A short critique on biomining technology for critical materials.

Being around for several decades, there is a vast amount of academic research on biomining, and yet it contributes less to the mining industry compared to other conventional technologies. This critique briefly comments on the current status of biomining research, enumerates a number of primary challenges, and elaborates on some kinetically-oriented strategies and bottom-up policies to sustain biomining with focus on critical material extraction and rare earth elements (REEs). Finally, we present some edge cutting developments which may promote new potentials in biomining.

Spare-part management in a heterogeneous environment.

Spare-part management has a significant effect on the productivity of mining equipment. The required number of spare parts can be estimated using failure and repair data collected under the name of reliability data. In the mining industry, failure and repair times are decided by the operational environment, rock properties, and the technical and functional behavior of the system. These conditions are heterogeneous and may change significantly from time to time. Such heterogeneity can change equipment's reliability performance and, consequently, the required number of spare parts. Hence, it is necessary for effective spare-part planning to check the heterogeneity among the reliability data. After that, if needed, such heterogeneity should be modeled using an adequate statistical model. Heterogeneity can be categorized into observed and unobserved caused by risk factors. Most spare-part estimation studies ignore the effect of heterogeneity, which can lead to unrealistic estimations. In this study, we introduce the application of a frailty model for modeling the effect of observed and unobserved risk factors on the required number of spare parts for mining equipment. Studies indicate that ignoring the effect of unobservable risk factors can cause a significant bias in estimation.

A Comprehensive Review of Work-Related Musculoskeletal Disorders in the Mining Sector and Scope for Ergonomics Design Interventions.

OCCUPATIONAL APPLICATIONS Work-related Musculoskeletal Disorders (WMSDs) are prevalent in many industries worldwide, including the large and labor-intensive mining sector. A systematic review was carried out to understand problems in the mining sector issues from three broad perspectives: 1) the prevalence of WMSDs among miners; 2) the association of occupational, psychosocial, environmental, and other risk factors with WMSDs causation; and 3) ergonomics interventions already proposed or implemented, and scope for design interventions. Our review revealed that automation, job aids, and displays are methods suitable for ergonomic design interventions. Ergonomic intervention strategies at various hierarchical levels, and the successive way forward as proposed in our review, could act as a catalyst in formulating problem-specific solution strategies by the participation of diverse stakeholders to implement a more human-centric workplace.

TECHNICAL ABSTRACT Background Work-related Musculoskeletal Disorders (WMSDs) are prevalent in the mining sector. While there are numerous factors responsible for the occurrence of WMSDs in this labor-intensive sector, research pertaining to ergonomic design interventions that address various causative factors has not been thoroughly addressed. Purpose We aimed to present an overview of WMSDs in the mining sector, along with plausible intervention strategies in diverse task contexts as suggested by earlier researchers. We also sought to identify the prominent research gaps and propose a way forward to formulate context-specific solutions by involving all stakeholders. Methods Relevant research publications were identified from electronic databases (Google Scholar and ScienceDirect) using appropriate search terms applicable to the mining sector and WMSDs. The literature search was restricted to journal papers, conference proceedings, books, reports, and relevant websites in the English language published between 1990 and 2020. Results Information extracted from the literature review was categorized under three broad topics: 1) the prevalence of WMSDs among miners; 2) associations of psychosocial, occupational, environmental, and other risk factors with WMSDs; and 3) ergonomics interventions in the mining sector. Following the systematic literature review, we outline ergonomics intervention strategies at various levels and provide future research directions to assist all stakeholders in implementing appropriate and context-specific ergonomics design interventions to provide a more human-centric workplace. Conclusions Based on our findings, it is evident that there is an urgent need for formulating and applying job-related ergonomics design intervention plans for occupational safety and well-being of miners in the mining sector.

Study on the dynamic characteristics of rock surrounding a wellbore in energy storage areas during deep geothermal energy mining.

