Assessment of Dust Generation Due to Opencast Coal Mining– An Indian Case Study

Every mine in India has to obtain environmental clearance fromthe Govt. Air pollution is one of the most important parametersto be considered in preparing an EIA. However, there is no welldefined method for predicting thr air pollution impact due tomining. Increasing trend of opencast (O/C) mining leads toproduction of huge quantities of dust. Emission factor data havebeen utilised to quantify the generation of dust. The projectunder study is one of the largest opencast project (OCP) forcoking coal. The main sources of air pollution have beenidentified. The rate of emission per unit of a given activityknown as an emission factor has been utilised, taking localfactors into account. It has been estimated that due to topsoilremoval, overburden (O/B) removal, extraction of coal, sizereduction generated 7.8 t of dust per day. Wind erosiongenerated 1.6 t of dust per day and the whole operationproduced dust which accounted for 9.4 mt/day. They cause airpollution in the work zone and surrouding locations. Themethodology adopted may be used to quantify generation for otherprojects also.     

Assessment of respirable dust exposures in an opencast coal mine

All major opencast mining activities produce dust. The major operations that produce dust are drilling, blasting, loading, unloading, and transporting. Dust not only deteriorates the environmental air quality in and around the mining site but also creates serious health hazards. Therefore, assessment of dust levels that arise from various opencast mining operations is required to prevent and minimize the health risks. To achieve this objective, an opencast coal mining area was selected to generate site-specific emission data and collect respirable dust measurement samples. The study covered various mining activities in different locations including overburden loading, stock yard, coal loading, drilling, and coal handling plant. The dust levels were examined to assess miners' exposure to respirable dust in each of the opencast mining areas from 1994 to 2005. The data obtained from the dust measurement studies were evaluated by using analysis of variance (ANOVA) and the Tukey-Kramer procedure. The analyses were performed by using Minitab 14 statistical software. It was concluded that, drilling operations produce higher dust concentration levels and thus, drill operators may have higher incidence of respiratory disorders related to exposure to dust in their work environment.     

Validation of two air quality models for Indian mining conditions

All major mining activity particularly opencast mining contributes to the problem of suspended particulate matter (SPM)directly or indirectly. Therefore, assessment and prediction are required to prevent and minimize the deterioration of SPM due tovarious opencast mining operations. Determination of emission rate of SPM for these activities and validation of air quality models are the first and foremost concern. In view of the above, the study was taken up for determination of emission rate for SPMto calculate emission rate of various opencast mining activitiesand validation of commonly used two air quality models for Indianmining conditions. To achieve the objectives, eight coal and three iron ore mining sites were selected to generate site specific emission data by considering type of mining, method of working, geographical location, accessibility and above all resource availability. The study covers various mining activitiesand locations including drilling, overburden loading and unloading, coal/mineral loading and unloading, coal handling orscreening plant, exposed overburden dump, stock yard, workshop, exposed pit surface, transport road and haul road. Validation of the study was carried out through Fugitive Dust Model (FDM) and Point, Area and Line sources model (PAL2) by assigning the measured emission rate for each mining activity, meteorologicaldata and other details of the respective mine as an input to the models. Both the models were run separately for the same set ofinput data for each mine to get the predicted SPM concentrationat three receptor locations for each mine. The receptor locationswere selected such a way that at the same places the actual filedmeasurement were carried out for SPM concentration. Statisticalanalysis was carried out to assess the performance of the modelsbased on a set measured and predicted SPM concentration data. The value of coefficient of correlation for PAL2 and FDM was calculated to be 0.990-0.994 and 0.966-0.997, respectively, which shows a fairly good agreement between measured and predicted values of SPM concentration. The average index of agreement values for PAL2 and FDM was found to be 0.665 and0.752, respectively, which represents that the prediction by PAL2 and FDM models are accurate by 66.5 and 75.2%, respectively. These indicate that FDM model is more suited for Indian mining conditions.     

