Amalendu Sinha

• Central Institute of Mining and Fuel Research

For the present study, a prototype diesel engine operated Forklift truck of 2 t capacity is developed for explosive gas atmosphere. The parts of the Forklift truck are assessed against risk of ignition of the explosive gases, vapors or mist grouped in Gr. IIA and having ignition temperature more than 200°C. Identification of possible sources of ign...

The in situ stresses have significant effects on the stability of openings, support requirements, parting stability, pillar strength, etc. In order to analyze the stability of underground structures, the measurement of magnitude and direction of horizontal stress is necessary in addition to knowing other geomining parameters and rock properties. In...

Methane gas derived from shale beds emerges as potential clean energy sources in USA, China and other petroleum producing countries. India is also looking forward to exploring and develop its shale gas resources to minimize the gap between great increasing demand and supply of natural gas. The preliminary estimates assimilated using the thickness o...

Reservoir triggered earthquakes have been occurring in the Koyna area, western India for the past five decades. Triaxial tests carried out on 181 core samples of Archaean granitoids underlying the Deccan Traps provide valuable constraints on rock strength properties in the Koyna seismogenic zone for the first time. The data include measurements on...

In some of the coalfields in India, coal seams are only developed but no extraction of pillars is possible due to the presence of surface or sub-surface structures and also non-availability of stowing materials which leads to huge amounts of coal being locked-up underground. Spontaneous heating and fire, accumulation of poisonous gases, severe stab...

Occurrence of Fuel-rich open fire is one of the serious threats to safety and productivity of coal mines. Many a times it causes virtual closure of mine for a long period or forever. Recovery of such mine needs to address several technical challenges. It requires careful approaches for safe sealing, avoidance of situation for occurrence of explosio...

Although gasification of high ash Indian coals is gaining importance, the resultant uncertainties associated with agglomerate formation are still unresolved. To address this, a suitable pilot scale Fluidized Bed Gasifier was utilized in this study. Stabilized operating conditions in terms of coal feed rate, air feed rate, bed temperature, etc., alr...

Ensuring energy security for the growing population with rising per-capita energy demand has emerged as one of the greatest challenges before India. The developing nation like India will continue to rely heavily on thermal power plants for meeting energy demands against restricted access to nuclear technology and mixed success of nonconventional en...

Open fire in coal mines is one of the most serious threats to miners, as well as to the mine. Open fire can often be effectively dealt with by prompt local action, otherwise it very quickly becomes uncontrollable. In one incident, none of the available open fire control technologies, viz., water deluge and sprinkler systems, high-expansion foam, hi...

Froth flotation has emerged as an effective and useful technique for separation of low volatile medium ash clean coal fines. The traditional flotation collector is diesel oil. However, this collector often gives lower concentrate yields. In the present article, an improved collector derived from coal tar, that is, a particular coal tar distillate f...

The results of beneficiation studies of high-ash fine coal using the Oleo-flotation process are presented. The influence of three key variables (diesel oil dosage, wash oil [a product of crude oil obtained during the process of refining at 275 to 300°C] dosage, and impeller speed) of the Oleo- flotation process on yield % and ash % is presented in...

Ground control is one of the most important activities in underground mines to control the roof and side fall injuries in India. Since long wooden prop and cog were being used to support the mines panels, or roadways. Scarcity of timber due to ecological reasons and therefore increase in its cost make the support designer's or engineers to innovate...

Longhole Stoping is a popular large scale underground mining method for metalliferous mine known for its ability to simplify stope sequencing. It encompasses advantage of Faster Stope Production Start leading to early return on investment. Ground support is a critical issue while designing of stoping parameters in this method. This can be achieved...

Optimization of support parameters for productive and safe mining is a challenge for mining industries. Formulation of technology for safe and productive mining needs scientific study of strata behaviour and necessary recommendations for extraction methodologies and support system. Numerical modeling technique provides study of strata behaviour bas...

A total of 33 samples of mine water discharges from the different mines of West Bokaro Coalfields of Hazaribag district of Jharkhand, India, were analyzed to carry out qualitative assessment and suitability for domestic, irrigation and industrial purposes. The electrical conductivity (EC) for measured samples and spatial differences reflects the wi...

Problem of coal seam fire due to spontaneous heating is globally recognised by all coal producing countries because it is an inherent property of coal. Since all coals are prone to spontaneous heating provided it is allowed to oxidize in favourable situation, hence proper diagnosis of the problem and application of comprehensive technology is requi...