Based on the engineering background in which the rock surrounding a wellbore is affected by a thermal shock, impact disturbances from drilling vibration, cyclic heat extraction and high temperature during hydrothermal geothermal energy mining, the environmental conditions in the shaft wall rock are simulated by means of high temperature, cooling, immersing granite in water with different curing temperatures and applying impact loads. Additionally, an experimental study on the mechanical characteristics of circular granite specimens under radial impact loads and in the heat treatment and water curing conditions is carried out. The results show that the inner diameters of the rings, heating temperatures, curing water temperatures and cycle heating times are less affected than other parameters by the impact load-strain curves of circular granite, which can generally be divided into three sections, i.e., the initial straight stage, nonlinear ascent yield stage and post-peak nonlinear decline stage. The factors in the test weaken the capacity of the circular granite to resist the impact, but the sizes of the inner diameters of the rings play a leading role. Dynamic tensile strain is generated in the inner wall along the impact direction during the impact, while compressive strain is produced on the inner wall in the vertical impact loading direction. By analysing the crack propagation and final failure mode of circular granite, it is found that dynamic tensile failures are generated, crack initiation starts from the inner wall along the impact loading direction, and the outer circle in the vertical direction lags behind. The crack starts early and develops quickly on one side of the transmission bar. Finally, the failure criterion is established on the basis of some assumptions and circular-granite deformation failure characteristics, and the parameters, measured by the Brazilian disk test, are reasonably verified via substitution into the failure criterion equation.

Prediction of remaining useful life (RUL) of Komatsu excavator under reliability analysis in the Weibull-frailty model.

It is an essential task to estimate the remaining useful life (RUL) of machinery in the mining sector aimed at ensuring the production and the customer's satisfaction. In this study, a conceptual framework was used to determine the RUL under the reliability analysis in a frailty model. The proposed framework was implemented on a Komatsu PC-1250 excavator from the Sungun copper mine. Also, the Weibull-frailty model was selected to describe the failure behavior and compare it with the classical-exponential model. The frailty model was also used to evaluate the impact of unobserved environmental conditions on the RUL values. Both applied models were fitted to the obtained data from 80 operational hours of the Komatsu PC-1250 excavator. Plotting the results from the reliability analysis of two models demonstrated that the mine system with the frailty model performs better than the classical model before reaching the reliability of 80%. Besides, the frailty model shows a coherent with the operational time of the excavator, while the classical model demonstrates a sinusoid variation. The obtained results may be used for the development of maintenance, preventive repairs planning, and the spare parts replacement intervals.

Engineering noise control for mines: Lessons from the world.

OBJECTIVE: The main objective of this article was to present some of the engineering noise control methods that are currently being used across the world in the mining industry, while at the same time interrogating noise control measures that could be applied to effectively reduce noise emissions from the equipment utilised within South African mines. BACKGROUND: A brief summary of the hearing conservation programmes used in South Africa is presented. Summarised research on the use of engineering noise control in South Africa is also presented, with an overview of the various engineering noise control methods applied across the world in dealing with occupational noise. METHOD: For illustrative purposes, case studies were used to show how engineering noise controls could be used to reduce the noise levels and risks within this context. RESULTS: Some of the case studies used have cited a reduction in the noise intensity emitted by machinery from a range of 93 dBA - 104 dBA to a range of 90 dBA - 94 dBA, demonstrating quite a significant reduction in the noise emission of the equipment. This article further provides recommendations on how South African mines could contextualise these methods. CONCLUSION: One of the key recommendations is encouraging the South African mining industry towards the documenting and publishing of those engineering noise control methodologies that have proven to be effective for shared best practice. A need was identified for extensive research to be conducted and documented evidence to be made available to assist the South African mining industry with locating and assessing current engineering controls available in South Africa. Machines and processes that require noise control should be identified and, lastly, the current barriers to the use of engineering noise control methodologies should be identified, with the main goals of finding ways to overcome the noise challenges in the mines.

Smart Glasses-Based Personnel Proximity Warning System for Improving Pedestrian Safety in Construction and Mining Sites.