Generation and Quantification of Hazardous Dusts from Coal Mining in the Indian Context

The increasing trend of opencast coal mining in India tends to release huge amounts of dust. But there is no well-defined method of estimating dust emission due to different coal mining activities. This paper examines the sources of dust emission due to coal mining activities, and focuses on the quantification of dust emission with the development and use of emission factors. Because of their site-specific nature, emission factors developed for one site may not give the correct results for another site. In the present investigation, prediction equations are utilized for the development of emission factors. For the applications of this concept, one large opencast coal project of Bharat Coking Coal Ltd. (BCCL) was investigated, and the total amount of dust emitted due to different mining activities was calculated by the utilization of emission factor data, which was estimated to be 9368.2 kg/day. This paper also focuses on the significance of this study in the field of environmental protection and likely impacts of such study. The paper concludes that once the amount of dust generation is estimated, the impact on air quality can be assessed appropriately and a proper air-pollution control strategy can be developed.     

Characterization of different road dusts in opencast coal mining areas of India

Dust from haul and transport roads are the major source of air pollution in opencast coal mining areas. Dust generated during mining operations pollutes air which causes different health problems. Various available techniques are implemented in the field to minimize and control dust in mining areas. However, they are not very effective because dust deposited on road surfaces are not removed by these techniques. For effective control of dust in opencast mining areas, it has to be regularly collected from road surfaces and may be converted into solid form, and subsequently can be used as a domestic fuel considering its physicochemical properties. The present paper describes a comparative study of qualitative and quantitative aspects of road dust samples of four coalfields of India. The pH of the dust was found to be in the range of 5.1–7.7. Moisture, ash, volatile matter, fixed carbon, water-holding capacity, bulk density, and specific gravity of dust samples were found to be in the range of 0.5–3.0%, 45–76%, 12.6–20.0%, 10.2–45.3%, 21.17–31.71%, 1.15–1.70, and 1.73–2.30 g cm⁻³, respectively. Observing the overall generation and characteristics of coal dust, it is suggested that coal dust from haul and transport roads of mining areas can be effectively collected and used as domestic fuel.     

Air quality assessment along Dhanbad - Jharia road

Road ambient air pollution status along Dhanbad – Jharia road isstudied and presented in this article. The selection of this areais made considering the importance of the road in Dhanbad district and the nature of activities taking place along the road, which reflect that the portion of road upto Dhansar can be considered as having commercial areas on both sides and that from Dhansar to Jharia as having industrial areas on both sides.For the assessment of the ambient air quality along the road monitoring is done at the following five locations: Indian Schoolof Mines (ISM), main gate; Bankmore; Dhansar police check post; Dhansar opencast project agent office and a residential house beside the Rajapur opencast project. The location of ISM, maingate is specially chosen as this represents a commercial shoppingcomplexes and the situation can be compared with that at Bankmore. Monitoring of ambient air quality is done following thestandard procedure prescribed in IS: 5182. In addition the concentration of lead, zinc, copper, iron, manganese, cadmium metals in SPM is also monitored. The ambient air quality is monitored in the months of September and November 1999, respectively, to represent monsoon and winter seasons. The SPM concentration observed at all the five locations in the winterseason is more than the permissible limits for commercial andindustrial areas. However, in the monsoon season, the SPM concentration is higher than the permissible limit at the twocommercial locations, i.e., ISM gate and Bankmore, while it isless than the prescribed limit for industrial areas at the remaining three locations. At the ISM gate and Bankmore the SPM generation is mainly by vehicular traffic while at other three locations it was in addition due to mining and other activities.     

Characteristics of Hazardous Airborne Dust Around an Indian Surface Coal Mining Area

Surface coal mining creates more air pollution problems with respect to dust than underground mining . An investigation was conducted to evaluate the characteristics of the airborne dust created by surface coal mining in the Jharia Coalfield. Work zone air quality monitoring was conducted at six locations, and ambient air quality monitoring was conducted at five locations, for a period of 1 year. Total suspended particulate matter (TSP) concentration was found to be as high as 3,723 μg/m³, respirable particulate matter (PM10) 780 μg/m³, and benzene soluble matter was up to 32% in TSP in work zone air. In ambient air, the average maximum level of TSP was 837 μg/m³, PM10 170 μg/m³ and benzene soluble matter was up to 30%. Particle size analysis of TSP revealed that they were more respirable in nature and the median diameter was around 20 μm. Work zone air was found to have higher levels of TSP, PM10 and benzene soluble materials than ambient air. Variations in weight percentages for different size particles are discussed on the basis of mining activities. Anionic concentration in TSP was also determined. This paper concludes that more stringent air quality standards should be adopted for coal mining areas and due consideration should be given on particle size distribution of the air-borne dust while designing control equipment.     

