International Journal of Mining and Mineral Engineering (11 papers in press)
Implementation of Industry 4.0 technologies in the mining industry a case study
by Arnesh Telukdarie
Abstract: In modern mining, it is imperative to have a real-time flow of information between enterprise level and shop floor systems. The gaps that exist between these spheres make it difficult for managers to have timely information for optimum decision making. A mining company needs instantaneous visibility on production, quality, cycle times, machine status, and other important operational variables to achieve optimum and effective operations. With the implementation of Industry 4.0 technologies at a Mine, the integration of fragmented shop floor and the enterprise level systems enables seamless communication in delivering optimum operations. This research demonstrates Industry 4.0 technologies as the mechanisms for integrating business systems, manufacturing systems and processes. The Industry 4.0 methods researched are deployed using Software Development Lifecycle (SDLC) process at a mining company to integrate systems such as manufacturing, plant, business partners, and SAP ERP. The results introduce a semi-smart Mine with real-time visibility of the overall mining status.
Keywords: Industry 4.0; Internet of Things; Industrial Internet of Things; Cyber Physical Systems; Big Data; ERP.
Effect of aggloflotation of coal slimes by use Flomin C9606 as a collector
by Richard Kasomo, Sammy Ombiro
Abstract: In many coal preparation plants and concentrators, coal slime (ultra-fine coal) form the major challenge due to difficulties in processing and upgrading. Several techniques are currently being devised in coal and mineral industries to aid in beneficiation of the coals in their finer sizes. Most of the ultra-fine coal particles are processed by oil agglomeration, selective flocculation or hydrophobic flocculation flotation techniques. In this research the main focus was hydrophobic flocculation flotation to utilize the ultrafine coal particles. In the study, the conventional flotation batch tests were conducted to determine the best collector and the best dispersant for this coal, then Flocculation experiments were carried out followed by the flotation. The effects of fundamentals parameters such as the type and dosages of flocculating reagents, the impeller stirring speed and the grinding fineness were also investigated. The optimum conditions for research were as follows: Flomin C9606 was determined to be the best collector, sodium Hexametaphosphate as the best dispersing agent, the impeller speed was determined to 1500rpm, and the best grinding fineness was achieved at 30 minutes. When the sample was processed by the flow sheet consisting of one stage rougher and one stage cleaner, the ash content of the raw coal was reduced from 22.73%, (raw coal) to 6.39%. This was achieved by four stage flotation cleaning with the solid combustible matter recovery of 86.28%. The overall ash reduction was 73.57% which met the minimum requirement to be used as a clean coal product in industries. It was therefore concluded that hydrophobic flocculation flotation using Flomin C9606 was capable of cleaning ultra-fine coal to obtain the clean coal product.
Keywords: Coal slimes; hydrophobic flocculation flotation; Flomin C9606; Froth flotation.
Impact of hydraulic fracturing and borehole spacing on gas drainage along coal seam
by Huayong Lv
Abstract: Hydraulic fracturing is a technology employed to improve coal seam permeability and gas drainage. This study uses theoretical analysis and field testing to examine the mechanisms of hydraulic fracturing of a coal seam, including the initiation conditions of boreholes and cracks, main crack forms, and expansion and extension processes. RFPA2D-flow software was used to develop a numerical simulation of double-hole hydraulic fracturing, from crack initiation to expansion and extension in the coal body. The numerical simulation revealed characteristics and evolution of the stresses, water pressure and acoustic emission around the boreholes and estimated the permeability improvement range of fracturing holes under conditions of different hole spacing. Results of a field industrial test showed that the daily gas drainage pure flows increased by 5.817.6 times, the average gas drainage velocity reached 3.76 m3/min (maximum 10 m3/min), the gas drainage rate of the working face reached 57.32%, and the influence radius of single-hole hydraulic fracturing is approximately 5 m. This study demonstrates that hydraulic fracturing and permeability improvement technology can greatly improve the gas drainage rate of boreholes in a coal seam.
Keywords: Hydraulic fracturing; Crack expansion and extension; Pressure relief and permeability improvement; Gas drainage.