A smart glasses-based wearable personnel proximity warning system (PWS) was developed for pedestrian safety in construction and mining sites. The smart glasses receive signals transmitted by Bluetooth beacons attached to heavy equipment or vehicles, with the proximity determined by the signal strength. A visual alert is displayed to the wearer when in close proximity. The media access control address of the Bluetooth beacon provides information on the approaching equipment or vehicle, which is displayed to the wearer so that they can respond appropriately. There was a detection distance of at least 10 m regardless of the direction the pedestrian was looking and the alert was successful in all 40 trials at ≥10 meters. The subjective workload was evaluated using the NASA task load index on ten subjects, either without a personal PWS, with a smartphone-based PWS, or with the smart glasses-based PWS. The mental, temporal, and physical stresses were lowest when using the smart glasses-based PWS. Smart glasses-based PWSs can improve work efficiency by freeing both hands of the pedestrians, and various functions can be supported through application development. Therefore, they are particularly useful for pedestrian safety in construction and mining sites.

Experimental study and dynamic characteristics analysis of partially liquid-filled annulus tubes.

As a useful technology, the horizontal drilling for underground coalmine has been applied in many fields such as gas drainage, water control, exploration and accurate drilling borehole engineering. In this paper, the annulus tubes are used to simulate the fluid transportation process between drilling rod and casing tube when drilling horizontally. The main goal of this research is to analyze the effects of eccentricity, fluid velocity, outer tube length and volume fraction on dynamic characteristics of partially liquid-filled annulus tube in a drillstring system. According to the Euler-Bernoulli beam model, the partially liquid-filled inner tube model and outer tube model are established respectively when considering the effect of transport fluid inside the annulus tubes. Based on the vibration characteristics of the tube, the added mass coefficient is proposed to calculate the natural frequencies of the outer tubes. And natural frequency is the frequency at which a system tends to oscillate in the absence of any driving or damping force. According to the compared results of experiments and simulations, the natural characteristics of outer tube depend on the tube design parameter (outer tube length) and the volume fraction of liquid filled in the outer tube. Furthermore, experiments have verified that the natural frequencies of the outer tubes can be directly calculated from the length of outer tubes. Therefore, it is feasible to propose the method of attaching liquid mass to tube mass to obtain the natural frequencies of outer tubes. According to the results, it can be concluded that: (i) The natural frequencies of tube decrease as the length of the tube increases; (ii) The increase of volume fraction of liquid in the tube can significantly reduce the natural frequencies of tube; (iii) The fluid velocity and eccentricity have less effects on the natural frequencies of tube; (ⅳ) The added mass coefficient of outer tubes can be calculated and it is not a fixed value, it varies with the volume fraction of fluid in annulus tubes. In this work, the inner and outer tube models are established respectively for fluid transportation process between a horizontal drilling rod and casing tube. The effects of four factors on the natural frequencies are compared, and the concept of added mass coefficient is proposed to obtain reasonable tube natural frequencies.

Emerging Ergonomics Issues and Opportunities in Mining.

Ergonomics is the scientific discipline that investigates the interactions between humans and systems to optimize both human and system performance for worker safety, health, and productivity. Ergonomics is frequently involved either in the design of emerging technologies or in strategies to alleviate unanticipated human performance problems with emerging technologies. This manuscript explores several such emerging issues and opportunities in the context of the mining sector. In mining, the equipment, tools, and procedures have changed considerably and continue to change. Body-worn technology provides a number of opportunities to advance the safety and health of miners, while teleoperation and autonomous mining equipment stand to benefit significantly from ergonomics applications in other sectors. This manuscript focuses on those issues and opportunities that can impact the safety and health of miners in the near term.

Prediction of the caved rock zones' scope induced by caving mining method.

Critical medium column theory has typically been used to predict the scope of caved rock zone (CRZ) caused by caving mining method. It is essential to understand the distribution laws of lateral pressure induced by caving mining method with different dipping angles. In this study, a self-designed scaled physical model was used to investigate the distribution laws with angles ranging from 80° to 90°, and ore drawing was employed in experiments to simulate caving mining method. The experimental results indicated that the distribution laws were divided into the reductive region and the extensive region during ore drawing. The reductive region was close to the drawing hole, and its scope was smaller than the other part. Moreover, decreasing the dipping angle was an effective way of controlling the maximum reduction rates and the scope of reductive region. By varying laws of lateral pressure, the predictive model of CRZs' scope was established. Additionally, the rock mass located outside the predictive CRZs' scope did not rupture based on the monitoring of Digital Optical Televiewing (OPTV), which was verified by the field test in Dabeishan Iron Mine, China. The results of the field test demonstrated that the prediction method used in this study was valid and could be used in practice.

