the northern side, hot spots fall below the satellite sensitivity limits. In the Czerwionka-Leszczyny dump, the hot spot at the top of the highest cone has been waning since the early 1985s (Nádudvari 2014;Nádudvari and Ciesielczuk 2018). The eastern side has also undergone self-heating ( Fig. 1b). ...
Many temporary- and permanent reservoirs of water occur on or in the immediate vicinity of coal-waste dumps in the Lower- and Upper Silesian Coal Basins (Poland). Little or nothing is known of the degree to which their water chemistry might reflect (a) reservoir type, i.e., whether permanent or temporary, (b) level of coal-waste thermal activity, i.e., whether inactive or self-heating or burnt-out or (c) region, i.e., whether the dumps lay in the Upper- or Lower Silesian basins. To provide some answers, concentrations of selected ions (NH 4⁺ , HCO 3⁻ , F ⁻ , Cl ⁻ , Br ⁻ , NO 2⁻ , NO 3⁻ , PO 4³⁻ ,SO 4²⁻ ) were determined by ion chromatography and of nineteen elements (Al, B, Ba, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, P, Pb, S, Si, Sr, Zn) by inductively coupled plasma mass spectrometry (ICP-MS). The data allow a number of observations. In temporary reservoirs, concentrations of ions and of major- and trace elements are relatively much lower and any correlations between components less significant; reservoirs exist for too short a time to allow any balance between coal waste- and water components to be established. A clear relationship does exist between concentrations of ions and of major- and trace elements and dump thermal activity. The highest concentrations occur where thermal activity is high and inorganic components are mobilized. Finally, a regional pattern of elemental- and ion concentrations in the dump waters reflects important regional differences in thermal activity.
... The temperatures measured at 30-cm depth are not the temperatures in the hot spot, which is deeper and much hotter. The land surface temperature for Landsat 7 ETM+ images was calculated according to (Chatterjee 2006;Weng et al. 2004;Nádudvari and Ciesielczuk 2018). ...
Self-heating occurring was studied in the Bytom coal-waste dump using petrographic, mineralogical, and organic geochemical to assess the changes induced by heating on organic material and quantify-qualify the emitted gases. The distribution of geochemical markers such as n-alkanes, alkylbenzenes, alkylcyclohexanes, phenols, sulfurous compounds, and emitted gases in the waste dump is outlined. Heating of organic material there is indicated by high vitrinite random reflectance (Rr)% values that typically characterize samples with short-chain n-alkanes, alkylbenzenes, and alkylmethylbenzenes. Contents of minerals showing minor alterations are high with ~ 90% in burned-out samples. Inside the dump where temperatures can reach up to 700-1300 °C and oxygen contents are significantly reduced, conditions favor coking. This situation is confirmed by the formation of enormous quantities of phenols and alkylbenzenes or by elevated amounts of H2 formed under low-oxygen conditions (pyrolysis). Aromatization, pyrolysis (thermal cracking), and oxidation are associated with the heating in the dump. Gases such as methane, ethane, propane, and ethylene formed during self-heating can serve as fuel for the fire inside the dump, in the process generating huge amounts of CO2.
Twenty-seven gases and sixteen rock wastes from the thermal active Rymer coal waste dump were collected. The composition and origin of gaseous, liquid, and solid pollutants emitted during the self-heating process and the development of these processes with time were established. Gases were subjected to determination of molecular and stable isotope (δ13C and δ2H) composition. Rock-Eval pyrolysis and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) were applied for evaluation of the quantity and molecular composition of pyrolysates released during the heating of rocks in temperatures from 100 to 650 °C. The main products of Py-GC-MS are released between 350 and 650 °C, namely alkanes, aromatic hydrocarbons, and aromatic alcohols. These components were also recorded in Py-GC-MS products of samples collected from the dump surface. Besides the high-molecular-weight organic compounds, in emitted gases CO2, CO, gaseous hydrocarbons, and S-compounds were recorded. The stable isotope data indicated that methane was generated mainly during the low-temperature thermogenic process, but a share of the microbial-originated gas was visible. The source of the CO2 was the oxidation of organic matter. The gaseous S-compounds were products of high-temperature decomposition of sulphides and organic S-compounds. The hydrocarbon and CO contents of the emitted gases proved to be good indicators for tracking of the self-heating processes.
Hot spot detection with satellite images, especially with synthetic aperture radar (SAR) images is still a challenging task. Several researchers have used TM/optical data for identification of hot spot but the use of SAR data is very limited for this type of application. The fusion of SAR data with TM/optical data may add additional information which in turn will lead for enhancement of detection capability of the hot spot. Therefore, this study explores the possibility of fusion of Moderate Resolution Imaging Spectroradiometer (MODIS) and Phased Array L-band Synthetic Aperture Radar (PALSAR) satellite images for the hot spot detection. Image fusion is emerging as a powerful tool where information of various sensors can be used for obtaining better results. For this purpose, vegetation greenness and roughness information which is obtained from MODIS and PALSAR satellite images, respectively , are used for fusion, and then, a contextual-based thresholding algorithm is applied to the fused image for hot spot detection. The proposed approach comprises of two steps: (1) application of genetic algorithm-based scheme for image fusion of MODIS and PALSAR satellite images, and (2) classification of the fused image as either hot spot or non-hot spot pixels by employing a contextual thresholding technique. The algorithm is tested over the Jharia Coal Field region of India, where hot spot is one of the major problems and it is observed that the proposed thresholding technique classifies the each pixel of the fused image into two categories: hot spot and non-hot spot and the proposed approach detects the hot spot with better accuracy and less false alarm.
W Górnośląskim Zagłębiu Węglowym do 1995 roku wydobyto 9,7 mld ton węgla i około 4 mld ton skały płonnej. Większość pustek poeksploatacyjnych nie była wypełniana podsadzką, co doprowadziło do rozwoju niecek osiadania. Formy te występują na obszarach o zróżnicowanej budowie geologicznej, intensywności urzeźbienia, stosunkach wodnych i użytkowaniu terenu. Można wyróżnić: niecki ustabilizowane (na nieczynnych polach górniczych), niecki w końcowej fazie rozwoju (na obszarach likwidowanych kopalń) oraz niecki intensywnie rozwijające się (na obszarach aktualnej i perspektywicznej eksploatacji). Pojawienie się w krajobrazie rozległych niecek, o głębokości kilkunastu metrów i różnym położeniu w stosunku do innych form rzeźby (dno doliny, stoki, wierzchowina), wywiera wpływ na przebieg współczesnych procesów geomorfologicznych, głównie fluwialnych i denudacyjnych.