The paper covers engineering studies undertook and likely preventive measures to be undertaken towards the critical boulders and steep slope surface stabilization around Ajanta caves: the UNESCO World Heritage site near Aurangabad in Maharashtra state of India. The slope failure and boulder dislocations due to the long-term rock mass deterioration,...

Bord and pillar is the most common and traditional method of coal extraction in India. This method accounts for over 95% of coal production from underground mines. Multiple seam coal production from in India, accounts for approximately 10% of the underground coal mines. In India, there are number of cases of parting failures in mines due to instabi...

The hydrogeochemical study of groundwater in Dumka and Jamtara districts has been carried out to assess the major ion chemistry, hydrogeochemical processes and groundwater quality for domestic and irrigation uses. Thirty groundwater samples were collected and analyzed for pH, electrical conductivity, total dissolved solids (TDS), total hardness, an...

The mechanized open-pit mining methods have been extensively adopted by Indian mines to meet the increasing demand of coal which results into major disposal problem of large volume waste material generated from mining operations in open-pit mines. The stability of waste dump slope depends on a number of geological and mining factors. In this paper,...

Considerable progress has been achieved in recent years in the whole field of blasting science and technology. This applies to explosives formulation, initiation systems and blast simulation through advanced numerical codes. The commercial explosives in the market today are not only generally cheaper and safer than before, but also more flexible in...

Electrical motors are used widely for the different applications in the petrochemical industry. Special design requirement of such motors are achieved by applying some type of protection techniques for safe operation in the explosive atmosphere. These are four type of protection techniques applicable to high tension machine as Ex ‘d’ type (flamepro...

In India, there are a number of cases of parting failures in mines due to instability of the parting between contiguous seam workings. So far, no suitable norm exists for predicting the stability of the parting during simultaneous depillaring of contiguous seams or sections, the latter being in thick seams. The factors affecting parting stability i...

This article presents beneficiation studies of coal fines using Oleo flotation process. Central Composite Design (CCD) integrated with Response Surface Methodology (RSM) was applied to develop a process model from an input-output data set of an Oleo flotation process. The effects of the operating parameter values, that is, diesel oil dosage, wash o...

The hydrogeochemical study of groundwater in Dumka and Jamtara districts has been carried out to assess the major ion chemistry, hydrogeochemical processes and groundwater quality for domestic and irrigation uses. Thirty groundwater samples were collected and analyzed for pH, electrical conductivity, total dissolved solids (TDS), total hardness, an...

A long mining history and unscientific exploitation of Jharia coalfield caused many environmental problems including water resource depletion and contamination. A geochemical study of mine water in the Jharia coalfield has been undertaken to assess its quality and suitability for domestic, industrial and irrigation uses. For this purpose, 92 mine w...

Stability of coal mine roadways is found to be a major problem in presence of in situ horizontal stress anisotropy especially in geologically disturbed zones. On most of the occasions, geological discontinuities become more prominent in a particular direction. Such condition causes instability in the roadways some times severely. In the present pap...

An attempt has been made to study the groundwater geochemistry in part of the NOIDA metropolitan city and assessing the hydrogeochemical processes controlling the water composition and its suitability for drinking and irrigation uses. The analytical results show that Na and Ca are the major cations and HCO3 and Cl are the major anions in this water...

Tunneling projects have become integral part of infrastructure development of power, irrigation and transportation sector. Although recent developments in tunnel boring machines shared much load of tunnelling projects, drilling and blasting method of tunnelling has become inevitable due to its operational flexibility and low capital cost. This pape...

Fire and explosion is the biggest problem in any industry that deals with explosive gases. Other than gas explosion dust ignition Is also a major concern during selection of an electrical apparatus. Keeping in view of this M/s. Larson & Toubro Limited, Vadodara & M/s. Macneill Engineering Limited, Kolkata submitted design documents for development...

The pace of developments in underground blasting technology is insignificant in contrast to developments in opencast blasting. Blasting practices in underground mines has limited flexibility due to many safety criteria, statutory and field constraints. This has narrowed the scope of major modifications in the solid blasting design vis-à-vis the eff...

Flyrock, a rock fragment thrown to an excessive distance, is a random event and an ongoing problem in opencast bench blasting. Existing criteria for a 'Flyrock Danger Zone' are rigid, such that blasting may not be permitted where there are structures within about 100 m. A statistical approach to the problem is proposed and new concepts of Factor of...

