Coal Exploration Research Articles

Geology and potential hydrocarbon play system of Lower Karoo Group in the Maamba Coalfield Basin, southern Zambia

This study attempts to augment geology and potential hydrocarbon play system database not only in the Maamba Coalfield basin of southern Zambia but in other similar continental non-marine Karoo rift basins in the region as well. Geological analyses were conducted through extensive outcrops and exposures and subsurface boreholes. Six (6) major lithofacies (diamictites, conglomerates, sandstones, siltstones, coal and mudstones) represents Lower Karoo Group sequence. Four (4) mudstone core samples were prepared for thin section petrography. In addition, six (6) samples of sandstones obtained from outcrops, exposures and cores were impregnated with blue epoxy before thin sectioning in order to facilitate easy recognition of porosity. Quantification of framework grain composition and porosity was achieved by point counting a total of 300 points per thin section. The identification of diagenetic constituents and pore types was made possible by the use of scanning electron microscopy (SEM). Rock-Eval pyrolysis analyses utilised 35 core samples of mudstones and coal.According to results of the analyses, three (3) deposition settings which include; alluvial, fluvial-lacustrine and lacustrine setting are envisaged. . Fluvial-lacustrine deposits are host to mudstones and coal source rocks and sandstone reservoir rocks. Mudstones and coal source rocks gave the total organic carbon (TOC) that is well above the recommended thresholds of 0.5 wt % and 2.5 wt % of gas and oil generation respectively. The hydrogen index (HI) values are mostly below 200 mg HC/g TOC, indicating fair quantities of type III kerogen. The thermal maturity readings measured by temperature Tmax range from 440 to 485 °C in agreement with calculated vitrinite reflectance (Rocalc) range of 0.76–1.57% indicating mature to post mature stages. This maturation is attributed to the burial temperatures and near-surface heat flows by faults. Production Index (PI) values are less than 0.1 suggesting some hydrocarbon expulsion possibly gases and gas condensates. Sandstones are moderate to poor sorted sublitharenites. Total porosity in sandstones range between 0 and 6.3%, averaging 2.5%, and is mainly secondary porosity resulting from dissolution of labile minerals and fracture. Deposition and diagenetic related controls influenced much of the reservoir quality in sandstones. Lacustrine mudstones are the potential seal rocks. The major Structural traps are faults (e.g. normal and reverse faults) and the stratigraphic traps are sandstones.In this study, our area of focus is in the north and central part of Maamba Coalfield Basin where coal mining and exploration activities are currently taking place. The southernmost part of the basin is under developed such that the hydrocarbon play system potential is still unknown. However, recent coal exploration drilling has revealed the presence of source rocks at depth overlain by extensive overburden seal rocks. Based on the play concept analysis, it is possible to find more encouraging results from this area.

Research on Coal Exploration Technology Based on Satellite Remote Sensing

Coal is the main source of energy. In China and Vietnam, coal resources are very rich, but the exploration level is relatively low. This is mainly caused by the complicated geological structure, the low efficiency, the related damage, and other bad situations. To this end, we need to make use of some advanced technologies to guarantee the resource exploration is implemented smoothly and orderly. Numerous studies show that remote sensing technology is an effective way in coal exploration and measurement. In this paper, we try to measure the distribution and reserves of open-air coal area through satellite imagery. The satellite picture of open-air coal mining region in Quang Ninh Province of Vietnam was collected as the experimental data. Firstly, the ENVI software is used to eliminate satellite imagery spectral interference. Then, the image classification model is established by the improved ELM algorithm. Finally, the effectiveness of the improved ELM algorithm is verified by using MATLAB simulations. The results show that the accuracies of the testing set reach 96.5%. And it reaches 83% of the image discernment precision compared with the same image from Google.

