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Rapid, precise and frugal surveying is a strategic factor in the present mechanized mining environment owing to rapid surface profile transformation in a short period. Determination of global coordinates with high accuracy using the satellite-based global navigation satellite system (GNSS) has been studied in the mining arena and is gradually becoming an essential component. A case study of Khanak Stone Mine, Haryana, India, is discussed here, highlighting the combination of GNSS system and terrestrial laser scanner for the preparation of a surface profile of a rugged terrain with the key objective to determine the precise in situ rock excavation in periodical phases. The actual tonnage of rock produced/transported from the mine has been calculated by determining the in situ density and bulk density in the laboratory. The study reveals that this survey of approach is apt to achieve quality plan and to obtain the goal of actual tonnage of rocks excavated. [ABSTRACT FROM AUTHOR]

Bord and pillar method of mining continues to be a major operation in India with about 160 mines producing 35 MT of coal. Owing to the exhaustion of near-surface deposits, environmental impacts and land acquisition issues associated with surface mining, underground coal mining is expected to take a leap in the next decade. Weak and layered roof strata in underground mining play a significant role in roof failures in development headings affecting both safety and productivity. Despite well-defined support design guidelines based on CMRI-ISM RMR, roof failures are still a cause of great concern. In this research, firstly, a risk matrix has been framed on the basis of stable and unstable roof conditions for evaluating the potentiality of roof failure. This was followed by the development of a modified Rock Mass Classification System (RMRdyn) considering Seismic velocity of rocks as one of the key parameters. A modified empirical relationship for rock load (RL) and a handy nomogram has been developed based on input parameters, namely, P-wave velocity, structural features, slake durability and groundwater condition. A guideline for roof support design has been framed based on rock load computed for RMRdyn values ranging from 25 to 70. The developed models have been validated by statistical tools. The study also presents the risk classes to enable rock engineers to design more rational support systems in coal mine development headings. [ABSTRACT FROM AUTHOR]

Electrochemical discharge machining (ECDM) is a hybrid machining formed by combining the principles of electrochemical machining and electrical discharge machining. The ECDM is unconventional micromachining that can fabricate holes, blind holes, micro-cavities and grooves on brittle insulating materials such as quartz, glass, silicon wafers and different composites that are difficult to machine. These non-conducting materials have sundry applications such as Micro Electric-Mechanical Systems, biomedical and electronics items. The ECDM provides maximum material removal rate and good surface quality with minor tool wear. The study describes how different process parameters affect machining. The assessment mainly focuses on various tool electrode geometries and materials that are used in ECDM. The present article investigates the ramifications of different types of electrolytes and additives mixed in electrolytes used during the ECDM process on the machined zone. This paper comprehensively reviews the effect of change in applied voltage, machining gap and an inter-electrode gap in the ECDM and it also analyses the fabrication of different materials including glass, quartz, ceramics and composites. [ABSTRACT FROM AUTHOR]

Global Navigation Satellite System (GNSS), an advanced surveying system, is used to determine three-dimensional points accurately. The present study was conducted in Kasta East Coal Block of the West Bengal Power Development Corporation Limited (WBPDCL), India, focusing on data generation, establishing boundary coordinates and mosaicing of mouza plans using real-time kinematic approach. Base station and primary control points were established by the static method. It evaluates the geospatial information using GNSS and quantification of the accuracy of the geo-referenced cadastral map of kasta east coal block of WBPDCL. Scanned mouza plans were converted to vector format through AutoCAD, oriented and placed precisely with the help of established ground control points. The features of the cadastral map were tuned by superimposing the vector cadastral map of the study area. Assessment of the vector cadastral map showed better accuracy and less distortion in large-area parcels/khasras. More variations were observed in small-area khasras. Similarly, smaller mouzas showed more variation compared to larger ones. Distortions were due to manual error in digitization and technical error in scanning. The methodology of mosaicing presented here will be useful for updating the cadastral maps with improved precision in digital cadastral plan preparation. [ABSTRACT FROM AUTHOR]