CFD simulations of DPM flow patterns generated by vehicles in underground mines for different air flow and exhaust pipe directions
by Ramakrishna Morla, Shivakumar Karekal, Ajit Godbole
Abstract: In this paper, an attempt is made to model Diesel Particulate Matter (DPM) flows generated by Load Haul Dumpers (LHDs) and trucks in an underground mine environment for different DPM flow and intake air flow directions and exhaust pipe directions. Field experiments were conducted and used to validate the computational fluid dynamics (CFD) models and to map the DPM flow patterns. The results obtained show that if the DPM and the intake air co-flow (flow in the same direction), the DPM was predominantly confined to the middle of the roadway. Alternatively, if the DPM and the intake air counter-flow (flow in opposite directions), the DPM tends to spread over the entire cross-section of the roadway. In the latter case, the vehicle operator will be more susceptible to exposure to high concentrations of DPM. Further, the DPM concentration near the vehicle was dependent on exhaust pipe location and direction. If the exhaust pipe is located at the rear or the top of the vehicle, the vehicle operator may be susceptible to exposure to high concentrations of DPM. If the exhaust pipe is located at the bottom of the vehicle, the operator is less likely to be exposed to high concentrations of DPM. Finally, in all cases, at 10 m downstream of the vehicle the DPM particles tend to spread over the entire cross section of the roadway, and downstream loading bays generally contained very high concentrations of DPM.
Keywords: Coal mines; DPM; Diesel-operated LHD; CFD simulation.
Mechanical Behavior and Failure Characteristics of Cemented Paste Backfill under Lateral Unloading Condition
by Hongjian Lu, Peng Liang
Abstract: A key issue associated with mine backfill design using the stage open stoping with the subsequent filling method is the determination of mechanical behaviour and failure characteristics of the cemented paste backfill (CPB). Especially for CPB under lateral unloading conditions during the excavation of secondary stope. In this research, a series of lateral unloading tests with RFPA3D were conducted to investigate the relationships among the cement-tailings ratio (1:4 and 1:8), lateral unloading stress (0MPa, 0.2MPa, 0.4MPa, 0.6MPa, 0.8MPa and 1.0MPa), mechanical behavior, failure modes and AE (acoustic emissions) characteristics. Similar mechanical behaviour of all the CPB specimens was obtained. With different cement-tailings ratios and preloading stress values, the ultimate failure modes of CPB specimens show different forms. Additionally, increasing the preloading stress value caused a rising of AE counts. The results of this study can provide a significant reference for the backfill design and study of underground mining.
Keywords: cemented paste backfill; mechanical behaviour; failure characteristics; lateral unloading; numerical simulation.
Investigating the effects of gemstone mining on the environs: a case study of Komu in Southwestern Nigeria
by Moshood Onifade, Adeyemi Aladejare, Bayo Adewumi
Abstract: Mining engineering practice involves the extraction of minerals from the earth with significant effect to the environment. Though this operation is important to living better lives but causes more damage to the landscape than ever before. This research examines the effects of gemstone mining by investigating soil and water samples collected from different locations of a mining community in Nigeria taking into consideration the concentration of heavy metals and micro nutrients, physiochemical parameters and cation exchange capacity present in these samples. These concentrations were compared with the World Health Organization (WHO) standards. The concentrations of heavy metals, micro nutrients and physiochemical parameters obtained from the sample locations varies from one location to another. The results for heavy metals concentration obtained from the soil samples are 0.30, 0.90, 0.09, 0.995 and 39.40 mg/kg for lead (Pb), copper (Cu), cadmium (Cd), zinc (Zn) and iron (Fe) respectively. The values of micro nutrients concentration in the soil are 4.90, 5.295 and 0.97 mg/kg for sodium (Na), magnesium (Mg) and aluminium (Al) respectively with sequence, Mg > Na > Al. The results of physiochemical parameters obtained from the water samples are 7.495 mg/L, 187.00 mg/L, 233.414 mg/L, 70.00 mg/L, 16.52 mg/L, 6.28 mg/L, 14.65 mg/L and 10.25 mg/L respectively for pH, hardness, chloride, alkalinity, total solids, total dissolved solids, total suspended solids, sodium and potassium. When the results of soil and water analysis were compared with WHO standards, it was found that the values obtained were lesser than the WHO acceptable limit for certain heavy metals. However, the concentrations of Cd and Fe in the soil samples are higher than the WHO permissible limit in soil which implies that the soil is toxic and not good for agriculture purposes.
Keywords: Gemstone mining; environment; pollution; WHO standards; soil analysis; water analysis.
Evaluation of the vibration accelerations of drill bit for the well rotative-vibration drilling using the cavitation hydrovibrator
by Olexiy Nikolayev, Yuriy Zhulay, Yuri Kvasha, Nikolai Dzoz
Abstract: Cavitation hydrovibrator is one of the promising devices to intensify drilling of geological prospecting and production wells. Cavitation hydrovibrator transforms the stationary flow of drilling mud into a discrete-pulsed flow of increased power. The mud oscillating flow in hydrovibrator is converted into high-frequency (1 000 Hz 20 000 Hz) vibrations of the drill bit. A method for determining the longitudinal vibrations of a drill string with bit has been developed. The method is based on the results of experimental studies of the dynamic interaction between longitudinal oscillations of the drilling string with rock massive by mathematical modeling this process with use finite-element discretization of drilling string. An obtained satisfactory convergence of the computed vibration accelerations of the drill bit and experimental data confirms the adequacy of the developed mathematical model and the ability with its help to determine the rational operational modes of the hydrovibrator.