Abstract: Coal fires are common and serious phenomena in most coal-producing countries in the world. Coal fires not only burn valuable non-renewable coal reserves but also severely affect the local and global environment. The Rujigou coalfield in Shizuishan City, Ningxia, NW China, is well known for being a storehouse of anthracite coal. This coalfield is also known for having more coal fires than most other coalfields in China. In this study, an attempt was made to study the dynamics of coal fires in the Rujigou coalfield, from 2001 to 2007, using multi-temporal nighttime Landsat data. The multi-temporal nighttime short wave infrared (SWIR) data sets based on a fixed thresholding technique were used to detect and monitor the surface coal fires and the nighttime enhanced thematic mapper (ETM+) thermal infrared (TIR) data sets, based on a dynamic thresholding technique, were used to identify the thermal anomalies related to subsurface coal fires. By validating the coal fires identified in the nighttime satellite data and the coal fires extracted from daytime satellite data with the coal fire map (CFM) manufactured by field survey, we found that the results from the daytime satellite data had higher omission and commission errors than the results from the nighttime satellite data. Then, two aspects of coal fire dynamics were analyzed: first, a quantitative analysis of the spatial changes in the extent of coal fires was conducted and the results showed that, from 2001 to 2007, the spatial extent of coal fires increased greatly to an annual average area of 0.167 km2; second, the spreading direction and propagation of coal fires was analyzed and predicted from 2001 to 2007, and these results showed that the coal fires generally spread towards the north or northeast, but also spread in some places toward the east.
Coal fires are serious problem in Raniganj coalfield as it is the case for some of the other coalfields of India like Jharia coalfield. Earlier efforts were made to map the coal fires of this coal-field based on satellite observation. But the restricted distribution of major coal fires in the particular portion of the coalfield makes the basis for finding the geological control if responsible for coal fire distribution. In present study, night time thermal data of ASTER (Advance spaceborne thermal emission and reflection radiometer) is used to map the latest distribution (December, 2006) of coal fires in the Raniganj coalfield. Coal fire map shows that most significant zone affected by fire is at the north-western portion of the coalfield; where NE-trending open cast mines are affected by fire. This fire zone is associated with high grade coal of the Barakar Formation. Coal fires are also mapped in open cast pits of Jambad-Mangalpur area occurring over rocks of the Raniganj Formation. By integrating geological map and satellite-derived coal fire map of Raniganj coal field, it is observed that the coal fires detected by remote sensing study are spatially associated with intraformational faults. These faults may have played significant role in supplying oxygen to these coal-fires and allowing them to propagate down the depth along the trends of the faults.
The VEGETATION (VGT) sensor in SPOT 4 has four spectral bands that are equivalent to Landsat Thematic Mapper (TM) bands (blue, red, near- infrared and mid-infrared spectral bands) and provides daily images of the global land surface at a 1-km spatial resolution. We propose a new index for identifying and mapping of snow/ice cover, namely the Normalized DiVerence Snow/Ice Index (NDSII), which uses reè ectance values of red and mid-infrared spectral bands of Landsat TM and VGT. For Landsat TM data, NDSII is calculated as NDSII TM =(TM3› TM5)/(TM3+TM5); for VGT data, NDSII is calculated as NDSII VGT =(B2› MIR)/(B2+MIR). As a case study we used a Landsat TM image that covers the eastern part of the Qilian mountain range in the Qinghai- Xizang (Tibetan) plateau of China. NDSII TM gave similar estimates of the area and spatial distribution of snow/ice cover to the Normalized DiVerence Snow Index (NDSI=(TM2› TM5)/(TM2+TM5)) which has been proposed by Hall et al. The results indicated that the VGT sensor might have the potential for operational monitoring and mapping of snow/ice cover from regional to global scales, when using NDSII VGT .
Self-heating and self-combustion are currently taking place in some coal waste dumps in the Upper Silesian Coal Basin, Poland, e.g. the dumps at Rymer Cones, Starzykowiec, and the Marcel Coal Mine, all in the Rybnik area. These dumps are of similar age and self-heating and combustion have been occurring in all three for many years. The tools of organic petrography (maceral composition, rank, etc.), gas chromatography-mass spectrometry, and proximate and ultimate analysis are used to investigate the wastes. Organic matter occurs in quantities up to 85 vol.%, typically a few to several vol.%, in the wastes. All three maceral groups (vitrinite, liptinite, and inertinite) are present as unaltered and variously-altered constituents associated with newly-formed petrographic components (bitumen expulsions, pyrolytic carbon). The predominant maceral group is vitrinite with alterations reflected in the presence of irregular cracks, oxidation rims and, rarely, devolatilisation pores. In altered wastes, paler grey-vitrinite and/or coke dominates. The lack of plasticity, the presence of paler-coloured particles, isotropic massive coke, dispersed coked organic matter, and expulsions of bitumens all indicate that heating was slow and extended over a long time. Macerals belonging to other groups are present in unaltered form or with colours paler than the colours of the parent macerals. Based on the relative contents of organic compounds, the most important groups of these identified in the wastes are n-alkanes, acyclic isoprenoids, hopanes, polycyclic aromatic hydrocarbons (PAHs) and their derivatives, phenol and its derivatives. These compounds occur in all wastes except those most highly altered where they were probably destroyed by high temperatures. These compounds were generated mainly from liptinite-group macerals. Driven by evaporation and leaching, they migrated within and out of the dump. Their presence in some wastes in which microscopically visible organic matter is lacking suggests that they originated elsewhere and subsequently migrated through the dump piles. During their migration, the compounds fractionated, were adsorbed on minerals and/or interacted. The absence of alkenes, and of other unsaturated organic compounds, may reflect primary diagenetic processes that occurred in coals and coal shales during burial and/or organic matter type. Their absence may also be a consequence of heating that lasted many years, hydropyrolysis, and/or the participation of minerals in the reactions occurring within the dumps. The wastes contain compounds typical of organic matter of unaltered kerogen III type and the products of pyrolytic processes, and mixtures of both. In some wastes, organic compounds are completely absent having been destroyed by severe heating. The distributions of n-alkanes in many samples are typical of pyrolysates. In some wastes, narrow n-alkane distributions reflect their generation over small temperature ranges. In others, wider distributions point to greater temperature ranges. Other wastes contain n-alkane distributions typical of unaltered coal and high pristane content or mixtures of pyrolysates and unaltered waste material. The wastes also contain significant amounts of final alphabeta hopanes. Polycyclic aromatic hydrocarbons are represented only by two- to five-ring compounds as is typical of the thermal alteration of hard coal. Correlations between the degree of organic matter alteration and the relative contents of individual PAHs and hopanes and geochemical indicators of thermal alteration are generally poor. The properties of the organic matter (its composition and rank), temperature fluctuations within the dumps, migration of organic compounds and mineral involvement are probably responsible for this. The processes taking place in coal waste dumps undergoing self-heating and self-combustion are complicated; they are very difficult to estimate and define. The methods of organic petrology and geochemistry give complementary data allowing the processes to be described. However, each of the dumps investigated represents a separate challenge to be surmounted in any regional attempt to delineate the regional environmental impact of these waste dumps.
