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A fully mechanised mining method using continuous miner (CM) for pillar extraction in single-pass is introduced in the year 2010 at Pinoura Mine of South Eastern Coalfields Limited, Bilaspur in India. Overall mining cycle time is reduced by single-pass pillar extraction as it does not require drivage of split galleries in pillars and support installation for such galleries. Further, inherent technical abilities of the deployed CM for faster cutting and quad-bolter for supporting, helped in faster recovery of pillars without creating any strata control issues. Rate of face advance varied between 5–15m/day with an average of 8m/day. Field observations found that CM based single-pass extraction is capable in dealing with the strata control issues during depillaring under weak and laminated (incompetent in nature) roof layers having rock mass rating value around 42. A total of eleven panels, have been depillared under the weak and laminated geology, ranging depth of cover from 59 to 149m in different panels of the mine. During field investigations in these panels, a maximum of 2.89MPa induced vertical stress is recorded and influence of caved roof over underground mining structures is observed up to 15m in the out-bye from the goaf edge. This paper deals with estimation of snook size and limiting roof movement value based on numerical simulation and field studies during the single-pass extraction below the incompetent geological formations. [ABSTRACT FROM AUTHOR]

Indian coal mining industry is in transition phase with the growing demand of coal and is likely to escalate further with the need of ultra-mega power projects as well as announcement of smart cities projects. Although, there exist sufficient coal reserves in India, continuous acquisition and possession of coal bearing land is required to minimize the existing gap prevailing between coal demand and supply.The solution of the problem lies not only in modification of laws and policies of industry, but also in modification of mining engineering practices towards sustainable development. This paper critically examines the cause of the problem in the light of Indian laws and practices of the industry. In this paper a method of exact reclamation of post-mining land has been designed as a solution to make easier land acquisition by way of proposing a system of returning back the exact reclaimed land to its owners under corporate social responsibility activity of the industry. The proposed conceptual model of interlinking corporate social responsibility with land exchange will encourage sustainable development practice by mining engineers, and may turn around the public image of the industry. [ABSTRACT FROM AUTHOR]

Sub-surface coal mine fires burn valuable resources and give rise to great threat in the local environs and people's health. Jharia coal field is one of utmost fire affected coal fields in India. This paper deals with the study of sub-surface coal fire using self-potential (SP) method, a cost-effective and non-invasive passive geophysical technique. SP method in coal fire mapping works based on redox potential generated by oxidation of coal and also on Thomson potential due to temperature gradient. Initially, SP anomaly map generated using electrode drift corrected field data. The SP anomalies in the present study area vary from ∼95 to ∼ −40mV. SP anomaly map has been continued to a height of 10m from the ground to remove the possible shallow surface noises. The upward continued anomaly map has been enhanced using first vertical derivative. Further, Euler's depth solutions have been estimated to understand possible geometry and source depth of sub-surface coal fires. The local geological map and field photograph corroborate well with the results for the characterization of coal seam fires. [ABSTRACT FROM AUTHOR]

The mineralogy and geochemical studies of the coal-mine shale collected from the Tirap opencast coal-mine (Makum coalfield, Northeast India) are reported in this paper. Thermo-chemical conversion (pyrolysis) of coal-mine shale has been studied to see its hydrocarbon potential. A combined approach using X-Ray diffraction (LTA-XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) equipped with an energy-dispersive X-ray spectrophotometer (EDS), X-ray fluorescence spectrometry (XRF), thermogravimetry-derivative and differential thermogravimetric (TG-DTG and DTA) analysis is made to obtain new information on the mineralogical and geochemical studies of a coal-mine shale (CMS) sample. Gas chromatography-mass spectrometry (GC-MS) analysis is performed to evaluate the quality of the liquid fraction (tar) obtained after pyrolysis at 600°C. The shale sample is dominated by quartz, clay minerals (kaolinite and illite), sulphate bearing phase like gypsum with minor proportion of anatase, probably as artifacts of the plasma-ashing process. GC-MS analysis illustrates the presence of highly oxygenated organic components (M.W. around 94-108) and high molecular weight (M.W. 256) cyclic sulphur (e.g. octathiocane with molecular formula S) compounds along with the complex N-containing organic sulphur compounds (M.W. around 255-486) in the tar produced. [ABSTRACT FROM AUTHOR]

During the pre-nationalisation period due to unscientific mining, large number of old workings exist below important structures at various coal fields in India. Mostly these old workings exist below National Highways and Railway track. These workings are generally at shallow depth. It has been observed that subsidence and pot holing are common in those areas. As a result the safety of vehicles and passenger trains plying over these areas endangered. Since the old workings are more than 60 years old in most of the cases the proper plan and survey documents are not available. So it is extremely difficult to exactly locate the underground mine workings/galleries/voids from the surface such that precautionary measures can be initiated for the safety of roads and railway tracks. Eastern Coalfields Limited (ECL) has indicated that there may be some old workings below the national highway (NH-2) near Dalmia colliery of SalanpurArea of ECL. The most sophisticated system, MineVue Radar was used for delineation of abandoned mine workings or mine galleries below NH-2. Two voids of size 1.8 m height at depth of 40 m and another of size 1.35 m height at a depth of 33.5 m were delineated and confirmed using direct core drilling method. After that, Mine management was informed about these voids to take precautionary measures for the safety of NH-2. Thus, this system has played an important role for the safety of important surface structures. This paper deals the application of MineVue radar system for delineation of mine galleries below NH-2. [ABSTRACT FROM AUTHOR]

