Indian Coal Mines Research Articles

Application of CMRI-ISM RMR for Stability Analysis of Development Workings for Ballarpur Underground Coal Mine - An Empirical and Numerical Approach

Abstract Roof bolt failures in the mine generally occur due to the poor identification of the weak rock layers and considered as a major concern for underground coal mines in terms of its productivity and safety. The triggering factor responsible for underground roof failure is the presence of weak bedding planes and various geological discontinuities. Geological disruptions present in the mine roof seriously affect the continuity of the rock layers resulting in block failure. However, numerous improved methods have been suggested by a number of researchers but still, the upholding of the accidents due to roof fall is considered as a major challenge for underground mine workings. Thus, it is necessary to give proper emphasis on characterization of the roof fall so that stability of the mine workings could be increased and movement of the weak and layered strata can be arrested by applying an adequate roof bolting system. This mechanism of roof support gives the composite binding between the rock layers by restricting the roof fall. The stability of mine workings can be also increased by proper application of rock mass classifications system and adequate design of support system and finally, by extensive simulation methods and statistical methods like FLAC 3D numerical and statistical modelling to ascertain the stability of the workings. CMRI-ISM RMR (Central Mining Research Institute – Indian School of Mines Rock Mass Rating System) classification system is the most popular and practiced method for roof support design in Indian coal mines which is being successfully used from last several years for roof support design in Indian geo-mining conditions. This forms the basis to estimate the rock load and support design. In this paper attempt has been made to assess the stability of workings and pillars below the railway track by using empirical and numerical approach. After both the studies it can be said that, the galleries and pillars underlying the railways track are stable, as factor of safety in each case is more than 2. Later on, the study was also extended to see the effects of subsidence on the surface which reveals that, there shall be no such effect on the surface due to underground workings as the value of NEW (non-effective width) is less than 0.4 for both the cases.

Design of Haul Roads in Open Cast Mines in India—A Mechanistic Design Approach

About 80% of total mining in India is carried out in coal sector through open cast mines where heavy dumpers are plying on the haul roads. Mine haul roads have witnessed an enormous increase in traffic density as well as hauling payloads in the recent past due to increase in coal mining activities. In the Indian scenario, the majority of these large open cast mines are facing the problems of under-performance due to inadequate design of mine haul roads resulting into fast deterioration through rutting and excessive settlement. The present design methodology used in India is broadly based on an empirical CBR (California Bearing Ratio) method. This method seems to have become irrational for optimum and practical design of the haul roads which carry the present-day heavy traffic. Through this paper, an attempt has been made to develop a design based on mechanistic design approach. The main criteria to ensure the structural safety of mine haul roads has been taken as vertical compressive strain over the subgrade which is responsible for rutting failure in a pavement. The critical value of vertical compressive strain has been estimated for the Indian mine conditions. KENPAVE software has been used to design an optimum haul road cross section for existing heavy axle loads and traffic density in open cast coal mines in India. In order to have better appreciation, an example has also been given which compares the design output using conventional and the mechanistic methods.

A time-lapse study using self-potential and electrical resistivity tomography methods for mapping of old mine working across railway-tracks in a part of Raniganj coalfield, India