Status of air pollution caused by coal washery projects in India

The importance of coal washeries in India is growing as local coals have a high ash content. At present, there are 23 coal washeries with an annual rated input of 45 Million Tonnes. During the various operations in washeries, large amounts of dusts and gaseous pollutants are generated. Four coal washery projects were surveyed to study their air pollution characteristics. Air monitoring stations were set up in local industrial, residential and sensitive areas and air pollution samples were collected along with micro-meteorological data. Diurnal variations of SPM, SO₂ NO_x and CO are discussed. SPM concentrations were found to exceed the permissible limits at all locations. SO₂ and NO_x were also found to exceed the permissible limit in residential and sensitive areas. It was observed that about 50% of the dust particles were less than 10 µ in diameter. Benzene soluble matter in SPM ranged from 45–62%.     

Equivalency of a personal dust monitor to the current United States coal mine respirable dust sampler

The United States National Institute for Occupational Safety and Health, through an informal partnership with industry, labor, and the United States Mine Safety and Health Administration, has developed and tested a new instrument known as the Personal Dust Monitor (PDM). The new dust monitor is an integral part of the cap lamp that coal miners normally carry to work and provides continuous information about the concentration of respirable coal mine dust within the breathing zone of that individual. Previous laboratory testing demonstrated that there is a 95% confidence that greater than 95% of individual PDM measurements fall within +/-25% of reference measurements. The work presented in this paper focuses on the relationship between the PDM and respirable dust concentrations currently measured by a coal mine dust personal sampler unit utilizing a 10 mm Dorr-Oliver nylon cyclone. The United Kingdom Mining Research Establishment instrument, used as the basis for coal mine respirable dust standards, had been designed specifically to match the United Kingdom British Medical Research Council (BMRC) criterion. The personal sampler is used with a 1.38 multiplier to convert readings to the BMRC criterion. A stratified random sampling design incorporating a proportionate allocation strategy was used to select a sample of mechanized mining units representative of all US underground coal mines. A sample of 180 mechanized mining units was chosen, representing approximately 20% of the mechanized mining units in production at the time the sample was selected. A total of 129 valid PDM/personal sampler dust sample sets were obtained. A weighted linear regression analysis of this data base shows that, in comparison with the personal sampler, the PDM requires a mass equivalency conversion multiplier of 1.05 [95% C.I.=(1.03, 1.08)] when the small intercept term is removed from the analysis. Removal of the intercept term results in a personal sampler-equivalent concentration increase of 2.9% at a PDM measurement of 2.0 mg m(-3).     

Air Quality Status of an Open Pit Mining Area in India

This investigation presents the assessment of ambient air quality carried out at an open pit coal mining area in Orissa state of India. The 24-h average concentrations of suspended particulate matter (SPM), respirable particulate matter (RPM, particles of less than 10 m aerodynamic diameter), sulphur dioxide (SO₂) and oxides of nitrogen (NO_x) were determined at regular interval throughout one year at 13 monitoring stations in residential area and four stations in mining/industrial area. During the study period, the 24-h and annual average SPM and RPM concentrations exceeded the respective standards set in the Indian ambient air quality standard (NAAQS) protocol in most of the residential and industrial areas. However, the 24-h and annual average concentrations of SO₂ and NO_x were well within the prescribed limit of the NAAQS in both residential and industrial areas. A management strategy is formulated for effective control of particulate matter at source and other mitigative measures are recommended including implementation of green belts around the sensitive areas.     