In the present paper, a methodology has been developed for the mapping of snow cover in Beas basin, Indian Himalaya using
AWiFS (IRS-P6) satellite data. The complexities in the mapping of snow cover in the study area are snow under vegetation,
contaminated snow and patchy snow. To overcome these problems, field measurements using spectroradiometer were carried out
and reflectance/snow indices trend were studied. By evaluation and validation of different topographic correction models,
it was observed that, the normalized difference snow index (NDSI) values remain constant with the variations in slope and
aspect and thus NDSI can take care of topography effects. Different snow cover mapping methods using snow indices are compared
to find the suitable mapping technique. The proposed methodology for snow cover mapping uses the NDSI (estimated using planetary
reflectance), NIR band reflectance and forest/vegetation cover information. The satellite estimated snow or non-snow pixel
information using proposed methodology was validated with the snow cover information collected at three observatory locations
and it was found that the algorithm classify all the sample points correctly, once that pixel is cloud free. The snow cover
distribution was estimated using one year (2004–05) cloud free satellite data and good correlation was observed between increase/decrease
areal extent of seasonal snow cover and ground observed fresh snowfall and standing snow data.
Mapping of snow and estimation of snow characteristics from satellite remote sensing data require that we distinguish snow from other surface cover and from clouds and compensate for the effects of the atmosphere and rugged terrain. The spectral signature of the snowpack is calculated from a radiative transfer model, accounting for scattering and absorption by the ice grains, water inclusions, and particulates. In interpreting the spectral reflectance measured from the Thematic Mapper, or from any other satellite, we need to account for topographic effects without requiring that satellite data be precisely registered to digital elevation data, because the poor quality of most digital elevation data introduces considerable noise into calculations of slope and azimuth. For a range of snow types, atmospheric profiles, and topographic illumination conditions, I estimate typical spectral signatures for the Landsat Thematic Mapper. TM images of the southern Sierra Nevada are analyzed to distinguish several classes of snow from other surface covers. Snow can be reliably distinguished from other surfaces and from clouds at all sun angles encountered in the mid-latitudes. In TM Band 1 or 2, snow is brighter than other natural surfaces, and in Band 5 clouds are usually much more reflective than snow. Therefore, the intersection of the following criteria maps the snow cover: planetary reflectance Rp in TM Band 1 is greater than about 0.16; Rp (TM5) is less than about 0.2; the normalized Band 2 – 5 difference, [Rp(TM2) − Rp(TM5)] / [Rp(TM2) + Rp(TM5)], is greater than about 0.4. Large surface grain sizes can be distinguished from areas where the grain size is finer at the snow surface, using TM Bands 2, 4 and 5. Because of saturation in TM Band 1, estimation of the degree of contamination by absorbing aerosols is not feasible. [Rp(TM2) − Rp(TM5)]/[Rp(TM2) + Rp(TM5)], is
Coal fire has been found to be a serious problem worldwide in coal mining processes. Coal fire burns valuable coal reserve and prevents access to proven reserve in the affected area. Moreover, it leads to severe environmental degradation of the region by an overall increase of the ambient atmospheric temperature, by the emission of obnoxious gases (e.g., SO2, NO, CO, CH4) along fissures and cracks and by causing land subsidence and collapse. Jharia Coalfield, Jharkhand, India, is known for being the exclusive storehouse of prime coking coal as well as for hosting the maximum number of known coal fires among all the coalfields in the country.In this paper, some of the important issues of coal fire mapping from satellite thermal IR data have been addressed in particular reference to Jharia Coalfield. Namely, these are: retrieval of true spectral radiance from raw digital data using scene-specific calibration coefficients of the detectors, thermal emissivity of surface materials to obtain kinetic temperature at each ground resolution cell of satellite data, field-based modelling of pixel-integrated temperature for differentiating surface and subsurface fire pixels in Landsat TM thermal IR data, identification of surface coal fire locations from reflected IR data and lateral propagation of coal fire.
The control of spontaneous combustion in spoil piles is an area of concern for a number of open cut coal mines. Spontaneous combustion in spoil may occur when carbonaceous waste materials are exposed to air. In large piles, the relatively high voidage within the pile may allow sufficient movement of air through the pile to sustain oxidation and heat generation. Over the past decade, ACARP and CSIRO have funded a number of projects aimed at providing a better understanding of the causes of spontaneous combustion in spoil piles and the development of control strategies. Work has focused on prevention measures but has also considered measures available to deal with well-developed fires. Field, laboratory and numerical modelling methods have been brought to bear on the issues. Individual projects have addressed: causes of spontaneous combustion including the relative reactivities of mine waste materials; the use of cover layers to prevent spontaneous combustion; the use of flyash grout to control an active fire; the emissions of air pollutants; and the emission of greenhouse gases. This paper provides a description of the work carried out to date with an emphasis on the major findings of the research and its application to open cut mines.
In this paper we compare two different methodologies for Fractional Vegetation Cover (FVC) retrieval from Compact High Resolution Imaging Spectrometer (CHRIS) data onboard the European Space Agency (ESA) Project for On-Board Autonomy (PROBA) platform. The first methodology is based on empirical approaches using Vegetation Indices (VIs), in particular the Normalized Difference Vegetation Index (NDVI) and the Variable Atmospherically Resistant Index (VARI). The second methodology is based on the Spectral Mixture Analysis (SMA) technique, in which a Linear Spectral Unmixing model has been considered in order to retrieve the abundance of the different constituent materials within pixel elements, called Endmembers (EMs). These EMs were extracted from the image using three different methods: i) manual extraction using a land cover map, ii) Pixel Purity Index (PPI) and iii) Automated Morphological Endmember Extraction (AMEE). The different methodologies for FVC retrieval were applied to one PROBA/CHRIS image acquired over an agricultural area in Spain, and they were calibrated and tested against in situ measurements of FVC estimated with hemispherical photographs. The results obtained from VIs show that VARI correlates better with FVC than NDVI does, with standard errors of estimation of less than 8% in the case of VARI and less than 13% in the case of NDVI when calibrated using the in situ measurements. The results obtained from the SMA-LSU technique show Root Mean Square Errors (RMSE) below 12% when EMs are extracted from the AMEE method and around 9% when extracted from the PPI method. A RMSE value below 9% was obtained for manual extraction of EMs using a land cover use map.