Mechanized room-and-pillar system of coal pillar mining using side dump loading machine or load haul dumper machine, or by continuous miner, is the presently most dominant underground method of extraction in India. Under this method of extraction, strata control is a major problem affecting safety and productivity of the mine. As per existing Direc...

The problem of fire in abandoned mines is a global challenge to all coal producing countries. The main and immediate concern is to save the vital surface structures like railway lines/roads, bridges, rivers/stream, overhead construction from such fires as well as protecting adjacent underground property of the mine either by isolating or digging ou...

High expansion nitrogen foam technology has been found an effective technique world over for controlling underground mine fire. In this paper the conventional methods adopted in coal mines for dealing afire have been briefly discussed. Attempts have been made to highlight the advantages and merits of high expansion foam technology over the other te...

In a coal mine when sealed off area having connection with atmosphere (surface) and intake airways only the condition becomes more worsen when active fire in such sealed off area creates sufficient drought due to fire. In such situation sometimes pressure created by the fan may not be sufficient to neutralize such suction pressure created by the fi...

Energy Efficient Motor with VSD differs from the other standard concepts in a number of important ways. It is a concept where Increased Safety (Ex 'e') motor with particular drive can save the energy and give the better performance with safety of margin which is very important for drives in the hazardous area. There are different safety aspects rel...

Fragalyst 3.0 is an advanced version of the Fragalyst 2.0 developed indigenously by CIMFR and Wavelet Group Pune. The software has multiple functions where the digital images of blasted fragments can be analysed for size distributions (BBSD) and the in situ block size distribution (IBSD) can also be determined using the joint frequencies in a blast...

An attempt has been made to carry out qualitative assessment of mine water discharges from the selected coal mining areas of Jharia, Raniganj and West Bokaro coalfields of Damodar Basin. 184 mine water samples were analyzed for pH, electrical conductivity (EC), major cations (Ca, Mg, Na, K), major anions (HCO 3 , SO 4 , Cl, NO 3), and heavy metals...

Rock blasting is an integral part of hydroelectric projects. Contour or perimeter blasting (seno stricto), although in vogue for quite some time has received scant attention from civil engineers and engineering geologists, particularly in India. This paper brings one such example in India where application of perimeter blasting yielded significant...

Reported in the present paper are the results of the study of propagation of SH waves in the plane of mirror symmetry of a monoclinic multilayered medium with displacement normal to the plane. Dispersion equation has been obtained analytically ussing Haskell’s matrix method, while the finite-difference method has been employed to model the SH-wave...

Occurrence of open fire in underground mines is one of the most feared hazardous because it may turn in to serious conflagration directly polluting the entire mine in a very short time. Delay in its control some time may push the mine for virtual closure. It is generally dealt either by isolation of fire covering large area or drowning in water the...

The present article deals with the propagation of SH-waves in a multilayered porous media with Weiskopf type anisotropy. Using Biot's theory of porous medium, the problem has been formulated. The finite difference method has been used here to model the wave propagation problem and also to analyze the effect of porosity and anisotropic factors on th...

Coal fines generated in Indian coal preparation plants account for 25%–30% of run-of-mine (ROM) coal. Coal cleaning is receiving increasingly greater attention of process engineers in view of the increase in amounts to be handled as well as the difficult washability characteristics of high-ash-content Indian coals. Froth flotation is usually practi...

Considering ground instability problems of underground coal mines at shallow covers, this paper reviews and describes problems of optimal extraction of coal stuck below surface/subsurface constraints at Indian coal fields. Importance of thickness and quality of inter-burden between the working horizon and surface/subsurface constraints is discussed...

The numerical modeling for prediction of longwall roof behavior has been studied. The modeling includes selection of appropriate material model and their properties to simulate the behavior of coal seam and rock beds in elastic and post failure states. The extent of the caving zone in the overlying strata behind the supports has been identified wit...

The chemical characteristics of surface, groundwater and mine water of the upper catchment of the Damodar River basin were studied to evaluate the major ion chemistry, geochemical processes controlling water composition and suitability of water for domestic, industrial and irrigation uses. Water samples from ponds, lakes, rivers, reservoirs and gro...

The knowledge of thermo-mechanical and transport properties of granites is required to understand and model a number of processes in the earth crust such as folding, geothermal activity, magmatic intrusions, plate tectonics and nuclear waste disposal. Authors have studied various thermo-mechanical properties of Indian granite (IG) at high temperatu...