北方沙尘对江苏环境空气中可吸入颗粒物浓度的影响

利用卫星遥感数据、气象观测资料和江苏省环境空气自动站的可吸入颗粒物的监测数据,对春季中国北方的沙尘暴过程对江苏环境空气中可吸入颗粒物浓度的影响分析发现,沙尘暴所含的沙尘粒子在冷空气的引导下可能进入江苏,对环境空气中可吸入颗粒物浓度将会产生较大的影响;北方沙尘暴所携带的沙尘粒子是春季江苏空气污染的重要来源之一,是预报空气质量异常偏高的重要依据之一。     

Assessing metal pollution in ponds constructed for controlling runoff from reclaimed coal mines

Constructing ponds to protect downstream ecosystems is a common practice in opencast coal mine reclamation. As these ponds remain integrated in the landscape, it is important to evaluate the extent of the effect of mine pollution on these ecosystems. However, this point has not been sufficiently addressed in the literature. The main objective of this work was to explore the metal pollution in man-made ponds constructed for runoff control in reclaimed opencast coal mines over time. To do so, we evaluated the concentration of ten heavy metals in the water, sediment, and Typha sp. in 16 runoff ponds ranging from 1 to 19 years old that were constructed in reclaimed opencast coal mines of northeastern Spain. To evaluate degree of mining pollution, we compared these data to those from a pit lake created in a local unreclaimed mine and to local streams as an unpolluted reference, as well as comparing toxicity levels in aquatic organisms. The runoff ponds showed toxic concentrations of Al, Cu, and Ni in the water and As and Ni in the sediment, which were maintained over time. Metal concentrations in runoff ponds were higher than in local streams, and macrophytes showed high metal concentrations. Nevertheless, metal concentrations in water and sediment in runoff ponds were lower than those in the pit lake. This study highlights the importance of mining reclamation to preserve the health of aquatic ecosystems and suggests the existence of chronic metal toxicity in the ponds, potentially jeopardizing pond ecological functions and services.     

Assessment of air pollution from small scale industry

Air pollution due to small scale industries have been found tocause serious occupational health hazards and adverse effects on vegetation and heritage. The study for air pollution impactassessment for brick kiln industries was undertaken. The stackmonitoring exercise was carried out to estimate the pollution level of SPM, SO₂, and NO_x. The ambient air quality was also measured in the vicinity of brick kilns to assess the impact of stack emission on ground level concentration. Characterisation of SPM for toxic metals were studied. Modelling exercise was carried to predict the impact of emission of brick kiln on surrounding environment. To minimise the emission level and ground level concentration, airpollution mitigation measures are suggested.     

Assessment of the sources of suspended particulate matter aerosol using US EPA PMF 3.0

The main purpose of this paper was to carry out a source apportionment of suspended particulate matter (SPM) samples using positive matrix factorization procedure. The central and local Government of Japan introduced strict emission regulations in 2002/10 and 2003/10, respectively, in curbing SPM pollution from major metropolitans. This paper also highlighted the impact of the measures taken by the central and local Government of Japan on the reduction of SPM and the contributions of sources. SPM samples were collected for 6 years starting from 1999 to 2005 at two sites, i.e., site A (urban) and site B (suburban) of Yokohama, Japan. Microwave digestion and inductively coupled plasma-mass spectroscopy (ICP-MS) were employed to measure Mg, Al, Ca, V, Cr, Mn, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, Cs, Ba, Pb and Bi, while water soluble ions (Na⁺, NH₄  ⁺_{4}^{\ \,+}, K⁺, Ca^2 +, Mg^2 +, Cl⁻, NO₃  ^-_{3}^{\ \,-} and SO₄  ^2-)_{4}^{\ \,2-}) as well as carbonaceous mass (EC and OC) were analyzed using ion chromatograph and CHN analyzer, respectively. The sources identified at two sites were automobile, soil dust, marine aerosol, mixed sources, and secondarily formed aerosol. Also, source quantification was performed. Automobile and soil dust were striking contributors at site A. Automobile and soil dust of SPM aerosol might be produced from local origin at current study areas. Besides, Asian dust had an impact on high concentrations of SPM aerosol in some certain period of the year due to the outflows of East Asian emission. In contrast, secondary aerosol in the form of sulfate and ammonium as well as mixed sources (coal, long-transported Cs, and other unknown sources) were remarkable at site B. Stationary/industrial combustion has apparently more impact on the release of SPM components at site B than A. Automobile regulations in 2002 and 2003, respectively, resulted in reduction of SPM by 28% for site A and 16% for site B. There was also net reduction of automobile contribution at both sites due to the above measures being implemented.     