The Permian–Triassic transition in the Moatize–Minjova Basin, Karoo Supergroup, Mozambique: A palynological perspective

The Permian–Triassic transition has been identified for the first time in the Karoo Supergroup of the Moatize–Minjova Basin in Mozambique. This transition was identified in the subsurface in deep (ca. 500m) coal exploration boreholes that penetrated the Matinde Formation. Two palynomorph assemblages (assemblage 1 and assemblage 2) assigned to the latest Permian were defined for the Matinde Formation. These assemblages are both dominated by taeniate pollen, cavate trilete spores of Kraeuselisporites spp., associated with conifer (Lueckisporites virkkiae) and pteridosperm pollen (Guttulapollenites hannonicus and Weylandites lucifer). Assemblage 3 represents a microfloral turnover. For the first time specimens of Lunatisporites pellucidus appear in an assemblage dominated by lycopod spore taxa such as Lundbladisporites spp. This assemblage was assigned to the Early Triassic and occurs at the top of borehole DW 132 within the Matinde Formation. The palynostratigraphic signature obtained for the Permian–Triassic transition puts the Moatize–Minjova Basin in the central Gondwana palaeobiogeographic province with strong affinities with the Karoo basins of Madagascar and the Salt Range Basin in Pakistan. These new data indicate that coal deposits accumulated in the Moatize–Minjova Basin until the latest Permian and that these are possibly more extensive temporally than previously described, opening new perspectives for coal and unconventional hydrocarbon exploration in this basin.

Evaluation of Automated Lithology Classification Architectures using Highly-Sampled Wireline Logs for Coal Exploration

Wireline logs are a supplemental data source to conventional core logging. The recent explosion of machine learning algorithms has provided researchers with ample opportunity to develop automated statistical tools for classifying lithology from wireline logs, which geologists can use to produce first-pass interpretations or to validate existing interpretations. Such automated interpretations can be particularly valuable information in the case of missing or damaged core samples. There exists, however, a need to evaluate said machine learning algorithms in the case where available wireline logs contain a wide range of different logs which are highly-sampled. This paper explores different machine learning algorithms and architectures for lithology classification using wireline data from project area Jundah East, 60 km north-west of Wandoan, Queensland, which is well known for coal mineralisation. We used seven well logs each containing 19 wireline logs sampled at 1 cm-1, available through the Queensland Digital Exploration (QDEX) data system. Three popular supervised machine learners, namely the Naive Bayes classifier, Support Vector Machine, and Multilayer Perceptron (an artificial neural network), are tested under two architectures: committee (one classifier per well log) and singular (one classifier for all well logs). The results show the Naive Bayes classifier, although computationally simple, achieves good results in general when training using a committee architecture on a large data set. For coal classification in particular, it achieved the sensitivity score of 0.79 and the specificity score of 0.97. While the committee and singular architectures generated similar results, the committee architecture provides the benefits of faster computation time as well as a flexible platform for the training of additional well logs.

The thermal history of the Karoo Moatize-Minjova Basin, Tete Province, Mozambique: An integrated vitrinite reflectance and apatite fission track thermochronology study

The Moatize-Minjova Basin is a Karoo-aged rift basin located in the Tete Province of central Mozambique along the present-day Zambezi River valley. In this basin the Permian Moatize and Matinde formations consist of interbedded carbonaceous mudstones and sandstones with coal seams. The thermal history has been determined using rock samples from two coal exploration boreholes (ca. 500 m depth) to constrain the burial and exhumation history of the basin. Organic maturation levels were determined using vitrinite reflectance and spore fluorescence/colour. Ages and rates of tectonic uplift and denudation have been assessed by apatite fission track analysis. The thermal history was modelled by inverse modelling of the fission track and vitrinite reflectance data. The Moatize Formation attained a coal rank of bituminous coals with low to medium volatiles (1.3–1.7%Rr). Organic maturation levels increase in a linear fashion downhole in the two boreholes, indicating that burial was the main process controlling peak temperature maturation. Calculated palaeogeothermal gradients range from 59 °C/km to 40 °C/km. According to the models, peak burial temperatures were attained shortly (3–10 Ma) after deposition. Apatite fission track ages [146 to 84 Ma (Cretaceous)] are younger than the stratigraphic age. Thermal modelling indicates two episodes of cooling and exhumation: a first period of rapid cooling between 240 and 230 Ma (Middle – Upper Triassic boundary) implying 2500–3000 m of denudation; and a second period, also of rapid cooling, from 6 Ma (late Miocene) onwards implying 1000–1500 m of denudation. The first episode is related to the main compressional deformation event within the Cape Fold Belt in South Africa, which transferred stress northwards on pre-existing transtensional fault systems within the Karoo rift basins, causing tectonic inversion and uplift. During the Mesozoic and most of the Cenozoic the basin is characterized by very slow cooling. The second period of fast cooling and denudation during the Pliocene was likely related to the southward propagation of the East African Rift System into Mozambique.