The first coal mining in India was started in the seventeenth century with an unplanned way in Raniganj coalfield, the coal capital of India. The coalfield was possessed by several small private companies which were nationalized in 1973. A part plan of Chanch/Victoria Area, Victoria West Colliery, BCCL, Raniganj Coalfield, India, indicates an underground coal mine gallery/goaf in the Begunia Coal-seam that connects to a Light Casting Factory. It was established as “Barakar Iron Works” in the year 1881 by the government at that time. It is understood that the approaching gallery was used for coal supply to the “Light Casting Factory” by the mining of “Begunia Coal-Seam”. Mostly, these are uncharted and very poorly documented with scarce mine plans. So, the present study attempts to explore the location, depth, extension, and condition of the old working gallery through time-lapse monitoring using a combined study comprising of Self-Potential (SP) and Electrical Resistivity Tomography (ERT) techniques. Four SP profiles data along a line and thirteen ERT profiles data in four different lines were collected across the expected site with different station/electrode spacing covering different profile length in four seasons, viz., Summer (May 2016), Monsoon (August 2016), Post-Monsoon (October 2016) and Summer (April 2017). SP data were analysed using simulated annealing (SA) optimization technique for the evaluation of model parameters. The ERT data were acquired using Wenner, Dipole–Dipole and Schlumberger arrays and inversion of the combined data set was performed using the 2.5D ZZRESINV inversion software. Prominent negative SP signature with equivalent low resistivity anomaly have been delineated that possibly indicate the presence of the old mine working/mine gallery. However, the overall results of time-lapse study inferred that the ground is stable. All results are corroborated with available lithology and field photographs.

Coal Mine Water Drainage: The Current Status and Challenges

Any form of mining is a potential threat to the environment. The extent of environmental degradation depends on the status of mine (working/abandoned), type of deposit, mining and processing methods and the geo-atmospheric conditions. Coal mining has huge impacts to local water resources, both surface and ground water. Surface waters are being contaminated through the discharge of mine water, which is also called mine drainage. Ground water is being contaminated due to pilfer of the aquifers. Coal mine drainage is found heavily acidic throughout the world. High acidic water also poses to contaminate with toxic heavy metal ions. Heavy metal pollution comprises the trace occurrences of elements, namely, arsenic, lead, cadmium, cobalt, copper and zinc, coming from the host rock on its exposure to mine drainage water in acidic environment. As the mine water flows over the host rock, metals are leached into the water and mix with the surface waterbodies. These chemicals can be highly toxic to humans and wildlife. Though the heavy metals can dissolve in mine drainage even in non-acidic pH conditions also, but leaching is increased manifold in the acidic environment. From underground coal mines, million liters of mine water is daily disposed to the natural water sources, which are commonly used by the local inhabitants. Most of the Indian coal mines are not generating acidic drainage due to dearth of pyrites in the seams. Thus, it is a common belief that Indian coal mine drainage does not need treatment for heavy metals and is directly discharged into the surface streams. This present study shows that despite the non-acidic mine drainage, Indian coal mine water comprises high heavy metal contaminants and demands immediate attention. It is also revealed that Indian coal mine drainage shows neutral/slightly alkaline water despite having significant iron content.

Fire Safety in Indian Coal Mines using Machine Learning Techniques

There are around 493 coal mines in India (300+ underground and around190 opencast mines) engaged in coal production for meeting energy and other requirements of our country. Coal and the process of mining itself creates an environment conducive for self-oxidation leading to build up of heat and subsequently break out of fire. This causes safety hazards, decrease in production, increased in de-settlement of colonies, fire related fatalities and risk to life and property. Occurrence of fires in coal mines has always been an undesirable proposition for the coal mining community worldwide due to its high hazard potential towards loss of human lives and property. However, with advent of AI/ML and deep learning, there emerges a vast scope of leveraging its application towards significantly reducing fire hazards in coal mining. Data capturing from such fiery mines, providing machine learning and predicting it beforehand for similar mining situations would significantly enhance safety standard in coal mining industry. This project proposes to develop an algorithm on getting input data from the past incidences/accidents of fire in coal mines and apply machine learning software to help it learn pattern/features vis a vis the fire outcomes. Once the learning is over and data trained, the programme would process the test data of other active projects and may predict for fire threat during forthcoming mining operation. The algorithm aims to enable mining personnel to assess and evaluate the risk of fire in their workplace and take informed decisions based on the predictions based on Machine learning outputs. Also, active fires can as well be studied and predicted in a similar way. This will help the mining team to decide about the right approach of continuing mining operation in such an affected area.

