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By Steven J. Schatzel, Mark M. Mazzella, Robert A. Kimutis, VASU GANGRADE, James D. Addis, Marcia L. Harris, Mayley Guitard

Researchers from the National Institute for Occupational Safety and Health (NIOSH) evaluated the impact of potential shale gas well breaches and subsequent gas inflow on selected mine ventilation systems of operating longwall panels using a 1:30 scaled Longwall Instrumented Aerodynamic Model (LIAM) and Sulfur hexafluoride (SF6) as a tracer gas. A series of tests were performed at 340, 400, and 500 cfm inflow levels utilizing different mine ventilation scenarios. Results suggest that the breached gas can be diluted to meet statutory levels when the longwall panel is adequately ventilated. The results enhance the understanding of the gas inflow and mine ventilation system interaction and provide critical information to the industry and regulatory agencies for improving miners’ safety.

Feb 1, 2024

By C. R. DeGennaro, Yongjun Zhang, J. Bickson, J. L. Carr, Chenming Zhou, J. R. Srednicki, B. Lambie, M. Girman, J. A. Galanko

Between 2005 and 2021, surface mining haul trucks were involved in 54 fatal incidents in the United States [1]. Collision warning and avoidance systems (CXS) can help haul truck operators navigate their route safely. The evaluation of CXS object detection performance for surface mining haul trucks relies on the positional accuracy of the ground truth instrument. As part of a holistic approach, researchers from the National Institute for Occupational Safety and Health (NIOSH) characterized the accuracy of a global navigation satellite system (GNSS) that serves as the ground truth instrument to determine object position and velocity in CXS object detection performance testing. We used precision surveying equipment to establish ground truth points for comparison with GNSS data collected for static positional measurements and reduced-scale straightline vehicle dynamic tests. We conducted these tests with real-time kinematics (RTK) and then satellite-based augmentation systems (SBAS). For the dynamic tests, we measured a distance error of 1.34 m (4.40 ft) using RTK and 1.50 m (4.92 ft) using an SBAS. This research will provide CXS manufacturers and CXS researchers a basis for evaluating the positional accuracy of CXS. Note that we did not evaluate any CXS in this experiment.

Feb 1, 2024

By B Y. Luan, Y Tian, W Zhou, X Lu, Q X. Cai

The unmanned driving technology in open pit coalmines is an important technology that relies on innovation to drive the development of the open pit coal mining industry in China’s transformation of growth drivers and industrial structure upgrading. It is an important path to solve the shortage of mine truck drivers in the future mining, an important way to improve the working environment of open pit mining personnel, and an important foundation for achieving flexible production capacity in open pit mining to cooperate with the coordinated development of new energy. The communication rules at intersections are key to ensuring the safety and efficiency of unmanned driving in open pit coalmines. This paper proposes a collaborative traffic strategy between unmanned trucks for the single bucket unmanned truck intermittent process system in open pit coalmines. Based on the gap theory, this paper analyses the conflict characteristics and establishes a coordinated traffic strategy for the common intersection and merging conflicts of unmanned truck trucks in open pit coalmines, A multi-agent system simulation platform was built to evaluate the coordinated traffic efficiency under different initial average gap sizes of vehicles, with intersection traffic density, vehicle speed, and gap changes as key indicators. The results show that under the simulation conditions of this article, when the initial average gap of vehicles reaches three (four) times or more of the safe distance, the coordinated traffic performance of intersection conflicts (merging conflicts) is better, and the traffic capacity of intersections is close to the traffic capacity without conflicts.