Evaluation of automated lithology classification architectures using highly-sampled wireline logs for coal exploration

Wireline logs are a supplemental data source to conventional core logging. The recent explosion of machine learning algorithms has provided researchers with the opportunity to develop advanced statistical tools for automatically classifying lithology from these logs, enabling geologists to rapidly produce first-pass interpretations and validate others, even when core samples are missing or damaged. However, the machine learning algorithms need to be evaluated in the case where wells contain a large number of wireline logs which are highly-sampled. This paper explores different machine learning algorithms and architectures for classifying lithologies (e.g. coal and sandstone) using wireline data from a project area well-known for coal mineralisation: Juandah East, 60km north-west of Wandoan (Queensland, Australia). We used data from seven wells, each containing 19 wireline logs uniformly sampled at 1cm, retrieved from the open Queensland Digital Exploration (QDEX) database.Three popular supervised machine learners, namely the Naïve Bayes classifier, Support Vector Machine, and Artificial Neural Network, were tested under two architectures: committee (one classifier per well log) and singular (one classifier for all well logs). Favourable performance was achieved under both architectures when the base classifier was tuned to maximise a coal-specific performance metric. Results show that the committee architecture increased overall accuracy, generally by increasing accuracy on the dominant lithology class and reducing the classification rate of minor lithology classes. Overall accuracy was further improved by post-processing to remove thin classified intervals (<10cm). The committee architecture provides the benefits of faster classifier training time through parallelisation, as well as a flexible platform for incorporating additional well logs without the need to retrain existing classifiers.

Mineral matter, major and trace element content of the Afşin–Elbistan coals, Kahramanmaraş, Turkey

The Afşin–Elbistan coal basin is one of the most important coal deposits of Turkey. The mineral matter, major and trace element concentrations of the Afşin–Elbistan coals and their modes of occurrence are discussed in this study. The coal seam is located within the Upper Miocene–Pliocene aged Ahmetcik Formation which is represented by fluvial–lacustrine facies. Thickness of the coal zone is 80m, but it reaches 105m in the Kışlaköy sector. A total of 86 samples were taken from the Kışlaköy open-pit mine and from the 14 boreholes drilled by the General Directorate of Mineral Research and Exploration (MTA) for coal exploration. The proximate, XRD, SEM-EDS, major and trace element analyses were conducted on the samples. The studied coals are characterized by relatively high moisture, ash, total sulfur, volatile matter contents and low gross calorific values. The mineral matters of the Afşin–Elbistan coal are represented by calcite, quartz, pyrite, feldspar, aragonite, opal-CT, gypsum, jarosite and clay minerals. Strontium, Rb, Sm, Zr, Hf, Nb, Mo, U, Zn, Pb, As, Mn, Co, Cr and Ni concentrations detected by EDP-XRF are higher than the world brown coal values. Many of the trace elements showing positive correlations with ash content imply inorganic affinity. The element concentrations of the coals are mainly related to the carbonate, silicate, sulfide, phosphate, ore minerals and fossil shells. However, some elements have also organic affinities.