Particulate matter (PM) emissions from stationary combustion sources burning coal, fuel oil, biomass, and waste, and PM from internal combustion (IC) engines burning gasoline and diesel, are a significant source of primary particles smaller than 2.5 microns (PM2.5) in urban areas. Combustion-generated particles are generally smaller than geologically produced dust and have unique chemical composition and morphology. The fundamental processes affecting formation of combustion PM and the emission characteristics of important applications are reviewed. Particles containing transition metals, ultrafine particles, and soot are emphasized because these types of particles have been studied extensively, and their emissions are controlled by the fuel composition and the oxidant-temperature-mixing history from the flame to the stack. There is a need for better integration of the combustion, air pollution control, atmospheric chemistry, and inhalation health research communities. Epidemiology has demonstrated that susceptible individuals are being harmed by ambient PM. Particle surface area, number of ultrafine particles, bioavailable transition metals, polycyclic aromatic hydrocarbons (PAH), and other particle-bound organic compounds are suspected to be more important than particle mass in determining the effects of air pollution. Time- and size-resolved PM measurements are needed for testing mechanistic toxicological hypotheses, for characterizing the relationship between combustion operating conditions and transient emissions, and for source apportionment studies to develop air quality plans. Citations are provided to more specialized reviews, and the concluding comments make suggestions for further research.
Coal-waste dumps are sources of a variety of pollutants, especially when coal-waste material undergoes self-heating. For this research, representative samples were taken from four dumps (Wełnowiec, Czerwionka-Leszczyny, Rymer and Anna) in the Rybnik region. The set of samples collected were divided into three subsets, namely, (1) expelled bitumen precipitated on coal waste, (2) thermally-affected coal waste and (3) highly-thermally affected coal waste from active- and inactive sites. To assess the characteristic features and impacts of self-heating, Rock Eval pyrolysis, measured random vitrinite reflectance (Rr %) and gas chromatography–mass spectrometry (GC–MS) of coal waste extracts were applied. Typical features of the bitumen expelled are elevated parameters of S1, PI, BI, and Py. Generally, the bitumen appeared at lower Tmax values. The self-heating in oxygen deficiency, i.e. under pyrolytic conditions caused thermal cracking of organic matter. Later the generated bitumen expelled from the self-heating zone, migrated and accumulated on colder coal-waste surfaces. This expelled bitumen, observed under fluorescence, shows irregular shapes and coats the organic particles with yellowish–greenish colours. Migrated bitumen is also found in highly-thermally affected, where Tmax values are extremely high due to the oxidation and maturation of organic matter (overmatured). R0 % values based on HI–Tmax comparison and the measured Rr % values generally well correlate in the burning coal waste and in highly-thermally affected samples. The greatest quantities of phenols (mostly C1–C2) occur in the bituminous subset, samples in which 2–3 ring PAHs also dominate. In addition, high relative percentages of phenols (mostly C1–C2) characterize thermally-affected coal waste, together with heavier pyrolytical PAHs; these samples were closer to the heating zone. In totally burned-out porous waste, the presence of adsorbed short-chain n-alkanes and lighter PAHs, and higher CPI, Pr/n-C17 and Pr/Ph values, reflect migration from an active self-heating zone.
Coal mining generates a great amount of waste that is typically dumped in the vicinity of the mines. In some cases, the dumps undergo self-heating and/or combustion during which gaseous pollutants are formed. These processes occur in some dumps in Upper Silesian Coal Basin, e.g. Starzykowiec-, Rymer Cones-, and Marcel dumps dating from the beginning of the 1900s. The heating dynamics are reflected in comparisons between air temperatures and temperatures measured on the surface, at a depth of ∼ 1 m, and also in CO, CO2, and O2 contents. The Rymer Cones dump is an excellent example of where air blowing into the dump interior can enhance these processes; heating is more intense in the western- and southern part of the dump most exposed to the wind. Temperatures can reach even 600°C there whereas, on the eastern side of the dump, they commonly lie in the range 60–80°C. In the other two dumps, temperature changes reflect the seasons. In these old dumps, it is very difficult to deal with hot spots and prevent temperatures from rising. Regular monitoring allows the identification of hot spots though it seems that the only way to deal with these is to intensify the combustion by enhancing air access and allowing the waste rocks to overburn.
The potential utility of Landsat-5 Thematic Mapper (TM) thermal infrared (band 6) and short wavelength infrared (bands 5 and 7) data for detecting and mapping sub-surface coal fires is analysed. The short wavelength infrared sensors have been used to locate the position of the fire front. The thermal band has been useful in distinguishing gross thermal anomalies from the background of solar warming. The resultant surface temperature anomalies are compared to surface temperatures derived from infrared thermal aerial survey and ground measurements. Correlation of these data indicate that the relatively high resolution of the TM data enabled the detection, mapping and quantifying of sub-surface coal fires zones.
Field and aircraft measurements were acquired in April 1995 in central Alaska to map snow cover with MODIS Airborne Simulator (MAS) data, acquired from high-altitude aircraft. The Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) is a 36-channel system that will be launched on the EOS-AM-1 platform in 1999. A vegetation-density map derived from integrated reflectances (Ri), from MAS data, is compared with an independently-produced vegetation type and density map derived from Thematic Mapper (TM) and ancillary data. The maps agreed to within 13%, thus corroborating the effectiveness of using the reflectance technique for mapping vegetation density. Snow cover was mapped on a 13 April 1995 MAS image, using the original MODIS prototype algorithm and an enhanced MODIS prototype algorithm. Field measurements revealed that the area was completely snow covered. With the original algorithm, snow was mapped in 96% of the pixels having <50% vegetation-cover density according to the Ri map, while in the areas having vegetation-cover densities ⩾50%, snow was mapped in only 71% of the pixels. When the enhanced MODIS snow-mapping algorithm was employed, 99% of the pixels having <50% vegetation-cover density were mapped, and 98% of the pixels with ⩾50% vegetation-cover density were mapped as snow covered. These results demonstrate that the enhanced algorithm represents a significant improvement over the original MODIS prototype algorithm especially in the mapping of snow in dense vegetation. The enhanced algorithm will thus be adopted as the MODIS at-launch snow-cover algorithm. Using this simple method for estimating vegetation density from pixel reflectance, it will be possible to analyze the accuracy of the MODIS snow-cover algorithm in a range of vegetation-cover in places where information on vegetation-cover density is not available from ground measurements.
Ammonioalunite, ammoniojarosite and their solid-solution series found on a burning coal dump at Czerwionka, Upper Silesian Coal Basin, Poland, were examined using powder X-ray diffraction, electron probe microanalysis, inductively coupled plasma mass spectrometry, infrared spectroscopy and thermal analysis methods. The minerals occur as yellow, fine-grained crusts and botryoidal masses in the outer part of a sulphate crust found ∼1 m below the surface. The crust is composed mainly of godovikovite and tschermigite that formed by interaction of sour fire gases or solutions and waste materials beneath the surface of the burning coal dump at temperatures of at least 80–100°C. The crystals often reveal oscillatory zoning due to different Al and Fe contents in thin bands, from near end-members to extensive solid solutions. Our analyses suggest the existence in nature of a complete solid solution between ammonioalunite and ammoniojarosite. They also carry essential amounts of chlorine.