Chemical characterization of PM10 and evaluation of health risk for the people residing around a highly mechanized opencast coal mine using FTIR spectroscopy

Air pollution in opencast coal mine area is a very critical issue. The gradual increase in the demand of coal extrction leads to implementation of high mechanization techniques in most of the mines. Implementation of high mechanization techniques in mine produces huge quantities of PM (particulate matter), which disperse to the surrounding area of the mine and degrade the environment. Different mining activities like drilling, blasting, loading and unloading of coal and overburden material, transportation on haul road, etc. are the responsible sources of PM generation in the coal mine. Apart from these sources, local sources also have contributions to the total PM generation in the surrounding environment. Coal mine PM contains hundreds of chemicals which have adverse effects on human body and other animals also. The type of chemicals present in the PM depends with the change in the geographic location and method of extraction process. Quartz is a common mineral found in the atmospheric PM which has adverse effects on human body with inhalation. So many research works have been carried out on the characterization of PM to evaluate its risk on the human body. Measurement of quartz in the working area is also become a statutory need for all type of mines. The quartz present in the PM not only affects the health of the mine workers but also has evidenced to affect the people residing near to the mine area. The health effect of the PM depends on the type of chemical present. In this paper, an attempt has been made to measure the PM10 concentration around a high mechanized opencast coal mine in India, and the seasonal variations were studied. Characterization of the PM10 was also performed to find out the functional groups by using FTIR spectroscopic technique. The FTIR analysis showed the presence of hydroxyl, methyl, carboxylate, aldehyde, inorganic carbonate, sulfonate, etc. in the PM10 of the study area. Mineralogical study also was done along with the quantification of quartz in different seasons of the study period. Finally, the health risk was evaluated for the people residing near the mine area due to the presence of quartz in the respirable air. From FTIR studies, it was inferred that strong mineral band of quartz, kaolinite, sepiolite, cerussite, and nacrite was present at all the stations. The concentration of quartz in the study area was found above the prescribed limit (6 μg m−3) recommended by USEPA for healthy air to breath. The health risk assessment due to quartz in respirable air showed high level of risk in all the stations of the study area. Winter season was found to be the riskiest among all the seasons in the year in terms of the presence of quartz in respirable air. This study made is unique as it was done to evaluate the health risk for non-occupational people in the study area.

Assessment of Exposure to Whole-Body Vibration of Dozer Operators Based on Postural Variability

The main aim of this work is to evaluate whole-body vibration (WBV) of dozer operators based on three sitting postures (i.e., with 15° lean forward inclination posture, vertically erect posture with no inclination, and with 15° lean backward inclination posture) in Indian surface coal mines. A seat pad tri-axial accelerometer was used to collect WBV data from six dozer operators for three different sitting postures. Results showed that except for Dozer-1, 2, 4, and 5 operators during lean forward sitting posture and Dozer-4 operator during vertical erected posture, no other dozer operators have exceeded an exposure limit value (ELV) of 1.15 m/s2 in any of the considered sitting postures. Similarly, the vibration dose value (VDV) based on exposure action value (EAV) of 9.1 m/s1.75 has surpassed for all the dozers. But no dozer operator has exceeded an exposure limit value of 21 m/s1.75. The outcome of the study infers that based on “above health guidance caution zone (HGCZ)” for daily vibration exposure, i.e., A(8) measurements, for the operator sitting in lean backward postures the vibration amplification was reduced by 32.89% less compared with lean forward posture and 16.23% less when compared with vertically erected posture. Similarly, based on VDV(8), the exposure to vibration for the lean backward posture was reduced by 33.34% when compared with lean forward posture and 17.11% less when compared with vertically erected posture. Based on the above observation, it is concluded that lean back inclination with a trunk flexion of 15° is a favorable sitting posture, as it exposes the dozer operators to minimum vibration.