Relações entre a Atividade Carbonífera e o Rural em Candiota, RS, Brasil: análises sobre representações sociais em um contexto de dilemas sobre a energia

A geração de energia termelétrica à base de carvão mineral tem despertado distintas opiniões e significados. O objetivo deste artigo é investigar as representações sociais que grupos e atores sociais no espaço rural compartilham em torno da temática da exploração do carvão mineral no município de Candiota (RS), sul do Brasil. Foi possível identificar algumas representações que compõem a relação entre o rural e o carvão no município. Do ponto de vista teórico e metodológico, optou-se pela Teoria das Representações Sociais, de Serge Moscovici, e pela abordagem estrutural das representações sociais de Jean-Claude Abric. Foram entrevistadas 46 pessoas entre janeiro e março de 2012. A representação central da atividade carbonífera no caso estudado situa-se em torno da ideia de "crescimento econômico", retratando um discurso embasado no universo reificado de alguns setores socioeconômicos e a pressão à inferência sobre grupos. Os entrevistados, em sua maioria, são favoráveis à atividade (53%), enquanto 28% são contrários e 19% não se consideram nem favoráveis nem contrários, variando seus argumentos conforme a posição social. No caso estudado, o grau de dependência em relação à exploração do carvão é instável e dinâmico.

Selection of strategic replacement areas for CBM exploration and development in China

At present, the increase in proved reserves and production of coalbed methane (CBM) in China depends mainly on several CBM bases in the southern Qinshui Basin and in the eastern margin of the Ordos Basin. Therefore, it is urgent to find new batches of exploration and development strategic replacement areas. For this purpose, we investigated the resources, reservoir properties, preservation conditions, and development conditions of CBM in China, and put forward eight general factors and four critical factors that can be used in establishing selection criteria of strategic replacement areas for affecting the CBM exploration and development in China. The eight general factors are resource abundance, coalbed thickness, gas content, original permeability, burial depth, hydrogeological conditions, coalbed depositional environment, and landforms, and the four critical factors include genetic type, stability type, later reservoir reformation, and damage degree of coal structure. Comparison shows that the low-rank coal area in the northwestern area, the northeastern medium-low rank coal area, and the southwestern medium-high rank and structurally-complex coal area are the major replacement areas for CBM following the northern area of China. Key factors affecting CBM enrichment in each of the three key areas, respectively, are: a) genetic type and stability of coal seams, b) genetic type and reconstruction of the reservoir by volcanic intrusion, and c) stability of coal seams and damage degree of coal structure. Based on these factors, a system for selection and evaluation of strategic replacement areas for CBM development was established. Fifteen blocks in the above three areas were evaluated by using multi-layered fuzzy mathematics, selecting eight favorable areas and seven relatively favorable areas that contain 1.8 trillion m3 of predicted CBM geological resources. The eight favorable areas include the Wucaiwan-Dajing coal exploration area in the Zhundong coalfield (eastern Junggar Basin), the Hami-Dananhu mining area in the Turpan-Hami Basin, the Longdong coalfield (eastern Gansu Province), the Yilan and Hegang coalfields in eastern Heilongjiang Province, the Hunchun coalfield in Jilin Province, the southern Sichuan coalfield, and the Shuicheng coalfield in Guizhou Province. These favorable areas were recommended to be the CBM exploration and pilot development target areas in the near future.

Favorable Areas Prediction in Jixi Basin

Based on coalbed methane geology theory, make use of coal and oil drilling data, from both of the coal reservoir characteristics and conservation conditions, Through comparative analysis of a number of geological factors of coalbed thickness, burial depth, metamorphic grade, gas content, roof and floor lithology, dip angle, etc, and found that there are many similarities between Jixi Basin and Black Warrior Basin in the United States of coalbed methane reservoir conditions. Furthermore, referred the domestic and abroad coalbed methane mining experience, a number of geological factors of Jixi Basin were made grading evaluation, optimized favorable blocks, and we found that the favorable coalbed methane target area are the F and H in the south of the basin, and the F block can be used as the preferred favorable coal exploration area.