The current paper presents experimental investigations as well as numerical simulations on the influence of water and humidity on the self-ignition of combustible bulk materials.It is well known, that bulk materials may undergo self-ignition if stored under specific conditions. In some cases, large amounts of these materials are exposed to a humid surrounding, e.g. dried coal in a moist atmosphere. Due to the effects of condensation and adsorption of water, additional heat is generated and transported into the bulk material. If the pile is stored slightly below its self-ignition temperature, the bulk material can become supercritical and an ignition occurs.Experiments were carried out for German lignite coal sampled in two different particle size fractions. They showed, that subcritical deposits turned to supercritical behaviour if the relative humidity in the surrounding was suddenly increased or water was poured on the surface of the sample. Besides the experiments, a numerical model was established to describe the effects of self-heating until ignition of the deposit, including the transportation of moisture. Simulations with this model led to satisfying results when compared to the experiments.
A critical analysis of various genetic and physical factors associated with certain Early and Late Permian and Oligocene coal seams and early Eocene lignite seams of India revealed that the high secondary porosity and small particle size, irrespective of petrographic and rank properties in sub-humid climate, favour spontaneous combustion. Large particle size, high rates of gas emission and highly wet or dry seams, in combination with each other tend to inhibit spontaneous heating in sub-humid, per-humid and semi-arid conditions. The susceptibility to auto-ignition of a coal or lignite seam is not uniform throughout its lateral extent and a high inherent porosity at any given rank stage and a high content of susceptible or oxidizable constituents are not sufficient to cause auto-ignition. However, coal seams having high contents of exceedingly porous inertinite macerals become prone to spontaneous combustion in sub-humid climate even without secondary porosity.A scheme for indexing spontaneous combustion susceptibility, based on the present study, has been proposed which is particularly suited to the Indian context.
An algorithm is being developed to map global snow cover using Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) data beginning at launch in 1998. As currently planned, digital maps will be produced that will provide daily, and perhaps maximum weekly, global snow cover at 500-m spatial resolution. It will also be possible to generate snow-cover maps at 250-m spatial resolution using MODIS data, and to study snow-cover characteristics. Preliminary validation activities of the prototype version of the snow-mapping algorithm, SNOMAP, have been undertaken. SNOMAP will use criteria tests and a decision rule to identify snow in each 500-m MODIS pixel. Use of SNOMAP on a previously mapped Landsat Thematic Mapper (TM) scene of the Sierra Nevada`s has shown that SNOMAP is 98% accurate in identifying snow in pixels that are snow covered by 60% or more. Results of a comparison of a SNOMAP classification with a supervised-classification technique on six other TM scenes show that SNOMAP and supervised-classification techniques agree to within about 11% or less for nearly cloud-free scenes and that SNOMAP provided more consistent results. About 10% of the snow cover, known to be present on the 14 March 1991 TM scene covering Glacier National Park in northern Montana, is obscured by dense forest cover. Mapping snow cover in areas of dense forests is a limitation in the use of this procedure for global snow-cover mapping. This limitation, and sources of error will be assessed globally as SNOMAP is refined and tested before and following the launch of MODIS.
Coal wastes produced during mining activities are commonly deposited in nearby dumps. These wastes mostly composed of minerals and variable amounts (usually 20–30%) of organic matter start to weather immediately after deposition. Oxidation of the organic matter can lead to self heating and self combustion as a result of organic and mineral matter transformations. The degree of alteration depends on the properties of the wastes, i.e., the maceral and microlithotype composition of the organic matter and its rank.
This review is intended to introduce the readers to the geotechnical properties of minestone obtained from various countries and to describe laboratory and field methods used to examine and evaluate such material. The contents of the paper consist of general information on the environmental consequences of coal mining, the origin of the by-product, and the classification of the material. Primary emphasis has been placed on describing the physical and mechanical properties with respect to geotechnical engineering. Characteristic properties, such as degradation, weathering, spontaneous heating, etc., are specific for this man-made soil and are discussed in relationship to civil engineering. Finally, the current and far-reaching effects of existing radioactivity is also presented. Preparation of the review is based on an extensive literature survey, as well as on the investigations of the author and practical applications.A general conclusion can be made from the reviewed data that a noticeable similarity does exist between the chemical, physical, and mechanical properties of minestone from different sources and countries. This is important because the research results and practical experience obtained in one country may then be applied to projects in another country.The review should be helpful in understanding the behavior of minestone during its transport for prospective utilization in different engineering projects. The author hopes that the information will be useful to those studying environmental, civil, and water engineering, as well as for designers and researchers investigating the potential use of this man-made (anthropogenic) soil in various fields of engineering.
Compositions and quantities of gases produced by different coal samples at different temperature ranges were analyzed by simulating experiments in the laboratory. It is found that they are related to three major factors, temperature, external water content and retardant ratio. The quantitative relations between gas makers and temperature are established. CO and C2H4 could be used as index gases for the prediction of coal spontaneous combustion in the low-temperature range for the experimental mine coal. The MEA-1A retardant had good performance in fixing the external water content of coal and inhibiting coal oxidation; it could be used in preventing the spontaneous combustion of coal prevention and its appropriate ratio was determined.
The coal mining industry in The Upper Silesian Coal Basin has existed for over 150 years. Recently the mining industry in the USCB has been found at a low ebb. About the thirty oldest coal mines were closed to reduce the operating costs of the mining industry. Coal exploitation over a long period in the Upper Silesian Coal Basin has caused considerable and often irreversible changes in the natural environment. After the ending of exploitation, apart from hitherto existing hazards, which are gradually decreasing, new ones may also appear. A few years ago the authorities of the Silesian agglomeration began to labour under the diffi culties connected with the process of winding up mining works and with the management of former mining areas. Their revitalization requires well-planned actions and suitable fi nancial expenditures. Keywords: environmental impact, Upper Silesian coal basin, exploitation. had been started in the area of the Orlova-Boguszowice overthrust. Recently the mining industry in the USCB has declined. The crisis is mainly connected with the shortage of coal resources and decreasing coal demand as well as the necessity of reducing the subsidy for coal mines. The thirty oldest coal mines operating in urbanized areas and with unfavourable mining and geological conditions, were closed to reduce the operating costs of the mining industry. A few years ago the Silesian agglomeration began to suffer diffi culties connected with the process of winding up the mining works and with the management of former mining areas.
Subsurface and surface coal fires form serious environmental, economic and safety problems in coal-producing countries like China and India. Remote sensing offers the possibility of detecting and studying thermal anomalies due to coal fires. Emissivity plays an important role in determining the surface temperature of a body using remotely sensed data. In the present study an attempt is made to use satellite-derived emissivity to estimate the surface temperature in Wuda, north China. With the use of multispectral thermal Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data (five bands in 8.125-11.65 µm region) in combination with a Temperature/Emissivity Separation (TES) algorithm, the anomalous pixels due to coal fires can be extracted from the background to achieve a qualitative study of coal fires. In the present study, during night-time overpass of ASTER, satellite images have been recorded and simultaneous field measurements were collected. These field measurements were used to process the satellite thermal data and to validate the results obtained. Using the TES approach, satellite-based temperature corresponded well with actual field measurements at selected locations.