Experimental research on the performances of water jet devices and proposing the parameters of borehole hydraulic mining for oil shale.

Oil shale is an unconventional energy source, and it is also a potential petroleum substitute. Nowadays, the energy shortage is becoming more and more prominent, oil shale has attracted the attention of energy researchers all over the world. Borehole hydraulic mining is an effective method to exploit the underground oil shale which has more prominent advantages than other conventional mining methods. Jet devices are the key component of borehole hydraulic mining, which include the straight cone nozzle, organ pipe nozzle and self-excited oscillation pulsed jet nozzle. Also, the reasonable mining parameters are also crucial in mining underground oil shale efficiency. The jet characteristics of the non-submerged water jet, submerged water jet, direct water jet, cavitating water jet, and pulsed water jet are also explained and compared based on theoretical analysis. The jet performance of the non-submerged water jet is better than the submerged water jet. Each type of jet devices has its own basic principles and optimal structural parameters. The best operating scheme of borehole hydraulic mining for underground oil shale is to use the pulsed water jet which is produced by the self-excited oscillation pulsed jet nozzle to break underground oil shale under the non-submerged condition. Moreover, the pulsed water jet should be placed parallel to the oil shale bedding. In addition, under the preconditions of ensuring the safety and reliability of the hydraulic mining equipment and pipelines connection, the jet pressure and jet flow should be raised as much as possible, so as to obtain the much higher mining efficiency. These results and conclusions can provide very valuable guidance for borehole hydraulic mining of underground oil shale.

Evaluation of commercially available seat suspensions to reduce whole body vibration exposures in mining heavy equipment vehicle operators.

As mining vehicle operators are exposed to high level of Whole body vibration (WBV) for prolonged periods of time, approaches to reduce this exposure are needed for the specific types of exposures in mining. Although various engineering controls (i.e. seat suspension systems) have been developed to address WBV, there has been lack of research to systematically evaluate these systems in reducing WBV exposures in mining heavy equipment vehicle settings. Therefore, this laboratory-based study evaluated the efficacy of different combinations of fore-aft (x-axis), lateral (y-axis), and vertical (z-axis) suspensions in reducing WBV exposures. The results showed that the active vertical suspension more effectively reduced the vertical vibration (∼50%; p's < 0.0001) as compared to the passive vertical suspension (10%; p's < 0.11). The passive fore-aft (x-axis) and lateral (y-axis) suspension systems did not attenuate the corresponding axis vibration (p's > 0.06) and sometimes amplified the floor vibration, especially when the non-vertical vibration was predominant (p's < 0.02). These results indicate that there is a critical need to develop more effective engineering controls including better seat suspensions to address non-vertical WBV exposures, especially because these non-vertical WBV exposures can increase risks for adverse health effects including musculoskeletal loading, discomfort, and impaired visual acuity.

Realizing modeling and mapping tools to study the upsurge of noise pollution as a result of open-cast mining and transportation activities.

INTRODUCTION: In open-cast mines, noise pollution has become a serious concern due to the extreme use of heavy earth moving machinery (HEMM). MATERIALS AND METHODS: This study is focused to measure and assess the effects of the existing noise levels of major operational mines in the Keonjhar, Sundergadh, and Mayurbhanj districts of Odisha, India. The transportation noise levels were also considered in this study, which was predicted using the modified Federal Highway Administration (FHWA) model. RESULT AND DISCUSSION: It was observed that noise induced by HEMM such as rock breakers, jackhammers, dumpers, and excavators, blasting noise in the mining terrain, as well as associated transportation noise became a major source of annoyance to the habitants living in proximity to the mines. The noise produced by mechanized mining operations was observed between 74.3 and 115.2 dB(A), and its impact on residential areas was observed between 49.4 and 58.9 dB(A). In addition, the noise contour maps of sound level dispersion were demonstrated with the utilization of advanced noise prediction software tools for better understanding. CONCLUSION: Finally, the predicted values at residential zone and traffic noise are correlated with observed values, and the coefficient of determination, R2, was calculated to be 0.6891 and 0.5967, respectively.