Sep 1, 2024

By J. Maritz, K. de Beer, S. M. Buthelezi

The economic upheaval of COVID-19 forced companies to invest in emerging technologies to aid recovery. One such technology is extended reality, which is becoming a mature and innovative tool. Early adopters are seeing significant benefits in learning, training, immersive data visualization, and remote assistance. In South Africa, the mining industry is increasingly interested in using extended reality to optimize and innovate operations. The Minerals Council of South Africa's July 2021 report highlighted the potential of extended reality's to achieve zero-harm production and modernize the industry. However, the extent of extended reality adoption in mining remains unclear due to limited information on its usage. This study addressed this gap by distributing an online survey to assess awareness, knowledge, and current uses of extended reality in South Africa’s mining sector. The results indicated that virtual and augmented reality had the highest levels of awareness and usage, primarily for learning and training. Mixed reality, however, had the lowest awareness and knowledge levels. In terms of applications, visualization and remote assistance had the least use cases. These findings highlight that the South African mining industry is deficient in its understanding and use of extended reality technologies. Without better awareness and application, the South African industry risks missing out on the full benefits of extended reality. The study underlines the need for the South African mining industry to improve its outlook on extended reality technologies to fully leverage their potential applications and benefits.

Jul 10, 2024

By Juliana Segura Salazar

Algumas estratégias vêm sendo incorporadas na cominuição de minérios, voltadas para reduzir os custos operacionais (OPEX) e garantir o funcionamento de suas operações no longo prazo. Paralelamente, elas permitem reduzir os impactos ambientais desta operação sob a ótica da sustentabilidade, devido às melhorias na eficiência de uso dos recursos e na mitigação das mudanças climáticas. Porém, a incorporação dessas estratégias é restrita pelo tipo de tecnologia empregada e pelo layout da usina e, portanto, o maior potencial de minimização dos impactos econômicos e ambientais encontra-se principalmente na etapa de projeto dos circuitos. Este potencial muitas vezes é desperdiçado, sendo ainda poucas as implementações sistemáticas adotadas na indústria mineral, visando melhorar a ecoeficiência dos processos. Neste trabalho é proposta uma metodologia fundamentada em princípios de sustentabilidade e aplicável ao beneficiamento de minérios, usando uma abordagem simplificada da Avaliação de Ciclo de Vida (ACV). A metodologia é focada na cominuição de minérios brasileiros, tendo sido aplicada ao beneficiamento de Itabiritos, os quais estão se tornando estratégicos no Brasil.

Aug 16, 2017

By A. Çelik

Wheel loaders are widely used in many sectors due to their mobility, operational flexibility, and low costs. The literature is mainly focused on improving the hydraulic, mechanical, and electronic subsystems of these machines in terms of efficiency or developing strategies for controlling these systems. In this study, the effects of the loader operator and different working conditions on the loading performance were investigated. The study was carried out at the Can Lignite Enterprise (CLI), which is a major coal producer in Turkey. In the study, which lasted approximately four months, a total of 808 measurements were performed to investigate seven different scenarios. The effect of a single parameter on loading performance was investigated in the first six scenarios. The results showed that the biggest impact on loading performance was caused by the operator's experience with 63.4%. On the other hand, the worst and most ideal working conditions determined from the first six scenarios were tested in the seventh scenario. It was tested as a script. The test results showed that the loading performance was 285.5% more effective under the most ideal operating conditions compared to the worst operating conditions. In addition, in the study, the loading performances of five loaders with four different capacities were examined in terms of energy efficiency and it was determined that the Kawasaki 115 work machine, which has a higher model and lower engine operating hours, was more advantageous. In the study, various suggestions were developed in parallel with the research results. The most prominent and easiest to implement of these suggestions is related to the selection of the loader operator.

Nov 27, 2024

By K. C. Sole, M. Makonese

Bushveld Belco is commissioning a plant for production of electrolyte used in vanadium redox flow batteries. Owing to the source material, the electrolyte is contaminated with Fe, at concentrations up to 140 mg/L, which negatively affects battery performance. This study examined the use of ion exchange to reduce the Fe concentration to the target value of < 100 mg/L from a feed solution containing 100 g/L V in 4 M H2SO4. Four resins with possible application were identified: Puromet MTS9570, Puromet MTX7010, Puromet MTS9500, and Puromet MTC1600H. Puromet MTS9570 outperformed the other three resins in all batch experiments with respect to loading capacity and selectivity over V, and was evaluated for Fe removal in fixed-bed column loading tests. Based on these data, preliminary sizing and design of a full-scale column was undertaken. Owing to the difficulty of eluting this resin, a philosophy of discarding the resin on loading to full capacity was considered. These data revealed that, despite the high selectivity of this resin for Fe over V, it would be too expensive and impractical to use this resin for full-scale operation under such conditions. It is recommended to remove iron earlier in the flowsheet prior to generation of the 4 M H2SO4 electrolyte.

