Faculty Publications
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Item Evaluation of Whole Body Vibration of Heavy Earth Moving Machinery Operators(Springer Nature, 2020) Jeripotula, S.K.; Mangalpady, A.; Raj, G.R.Operators of Heavy Earth Moving Machinery (HEMM) performing routine tasks in surface mines are highly vulnerable to whole body vibration (WBV) due to their continuous exposure to vibration. In the present study seventeen types of machinery were considered for the evaluation of the operator’s exposure to WBV. The measurements were made by placing the triaxial seat pad accelerometer on operator’s seat-surface as well as at the seat-back. Among these machinery one shovel, two front-end loaders, three drills, one grader and one water sprinkler were found to have RMS values in the severe zone as per ISO2631-1:1997 standards for seat-surface measurements. Similarly, for the seat-back measurements, one front-end loader, two drills, one grader and one water sprinkler were experienced the highest RMS value. For both seat-surface and seat-back measurements, Z-axis (i.e. vertical direction) was found to be a prominent axis for most of the machinery. © 2020, Springer Nature Switzerland AG.Item Investigation of iron ores based on the bond grindability test(American Institute of Physics Inc. subs@aip.org, 2020) Hanumanthappa, H.; Vardhan, H.; Raj, G.R.; Kaza, M.; Sah, R.; Sinha, A.; Shanmugam, B.K.Grinding is a process of reduction of lumps to powder depending on the requirement of particle size and particle shape. The present investigation involves the identify the physical properties of three different types of iron ores by using Bond ball mill. The result shows that the maximum Bond work index of 14 KWh/mt was obtained for 'A' type iron ore sample. The Bond work index for 'B' and 'C' type iron ore sample are of 11 and 10 KWh/mt. The variation of BWI of three iron ore sample may be varied during the geological formation of each iron ore sample. The output product of three iron ore sample composed of three different size fractions when ground in Bonds ball mill. Based on the BWI and output product size of three iron ore samples are classified as hard ore ('A' type iron ore sample), medium hard ore ('B' type iron ore sample) and soft ore ('C' type iron ore sample). The classification of different types of iron ore helps to run the plant scale ball mill by setting suitable operating parameters to the ball mill. © 2020 Author(s).Item The screening efficiency of linear vibrating screen-An experimental investigation(American Institute of Physics Inc. subs@aip.org, 2020) Shanmugam, B.K.; Vardhan, H.; Raj, G.R.; Kaza, M.; Sah, R.; Hanumanthappa, H.Screening is a process of continuous physical separation of two or more powdered material depending on the particle size and particle shape. The present investigation involves the study of screening efficiency obtained in the widely used plant scale linear vibrating screen. The present investigation also involves the recommendations for improving screening efficiency. The result shows that the linear vibrating screen has the maximum screening efficiency of 65.92% for first 10 minutes of screening and reduced up to 59.34% for 60 minutes of screening. The reduction in screening efficiency with respect to screening time is due to the screen blinding. The screening of powdered materials faces the problem of screen mesh blinding which reduces the screening efficiency. The present authors recommend utilizing the screen configuration of circular vibrating screen which can provide higher screening efficiency with reduced screen blinding. The utilization of circular vibrating screen will reduce the screen blinding and prevents the labor requirement for removing screen blinding thereby increasing the efficiency and the production rate of screening. © 2020 Author(s).Item A Systematic Review on Implementation of Internet-of-Things-Based System in Underground Mines to Monitor Environmental Parameters(Springer, 2024) Naik, A.S.; Kumar Reddy, S.K.; Raj, G.R.The automation in the mining industry by adopting Internet of Things (IoT) technology is great potential to improve safety and efficiency. The mining industry is recognized globally for its valuable resources (gold, coal, iron ore, etc.) which are obtained by mining below the surface. The productivity and safety of mine personnel are impacted by several environmental parameters in underground mines, such as toxic gases, flammable gases, elevated levels of carbon dioxide (CO2), and decreased levels of oxygen (O2) concentrations. The presence of these gases is a significant issue and needs to be dealt with suitably. There are various methods to monitor the percentage of gases and provide a suitable course of action in case of an increase in the threshold limit of gases. Each system has its limitations. Wireless monitoring systems are indispensable in underground mines. This paper presents the methodology to adopt IoT in underground mines to measure environmental parameters in underground mine areas, the structure of installation of sensors in underground mines, threshold limits of gases, and underground mine disasters which were caused by gas explosion accidents. Further, it evaluates wireless sensor networks (WSNs) techniques ZigBee and LoRa for underground mines applications. Subsequently, it proposed a real-time industrial safety system in underground mines with its working, effectiveness, and scope are discussed. © The Institution of Engineers (India) 2023.Item Evaluation of Whole-Body Vibration (WBV) of Dozer Operators Based on Job Cycle(Springer, 2019) Jeripotula, S.K.; Mangalpady, A.; Raj, G.R.Dozer operators are frequently exposed to high levels of occupational vibration. So far, no study reported component wise evaluation of dozer cycle of operation. In the present study, WBV data were collected by placing the trial accelerometer at operator’s seat-surface and at seat-back. Frequency-weighted root mean square (RMS), vibration dose value (VDV) and crest factor were collected for each dozer for two phases’ forward motion and return motion. All the dozers under study were