PERTUMBUHAN BEBERAPA JENIS LEGUMINOSA PAKAN YANG DITANAM PADA MEDIA TANAH BEKAS PENAMBANGAN BATUBARA DENGAN PERBAIKAN BAHAN ORGANIK

Conditions of post coal mining areal which having losing of vegetation because of coal exploration usually have high soils acidity (pH < 5) and poor of organic matter and nutrient for plants to growing good. The mining company usually adding organic matter and planting forage legume to increase the organic matter of the soils. Objective of the research was to evaluate the growth of some forage legume that adapted on post coal mining soils dan the respone of organic matter added for post coal mining soils. Factorial Completely Randomized Design (CRD) with three replications were used in this experiment. The first factor was four kinds of forage legume, i.e. (L1 = Centrosema pubescens; L2 = Pueraria javanica; L3 = Calopogonium mucunoides; and L4 = Crotalaria juncea). The second factor was three kinds of plant medium (M0 = non post mining soil; M1 = post coal mining soil without organic matter added; and M2 = post coal mining soil with organic matter added (2% of organic carbon)). Collected data were analyzed by Analysis of Variance (ANOVA), followed by Least Significant Defference (LSD) at 5% level of sifnificant. The result of this experiment showed that application of organic matter on post coal mining soils increased the measured parameters (plant height, root lenght, leaf number, and root nodule number) of forage legume. According to the result of this experiment, concluded that Calopogonium mucunoides (L3) was more adapted on post coal mining soils than the other forage legumes, but Crotalaria juncea (L4) was more responsive for organic matter added.

Letter from chief editor

As a country with abundant coal, lean oil and scarce gas, China has been depended too much on coal. Coal accounts for about 66 % (www.zgmt.com.cn) of primary energy consumption of China in 2013. China’s raw coal output totaled 3.6 billion tons, but coal consumption approximated 4 billion tons, 47.4 % and 50.3 % of the world’s gross coal output and consumption separately (www.BP.com). America, Australia, South Africa, Germany, Poland, Russia, India, Indonesia, Mongolia and Vietnam are also big coal producers. According to IEA projections, the world’s coal production and consumption will continue to increase in the future 20 years. The production and use of coal couldn’t be possible without successful efforts to study and solve a series of scientific and technological problems and to exchange and summarize the results, experiences and lessons in the research and engineering process. Journal of Coal Science & Engineering (China), as the technological exchange platform on coal development, published by China Coal Society, already fails to address the current demands of domestic coal science & technology circle. So it’s urgent to shift the fields of academic exchange from the previous stress on coal exploration and development to coal conversion, efficient use and environmental protection. After two years’ preparation, this new journal: International Journal of Coal Science & Technology (JCST), is established. This academic journal will be the first publication which focuses purely on one of the current crucial global topics, coal science and technology. JCST will publish original, high-quality, peer-reviewed research or review articles dealing with coal science and technology, mainly including:

Palynology, Palynostratigraphy and Paleoenvironmental Analysis of Maiganga Coal Mine, Gombe Formation, Nigeria

Palynological analysis provides data for determinations of ages, palynostratigraphy and paleoenvironments of the studied parts of Gombe Formation (around Maiganga coal mine) in the Upper Benue Trough. The studied sections of the formation were sampled from the drilled cores of the strata derived from the coal exploration drilling project carried out at Maiganga. A total of 174 core samples from three boreholes that penetrated the strata have been studied for their palynofloral contents and the results used to date, zone and interprete the paleoclimatic conditions of the paleoclimatic conditions of the studied strata. The aim was to establish their microfloral assemblages, age, paleoclimate and biozonation. The standard maceration method was employed for the palynological analyses employing both acid and hydrogen peroxide as the processing media. The studied boreholes (BA-7, BA-16 and BA-17) were considerably rich in palynomorphs especially the samples processed with H2O2. Majority of the pollen and spores observed from the study included Proteacidites sigalii, Retidiporites magdalensis, Monoporites annulatus, Cingulastisporites ornatus,Rugulatisporites caperatus, Scabratriporites annellus, Proteacidites longispinosis, Distaverrusporites simplex and Foveotrilete margaritae. The recovered marker species have been used to date the studied section Early-Late Maastrichtian. The analyses of the palynomorphs were used to interpret the paleoclimate of the studied sections as well as zoning the sections into two palyzones, Proteacidites sigalii-Echitriporites trianguliformis and Cyathidites spp-Laevigatosporites haardtii zones. The paleoclimatic conditions were inferred to belong to the Late Cretaceous Palmae province.