徐州市不同类型颗粒物重污染过程特征及组分差异性分析

经过多年的大气污染防治,我国空气质量有了大幅改善,但重污染过程仍有发生。对2018—2021年徐州市3种不同类型颗粒物重污染过程的污染特征、演变趋势、PM_2.5组分特征和相关性及污染成因分析结果表明:在不同类型的重污染过程中,二次无机离子NO₃^-、SO₄^2-、NH₄⁺在PM_2.5中的占比均是最高。在累积型重污染期间,NO₃^-、SO₄^2-、NH₄⁺分别增长144%、142%、183%,二次无机离子对PM_2.5的增长贡献较大。结合相关性分析及SOR、NOR值发现,硝酸盐和硫酸盐的二次生成作用显著。在沙尘型重污染期间,结合雷达监测结果及后向轨迹图可以看出,沙尘沉降至高空与近地面污染物叠加造成颗粒物高值。化学组分中Ca²⁺、Mg²⁺浓度对PM_2.5浓度的影响最大,二次生成和转化对其影响较小。在烟花燃放型重污染期间,和烟花爆竹有关的K⁺、Mg²⁺、Cl^-离子较污染前分别上升1 112%、2 058%、和239%,对污染过程影响显著。     

我国西北典型大城市大气可吸入颗粒物浓度分布特征

我国西北地区冬季寒冷、春季多风沙天气,空气中的可吸入颗粒物(PM10)浓度较高,利用兰州、西宁、乌鲁木齐、银川、呼和浩特等城市2000年6月～2007年12月每日浓度最高的大气主要污染物(SO2,NO2,PM10)浓度资料,研究了5个省会城市PM10分布特征。结果表明,五个城市PM10污染都较严重,PM10为主要污染物的日数每月平均超过20天。五个城市的季节分布特征类似,冬春季浓度较高,平均值都达到了国家二级污染标准,夏秋季相对低一些。其中,兰州和乌鲁木齐冬季浓度值远高于其他城市。五个城市均属煤烟沙尘型污染,但煤烟和沙尘的影响程度有所不同。     

京津冀地区经济发展与PM10浓度变化的灰色关联分析

近几年,京津冀地区因灰霾天气频发而备受关注。通过分析京津冀地区PM10浓度变化与主要经济指标的关系,查找京津冀地区空气污染原因,并为今后污染控制措施提供参考。采用灰色关联分析法,对2007—2012年京津冀地区PM10与GDP、钢铁产量、煤炭消费总量、原油消费总量、天然气消费总量5项经济指标进行了分析,结果表明,在与本地经济指标的关联度方面,京津冀地区、北京市、天津市的PM10与煤炭消费总量相关性高;河北省略有不同,钢铁产量为关联度最高的经济指标。在与京津冀地区经济指标的关联度方面,相比本地,北京市、河北省均呈现较大差异性,天津市差异性较小,说明北京市、河北省空气质量受自身影响较大,天津市空气质量受区域传输影响明显。建议整个京津冀地区均应重点加大"控煤"力度,天津市还需加强区域联防联控力度,河北省应加快钢铁企业转型升级,压缩过剩产能。     

Measurements of SO2, NO X and SPM in an industrial area at the Aegean coast of Turkey