Prediction of Rock Load Emphasizing Excavation Damage of <i>in situ</i> Rocks Caused by Blasting in Coal Mines

Roof failure in coal mines is strongly related to the frequency of laminations and their movement when the load acts upon them. Detachment of roof bolts from mine roof due to improper estimation of extent of weak zone is one of the major problems in underground coal mines, thus affecting the safety and productivity of workings. The most popular and practised method for roof support design in Indian coal mines is the Central Mining Research Institute-ISM geomechanical classification system. Irrespective of such an established system of support design, accidents due to roof fall still persist. Here we review various available classification systems for rock load estimation and identify their limitations. The study has been extended taking into consideration the case study of KTK-6 incline of Singareni Collieries Company Limited by proposing a modified rock mass classification system based on seismic wave velocity as a key descriptor. A modified rock mass rating (RMR) system (RMRdyn) with inclusion of seismic velocity as one of the parameters is proposed for the estimation of rock load. Enhancement in rock load by 20% has been found for RMR CMRI-ISM values less than 40 according to the new rock load relation. This resulted in under-supporting of the roof and thus might have caused failures. For cases with RMR CMRI-ISM values more than 60, the earlier equation overestimates rock load by about 25% resulting in over-supporting. Thus, estimation of rock load from the proposed new equation appears to be more rational as it takes into account the actual damage zone.

Optimum Chain Pillar Design at the Deepest Multi-Seam Longwall Workings in India

High-production methods like longwall mining with hydraulic powered supports are necessary to increase underground coal production in India. Longwall mining had a mixed success record for Indian geo-mining conditions. In this paper, an analysis is presented to optimally design an array of chain pillars in multi-seam longwall mining panels in the deepest coal mine in India. The study found that a chain pillar of 80-m width and 195-m length is necessary for long-term stability without any reinforcement. It was also observed that an optimum chain pillar can be designed by providing suitable side reinforcement (side bolting) which will reduce the chain pillar dimensions to 55-m width and 160-m length. Optimum design of chain pillars will reduce the coal locked up in these chain pillars by ~ 77%. This will also reduce the gestation period of longwall mining panel development. This paper also evaluates the maximum tensile subsidence strain induced at the surface and finds that the values are within the safe working limit of 3 mm/m. Thus, this paper finds direct application in the design of future multi-seam retreating longwall mining panels in Indian geo-mining conditions.

Musculoskeletal Disorders Among Dozer Operators Exposed to Whole-Body Vibration in Indian Surface Coal Mines

Dozer operators are frequently exposed to whole-body vibration (WBV) during the execution of their work. Occupational exposure to WBV in Indian surface coal mines was evaluated by measuring vibration intensity and duration of exposure. A triaxial accelerometer was placed on the operator seat surface for taking the readings. Based on frequency-weighted root mean square acceleration equivalent to 8-hr shift duration, i.e., (A(8)) all dozer operators have exceeded an Exposure Action Value (EAV) of 0.5 m/s2, and 90% of dozers did not exceed Exposure Limit Value (ELV) of 1.15 m/s2. Based on Vibration Dose Value (VDV (8)), all dozer operators have exceeded Exposure Limit Value (EAV) of 9.1 m/s1.75, but no dozer operators have exceeded Exposure Limit Value (ELV) of 21 m/s1.75. Further, an epidemiological study was performed for identifying the extent of musculoskeletal disorders (MSDs) among dozer operators. For the detailed study, 42 dozer operators and 22 controls were selected from 2 surface coal mines. The control group was not exposed to WBV. It was seen from the cross-sectional study that pain in the lower back was predominantly higher (83.33%) in the exposed group when compared with the control group (31.81%). Likewise, pain in the neck (47.61%), shoulder (42.85%), knees (42.85%), and ankle (11.90%) was higher in the exposed group than that of the control group (22.71%, 0%, 45.45%, and 4.54%). A significant observation among the exposed group was that there was degradation in the quality of life. The outcome of the study would assist in monitoring and mitigation of machinery-induced vibration diseases (MIVD) in India and generally applicable to most of the mechanized mines as well. However, comprehensive studies are still needed to enunciate the magnitude extent.