Dec 11, 2024

By F. D. Agrensa, J. Hadjigeorgiou, E. Storimans, S. J. Thorpe

Reinforcement and surface support are part of an integrated system that transfers and shares loaduntil the excavation surface is stabilized or until the ground support system fails. Steel mesh is the most popular primary surface support element in underground hard rock mines in Canada. Mesh straps are a secondary surface support that provide additional containment as they distribute the load between and across the reinforcement elements. This investigation addresses the role of steel properties, and in particular steel chemistry, in the long-term performance of mesh and mesh straps when exposed to an aggressive corrosive environment. It reports on comparative accelerated corrosion studies to compare the resistance to corrosion of different surface support elements. This has significant implications on the choice of surface support and the anticipated rehabilitation requirements.

Oct 9, 2024

By Hillary W. Clair

An equation is derived for the rate of reaction of a sphere of metal oxide in a restricted enclosure through which a reducing gas is flowing . The equation takes into consideration the reaction rate coefficient , transport through the gas and through the porous shell of reduced oxide , the rate of gas flow , and the volume of the enclosure . The equation serves as a model for predicting the course of reduction of a particle of metal oxide in a shaft furnace .

Jan 1, 1964

By M J. Nugus

The structural models developed by exploration and mining geologists are most commonly concerned with the ‘main structures’ or key constituents that pertain to the associated mineralisation. To this end, it is recognised that the geological and exploration models, which are developed, are essentially ‘fit for task’ and the scale-related variances are not always realised at an early stage. In fact, in many cases anomalous intercepts along different trends and of variable apparent continuity have often been neglected as ‘back scatter’ and not important. Recognition of the importance of subordinate structures as mineralising hosts suggests that additional opportunities exist outside the primary and main structures. History shows that opportunities are often not realised where gold is hosted in orientations not parallel to the predominant trend of the schistosity, main fault or shear zone.Another reason for the importance of subordinate structures can be understood from their roles in a percolation network. Subordinate structures can access the large fluid fluxes provided by backbone elements, but, as dangling elements, they provide greater opportunities for gold precipitation mechanisms and hence may constitute essential parts of the resource. Therefore, the role, understanding and consideration of the smaller-scale and orthogonal structures should be considered during all facets of exploration, resource development, delineation and mining.

Aug 22, 2011

By R Goddard

An alternative stoping method has been adopted for narrow vein stoping at the Tasmania Mine in Northern Tasmania. Colloquially described as ‘Radial-in-Reef’ (RiR) stoping, the method employs the drilling of radial rings in the plane of the Reef from a drill stub located at the geographic centre of the proposed stope panel.Production from the Western Zone of the Tasmania Reef has been undertaken remotely from the Reef since 2007, after a detailed geotechnical engineering analysis indicated that the integrity of the sill drives could not guarantee an acceptable level of confidence should an anticipated seismic event occur within a radius of 10 m. The key tenet of the remote mining approach was the exclusion of personnel from sill drives once stoping had commenced. The remote mining method had to be ‘retrofitted’ to four existing stoping blocks totalling 11 sill drives which totalled 160 m vertically. The remote mining method proved to be complex, cumbersome and very expensive. However, the ore was extracted successfully.By early 2010, previously developed ore had largely been exhausted and the future development with an orebody open at depth presented the opportunity to review the current extraction method. However, the new extraction method needed to maintain the tenet of excluding personnel from sill drives of active stoping blocks, but seek opportunities to reduce the difficult and costly aspects of the previous method. The new ‘Radial-in-Reef’ stoping reduced the development requirement from six to two drives per ore block. Cost implications aside, the significant reduction in prestoping extraction ratio was expected to also reduce the likelihood of seismicity. Transverse production rings were designed to be drilled radially from a drill stub mined from a mid-stope footwall drive. Stopes totalling up to 7000 tonnes were planned be fired in a single electronic blast. Extraction was designed to take place from a basal sill drive under teleremote operation. At the time of writing, the method was under trial.