Data from continuous measurements of SO₂ NO _x , suspended particulate matter (SPM) and meteorological parameters at seven sites around a highly industrialized region in the Aegean coast of Turkey, between July 15, 1991 to July 31, 1992 were used to evaluate spatial and temporal variations of air quality parameters. Low annual averages and insignificant differences between day and night concentrations were observed at stations far from sources. At stations close to sources, annual average concentrations were high and diurnal patterns were significant. Annual average SO₂ and SPM concentrations in all stations used the Krigging technique to assess the impact of industries on air quality in the surrounding airshed. Results have demonstrated that Turkish air quality standards for SO₂ were exceeded in a circle with a radius of 4 km and which was centered on the petrochemical complex and refinery. Similarly, standards for SPM were exceeded in a circle with a radius of 1.2 km and which was centered on the ironwork plants. Both SO₂ and SPM showed well defined diurnal variations, particularly in stations close to sources. The SO₂ concentrations showed a maximum during day-time, while SPM concentrations peaked after midnight. Although annual average SO₂ and SPM concentrations were highly variable depending on distances between stations and sources, background concentrations of the same pollutants, calculated by stripping episodes from data, did not change significantly from one station to another. Long range transport and resuspension of local soil were suggested as sources of background SO₂ and SPM, respectively. The difference between observed and background concentrations of SO₂ and SPM in each station was related to the impact of industries on air quality at that particular site.     

Ambient Air Quality Status in Raniganj-Asansol Area, India

This investigation presents the assessment of ambient air quality with respect to suspended particulate matter (SPM), sulphur dioxide (SO₂) and oxides of nitrogen (NO_X) at four sites (RGC, SRS, BBC and BCC) in the Raniganj-Asansol area in West Bengal, India. Ambient air was monitored with a sampling frequency of twenty four hours (3 × 8 hours) at each site on every alternate day (3 days a week) covering a period of one year. A total of 429 samples were collected from RGC, 429 from SRS and 435 each from the BBC and BCC sites. Meteorological parameters such as temperature, relative humidity, wind-speed and wind-direction were also recorded simultaneously during the sampling period. Monthly and seasonal variation of these pollutants have been observed and recorded. The annual average and range values have also been calculated. Results of the investigation indicates that the 95th percentile values of SPM levels exceed the limits (200 g m^-3) at RGC, SRS and BBC sites and is within the limit of 500 g m^-3 at the BCC sites. The 95th percentile values of SO₂ levels did not exceed the reference level at any of the monitoring stations. The 95th percentile values of NO_X are found to be exceeding the limit (80 g m^-3) at RGC, SRS and BBC sites but is within the prescribed limit of 120 g m^-3 at the BCC site. Further, it has been observed that the concentrations of the pollutants are high in winter in comparison to the summer or the monsoon seasons. Results of the investigation indicates that industrial activities, indiscriminate open air burning of coal by the local inhabitants for cooking as well as coking purposes, vehicular traffic, etc. are responsible for the high concentration of pollutants in this area.     

青海高原一次沙尘重污染天气成因分析

利用常规观测的卫星云图资料、地面资料、探空资料、地面污染物监测数据,结合拉格朗日粒子扩散模型(LPDM)污染源溯源方法,对2018年2月青海高原一次沙尘重污染天气的主要成因以及沙尘传输特征进行了分析。结果表明:此次重污染天气受高空低槽东移影响,在300~700 hPa形成了强烈的辐散下沉,槽后的高空急流随之东移。在其东移过程中,受高空急流动量下传及偏北气流中的冷空气共同作用,青海东部出现了大风沙尘天气。边界层中逆温层的存在是此次污染天气持续的重要原因之一,加之未出现明显降水,不利于大气污染物的扩散。通过运用LPDM对此次污染天气的运动轨迹进行分析来看,气团影响的模拟高度层距离地面100 m,气团层趋势一致。研究区地处青藏高原,海拔较高,0~100 m高度的气团足迹可以反映出PM 10污染气团的输送路径。同时,0~100 m是主要的人为源排放空间,也是对人类活动影响较大的区域。气团足迹与PM 10浓度的变化趋势一致,即青海东部沙尘污染主要是由河西走廊沙尘倒灌进入青海东部导致,这与天气学分析结果一致。