As we write (May 1992) a lava flow that began at a fissure high on the southeast flank of Mount Etna, Sicily, on 14 December 1991 (Smithsonian Institution, 1991, 1992) has been threatening the town of ZalTerana for several weeks and considerable media attention has been given to attempts to divert the flow, or to breach its levees, so that the lava spreads laterally rather than continuing downslope into the town. In order fully to understand the behaviour of an active lava flow it is important to measure as many relevant properties as possible. Among these are the volumetric rate of effusion, the steepness of the slope and other terrain properties, the planimetric form of the flow, the rate of advance of the head of the flow, and the temperature and viscosity of the lava (Walker 1973, Crisp and Baloga 1990). Only when at least several of these parameters are well-constrained can realistic models be created that are capable of predicting the course of the flow.
A coal seam fire in interior Alaska was suspected to have started the Rex Creek forest fire in the summer of 2009. With prevailing winds, the forest fire spread rapidly to the north and within eleven days it burned about 410 km2 of boreal forest. Coal seam fires can go unnoticed and unreported when present in remote and inaccessible areas. However, they still pose a serious threat to the surroundings. We used summer-time thermal infrared images from 1999 through 2009 acquired by the Landsat satellite and, through the process of image stacking, identified a region where the surface persistently showed temperatures 5 °C to 14 °C higher than the background areas. Field validation confirmed that this thermal anomaly area corresponds to a previously undocumented shallow coal seam fire. Superimposing the boundary of the Rex Creek forest fire revealed that the coal seam fire was at the southern end of the burn area where the forest fire originated. Plotting the location of all lightning strikes during this period helped to rule out lightning as the cause of the forest fire. Coal fires and forest fires can have a complex and dynamic relationship, one being the possible cause of the other. A thorough inventory of all past and present known coal seam fire locations can help to update forest fire hazard maps. A detailed map of shallow coal seam areas can help to prioritize fire fighting operations in order to avoid the chance of starting a new coal seam fire.Research Highlights► A wild fire in Alaska's boreal forest was started by an undocumented coal seam fire. ► Fire spread, wind, lightning, and satellite data revealed the sequence of events. ► Coal fires and forest fires have a complex relation, one possibly causing the other. ► At high latitudes coal is abundant but high latitude coal fires are poorly understood.
Remote sensing of urban heat islands (UHIs) has traditionally used the Normalized Difference Vegetation Index (NDVI) as the indicator of vegetation abundance to estimate the land surface temperature (LST) – vegetation relationship. This study investigates the applicability of vegetation fraction derived from a spectral mixture model as an alternative indicator of vegetation abundance. This is based on examination of a Landsat Enhanced Thematic Mapper Plus (ETM+) image of Indianapolis City, IN, USA, acquired on June 22, 2002. The transformed ETM+ image was unmixed into three fraction images (green vegetation, dry soil, and shade) with a constrained least-square solution. These fraction images were then used for land cover classification based on a hybrid classification procedure that combined maximum likelihood and decision tree algorithms. Results demonstrate that LST possessed a slightly stronger negative correlation with the unmixed vegetation fraction than with NDVI for all land cover types across the spatial resolution (30 to 960 m). Correlations reached their strongest at the 120-m resolution, which is believed to be the operational scale of LST, NDVI, and vegetation fraction images. Fractal analysis of image texture shows that the complexity of these images increased initially with pixel aggregation and peaked around 120 m, but decreased with further aggregation. The spatial variability of texture in LST was positively correlated with those in NDVI and in vegetation fraction. The interplay between thermal and vegetation dynamics in the context of different land cover types leads to the variations in spectral radiance and texture in LST. These variations are also present in the other imagery, and are responsible for the spatial patterns of urban heat islands. It is suggested that the areal measure of vegetation abundance by unmixed vegetation fraction has a more direct correspondence with the radiative, thermal, and moisture properties of the Earth's surface that determine LST.
Natural underground coal fires are fires in coal seams occurring subsurface. The fires are ignited through a process named spontaneous combustion, which occurs based on a natural reaction but is usually triggered through human interaction. Coal mining activities expose coal to the air. This leads to the exothermal oxidation of the carbon in the coal with the air's oxygen to CO2 and – under certain circumstances – to spontaneous combustion. Coal fires occur in many countries world wide – however, currently the Chinese coal mining industry faces the biggest problems with coal fires. Coal fires destroy the valuable resource coal and furthermore lead to many environmental degradation phenomena such as the deterioration of surrounding vegetation, land subsidence and the emission of toxic gasses (CO, N2O). They additionally contribute to the emission of green house relevant gasses such as CO2 and CH4 to the atmosphere.
China is the biggest producer of coal in the world and mines about 1000 Mt of raw coal per year. Approximately 70% of China's energy consumption is covered by coal. At the same time, it is estimated that about 20 Mt of coal are being burnt in uncontrolled coal fires in China each year. Because these coal fires are spread out over the whole northern part of the country, stretching from Xinjiang province in the West to the Pacific coast in the East, it is extremely difficult to keep an overview of the development of known fires as well as of newly developing ones.
In the Douro Coalfield anthracites were exploited for decades (1795–1994). Besides many small mines Douro Coalfield had two principal mining areas (S. Pedro da Cova and Pejão). Coal mining activities cause several impacts on the environment, one of which is the amount of discard or waste which was disposed of all over Douro Coalfield resulting in one of the most significant and severe impacts on the environment. Over 20 waste piles exist in the old mining areas, geographically dispersed, and three of them are presently burning. Their ignition was caused by forest fires during the summer of 2005. Samples from the burning and unburned zones of the waste piles were studied as were the gas from vents and the minerals resulting after combustion. Geochemical processes and mineralogical transformations in the burning coal waste pile were investigated. Microscopic analyses of the samples identified some particular aspects related with combustion: oxidation of pyrite, the presence of iron oxides, organic particles with cracks and rims with lowered (suppressed) Rr, devolatilization vacuoles and some char structures. The occurrence of vitreous (glassy) material as well as Fe–Al spinels in the burning coal waste provide evidences that the combustion temperature could have reached values above 1000 °C. Due to combustion, and as expected, the samples studied reported high ash yields. Samples taken from the burning zones reported an increase of As, Cr, Li, Nb, Ni, Pb, Rb, Sr and LREE concentrations and a decrease in Zr and HREE concentrations. Enrichment in Cs, Li and Rb was noted when comparing with the geochemical composition of black shales and world coals composition that is related with the contribution of granitic rocks in the sediments that originated the main lithologies of the Douro Coalfield (carbonaceous shale and lithic arenites). Cluster analyses (R-type and Q-type) were performed to understand the trend between the unburned and burning samples and it seems that some chemical variations are responsible for this separation.Elemental sulphur and salammoniac (ammonium salt) are the coal fire gas minerals neoformed on the surface of piles, near the burning zones. They were identified by different techniques, mainly SEM-EDX, XRD and FTIR. Relatively high concentrations of several aromatic compounds were detected in the gas collected at the studied areas, as well as aliphatic hydrocarbons. The highest concentrations of aromatic hydrocarbons were measured in gas samples from S. Pedro da Cova waste pile. The exposure to hazardous compounds present in the gas is a serious risk to human health and the environment.