Mar 21, 2011

By K. A. Fowler, L. W. Higley

The effect of uranium on the transformation kinetics and the hardenability of a low- alloy steel was evaluated . Isothermal transformation curves were developed from metallographic studies , and hardenability was determined by standard Jominy end- quench tests . For the steels investigated , the addition of 0.15 weight- percent uranium was found to produce a significant shift in the isothermal transformation curve and caused a related increase in hardenability . These effects diminished rapidly when the uranium content was increased above 0.2 weight - percent .

Jan 1, 1964

By Chris Roos

The mining industry has made strides in planning for operations to be safe for the workforce and public, to protect the natural environment, and to maximize value for shareholders. However, many of the techniques used to accomplish these goals are based on estimated models of mineral content, production efficiency, and economic performance. The industry has begun to recognize the need for understanding the uncertainty in these models, how it affects their decisions, and what the potential impacts are for each project. The challenge has become how technical professionals can effectively communicate the impact of this uncertainty and its importance to both technical and non-technical audiences. This paper presents mining engineers (and other technical professionals) with traditional and modern principles of data visualization and technical communication that can assist with communicating the effects of uncertainty in the mine planning process.

Jun 25, 2023

By Suthan Pooranampillai

Verification of drilled shaft resistance is primarily obtained through the use of different load testing methods. Procedures utilized include conventional top down static loading, the Osterberg load cell (O-cell) test and dynamic tests such as the Statnamic method. The O-cell test provides a means of obtaining separately the base and side shear resistance behavior of drilled shafts (cast-in-drilled-hole). Alternatively, the Statnamic load test method enables the engineer to derive base and side shear behavior separately, based on measurements of load, accelerations and strains along the length of the shaft. However, due to time and cost constraints these tests can only be performed on selected shafts within a project. Post grouting of a drilled shaft base embedded within a cohesionless material, with a low mobility compaction grout, will essentially pre-load the shaft base soil against the side shear and self-weight in much the same manner as an O-cell load test (when the load cell is placed within the base vicinity). Therefore, successful post grouting of a drilled shaft would enable verification of both shaft side shear and base resistance simultaneously on each and every shaft it is carried out on. Additionally, such post grouted shafts display stiffer load-displacement response during subsequent downward, superstructure induced, loading compared to ungrouted shafts. Verification of resistance on each and every shaft through the use of post grouting will allow an increase in resistance factors (reduction in safety factor) used in the design. Two 6 ft. diameter drilled shafts were constructed in Fredonia, WA, for WSDOT, each with an approximate length of 52 ft. The shafts were terminated within medium dense poorly graded silty sand. Statnamic load testing of the shafts indicated maximum derived static side shear and base resistances of 2545 kips and 507 kips (1.6 in. displacement) for shaft One and 2466 kips and 212 kips (1.4 in. displacement) for shaft Two. Shaft Two was subsequently grouted, with a low mobility compaction grout. Shaft base mounted total earth pressure cells measured a maximum sustained pressure of 55.44 ksf during the compaction grouting operation. Shaft displacement reached 0.65 inches in the upward direction at termination of grouting. Comparison of grouting data with initial load test information indicates that properly instrumented post grouting verifies shaft base and side shear resistance. In addition, these grouting induced resistances were much higher than design values supplied by the engineer using conventional resistance factor design. Large scale laboratory testing also shows that base grouting verifies higher soil resistances than permissible in conventional design.