Analysis on Rock Properties Based on Exploration of Hole Wall's Stability

Hole wall's stability is a complex problem which exploration engineering has been working to solve. There are many reasons which may lead to hole wall's instability. Aiming at hole wall's stability in coal exploration, this paper takes shale as objects of study and uses the MPC method (for example: analyzing on rock's microstructure characteristics, physical and mechanical properties, and chemical characteristics) to make a thorough research on unstable coal shale formations in a work area in LuoPing district. The results show that the shale in the area has high content of the mixed-layer of illite and smectite, water intrusion dramatically decreases rock strength and elastic modulus and leads to poor mechanical properties. Considering the coupling effects of mechanical properties as well as the drilling fluid sealing characteristics of drilling fluid must be improved and its osmotic pressure should be reduced.

An environmentally-friendly integrated seismic imaging for coal exploration in the Miocene Soma Basin, Western Turkey

Seismic reflection data from target depths of several hundred metres have been acquired and processed as an aid for lignite exploration in the Miocene Soma Basin, western Turkey. An environmentally-friendly approach was followed by acquiring the data with mini-vibroseisseismic source along crooked lines, using available mountain/forest and village roads; quality control tests were conducted to determine optimal field parameters that would yield dataset with best signal-to-noise (SN) ratio prior to real data acquisition; and stratigraphic interfaces giving rise to reflection events in the seismic data were identified from the vertical seismic profiling (VSP). Stacked seismic sections were successfully correlated with geological cross-sections drawn based on available borehole data. Thus, it is shown that decreasing time and the cost for coal exploration is possible by utilising surface and VSP. Environment friendly approach of the seismic method applied in this study is also beneficial in regard to environmental concerns.

Optimising seismic data acquisition parameters for open-cut coal exploration using a shallow high resolution reflection seismic test survey

A shallow high-resolution seismic reflection test survey was conducted in the Maryborough Basin in an area near Gundiah, Queensland. The purpose of the seismic reflection test survey was to evaluate the application of using high resolution seismic data acquisition methods to detect thin coal seams at between 30m to 150m depth for open-cut coal exploration. The seismic test survey tested three seismic sources which included a 50kg weight-drop from 2m height, a 7kg sledgehammer, and a 12g (blank cartridge) in-hole shotgun. Seismic forward modelling indicated that thin coal seams (1 to 2m thickness) should provide seismic reflections at shallow depths of 30m, using 72 channel recording with 2m geophone intervals. The seismic source tests showed that the 12g in-hole shotgun produced the strongest seismic signal at the furthest geophone offsets. The seismic recording spread consisted of 96 seismic channels with single spiked 30hz geophones spaced at 2m geophone intervals. Based on the seismic source tests, the 12g in-hole shotgun was used to record a seismic test line with shot-points recorded from one end of the 96 channel spread through to the other end of the spread. The recording arrangements provided seismic data to both test data quality with shot to receiver offset, and examine the optimum common depth point (CDP) fold coverage to use for a larger seismic survey. Based on the seismic data processing results, a larger seismic survey could be conducted using a 72 channel recording spread with 4m geophone and shot-point intervals and achieve production rates of 400m per day with a 3-man crew.

Internal Combustion Impulse Source vs. Mini-vibrator vs. Nomad 65 vibrator shot tests