A comparative investigation of inter-row delay timing vis-à-vis some rock properties on high sandstone benches

The inter-row delay timing plays a pivotal role in any blast round as it not only influences the mechanism offragmentation, but also offers a vast potential in improving the overall results of fragmentation. It is in this perspective thatthe current study presents a comparative investigation of the influence of inter-row delay timing on fragmentation in twodifferent strength sandstone formation in large-scale, multi-row blast rounds of a two surface coal mines in India. Theinvestigations are based on full-scale field blasts. The study highlights the role of p-wave velocity and brittleness vis-à-visimpedance to shock wave propagation during the initial as well as final stages of rock breakage. Given this, the role ofshattering effect (in stronger sandstone formations) and heaving effect in weaker strength sandstone has been clearlyestablished in the rock breakage mechanism. Furthermore, the study also suggests that for weaker sandstone, longer interrowdelay timing (15-25 ms/m of effective burden) yields the best fragment size results. Similarly, for stronger sandstoneformation, shorter inter-row delay timing (10-17.85 ms/m of effective burden) yields the best fragment size results.

Application of Foam Stopping for Mitigation of Spontaneous Heating In Underground Coal Mines

The problem of spontaneous heating is a major threat to safety and productivity in mines all over the world. In India, more than 80% of fires are caused due to Spontaneous Combustion. The applicability of inert gases is expensive, time-consuming and is a very tedious process. Hence the application of advanced technologies becomes essential to be introduced in mines. In this context, Central Mine Planning and Design Institute (CMPDI), Ranchi, India carried out an R&D project entitled “Construction of quick setting stopping in case of fire in an underground mine using expansion foam agent” under the funding from the Ministry of Coal, Government of India. Under this project, two Indian mines were selected in consultation with MCL for carrying out the proposed work in Orient Mine No.3 and Bundia Mine of MCL (Ib Valley AREA). Coals from both the mines have been collected and analysed in the laboratory. The proximate analysis and CPT/IPT results show that both the coals are moderately prone to spontaneous heating. Considering both intrinsic and extrinsic properties, two stoppings were constructed in the Hirakhand Bundia mines and four in orient mines. Periodic supervision along with the altering ingress of air from intake was been checked. After careful supervision of nearly 4 years, the stoppings proved to be strong enough to be leakage proof. This paper describes the application of foam technology as stopping to avoid air entry, thus preventing the occurrences of spontaneous heating/fire in a panel of Indian coal mines.

Associations of job-related hazards and personal factors with occupational injuries at continuous miner worksites in underground coal mines: a matched case-control study in Indian coal mine workers.

A wide range of job-related hazards and personal factors may be associated with injury occurrences at continuous miner worksites but their role has been little documented. To address this issue, a case-control study in India was conducted to compare 135 workers with an injury during the previous 2-yr period and 270 controls without injury during the previous 5-yr period (two controls for each injured worker, matched on age and occupation). Data were collected through face-to-face interviews using standardized questionnaire and analyzed using conditional logistic regression models. We found that the injury occurrences were multifactorial and associated with hand tool-related hazards (adjusted odds ratio/ORa=3.69, p<0.01), working condition-related hazards (ORa=3.11, p<0.01), continuous miner-related hazards (ORa=1.95, p<0.05), and shuttle car-related hazards (ORa=6.95, p<0.001), along with big family size, no-formal education, and presence of disease (adjusted odds ratios varying between 2 to 4). Stratified analyses showed that among the 36–60 yr-old workers, hand tool-related hazards, working condition-related hazards, and shuttle car-related hazards had significant ORa (6.62, 4.38 and 15.65, respectively with p<0.01,) while among the younger workers, only shuttle car-related hazards had significant ORa (4.25, p<0.05). These findings may help to understand the risk patterns of injuries and to implement appropriate prevention strategies.