Jan 1, 2010

By Nicolas Moscoso, Gerald Verbeek, Marcel Bielefeld, Rob van Dorp

Upon recently, most offshore foundations were based on a number of driven piles that were installed with an impact hammer. With the increase in offshore windfarms two major developments have occurred: the shift from jackets to monopiles, leading to increase of the diameter of the foundation piles, and a shift from impact hammers to vibro hammers. As the use of vibratory hammers is becoming more and more common practice, the need for accurate vibro-driving simulation software has increased, which requires that the soil modelling is enhanced to address soil fatigue during pile driving and to predict reliably the soil behavior and resistance during pile driving. In addition pile driving monitoring, which is routine for piles driven with an impact hammer, needs to become common practice. This paper addresses advances in soil modelling that allows more accurate pile driving simulation as well as the application of Vibro Driving Analysis (VDA) or Monitoring (VDM) to validate the simulation results. This is illustrated by a case study of the test pile for the Delft Offshore Turbine project, a 28 m long monopile with a diameter of 4 m that was driven 15 m into dense sand layers using a vibro hammer. After some 6 months the pile was extracted, and pile driving simulations and VDA were done both for the installation and extraction phase. 1. INTRODUCTION At the end of 2017, the total worldwide offshore wind power capacity was 18.8 GW [1]. The vast majority of offshore wind farms are currently in Northern Europe, which together account for over two thirds of the total offshore wind power installed worldwide, followed by East Asia, while developments in North America are still in very early stages.

Jan 1, 2019

By J. Petersen, M. Reuter, E. Asselin, M. Becker, N. Uys

In order to meet society’s ever-increasing demand for metals and address the numerous technical, economic and environmental challenges within the current mining context, a holistic approach to process design, which is grounded in mineralogy, is needed. This would ensure that the impact of varying process mineralogy (and associated chemistry) on technical considerations and the associated economic implications and environmental consequences are taken into account upfront. This investigation focuses on the commodity zinc due to its strategic value coupled with limited resource availability and the wide variety of substantially different process technologies in existence. As the most commonly processed zinc ores contain zinc sulphides, the mineralogy/chemistry of these ores and their associated process routes will be discussed. The findings have been generated through the analysis of two case studies, Teck’s Trail Operations (British Columbia, Canada) and Hudbay Minerals’ Flin Flon Operations (Manitoba, Canada). The flotation of zinc sulphide ores to produce concentrates with varying mineralogy, represents the starting point for both case studies. The hydrometallurgical process routes for the further refining of zinc and other valuable metals include roast-leach-electrowinning (RLE), and zinc pressure leaching (ZPL). The effect of process route choices on primary metal recovery (Zn), coproduction of other base metals (Cu, Pb), potential for other valuable metal production (Ag, Au) including less well known, but increasingly important trace elements (In, Ge), and the production of other by-products (H2SO4, S0) are discussed. The economic and environmental implications of these aspects will also be considered. It is concluded that a quantitative modelling approach must be taken where waste management is integrated into process system design and simulation as a key unit operation. Keywords: Zinc Sulphide Processing; Design Decisions; Mineralogy

Jan 1, 2020

By Wenbing Guo, Mingjie Guo, Hebing Zhang

As resources are depleted in coal mines, isolated support pillars are often mined. Cemented paste backfill has been used to provide support during the mining of these pillars due to its safe and green mining characteristics. However, traditional cemented paste backfill mining has some shortcomings, such as poor adaptability to geological structure, leakage of paste during filling, imperfect roof-contact in partially backfilled areas, and insufficient roof strata support before the backfill reaches its design strength. This paper presents the results of a case study where L-shaped interval cemented paste backfill technology has been safely used to mine an isolated coal panel beneath existing surface structures. This backfilling method has the advantages of preventing paste leakage, improving the backfilled ratio, reducing surface subsidence, and strongly adapting to geological structure. During this field application, the setting pressure of the backfill shield reached 20 MPa, the compressive strength of the backfilling body reached 2.0 MPa, and the backfilled ratio reached 93.7%. Observational ground monitoring showed that roof-to-floor convergence in adjacent roadways ranged from 132 to 167 mm. No obvious fractures or separations in the overlying strata were observed by a borescope. The maximum surface subsidence was 342 mm, the subsidence factor was 0.136, and the damage to surface buildings was within Grade I (slight damage). This case study clearly demonstrates that the L-shaped interval cemented paste backfill method can be safely used to mine the isolated coal panel beneath surface buildings.