The most popular crash barriers made so far are made up of steel-reinforced concrete (RC), which has high flexural rigidity but poor energy absorption. Consequently, when a vehicle collides with such crash barrier, the vehicle is seriously damaged and occupants may be fatally injured due to the severe impact of the collision. Hence, in order to enhance the safety of road users, a pre-fabricated textile-reinforced concrete (TRC) crash barrier prototype is developed using glass and basalt textile as reinforcement. The experimental investigations are carried out on both glass and basalt TRC crash barrier at the laboratory level under impact load to study the level of impact and deceleration rate. The performance of TRC crash barriers are also compared with RC crash barriers of equivalent calibrated reinforcement ratio. The lesser impact force and the lower rate of deceleration and higher energy absorption characteristics were experienced during the impact test for TRC crash barriers when compared to that of conventional RC barrier. Present study indicates that the application of TRC in crash barriers can improve the safety of the occupants and reduces damages to the impacting vehicles. [ABSTRACT FROM AUTHOR]

Steel-concrete sandwich composite system consists of steel skin and concrete core. The aim of this paper is to present methods for analysis and preliminary design of a recently developed new class of sandwich composite system laced steel-concrete composite for flexural loads. In laced steel-concrete composite system, continuous lacings are used in place of discrete shear connectors which are generally welded to the skin of the composite. Specimen laced steel-concrete composite systems were subjected to laboratory-controlled experimental investigations. Subsequently, three analytical methods are formulated for evaluating the moment-curvature relation of laced steel-concrete composite system. All the methods exploit the prismatic nature of the laced steel-concrete composite system to derive the moment-curvature relation and employ virtual work principle to evaluate the deflection of the laced steel-concrete composite system. In the first method, the stress-strain relationship of the steel and concrete in tension and compression is utilized to analyse the cross-section of laced steel-concrete composite system. In the second method, fibre-based analysis is used to obtain the response of laced steel-concrete composite system. The third method is based on equivalent transformed section in which the tensile stress-strain behaviour of concrete is represented by an equivalent area under tension. The methods are validated by comparing the predicted values with those of the two- and multi-point loading experiments carried out on laced steel-concrete composite beam and one-way laced steel-concrete composite slab, respectively. All the three methods are found to satisfactorily predict the response of laced steel-concrete composite system. A limited parametric study is carried out by using these analytical methods to identify the role played by the lip and web of the cover plates, tensile strength of concrete and confinement of concrete on the structural response of the laced steel-concrete composite system. In the end, guidelines and charts which can be used for preliminary design of laced steel-concrete composite system for flexure loads are presented. [ABSTRACT FROM AUTHOR]

Analysis of non-uniqueness model in resistivity imaging data is vital in inaugurating the consistency of models. Nevertheless, such analysis is moderately unusual in resistivity imaging data set. Electrical resistivity tomography (ERT) technique is being constantly used in many scientific areas including engineering, environmental and archaeological survey. Primarily, the inversion algorithm techniques are employed on synthetic model data set with and without some random Gaussian noise, and its validity is tested by filed data set. The study was conducted in the premises of Central Institute of Mining and Fuel Research (CIMFR), Dhanbad by laying an ERT profile of 480 m length with 5 m electrode spacing using Syscal Pro (Iris instrument) resistivity meter. Two standard arrays were used in this study namely Wenner-Schlumberger and dipole-dipole array. The data set was mixed to a single array to achieve better resolution and enhanced clarification. On processing data by Prosys-II software, it was exported in Res2Dinv software for inversion. In this context, data was inverted by different algorithm techniques i.e. least square (L2-norm) and robust inversion (L1-norm). Exemplary results related to the heterogeneity of the resistivity structure within the high and low resistivity anomaly were obtained by robust inversion method. The obtained results are in broad agreement with the simulation model. [ABSTRACT FROM AUTHOR]