Spontaneous combustion and low-temperature oxidation of waste coal in open-cut coal mines represents a potentially large source of greenhouse gas emissions. In this paper, emission fluxes of CO2 and CH4 from spoil piles and waste coal dumps measured at 11 mines in the Hunter Valley and Bowen Basin in Australia are presented. The data displayed considerable scatter, which is consistent with the inhomogeneous nature of spoil pile material and permeability of surfaces. Despite the scatter, emissions were able to be classified into three broad categories according to the intensity of the spontaneous combustion present in the material. Average emissions ranged from about 12 kg CO2-e yr− 1 m− 2 to 8200 kg CO2-e yr− 1 m− 2, depending on the intensity of the spontaneous combustion. There was also, within the scatter of the data, an approximately linear trend of increasing emission flux with increasing surface temperature.A key finding of the research is that the emission rates of greenhouse gases from spoil piles where there is no spontaneous combustion, but only low-temperature oxidation of coal and coal waste, are similar to the emission rates due to biological activity from vegetated surfaces. However, further research is required to quantify the degree to which spoil piles that have no spontaneous combustion contribute to the anthropogenic atmospheric CO2 burden.
The self-heating of coal mainly involves exothermic reactions of oxygen at reactive radical sites within the coal and the enhancing or moderating effect that water has on these reactions. The thermal response of samples of low-rank coals, dried by heating under nitrogen flow at 105°C and exposed to dry oxygen, is similar to or slightly less than that observed when they are flow-dried at 30°C and tightly bound moisture remains. The most likely reason is that moisture affects the nature of the radical sites where oxidation occurs. By hindering the formation of stabilized radicals, it encourages faster oxidation which may lead to enhanced thermal response, although some of the extra heat may be taken up by the residual moisture. When loosely bound moisture is allowed to remain in the coal, the thermal response on exposure to dry oxygen decreases very quickly, due mainly to hindered access to reactive sites and dissipation of heat generated by any oxidation that does occur. The effect of desorption is comparatively minor and the course of the oxidation reaction responsible for generating heat does not appear to be changed by the presence of small quantities of loosely bound moisture.
The environmental characteristics of coal gangue dumps in Yangquan (Shanxi Province, China) were investigated. The amounts of coal gangue are very high in this coal region given the large coal production. As a result, widespread spontaneous coal gangue combustion gives rise to serious environmental problems. Coal gangue (including bulk gangue and specific lithologies, such as coal, kaolinite-rich material, sandstone, carbonate minerals, and sulfide mineralizations), fired coal gangue and condensate products from gas vents were fully characterized with respect to mineralogy, chemistry and leaching potential. The mineral paragenesis of the fired coal gangue (cristobalite, mullite, hematite, trydimite, cordierite) showed that the combustion temperature could reach 1200 °C. This was also corroborated by laboratory calcination tests. During this combustion some elements such as C, Cl, F, S, N, As, Cd, Hg, Pb, Sn, Ge and Se are emitted into the atmosphere. However, condensation processes accounted for the partial trapping of gaseous emissions of As, S, N, Hg and Se. Thus, condensate mineralizations of elemental sulfur and ammonium salts enriched in Se, As and other trace elements are frequent in the gas vents. The leaching potential of trace elements in the fresh coal gangue was relatively low, but the leaching of weathered coal gangue and the gas vents condensates could give rise to environmental problems, as these materials produce acidic leachates and yield relatively high leachable levels of a number of elements.
Spontaneous combustion of coal seams in the Witbank and Sasolburg coalfields, South Africa, was studied in order to determine if toxic chemical elements and compounds are being mobilised into the environment. Samples of the minerals forming on the surface of coal seams, and gases escaping from vents, were analysed to verify the presence of these elements and compounds.Gas temperature measurements at coal-fire vents range from 34 °C to 630 °C. The coal-fire gas minerals (CFGM) identified included sulphur compounds and salammoniac. X-ray diffraction (XRD) studies of CFGM by-products confirmed the presence of mascagnite ((NH4)2SO4), illite ((Al,Si)4O10[(OH)2,H2O]) letovicite ((NH4)3H(SO4)2), phlogopite (KMg3(AlSi3)O10(F,OH)2), titanium dioxide (TiO2), barite (BaSO4), iron sulphate (FeSO4), gypsum (CaSO4·2H2O) and silicate. An unknown and unclassified sulphur–nitrogen–chlorine CFGM was also identified. The minerals are interpreted to have formed by condensation or sublimation; several may be alteration products. Other heavy elements found in the CFGM's are mercury, arsenic, lead, zinc, and copper. Arsenic and mercury were the major elements of potential environmental significance found accumulating around coal-fire vents.Relatively high concentrations of toluene, benzene and xylene were found in the gas collected at both Witbank and Sasolburg coalfields. Benzene, toluene and xylenes are known to possess carcinogenic proprieties. Thirty-two aliphatic compounds were detected, as well as halogenated compounds including bromomethane, iodomethane and trichloromethane in low concentrations, and dichloromethane and chloromethane in high concentrations. The highest concentrations of halogenated compounds were measured for gas samples from the Witbank coalfield. High concentrations of carbon monoxide, carbon dioxide, and methane were also detected.The nature of the risks to human health and the environment of most of the compounds in gas and CFGM by-products of spontaneous combustion at the Witbank and Sasolburg coalfields are unknown and merit investigation. Fires caused by spontaneously combusted coal are pervasive in the coalfields and the health consequences of exposure to hazardous elements are a serious risk. It would be prudent to undertake an environmental impact assessment of these elements in order to determine the extent of their impact on mine workers and the environment in the Witbank and Sasolburg coalfields.
