IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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An Approach to Assess Influence of Rock Properties on the Operating Parameters of Surface Miner
No full textApplication of Surface Miners has increased phenomenally all around the world for rock excavation in varied rock mass conditions. There are numerous models of surface miners with wide range of specifications. Ability of surface miner to operate and cut effectively in rock is limited to strength property of rock. An exhaustive knowledge of rock and machine interaction is imperative for smooth operation and mass production of surface miner. The paper presents the influence of machine operating parameters on power consumption with respect to rock strength. Operating parameters such as cutting depth and cutting speed can be controlled by estimation of power required for cutting. Uniaxial compressive strength is almost exclusively used for description of the strength of the rock. The effect on power in relation to depth of cut were analysed for varied strength of rock. Cutting speed was also studied for different uniaxial compressive strength at varied depth of cut
Biomass waste utilisation in low-carbon products: harnessing a major potential resource
No full textThe increasing demand for food and other basic resources from a growing population has resulted in the intensification of agricultural and industrial activities. The wastes generated from agriculture are a burgeoning problem, as their disposal, utilisation and management practices are not efficient or universally applied. Particularly in developing countries, most biomass residues are left in the field to decompose or are burned in the open, resulting in significant environmental impacts. Similarly, with rapid global urbanisation and the rising demand for construction products, alternative sustainable energy sources and raw material supplies are required. Biomass wastes are an under-utilised source of material (for both energy and material generation), and to date, there has been little activity focussing on a ‘low-carbon’ route for their valorisation. Thus, the present paper attempts to address this by reviewing the global availability of biomass wastes and their potential for use as a feedstock for the manufacture of high-volume construction materials. Although targeted at practitioners in the field of sustainable biomass waste management, this work may also be of interest to those active in the field of carbon emission reductions. We summarise the potential of mitigating CO2 in a mineralisation step involving biomass residues, and the implications for CO2 capture and utilisation (CCU) to produce construction products from both solid and gaseous wastes. This work contributes to the development of sustainable value-added lower embodied carbon products from solid waste. The approach will offer reduced carbon emissions and lower pressure on natural resources (virgin stone, soil etc.)
Optimization of ventilation system for prevention of spontaneous heating/fire during extraction of thick coal seam - a CFD approach
No full textPerformance and Kinetic Evaluation of Synthesized CuO/SBA‐15 Oxygen Carrier for Chemical Looping with Oxygen Uncoupling
No full textChemical looping oxygen uncoupling (CLOU), a variant of chemical looping combustion (CLC), is one of the most promising combustion technologies for inherent separation and feasible capture of carbon dioxide. Herein, synthesized SBA‐15, a highly ordered mesoporous silica support, is used to host CuO for developing a new variant of an oxygen‐carrier material. Based on thermoanalytical evaluations, a typical CuO/SBA‐15 composition with 36 mass% CuO loading is identified as highly suitable with an average oxygen transport capacity of 3.61%. In addition, extensive studies along with model‐dependent kinetic evaluations are carried out using isothermal thermogravimetric data for the reduction–reoxidation of CuO/SBA‐15. It is observed that the Avrami‐Erofeev random nucleation and subsequence growth model (A2) fitted well for the reduction reaction, while the 3D diffusion model (D3) described suitably the reoxidation reaction in the temperature range of 800–950 °C. Reduction–reoxidation rate data and kinetic information derived from corresponding isothermal conversion curves can contribute immensely to design and establish operational strategies for interconnected CLOU reactors
Co-gasification of coal and biomass an emerging clean energy technology: Status and prospects of development in Indian context
No full textCo-gasification of coal and biomass is emerging as potential clean fuel technology to achieve high thermodynamic efficiency with relatively low CO2 emission. The coal and biomass have been exclusively gasified more than a century to obtain gas–liquid fuels and the production of chemicals. Co-gasification has higher efficiency than the solitarycoal gasification because the cellulose, hemicellulose and lignin content of biomass help to ignite and enhance the rate of gasification. It is suggested that the extensive research on carbon reactivity pattern, heat release, reaction kinetics, etc. may support to reduce the uncertainties in the co-gasification performance of coal and biomass blends, particularly in India. The prospects of co-gasification technology in Indian context have been discussed considering the abundance of varieties of coal and biomass. The suitability of existing gasifier procedures and their limitations with operating parameters like temperature, residence time, density optimisation, feed rate, agglomeration intensity, the tar formation and techno-economics involved are described. Also, this paper reviews the research highlights of the history of co-gasification and the advancement in upcoming challenges like a design of gasifier, access and preparation of biomass, disposal of residue, environmental concerns and reassurance to the operators for execution of large and small-scale projects
Slump test: laboratory and numerical simulation-based approach for consistency of mill tailings paste