Around 12.5m-thick Zero seam of Chirimiri colliery underneath Bartunga hill of M/s South Eastern Coalfield Limited (SECL) was found in two sections; 3.5m top and 6.0m bottom section, with a highly laminated 3.0-m-thick parting between the two sections. The laminated parting, comprised of alternate layers of shale, carbonaceous shale, coal and mudst...

Since ground control operation is an 'imprecise' area of engineering due to the fact that we are dealing with a material produced by nature (the ground). In many circumstances, our fundamental understanding of soil and rock behavior still falls short of being able to predict how the ground will behave. Cause-wise analysis of mine accidents reveals...

Coal seams sometimes have non-coal bands which can be either soft (clay, shale), leading to a reduction in pillar strength, or hard (sandstone), giving stronger pillars. Such "sandwich" pillars can also be created when the thin rock parting between two seams in close contiguity collapses. To define the strength of such pillars, six cases of failed...

The measured response of residential structures is a critical indicator of troublesome or potentially damaging ground vibrations. A study was conducted to evaluate the response of structures in environmentally sensitive areas in the proximity of four open-pit coal mines in India. The study involved 215 blasts, employing one-, two- and three-hole ca...

The chemical characteristics of surface, groundwater and mine water of the upper catchment of the Damodar River basin were studied to evaluate the major ion chemistry, geochemical processes controlling water composition and suitability of water for domestic, industrial and irrigation uses. Water samples from ponds, lakes, rivers, reservoirs and gro...

Surface, subsurface and mine water collected from rural, urban, industrial and coal mining areas of Dhanbad district have been analysed to assess the major ion chemistry, the weathering and geochemical processes controlling the water composition and suitability of water for domestic, industrial and agricultural uses. Ca, Mg, and HCO3 dominate the c...

Surface, subsurface and mine water collected from rural, urban, industrial and coal mining areas of Dhanbad district have been analysed to assess the major ion chemistry, the weathering and geochemical processes controlling the water composition and suitability of water for domestic, industrial and agricultural uses. Ca, Mg, and HCO3 dominate the c...

The present study investigated the chemical composition of wet atmospheric precipitation over Dhanbad, coal city of India. The precipitation samples were collected on event basis for three years (July 2003 to October 2005) at Central Mining Research Institute. The precipitation samples were analyzed for pH, conductivity, major anions (F, Cl, NO(3),...

Underground coal mining in India has slipped its place of prominence due to its low production and productivity. Technological vacuum is, undoubtedly, the main reason behind this scenario. The Indian mining industry is starving to have suitable technologies to counter the low productivity problem from the conventional depillaring technologies. In I...

During opening of a new underground coal mine through inclines, some times it is very difficult to make first opening in the rocks even at some depth if the strata is not competent, especially in the case of poorly cemented medium to coarse grained sandstone. Support of the lip (mouth of the opening) in loose strata is very complex job. When the op...

In Indian coalmines, CMRI- RMR and NGI-Q Systems are mostly used for formulating design of support in rock engineering. Geotechnical investigation of the roof rocks plays an important role in the selection of different parameters used in rock mass classifications. In India, Bord and Pillar Method of mining is very much in practice in underground co...

In order to assess the damage to openings in underground coal mines due to blasting in nearby surface mines, vibration and roof strata behaviour were monitored in seven mines having a different rock mass rating (RMR) in India. In total, 202 blasts were examined and 603 vibration data were recorded. The data were analysed to define the threshold val...

India is bestowed with a long cosat of more of less 7500 km. This long coastal tract has a vast resource of placer minerals such as ilmenite, rutile, leucoxine, monazite, zircon, etc. But this large reserve base does not make India a global player in the market of placer minerals. The production to Reserve Ratio (PPR) in India is 0.001 while it is...

Fly ash (FA) from Chandrapura Thermal Power Station in Jharkhand, India were used to amend soil from fallow land in the proportion equivalent to 60, 120, 180, 240 tons/ha in selected vegetables and 10, 20, 30, 40, 50% in selected leguminous crops economically grown in the region, and performance of individual species has been evaluated. In both the...

Steel wire ropes are extensively used for haulage purposes in mine winders and aerial ropeway carrying/haulage/track ropes for transportation of passengers and play a vital role in these installation. Structural integrity of these wire ropes is to be monitored to safe guard human lives. Regular periodic non-destructive investigation right from the...