Assessment of the Susceptibility of Coals to Spontaneous Heating using Wet Oxidation Potential Difference Technique

This study is proposed to assess the susceptibility of coals from different Indian coal mines and correlation study to fi nd out the suitability of the methods for assessment of spontaneo us heating of coals. The wet oxidation potential difference experiments (WOPD) were conducted forT20TdifferentTcoalTsamplesTcollected from different India coal mines. the coal samples were collected by channel sampling and prepared according to the Indian Standards. the energy content of all the coal samples in terms of calorific values was measured with the Bomb Calorimeter and proximate analysis was also conducted so as to obtain volatile matter, fixed carbon, moisture content and calorific value. Correlation study was carried out to find the suitability of the methodto assess the spontaneous heating sus ceptibility of coal. Generally, Crossing Point Temperature (CPT) method is used for assessment of spontaneous heating susceptibilit y of coal. However, this method has certain drawbacks. The results are depend re not reproducible. More over, it takes long hours (more than three hours) to complete the experiment. In comparison to CP, WOPD experiments only takes about 40 minutes for completion and the results are reproducible as well. From the correlation analysis, it was found that WOPD indicated a very fair accuracy for the measure of spontaneous heating susceptibilityas it showed high correlation with the intrinsic propertiessuch as moisture and volatile matter.

GHG Inventory for Opencast Coal Mining in India Based on Stoichiometric Combustion of Diesel and Simulation of Ethanol-Diesel Blend for Emission Reduction

GHG Inventory for Opencast Coal Mining in India Based on Stoichiometric Combustion of Diesel and Simulation of Ethanol-Diesel Blend for Emission Reduction

Management Of Coal Mine Overburden And Fly Ash using Bamboo Cultivation

Coal mine in India is one of the biggest source of energy production. Coal is the major component used in thermal power plants which helps in consuming 71% of electricity generated by these thermal power plants in India. In opencast coal mining excavation of coal is done and huge area is abandoned after coal is being excavated. The OBD soil which is present at these mine sites is very poor in nutrients that it is usually unfavorable for any type of plantation to be carried out. Keeping this in mind another factor comes across is that thermal power plants are located nearby coal mines which gives fly ash as combustion product of coal and disposal of this fly ash is very crucial. Therefore, this fly ash can be used along with coal mine OBD soil which it has efficiency in improving soil fertility in many ways. Revegetation is one of the most accepted way of soil reclamation and reduction in soil erosion. The suitability of soil for growth of bamboo is checked by planting bamboo saplings in an area of 3 x 3 feet having depth 1 foot in a systematic manner by attempting field trial.

Analysis of Accidents Due to Slope Failure in Indian Opencast Coal Mines

Opencast mining operation involves removal of bulk quantities of overburden, dumping and backfilling in excavated areas. A phenomenal increase in the share of opencast production (93%) in Indian coal industry has resulted into significant problem of waste dumps at present with greater height of the dump constructed over minimum area and giving rise to increasing danger of dump failures. Dangerous occurrences, incidents, accidents and disasters due to dump failure in Indian opencast mines are quite common, resulting in injuries and fatalities. In 2016, a disaster due to dump failure in Rajmahal coalfield of ECL, killed 23 workers. Even though all such accidents are being analysed and recommendations made in each case, similar accidents are not prevented. Unfortunately we seem to miss the lessons each time from these past incidents or accidents. In this communication, we analyse an accident due to dump slope failure in Indian opencast coal mine, in which a giant debris flow occurred during routine mining operation. In addition, we identify the gaps in our learning system and the thrust on improving safety by analysing accidents using root cause analysis techniques and to improve the stability of the dump.