found to be in severe zone with respect to measured RMS, during forward motion and return motion, irrespective of type of measurements (i.e., seat-surface and seat-back). As per VDV, out of eight dozers three dozers were found to be in caution zone during forward motion and three in return motion. According to EU Directive 2002 (as per RMS), all the dozers under study have reported exposure action value above 0.5 m/s2. Further, out of eight dozers, four dozers have shown exposure limit value above 1.15 m/s2 for seat-surface measurements and three dozers for seat-back measurements. Vibration mitigation strategies should be adapted not just based on intensity of vibration but also with respect to dominant axis of vibration. Considering the severe health risk due to the translational vibration (i.e., in x-direction), the vibration risk in the forward x-direction can be reduced by using seat belt; similarly in rear x-direction it can be attenuated by placing lumber-assisted back rest. © 2019, The Institution of Engineers (India).Item A comparative study on a newly designed ball mill and the conventional ball mill performance with respect to the particle size distribution and recirculating load at the discharge end(Elsevier Ltd, 2020) Hanumanthappa, H.; Vardhan, H.; Raj, G.R.; Kaza, M.; Sah, R.; Shanmugam, B.K.The discharge end design of a ball mill plays an important role in discharging the desired particle sizes (?150 + 10 µm) and the percentage of recirculating load from the discharge end of the ball mill. In continuous wet ball mills, the composition of feed (hard ore or soft ore) to the mill varies continuously, leading to uncontrolled grinding in the mill. In view of this, a new design of the discharge mechanism has been implemented to remove the ground particles of desired particle size fraction with minimum recirculating load (+150 µm). The results from the discharge end with lifters (closed and open) show that the particle size fraction obtained from the discharge end has a maximum percentage of desired particle size fraction when the mill is operating at 60% critical speed. Discharge end without lifters has an uncontrolled particle size distribution in the discharge and the percentage of desired-size particles discharged was found to be very less. Also, the percentage of the recirculating load is minimum in the case of discharge end with lifter design compared with discharge end without a lifter. Hence, a new design of lifters in the discharge end leads to the discharge of the desired particle size fraction with minimum recirculating load. © 2019 Elsevier LtdItem Evaluation of Whole Body Vibration (WBV) of Dumper Operators Based on Job Cycle(Springer, 2020) Jeripotula, S.K.; Mangalpady, A.; Raj, G.R.Dumper operators are frequently exposed to whole body vibration (WBV) in surface mines. Surface mining activities involve the amalgamation of comparatively high intensity of vibration and extended exposure durations. Efficient risk reduction mandates knowing of important phases of a task that poses a threat to health of dumper operators. So far in India very limited studies have been reported on WBV exposure with regard to surface mines. This paper evaluates WBV of dumper operators based on ISO 2631-1:1997 Standards and European Union (EU) Directive 2002 for different phases of job cycle. Six dumpers were considered for this study and the vibration measurements were made for all the four phases of the job cycle by placing the triaxial accelerometer on the operator’s seat-surface and at the seat-back, independently. The findings of the study revealed that the haulage task (loaded travel and empty travel) remains the chief contributor to vibration exposure according to seat-surface and seat-back measurements. Maximum frequency weighted root mean square (RMS) of 1.12 m/s2 and 1.09 m/s2 were reported for empty travel task for seat-surface and seat-back measurements, respectively. For seat-surface measurements based on RMS, Z axis remains as the dominant axis of vibration for all the dumpers during haulage task, whereas for seat-back measurements, the dominant axis varies between X and Y. Exposure action value (EAV) based on RMS has exceeded the threshold value of 0.5 m/s2 for all the dumpers during loaded travel and empty travel for seat-surface as well as for seat-back measurements. © 2019, Society for Mining, Metallurgy & Exploration Inc.Item Musculoskeletal Disorders Among Dozer Operators Exposed to Whole-Body Vibration in Indian Surface Coal Mines(Springer, 2020) Jeripotula, S.K.; Mangalpady, A.; Raj, G.R.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. © 2020, Society for Mining, Metallurgy & Exploration Inc.Item Assessment of Exposure to Whole-Body Vibration of Dozer Operators Based on Postural Variability(Springer, 2020) Jeripotula, S.K.; Mangalpady, A.; Raj, G.R.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. © 2020, Society for Mining, Metallurgy & Exploration Inc.Item Estimation of Grinding Time for Desired Particle Size Distribution and for Hematite Liberation Based on Ore Retention Time in the Mill(Springer, 2020) Hanumanthappa, H.; Vardhan, H.; Raj, G.R.; Kaza, M.; Sah, R.; Shanmugam, B.K.Iron ores obtained from different sources differ in their chemical and physical properties. These variations make the process of grinding a difficult task. The work carried out in this context focuses on three different samples of iron ore, viz., high silica high alumina, low silica high alumina, and low silica low alumina. The grinding process for all the three iron ores is carried out individually in Bond’s ball mill and the total retention time taken by each iron ore sample is calculated. The present investigation focuses on utilizing the calculated retention time of the iron ore as a standard grinding reference time to the laboratory ball mill for optimizing the grinding time of each ore. The desired P80 (150 ?m) with an acceptable range of hematite liberation (> 75%) was obtained in the laboratory ball mill after reducing 6 min from the total retention time taken in the Bond ball mill. © 2020, Society for Mining, Metallurgy & Exploration Inc.