Coal wastes produced at various stages of coal mining, washing and deposition on dumps are a source of many pollutants. In some cases, the dumped coal waste undergoes self-heating and self-combustion processes that reflect the properties of the organic matter present (maceral composition and rank) and the history of heating (rate, time and temperature of heating). In the examination of the coal wastes from the Rymer Cones dump, petrographic- and gas chromatography-mass spectrometry (GC-MS) techniques were used to provide different sets of complementary data. Unaltered- and variably-altered macerals (mostly vitrinite) characterise the investigated material. Vitrinite of elevated reflectance and massive coke particles indicate that the rate of heating was low and that the availability of air was very limited; heating took place under pyrolytic conditions. Irregular cracks in particles probably also resulted from slow heating. The temperature of the heating processes, dynamically changing in time and place throughout the dump, led to chemical changes in organic matter such as the formation of phenols and their derivatives, and alteration in distributions of n-alkanes, hopanes and moretanes and polycylic aromatic hydrocarbons (PAHs) occurring in pyrolysates. Some of these compounds formed as a result of the thermal destruction of liptinite and vitrinite macerals at various temperatures and migrated from within the dump. The changes that occurred within the dump are also reflected in values of geochemical parameters based on the same compounds, such as CPI, Ts/(Ts + Tm), MNR, DNR, TNR-1, TNR-2. Lighter compounds were probably released into the atmosphere and others, especially phenols that are easily soluble in water and PAHs, were most probably leached into deeper parts of the dump and even into underground waters since they are absent in some samples or significantly decreased in concentration. These processes probably still continue — it is this fact that creates a potential hazard to the environment.
Ground-based surveys of three coal fires and airborne surveys of two of the fires were conducted near Sheridan, Wyoming. The fires occur in natural outcrops and in abandoned mines, all containing Paleocene-age subbituminous coals. Diffuse (carbon dioxide (CO(2)) only) and vent (CO(2), carbon monoxide (CO), methane, hydrogen sulfide (H(2)S), and elemental mercury) emission estimates were made for each of the fires. Additionally, gas samples were collected for volatile organic compound (VOC) analysis and showed a large range in variation between vents. The fires produce locally dangerous levels of CO, CO(2), H(2)S, and benzene, among other gases. At one fire in an abandoned coal mine, trends in gas and tar composition followed a change in topography. Total CO(2) fluxes for the fires from airborne, ground-based, and rate of fire advancement estimates ranged from 0.9 to 780mg/s/m(2) and are comparable to other coal fires worldwide. Samples of tar and coal-fire minerals collected from the mouth of vents provided insight into the behavior and formation of the coal fires.
A coal-waste heap in Avion, northern France, that has been undergoing subsurface combustion for several decades, is marked by the occurrence of efflorescences at combustion sites where gas and water vapor escape from surficial cracks and vents. Analysis of the efflorescences show that twenty different species of mineral are present, comprising various sulfates, as well as halides and native sulfur. The constituents needed for the formation of these minerals are ultimately derived from the heap of coal-mine waste, composed mainly of pyrite-bearing carbonaceous shale, coal and minor amounts of sandstone. They may be partly released by acid weathering of waste-heap materials prior to combustion, but largely by thermal decomposition and oxidation of those materials during combustion processes. Formation of the efflorescences near gas-discharge zones indicates transport of constituent to those zones from the inner part of the waste heap, which can occur in the gas phase for some elements (S, N, H and Cl), but would require droplets of water vapor as carriers for most cations. Interaction between condensate solutions and the local debris at the surface of the waste heap may also contribute to cations input prior to the formation of secondary minerals. Most minerals formed from a liquid phase along the rock-debris surface at low temperatures (T ≤ 100°C), as confirmed by the occurrence of fluid inclusions. Only salammoniac, native sulfur and mascagnite (where crystallized as a monocrystalline phase) were formed directly from a gas phase. The coal-waste heap shows great variations in mineral assemblages among sampling sites, which must be related to variations in waste composition and in conditions at the level at which the elements are released and where mineral formation takes place.
Coal fires cause severe environmental and economic problems. Although satellite remote sensing has been used successfully to detect coal fires, a satellite data based concept that can quantify the majority of the detected coal fires is still missing. Recently, the determination of fire radiative energy (FRE) has been introduced as a new remote sensing tool to quantify forest and grassland fires. This thesis tests the concept of remotely measured FRE, with a view to ascertaining its potential applicability to coal fires. It contains an investigation of a new generation of satellite instruments, including the operational Enhanced Thematic Mapper (ETM) instrument, the experimental Bi-spectral InfraRed Detection (BIRD) satellite sensor and the experimental Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), which explores the potential of these sensors to determine coal fire radiative energy (CFRE). Additionally, based on the results of this analysis, the thesis presents a new, automated ETM and ASTER data based algorithm, adapted to quantify coal fires in semi-arid to arid regions in northern China.
Field observations carried out in September 2002 and 2003 in three coalfields in northern China (the Wuda, Gulaben and Ruqigou coalfields) demonstrate that coal fire related, surface anomalies are significantly cooler than forest and grassland fires. The theoretical investigation of the ASTER, ETM and BIRD instruments outlines the fact that the thermal infrared (TIR) or mid infrared (MIR) spectral channels of the ASTER, ETM and BIRD instrument are particularly effective in registering these ‘warm spots’, whilst the short wave infrared (SWIR) spectral range is, however, insufficiently sensitive to be able to register spectral coal fire radiances. The commonly used bi-spectral fire quantification method (Dozier, 1981) can be applied to BIRD data in order to quantify relatively large and / or hot coal fires. However, existing FRE retrieval approaches fail to quantify coal fires via ASTER and ETM instrument data. In this thesis, a new CFRE retrieval method is presented, which links the fire and background TIR spectral radiances to the CFRE through an empirical relationship.
This newly developed TIR method is applied to visually detected fire clusters from night-time ASTER data, and from both day- and night-time ETM data, taken from the three study coalfields in northern China. The ASTER and ETM CFRE values, calculated via the TIR method, are compared to CFRE estimates from BIRD data, calculated via the existing bi-spectral method. Despite the different spatial resolution and spectral properties of the ETM, ASTER and BIRD instruments, CFRE computed from ASTER, ETM and BIRD data show good correlations with one another. However, CFRE retrievals from daytime data appear to be very undependable to background temperature variations, while CFRE, estimated from night-time data, appears to be relatively stable. A comparison between night-time ETM-derived CFRE and the figures given by local mining authorities for total coal fire induced, coal loss estimates in the Wuda coalfield gives a clear indication that the overall dimension of the coal fire problematic can in fact be approximated via satellite data CFRE retrievals. It is thus expected that CFRE derived from night-time satellite data will become a crucial tool in obtaining reliable, quantitative information for coal fires.
A multi-temporal comparison of CFRE retrievals from night-time BIRD and ETM data, covering the Ruqigou and Wuda coalfields, indicates that only major shifts or activity changes in coal fire induced, surface anomalies can be observed by means of these data. These results, which could only partially be verified by field observations, indicate that ETM or BIRD data can be used to monitor major changes in coal fire related, surface anomalies. These data however cannot entirely replace detailed field observations, especially in case of smaller and / or cooler coal fire related, surface anomalies.
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