Innovation, systemic appropriation and prevention in the granite mining sector: The case of humidification.

BACKGROUND: This research was conducted in the Brazilian granite mining sector. After epidemiological studies, it was established that professional pneumoconiosis is related to the inhalation of dust. Therefore, the Brazilian mining health and safety regulatory standard made it compulsory to provide humidification throughout the extraction and mineral treatment processes. OBJECTIVE: To develop the concept of systemic appropriation of the technological innovations that aim to protect the worker's health. Until now, appropriation has usually been presented in its individual dimensions. In this article, the focus is placed on the collective and organizational aspects of this appropriation. METHODS: Two methodological approaches were used: interviews with the different individuals involved in order to report the history of the implementation of technical devices which meet the humidification norm; and ergonomic analysis of the work of the operators who used these devices. RESULTS: The appropriation of the technical devices occurred at two distinct levels: 1) Individual, related to the direct contact of the operator with the instrument; 2) Systemic, as the effects of the innovation propagated through the system affecting interdependent tasks, adaptation of the work organization and new production strategies. CONCLUSIONS: The implementation of prevention norms require innovations which are necessarily accompanied by transformations in the companies' techniques, work and management.

Vehicle autonomous localization in local area of coal mine tunnel based on vision sensors and ultrasonic sensors.

This paper presents a vehicle autonomous localization method in local area of coal mine tunnel based on vision sensors and ultrasonic sensors. Barcode tags are deployed in pairs on both sides of the tunnel walls at certain intervals as artificial landmarks. The barcode coding is designed based on UPC-A code. The global coordinates of the upper left inner corner point of the feature frame of each barcode tag deployed in the tunnel are uniquely represented by the barcode. Two on-board vision sensors are used to recognize each pair of barcode tags on both sides of the tunnel walls. The distance between the upper left inner corner point of the feature frame of each barcode tag and the vehicle center point can be determined by using a visual distance projection model. The on-board ultrasonic sensors are used to measure the distance from the vehicle center point to the left side of the tunnel walls. Once the spatial geometric relationship between the barcode tags and the vehicle center point is established, the 3D coordinates of the vehicle center point in the tunnel's global coordinate system can be calculated. Experiments on a straight corridor and an underground tunnel have shown that the proposed vehicle autonomous localization method is not only able to quickly recognize the barcode tags affixed to the tunnel walls, but also has relatively small average localization errors in the vehicle center point's plane and vertical coordinates to meet autonomous unmanned vehicle positioning requirements in local area of coal mine tunnel.

Wadi el-Sheikh: A new archaeological investigation of ancient Egyptian chert mines.

This article provides an overview of the first results from archaeological investigations at Wadi el-Sheikh in Egypt by the University of Vienna Middle Egypt Project. Chert was an important raw material used to produce tools, implements and jewelry in ancient times. Wadi el-Sheikh was exploited over thousands of years as it was probably the most important source of chert in Pharaonic civilization. The results of our new investigations that involved surveys and test excavations indicate the presence of large scale mining activities in the first half of the 3rd Millennium B.C.E. which allow for detailed insights into the amount of raw material extracted, the mining methods used and the lithic products manufactured in this area. These aspects are contextualized on the background of ancient Egyptian state-organized resource acquisition strategies and economy.

Ergonomics in the arctic - a study and checklist for heavy machinery in open pit mining.