Keywords: rotative-vibration well drilling; high-frequency downhole cavitation hydrovibrator; drill bit; longitudinal acceleration;.
Investigation of DPM dispersion in unventilated dead-ends using transient flow modelling
by Ramakrishna Morla, Shivakumar Karekal, Ajit Godbole
Abstract: This paper presents a detailed study of DPM dispersion in unventilated dead-end cross-cuts in an underground mine. The dispersion and dilution of DPM was measured in dead-end with time when the air is flowing in the main gallery. Parametric studies were conducted by varying the dead-end cross-cut lengths (10 m,15 m, 20 m and 25 m), varying cross-cut angles (450, 900 and 1350) with the main gallery and varying the velocities (0.5 m/s,1m/s ,2 m/s, 3 m/s, 4 m/s) in the main gallery across the cross-cuts. The results obtained show that longer time durations are required to dilute DPM for greater dead-end cross-cut lengths and angles. For 50 m dead-end cross-cut, it took five hours to reduce DPM concentration from 820
Keywords: Dead-end; cross-cut; DPM; CFD; Unventilated areas; Transient Flow.
Enhancing productivity through effective spoil stability management in an open cast coal mine
by Nompumelelo Mpembe, Bekir Genc
Abstract: The paper investigated the best practical dig spoil sequence which addressed circular failure in waste spoil piles and enhanced productivity through an improved coal exposure rate. This involved the evaluation of two overhand - chop and three dozer pushover dig spoil sequences through DragSim software and an MS Excel dragline calculator. The software provided spoil profiles for geotechnical analysis and the calculator generated productivity indicators (digging rate, coal exposure rate and rehandle percentage). The sequences were ranked in terms of the ability to meet the mine budget requirements and best practice standards for stability and productivity.
The best practical dig spoil sequence was the oblique spoil side dozer pushover sequence. It was recommended that Pit B be split in two halves: a modified overhand - chop and oblique spoil - side dozer pushover sequence for the first and second half, respectively.
Keywords: Opencast coal mining; stability management; DragSim software; dig spoil sequence; circular failure; waste spoil pile and competent weathered sandstone.
An approximate analytical solution to the fragment size predicted by image analysis
by Abiodun Lawal
Abstract: Fragmentation of rocks plays an imperative role in the determination of the economic viability of mining operations. The determination of the fragment size is usually done using an empirical model or image analysis. The predictions of the most commonly used empirical model (Kuz-Ram) are overestimated though they are simple to implement while that of the image analysis is accurate though difficult to implement and costly. This proposed research is aimed at harnessing the advantage of the image analysis to modify the inaccuracy in the Kuz-Ram model. The aim is achieved through the data available in the literature. The original Kuz-Ram model has been modified analytically and the least square method implemented in the Matlab environment was used to solve for the unknown in the modified model. The obtained results show that the rock factor coefficient is 0.03739 as against the traditional 0.06. The overall error between the proposed model and the image analysis is 3.5% while that of the original Kuz-Ram model and the image analysis is above 60%. Hence, the proposed model can give a reasonable prediction of the fragment size predicted using image analysis with zero cost and is simple to implement.
Keywords: Rock fragmentation; image analysis; Kuz-Ram model; least square method; rock factor.
Mine health and safety: Influence of psychosocial factors on musculoskeletal disorders among miners in Pakistan
by Izhar Mithal Jiskani
Abstract: Mine health and safety is considered to be one of the fundamental determinants of sustainable mining. The purpose of this study was to analyze the severity of musculoskeletal disorders (MSDs) and to investigate the influence of psychosocial factors on its development. The data from 252 coal miners was collected through a self-administered questionnaire. Ordinal logistic regression modeling was performed to examine the association between MSDs and psychosocial factors. The results show that miners face moderate to severe risks of MSDs. The elbow, lower back, and knee were the most commonly reported complaints. Job demands and control at work were the psychosocial factors that increase the risk of developing MSDs. Whereas, low monotony at work and commitment to the organization reduce the chance of developing MSDs. The findings of this study will be a significant endeavor to formulate preventive management programs to promote miners health and safety.
Keywords: mine health and safety; musculoskeletal disorders; psychosocial factors; sustainable mining.