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By Samir Kumar Pal, Rajasekar Rathanasamy, Gobinath Velu Kaliyannan, Moganapriya Chinnasamy, Sathish Kumar Palaniappan

The research examines the performance of uncoated and coated tungsten carbide-cobalt rock cutting bits. It aims to optimize process variables (cutting speed, depth, coating material) considering multiple output responses (cutting forces, specific energy, wear rate, material removed, angle of reaction forces). The study uses a hybrid optimization technique combining Taguchi design, grey relational analysis, and fuzzy logic. The optimal parameter combination was found to be cutting speed: 200 mm/s, cutting depth: 6 mm, and titanium aluminum silicon nitride coating.

Apr 24, 2022

By Xiaolong Bi, Shaohua Luo, Longjiao Chang, Shiyuan Cao, Jianan Liu

The abstract discusses the extraction of silica from nickel laterite ore using a hydrothermal process with sodium hydroxide. The effects of reaction temperature, time, and NaOH-to-ore ratio on silica extraction were investigated. The optimal conditions were determined, achieving over 98% silica extraction. The mechanism involves the reaction of Si in lizardite and quartz with sodium hydroxide, forming sodium silicate solution. Other metals like Mg, Fe, and Ni are enriched in the residue.

Apr 21, 2022

By V. K. Reddy Kallam, NEHA PANDEY, Sunil Kumar Tripathy, ARIJIT BISWAS

The study investigates SO2 leaching of low-grade ferruginous manganese ores to selectively recover manganese as MnSO4 and produce battery-grade electrolytic manganese dioxide (EMD). The effects of leaching parameters (duration, temperature, SO2 flow rate) on Mn recovery were studied. Under optimum conditions, 97.9% Mn recovery was achieved. The MnSO4 leach liquor was purified and used for electrowinning EMD with 88.01% purity and battery-active γ structure.

Apr 20, 2022

By Bo Hyun Kim, Mark K. Larson

This study was developed as part of an effort by the National Institute for Occupational Safety and Health (NIOSH) to better understand rock-mass behavior in longwall coal mines in highly stressed, bump-prone ground. The floor-heave and nofloor- heave phenomena at a western US coal mine could not be properly simulated in numerical models using conventional shear-dominant failure criteria (i.e., Mohr–Coulomb or Hoek–Brown failure criterion). The previous numerical study demonstrated these phenomena using a user-defined model of the s-shaped brittle failure criterion in conjunction with a spalling process in the FLAC3D numerical modeling software. The results of the FLAC3D modeling agreed with the observations of the relative amounts of heave from each gate-road system. However, the FLAC3D model adopted many assumptions and simplifications that were not very realistic from a physical or mechanical perspective. To overcome the limitations of the FLAC3D model, 3DEC modeling in conjunction with the discrete fracture network (DFN) technique was performed to better understand the true behavior of floor heave associated with underground mining in an anisotropic stress field. The effect of stress rotation in the mining-induced stress field was considered by using a different geometry of rock fractures in the coal seam. The heterogeneity of the engineering properties (i.e., cohesion and tensile strength) were also considered by using Monte Carlo simulations. Consequently, the 3DEC models using the DFN technique resulted in predictions of floor heave that agreed with observations of the relative amounts of heave from each gate-road system, but the cause of heave was mainly related to the degree of anisotropy instead of the size of the pillar.

Apr 14, 2022

By Lana Alagha, Keitumetse Cathrine Monyake

The abstract discusses the synthesis and investigation of polyacrylamide functionalized chitosan polymers (CS-PAMs) as selective depressants for pyrite in the flotation of galena and chalcopyrite from complex sulfide ore. The study employed response surface methodology (RSM) to model and optimize the flotation process, varying parameters like the degree of deacetylation of chitosan, weight ratio of chitosan to acrylamide, and CS-PAM dosage. The developed RSM models effectively predicted iron and lead grades and recoveries, while optimization showed optimal pyrite separation from galena and chalcopyrite using CS-PAM synthesized from chitosan with a high degree of deacetylation and a specific chitosan:acrylamide weight ratio.