BACKGROUND: Heavy mining vehicle operators at arctic mines have a high risk of discomfort, musculoskeletal disorders and occupational accidents. There is a need for tailored approaches and safety management tools that take into account the specific characteristics of arctic work environments. OBJECTIVE: The aim of this study was to develop a holistic evaluation tool for heavy mining vehicles and operator well-being in arctic mine environments. METHODS: Data collection was based on design science principles and included literature review, expert observations and participatory ergonomic sessions. RESULTS: As a result of this study, a systemic checklist was developed and tested by eight individuals in a 350-employee mining environment. CONCLUSIONS: The checklist includes sections for evaluating vehicle specific ergonomic and safety aspects from a technological point of view and for checking if the work has been arranged so that it can be performed safely and fluently from an employee's point of view.

A comparative life cycle assessment of material handling systems for sustainable mining.

In this comprehensive LCA comparison study, main objectives are to investigate life cycle environmental impacts of off-highway mining trucks and belt conveyors in surface mining. The research methodology essentially entails determination of the functional unit as 20,000 tons/day coal production transported for 5 km distance. After the system boundary was selected as the entire life cycle of material handling systems including pre-manufacturing of steel parts and plastic components, manufacturing, transportation, and utilization data was compiled from equipment manufacturers and the Eco-invent database. Life cycle impact categories for both material-handling systems were identified and the developed model was implemented using SIMAPRO 7.3. Climate change and acidification were selected as major impact categories as they were considered to be major concerns in mining industry. Although manufacturing stage had a significant impact on all of the environmental parameters, utilization stage was the hotspot for the selected impact categories. The results of this study revealed that belt conveyors have a greater environmental burden in climate change impact category when compared to the trucks. On the other hand, trucks have a greater environmental burden in acidification impact category when compared to the belt conveyors. This study implied that technological improvement in fuel combustion and electricity generation is crucial for the improvement of environmental profiles of off-highway trucks and belt conveyors in the mining industry. The main novelty of this study is that it is the first initiative in applying LCA in the Turkish mining industry.

Mobility of as, Cu, Cr, and Zn from tailings covered with sealing materials using alkaline industrial residues: a comparison between two leaching methods.

Different alkaline residue materials (fly ash, green liquor dregs, and lime mud) generated from the pulp and paper industry as sealing materials were evaluated to cover aged mine waste tailings (<1% sulfur content, primarily pyrite). The mobility of four selected trace elements (Cr, Cu, Zn, and As) was compared based on batch and column leaching studies to assess the effectiveness of these alkaline materials as sealing agents. Based on the leaching results, Cr, Cu, and Zn were immobilized by the alkaline amendments. In the amended tailings in the batch system only As dramatically exceeded the limit values at L/S 10 L/kg. The leaching results showed similar patterns to the batch results, though leached Cr, Cu, and Zn showed higher levels in the column tests than in the batch tests. However, when the columns were compared with the batches, the trend for Cu was opposite for the unamended tailings. By contrast, both batch and column results showed that the amendment caused mobilization of As compared with the unamended tailings in the ash-amended tailings. The amount of As released was greatest in the ash column and decreased from the dregs to the lime columns. The leaching of As at high levels can be a potential problem whenever alkaline materials (especially for fly ash) are used as sealing materials over tailings. The column test was considered by the authors to be a more informative method in remediation of the aged tailings with low sulfur content, since it mimics better actual situation in a field.

Managing equipment innovations in mining: A review.

BACKGROUND: Technological innovations in mining equipment have led to increased productivity and occupational health and safety (OHS) performance, but their introduction also brings new risks for workers. OBJECTIVE: The aim of this study is to provide support for mining industry managers who are required to reconcile equipment choices with OHS and productivity. METHODS: Examination of the literature through interdisciplinary digital databases. Databases were searched using specific combinations of keywords and limited to studies dating back no farther than 1992. The ``snowball'' technique was also used to examining the references listed in research articles initially identified with the databases. RESULTS: A total of 19 contextual factors were identified as having the potential to influence the OHS and productivity leverage of equipment innovations. The most often cited among these factors are the level of training provided to the equipment operators, operator experience and age, supervisor leadership abilities, and maintaining good relations within work crews. CONCLUSIONS: Interactions between these factors are not discussed in mining innovation literature. It would be helpful to use a systems thinking approach which incorporates interaction between relevant actors and factors to define properly the most sensitive aspects of innovation management as it applies to mining equipment.