The utilization of innovative technology by the coal mine industry requires proper guidance of sub-surface information so that it can provide uninterrupted exploration with less time and minimum cost. Sufficient knowledge about the coal beds that is variation of thickness, depth, and associated structures will facilitate the mine engineer to run machinery systematically. Conventional geological reports based on borehole data may not sufficient to adopt state-of-the-art drilling technology. To address these issues, high-resolution seismic survey (HRSS) was conducted to delineate the thickness of coal seams and mapping of structural features which are associated with coal seams. An effort was made to demonstrate the high-resolution seismic reflection study for picking of minor faults locations and thickness of coal seams in the central part of the Sohagpur, Gondwana basin that occurs at the junction of the Mahanadi and Son-Narmada rift systems in central India. The study reveals thick Barakar Formation and coal seams at a depth range of 300 to 550 meters. The thickness of coal seams and the location of minor faults were interpreted with the help of attribute analysis from the seismic sections. The obtained results from the seismic survey were useful for the selection of potential target zones which are favourable for drilling. [ABSTRACT FROM AUTHOR]

Anthropogenic seismicity has been observed due to filling of artificial water reservoirs, geothermal and natural oil/gas production, and gold/coal mining under favorable geological conditions. Among these, artificial water reservoir triggered seismicity (RTS) is most prominent, with over 200 sites globally where RTS has been observed, including 5 sites where earthquakes exceeding M 6 magnitude occurred. Koyna, located near the west coast of India in stable Deccan Volcanic Province is the most prominent site where the largest RTS event of M 6.3 occurred in 1967, and the RTS has continued till now, for near field study of earthquakes. Here we present a summary of (a) global RTS, (b) scientific work carried in the Koyna region, (c) characterizing RTS, and (d) establishing a 3 km deep Pilot Borehole laboratory as a precursor to setting up of a ∼ 7 km deep bore hole laboratory. The work being carried out is providing necessary inputs for the design of the ∼ 7 km deep borehole laboratory for the near field studies of RTS and shed light on the geneses of earthquakes in general and RTS. [ABSTRACT FROM AUTHOR]

North Karanpura coal field is the western most marginal coal bearing segment of east-west trending Damodar valley basin. It consists of middle Permian Barakar Formation with sandstone, siltstone, coal and shale being the dominant lithofacies, deposited in a fluvial meandering environment, giving rise to repetitive fining upwards cycles. Study of geophysical logs, the drilled core holes were used to identify lithofacies, correlate coal seams with splitmerge behavior; which has been used to understand lateral and vertical facies disposition. Geophysical logs have been employed to compute various coal assay parameters-ash, fixed carbon, moisture, volatile content, cleat porosity, vitrinite reflectance seam wise. Study of log based coal assay parameters, calibrated with lab based values depicts lateral coal quality variation, i.e. decreasing ash content, higher fixed carbon from east to west, which can be a great proxy for future development of field or mine planning. [ABSTRACT FROM AUTHOR]

2D Resistivity Imaging survey is a relatively a new technique used for detecting old, abandoned & unapproachable waterlogged areas in underground mines in recent years. Hingir Rampur Colliery of Mahanadi Coalfields Limited (MCL) was facing problem due to presence of unapproachable underground waterlogged coal workings. Mine management was extracting coal in Seam I of Hingir Rampur seam (HR Seam) at the depth of 100 m. As they had planned to progress the workings of Seam I towards waterlogged goaves of 9 & 11 pits, they proposed to explore the status of waterlogged workings between Seam I of Hingir Rampur colliery and waterlogged goaves of 9 & 11 pits so that they could leave at least 60 m coal barrier from the waterlogged area to check inundation hazard. For this purpose, Resistivity Imaging (RI) survey were conducted along the six profiles A, B, C, D, E and F in Hingir Rampur colliery in the proposed area for exploration of the waterlogged workings between Seam I and waterlogged goaves of 9 & 11 pits. Pole-pole array of RI survey was used in this study. Considering the indirect approach of geophysical methods, two boreholes (CMRI-31&CMRI-32) were being drilled along the profiles D and F to confirm the RI data, which were nearer to the coal extraction site. After correlating and corroborating of borehole data with RI data, it was confirmed that strata were hard, compact and dry at 60 m from the surface and continued up to 146 m depth. Hence, it was concluded that mining can be done safely at the depths varying from 100 m to 146 m. [ABSTRACT FROM AUTHOR]