Over the last two decades 3D reflection seismic has been applied for mine planning in South Africa. For coal exploration, the mining targets are at shallower depths of less than 400m. The challenge set by the mining companies is to obtain high-resolution seismic data with maximum vertical resolution at this depth of investigation. The cost of geophysics must also be more attractive than that of the 'total drilling' alternative. Seismic source trials were therefore conducted at one mine site. The ICIS (Internal Combustion Impulse Source) has been developed by CGG to provide a solution for shallow target surveys and for in-fills where access for conventional sources is restricted. The source is self-contained, powered by readily available propane gas and oxygen, capable of 3,000 impacts per 16 oz. standard propane canister. A GPS-driven high-accuracy clock and a specially developed impact sensor provide accurate time-stamping and recording of time-break information to better than 1 I¼s. The shooting system integrates seamlessly with Sercel SN408 or SN428 recording systems, using an additional system process that allows the observer to switch rapidly from explosive or vibroseis mode to ICIS on a shot-by shot basis. The ICIS and Mini-vibrator performance were tested in shallow coal prospects, where existing 2D data have been acquired by Nomad 65 heavy vibrator. The tests demonstrated that ICIS is well suited to image target depths less than 500m with frequencies up to 100Hz. The comparison with the vibroseis sources showed that ICIS i) Delivered very good near offset data (> 50m) and for up-hole/low velocity layer survey ii) Required more shots per shot point in the medium offset range (1000m) due to its low energy iii) Not designed for far offset data (3000m). ICIS was found to be a viable geophysical and logistic solution for certain high-resolution mineral surveys.

Coal and rock fissure evolution and distribution characteristics of multi-seam mining

Henan Pingdingshan No.10 mine is prone to both coal and gas outbursts. The E9–10 coal seam is the main coal-producing seam but has poor quality ventilation, thus making it relatively difficult for gas extraction. The F15 coal seam, at its lower section, is not prone to coal and gas outbursts. The average seam separation distance of 150m is greater than the upper limit for underside protective seam mining. Based on borehole imaging technology for field exploration of coal and rock fracture characteristics and discrete element numerical simulation, we have studied the evolution laws and distribution characteristics of the coal and rock fissure field between these two coal seams. By analysis of the influential effect of group F coal mining on the E9–10 coal seam, we have shown that a number of small fissures also develop in the area some 150m above the overlying strata. The width and number of the fissures also increase with the extent of mining activity. Most of the fissures develop at a low angle or even parallel to the strata. The results show that the mining of the F15 coal seam has the effect of improving the permeability of the E9–10 coal seam.

Estimating greenhouse gas emissions from open-cut coal mining: application to the Sydney Basin

A new site-specific (Tier 3) method has been developed to determine greenhouse gas emissions from open coal mining. The Tier 3 method presented here is based on extensive measurement of gas emissions from open-cut coal mines and the physics of gas desorption from coal. It was adopted by Australian National Greenhouse and Energy Reporting in 2009 and since 2012 formed the scientific basis for the Australian Government guidelines on calculating greenhouse gas emissions from open cut mines. The main strength of this method is its site-specific nature and accuracy, as well as its ability to be integrated with routine coal exploration programs. New concepts were produced for the model: a coal mine is regarded as a ‘gas reservoir,’ with coal seam gas being emitted from a ‘gas release zone’ that consists of sedimentary geological units (emission layers) above and below the base of the mine. The primary data required for the method are the in situ gas content and gas composition of the coal and carbonaceous rocks contained within the gas-release zone. These data are obtained through direct measurement of gas desorption from bore cores. To reduce gas drilling, a mine lease is compartmentalised into ‘gas zones’ of similar gas content and reservoir properties. The outputs of the method are emission density (the potential volume of gas emitted from mining site per unit area of the ground surface) and emission factor (the gas volume emitted per tonne of raw coal extracted). Owing to spatial variability and errors of measurement, the estimate of emissions is associated with uncertainty. A simple method of calculating uncertainty of emissions is presented in this work.

The Impact Analysis of Subsidence on Vegetation Growth in Songzao Mining

In this paper, to gradually comprehensive analyze the impact of coal exploration to vegetation growth, Chongqing Songzao Mining was selected as the study area, vegetation index changes of the past decade were analyzed from a macro perspective using three remote sensing data, and then species composition and community structure of different times collapse area was analyzed using microscopic samples investigate. This paper argues that Songzao Mining exploitation of coal resources affected the local forest and grassland vegetation, but not on a wide range of forest and grassland ecosystems adversely affected, the area of forest and grassland ecosystems can carry local failure, and through the self-healing approach ultimately make forest grass ecosystem to stabilize.