Apr 9, 2022

By Jordi Vives-Costa, J. J. de Felipe, Lluís Sanmiquel, Maria Niubó

The article evaluates the convective heat transfer coefficient of ventilation air in a potash mine. The energy balance is obtained through thermal characterization of the ventilation air and rock, allowing for the calculation of heat transfer parameters. Different models for calculating the convective heat transfer coefficient are analyzed. The results indicate that the Pethukov–Kirilov, Gnielinski, and modified Dittus–Boelter models are optimal for this mine. The study also indirectly examines the conductivity of the adjacent rock, suggesting saturation throughout the studied section and the presence of liquid water upwelling in a specific section.

Apr 7, 2022

By Zhiyuan Shen, Dan Zhao

The abstract discusses the importance of reliable mine monitoring systems for preventing accidents. It focuses on diagnosing ventilation system failures caused by roadway faults that alter airflow resistance. The paper proposes using an improved Support Vector Machine (SVM) method to identify the fault location based on changes in air volume detected by wind speed sensors. The approach involves building a sensitivity 0-1 matrix and establishing a roadway fault scope library. The improved SVM method is tested on the Daming coal mine, demonstrating its effectiveness in diagnosing fault locations, reducing training time, and improving accuracy compared to traditional SVM.

Apr 5, 2022

By S. M. Hossaini, M. Ataei, H. Moosavi

The abstract highlights the importance of pillar stability in underground coal mines and the influence of rock mass strength and joint orientation on pillar behavior. The study employs numerical modeling using the distinct element code (UDEC) to investigate the impact of these factors on pillar stability. The research considers different joint orientations and varying rock mass strengths, analyzing parameters like stress distribution, displacement, and failure patterns. The findings reveal that both joint orientation and rock mass strength significantly affect pillar stability, with specific combinations leading to reduced safety factors and increased deformation. The study concludes by emphasizing the importance of considering these factors in pillar design for safe and efficient mining operations.

Apr 4, 2022

By S. M. Hossaini, M. Ataei, H. Moosavi

The abstract highlights the importance of pillar stability in underground coal mines and the influence of rock mass strength and joint orientation on pillar behavior. The study employs numerical modeling using the distinct element code (UDEC) to investigate the impact of these factors on pillar stability. The research considers different joint orientations and varying rock mass strengths, analyzing parameters like stress distribution, displacement, and failure patterns. The findings reveal that both joint orientation and rock mass strength significantly affect pillar stability, with specific combinations leading to reduced safety factors and increased deformation. The study concludes by emphasizing the importance of considering these factors in pillar design for safe and efficient mining operations.

Apr 4, 2022

By S. N. Gurulaxmi, Veerendra Singh

The abstract discusses the increasing consumption of manganese ores and the need to utilize low-grade ores and rejects. The study focuses on developing a low-cost process using a cupola furnace to recover manganese values from these resources. The process involves smelting ore blends to produce high MnO slag and pig iron. The study investigates various factors to improve iron reduction and separation from MnO-bearing slag. The results show that the process can produce slag with MnO > 35% and Fe(t) < 5% using low-grade Mn ores. The process also achieves Fe reduction between 50 and 70%. The cupola furnace offers advantages like low cost and ease of operation, making it suitable for processing low-grade ores and rejects to produce synthetic MnO-enriched products for various industries.

Apr 1, 2022

By AJIT SWAIN, SUNATI MOHANTY

The abstract discusses the importance of predicting the dewatering performance of industrial hydrocyclones from laboratory models. It highlights the challenge of scaling up design and operating parameters for efficiency estimation. The paper describes experiments with a 2-inch and 4-inch hydrocyclone using silica sand. It details the development of a model using the Nageswararao hydrocyclone model and a simulator to estimate model parameters. The model is validated with experimental data, and a new model is developed using 4-inch hydrocyclone data. The technique is then extended to predict dimensions for a full-scale dewatering cyclone operating at higher throughput and solid concentration.

Mar 30, 2022

By Nasser Madani, SULTAN ABULKHAIR

The abstract of the paper discusses the challenge of quantifying iron content in a coal deposit in Kazakhstan. The iron dataset is limited, coming from only three drill holes and some stope samples, while a large amount of geological information is available from legacy drill hole data. The paper proposes a workflow using multiple-point geostatistics to model geological domains and two-point geostatistics to model iron content within these domains. The results show that the direct sampling (DeeSse) algorithm effectively reproduces the complex seam layers, and sequential Gaussian simulation models the iron within each domain.