Jul 1, 2023

By Xiaoxu Sun, Jianchao Yao, Qiheng Zhu, Dubo Wang, Jiancheng He, Shijie Lu

Tower mill is considered to have a better regrinding and fine grinding effect compared with ball mill, and its application is much broader. The spiral agitator of the tower mill is driven by the motor. Media inside the mill is under the combined actions of the spiral mechanism, the cylinder, and media nearby, and these parameters are key factors affecting the grinding effect. However, it is not possible to obtain detailed information of kinematic law of media based only on traditional laboratory experiments, let alone the relationship between parameters of kinematic law of media and grinding effect. Experimentation is the only way to develop industrial equipment. However, this is time-consuming and costly, which hampers the further research of the tower mill’s grinding mechanism. The paper selects two structural parameters (gap between the edge of the spiral agitator and the cylinder wall, ratio between the diameter of cylinder and that of the spiral shaft.) and three operating parameters (diameter of media, filling ratio, the speed at the edge of the spiral agitator) as variables to do an orthogonal designed experiment of five factors, four levels, and thereby obtaining change law of grinding indicators of different parameters. Experimental equipment may be simplified to enable an applicable simulation strategy. Simulation based on a discrete element method is conducted to obtain the change law of the speed of media, collision frequency, normal force, and radial force. The relational curve between parameters of kinematic law of media and energy consumption of grinding is clarified, and key factors affecting grinding efficiency are determined. Those factors will be used for optimising the design and operating process. The research result of this paper obtained from laboratory experiments and computer simulation provides data support and theoretical bases, and has directive meaning and applicable value for tower mill’s optimisation and large-sized design. Keywords: Tower mill, discrete element method, kinematic law of media, energy consumption of grinding

Jan 1, 2020

By Huijun Shao, Qiang Liu, Zhengming Yi

The increase of the proportion of high Al2O3 content iron ore fine in iron and steel enterprises has brought about a series of problems such as the increase of the viscosity of blast furnace slag and the difficulty of the separation of slag and iron. In order to solve this problem, the effect of increasing MgO content on the technical and economic index, the cold strength, and metallurgical properties of high basicity and high-alumina sinter was studied through sinter pot test. Nova400NanoSEM field emission scanning electron microscope was used to analyze sinter microstructure. The experimental results show that when the MgO content fraction in the sinter with high basicity and high aluminum increases from 1.72 to 2.49%, the vertical sintering speed decreases by 4.38mm/min, the utilization coefficient decreases by 0.51t/(m2 h), and the low-temperature reduction degradation index increases by 6.7%. When MgO content in sinter is 2.11%, drum index and reducibility index are the highest, reaching 61.93% and 86.39% respectively. Mg2+ is mainly solid dissolved in the magnetite lattice and replaces Fe2+, up to 3.64%. The generated magnesie-containing magnetite inhibits the phase transition from Fe3O4 to Fe2O3 oxidation process in the sinter cooling process, which reduces the generation of secondary hematite and is conducive to improving the low-temperature reduction degradation performance of sinter.

Jul 4, 2021

By Neel Gupta, Brijes Mishra

Coal mining activity disturbs the natural equilibrium of in situ stress state such that the induced stresses deform the surrounding rock mass. Although the installation of roof supports typically prevents rock deformation, rock mass failure may still occur in bolted roof. The erratic failure of rock mass after few days to months and years of excavation is the result of time-dependent deformation of roof rock under constant surrounding stresses. In the current research, the triaxial laboratory creep experiments proved that Marcellus shale exhibits time-dependent deformation under constant stress that was smaller than the failure strength. However, unlike conventional experimental results, the time-dependent deformation did not depend on the level of constant stress. The often-neglected initial state of specimens and intrinsic heterogeneity highly influenced the time-dependent failure of Marcellus shale.

Jul 27, 2021