No full textSolid-to-water proportion decides the effectiveness of paste backfill in terms of transportation characteristics during mine backfilling. This article highlights various laboratory tests conducted to determine the optimum solid-to-water ratio. Also, numerical simulation was carried out using computational fluid dynamics technique (ANSYS FLUENT) to understand the slump lifting process and variation in volume of the paste with time. The optimum slump and spread for lead–zinc mill tailings paste were in the range 190– 200 mm and 330–340 mm respectively. The optimum water content in the paste fill for this study was found to be 23 wt%. Results show that the solid percentage is inversely related with slump and spread. Also, an optimum slump lifting speed needs to be maintained for accurate values of slump and spread
Optimisation of binder alternative for cemented paste fill in underground metal mines
No full textTo maximise ore recovery safely and economically, a proper backfill design of required strength is imperative to facilitate extraction of adjacent stopes. Ordinary Portland cement (OPC) has a direct impact on the strength gained by the paste fill mix and is also a major contributor to the backfilling cost. This has prompted the users to go for partial replacement of OPC with readily available industrial wastes such as fly ash and jarosite to obtain a paste mix of desired strength. This paper highlights the use of a mathematical model to predict the strength requirement (unconfined compressive strength and cohesion) of self-supporting paste fill for secondary pillar extraction of stopes in metal mines. This paper also highlights extensive laboratory investigation carried out for partial replacement of OPC with fly ash and jarosite to map the changes in the strength of paste mix with time. Initially, the percentage of OPC required to achieve the designed strength was evaluated and subsequently, the percentage of OPC in the mix was replaced gradually with fly ash and jarosite. Laboratory results indicated that the strength of the paste mix increases with curing period (7, 14, 28 and 56 days) and the chemical composition of the ingredients also played a major role in strength development. The results were then compared with the required strength predicted from the model to obtain proper paste mix for existing mine’s stope dimension
Earthing System Design for Electrical Installations of Building Construction and Laboratory Equipments
No full textThis paper presents the design of earthing system for electrical installations for domestic, commercial and laboratories, etc.
and calculation of its technical parameters. Successful operation of entire building power system depends on efficient and satisfactory
performance of well-designed earthing system. Lack of safe and effective earthing system can result in non-operation of control and
protective devices. (Earthing/ Proper grounding) of system design deserves considerable attention for all the building power system.
Earthing system has to be safe as it is directly concerned with safety of persons living in building and working within the building power
system. Main concern of this work is designing safe and cost effective earthing system for building power system situated at such
locations where soil of the site is non-uniform. Initially significance of earthing is explained & methodology for design of building power
system earthing system. Earthing is very important to achieve instruments and personnel protection. Operation of any electrical and
electronics instrument or appliances directly affected by value of earthing. Standard formulas are used in design of earthing system to
get required values such as touch and step voltage criteria for safety, earth resistance, minimum conductor size and electrode size and
resistivity of soil
Stability Evaluation of Old and Unapproachable Underground Mine Workings below Surface Structures
No full textThere are many places in the different countries of the world where working in the underground mines have been done below surface structures such as railway lines, roads, buildings, villages/residential colonies, pipelines, etc. The workings are generally old, abandoned and presently unapproachable. In some places, important delicate surface structures are installed above a portion of old abandoned underground workings. Safety of these important surface structures above old underground mine workings is a serious concern in many countries all over the world. Many times, it is difficult to move or divert these surface structures due to a number of reasons including technical problems, the involvement of huge expenditures and socio-economic issues. There is a need to assess the stability of these places and the procedure to stabilise the places if found unstable to make the structures safe. Hence, there is a need of proper stability assessment of the ground below these surface structures. The railway line is one of such important structures, where stability should be ensured for the safety of the passengers. In India, many underground workings are present below railway lines. Most of the workings are old and unapproachable and their stability status is in doubt. Dismantling or diverting of the important railway lines is a high-level policy matter and involves huge time and money besides complicated socio-political issues like the rehabilitation of the affected people. But the safety of the commuters using railways passing over the coal-bearing areas having mining activities cannot be compromised. Therefore, it is highly preferable to take protective measures instead of dismantling and diversion of lines, wherever possible. It is necessary to establish the position and dimension of the inaccessible underground workings below these types of important surface structures and carry out its stability analysis to take appropriate protective measures for the safety of the structures and commuters. This paper highlights the delineation procedure of the unapproachable underground roadways below surface structures with special reference to railway lines and its stability evaluation with case studies. Appropriate protective measures have also been suggested which are proved to be effective and validated the results of the study