Mar 30, 2022

By Charlotte Abena Benyarku, Albert Buabeng, Eric Stemn

The abstract highlights the increasing use of mobile equipment in mining and its contribution to accidents. The research analyzes injury narratives from Ghanaian surface gold mines to understand the involvement of mobile mining equipment in injuries and explore the use of injury narrative data as a human factors tool. The study identified priority human factor issues, such as operating mobile mining equipment, part removal/installation, and the operator's cabin. The use of Sankey diagrams for multivariable analysis effectively identified specific operator-centered issues that warrant further investigation for improved safety interventions.

Mar 29, 2022

By Jürgen. F. Brune, CLAIRE STREBINGER, ADITYA JUGANDA, Gregory E. Bogin Jr

The abstract highlights the risk of methane gas explosions in underground coal mines and the potential of computational fluid dynamics (CFD) modeling to simulate such events and assess their impact on mine ventilation. The study focuses on developing CFD models for large-scale explosions in longwall mines, specifically simulating methane gas explosions resulting from face ignition during coal cutting. The research demonstrates the integration of a combustion model into a longwall mine ventilation model and shows how the availability of explosive gas mixtures significantly affects flame propagation and explosion pressure.

Mar 27, 2022

By Jie Zhang, Xi Zhang, Yu Wang, Wei Zhao

The study proposes a novel reagent scheme where adding a small amount of citric acid (CA) significantly improves the depression effect of sodium silicate on calcite and fluorite. The flotation results suggest optimal concentrations for CA and sodium silicate, achieving nearly complete depression of the minerals. Theoretical analysis indicates that CA dissolves calcium ions on the mineral surface, enhancing the adsorption of sodium silicate and preventing collector adsorption.

Mar 27, 2022

By İlknur Erol

The abstract highlights that hearing loss is an occupational disease caused by noise exposure in the workplace. The study investigates noise-induced hearing loss among miners in underground coal mines in Turkey, considering factors like occupation, age, and exposure time. The research employs logistic regression analysis to reveal the relationship between hearing loss and these factors. The findings suggest that occupational groups and duration of noise exposure significantly affect hearing loss. Miners in production groups and those exposed to noise for 10-14 years have a higher risk. The study concludes that age does not significantly increase the probability of hearing loss.

Mar 24, 2022

By Yakup Cebeci, Leyla Kalender, Ceylan Yarluğkal Altınışık, Hikmet Sis

The abstract highlights the challenges in concentrating complex and non-sulfide lead-zinc ores and emphasizes the importance of froth flotation for their beneficiation. The study focuses on using process mineralogy to understand the flotation behavior of these ores from the Görgü region. The ore samples were characterized using various techniques, revealing oxidation and carbonation of primary minerals. The flotation results were interpreted in light of the mineralogical data, explaining the poor outcomes due to the complex nature of the ore, poor liberation, and lack of hydrophobicity.

Mar 22, 2022

By Jürgen Brune, Purushotham Tukkaraja

This editorial introduces a special focus issue on mine ventilation innovations. It highlights key areas such as ventilation on demand, automation, thermal management, atmospheric monitoring systems, and prevention of mine fires and explosions. The issue aims to address the critical role of mine ventilation in maintaining the health and safety of miners.

Mar 21, 2022

By A. Juganda, H. PINHEIRO, J. Brune, N. SANDOVAL, G. Bogin, K. Gallagher, F Wilson

The present work discusses the nuances of scaling and flow similarity to develop a 1/40th scale version of a longwall coal mine. Details on the geometric, kinematic, and dynamic scaling of the physical model are presented and discussed. This works also discusses using a 30% CO2 – 70% He gas mixture as a surrogate for methane. It also presents the implications of various Reynolds numbers (ranging from 7,000 to 140,000) and rotation of the shearer drums in the dynamic representation of the airflow and gas mixtures in the physical scaled model.

Mar 19, 2022

By Jessica M. Wempen, William G. Pariseau, Dallan J. Coons, Michael K. McCarter, Erik C. Westman

The abstract discusses the importance of proper pillar sizing in underground mining for safety and efficiency. It highlights the use of theoretical models, geotechnical measurements, and numerical modeling in predicting pillar behavior. The research focuses on using seismic tomography to image stress changes in a yield pillar at a longwall mine as the longwall face approaches. The study aims to compare the stress distribution imaged using tomography with theoretical models, geotechnical measurements, and numerical models.

Mar 18, 2022