Assessment of the Strength of Inclined Coal Pillars through Numerical Modelling based on the Ubiquitous Joint Model

The inclined coal pillars, formed during the underground extraction of the inclined coal seam, are different from the flat coal pillars due to the high strength anisotropy of the inclined bedded rock, and the asymmetrical stress distribution. To ease the manoeuvring of the men and machinery in the inclined coal mine, the pillars are developed along the apparent dip. Thus, the pillars become rhombus-shaped with acute-angled corners which crush rapidly due to the high stress concentration. No suitable formula is found to estimate the strength of the inclined coal pillar that incorporates all these factors. Thus, the use of the available coal pillar strength formulae may endanger the extraction of the inclined coal seams. This study elucidates the procedures to estimate the strength of the inclined coal pillars by the numerical modelling technique. The ubiquitous joint model is used to simulate the shearing characteristics of the inclined strata. The parametric study shows that the strength of the inclined coal pillars decreases with the increase of the dip of the coal seams. It is also obtained that the strength of the pillars decreases with the decrease of the value of the acute angle of the corners. The peak stress distribution and the strain accumulation over the inclined pillars at the time of failure are plotted in three-dimensional graphs which show the asymmetrical characteristics of the inclined coal pillars. The analysis of variance shows that the dip of the coal seams and the acute angles of the corners have a statistically significant effect on the strength of the inclined coal pillars. Based on the results of the simulation, the best fit relation is established by the multivariate non-linear regression technique to estimate the strength of the inclined coal pillars. The coefficient of determination (R2) and the root mean square error of the model are obtained as 0.92 and 0.065, respectively. The validation of the developed model has been carried out by the stable and failed inclined pillar cases of different underground inclined coal mines in India. Comparisons of the safety factors, obtained from the developed model and the flat pillar strength formula, indicate that the flat pillar strength formula overestimates the strength of the inclined coal pillars. The developed model can be used to design the inclined coal pillars for safe extraction of inclined coal seams.

Negotiating the Mines: The Culture of Safety in the Indian Coalmines, 1895–1970

This article explains the way mineworkers negotiated workplace hazards and articulated their ideas of safety. Mineworkers increasingly attained mining sense and made use of it, thereby surviving terrible working conditions and seeking to mend the accident-control mechanism. The formation and function of their mining sense were part of the industrialization process. It involved mineworkers’ particular ways of adaptation—quixotic and prudent—to the demand made by work relations. The miners’ unions strove to push the safety regime beyond voluntary codes of discipline and practical and technological solutions. They invested in legislative disciplining and sought informed safety-supervisory controls. They got involved in ‘civic engagement’ with agreeable investigators and legislators within the colonial context and afterwards. Confronted with the limits of such measures, the rank-and-file moved on, from the latter half of the 1950s to direct action in the very mining faces, thereby insisting on the right to withdrawal from danger. The historiographies which argued that Indian workers knowingly acquiesced to perilous mining to maintain livelihoods inadequately lend us the safety ideas shared and action at protection prevention undertaken by mineworkers. This article shows that Indian mineworkers reinforced the safety campaign through their strategic manoeuvring in legislative and workplace struggles as did their counterparts in Britain and some other societies.

Pyrolysis characteristics and kinetics of Indian low rank coal using thermogravimetric analysis

The present research work deals with the thermogravimetric analysis (TGA) and kinetic analysis of three typical Indian low rank coals selected from Indian coal mines at various temperature ranges. Experiments were performed at four different heating rate (50, 100, 150, 200 K/min) for three typical Indian low rank coal samples in a nitrogen atmosphere from temperature range 30–950 °C. The peak of temperature and mass loss for Indian low rank coal were evaluated. Current study also deals for the utilization and the behaviour of Indian low rank coal during the pyrolysis by using TGA. The activation energy for Indian low rank coal were calculated based on TGA data by using Friedman Method. Corresponding calculated mean value of activation energy for Indian low rank coal is found 49.132 kJ/mol. These experimental results help to explain and predict the behaviour of Indian low rank coal in practical applications.