Mining Costs Research Articles

Rational parameters of drilling and blasting works providing the least costs of ore mining and processing

Отгрузка разрушенной горной массы требуемого качества и количества на обогатительную фабрику является одной из основных задач подготовительных работ при добыче полезных ископаемых. Основным способом регулирования этого процесса является оптимизация параметров и технологий ведения буровзрывных работ. На Актогайском месторождении возникла проблема с увеличением крепости добываемой руды по мере углубления карьера, что сильно влияет на производительность обогатительной фабрики. В статье приведен опыт проведения мероприятий по оптимизации БВР для улучшения работы обогатительной фабрики, а точнее стабилизации процесса первичного дробления руды. В статье приведены методы расчета рациональных параметров и результатов БВР. Проведен расчет рациональных параметров БВР, а также расчет гранулометрического состава взорванных пород при рациональных параметрах и при предложенных для экспериментальных взрывов Қажетті сападағы және көлемдегі бұзылған тау жынысын байыту фабрикасына жөнелту пайдалы қазбаларды өндіруге дайындық жұмыстарындағы негізгі міндеттердің бірі болып табылады. Бұл процесті реттеудің негізгі әдісі бұрғылау-жару жұмыстарының параметрлері мен технологияларын оңтайландыру болып табылады. Ақтоғай кен орнында карьердің тереңдеуімен өндірілетін кеннің беріктігінің артуы проблемасы туындады, бұл байыту фабрикасының өнімділігіне айтарлықтай әсер етеді. Мақалада байыту фабрикасының жұмысын жақсарту, дәлірек айтқанда, кенді бастапқы ұсақтау процесін тұрақтандыру мақсатында бұрғылау-жару жұмыстарын оңтайландыру шараларын өткізу тәжірибесі баяндалған. Мақалада бұрғылау-жару жұмыстарының ұтымды параметрлерін есептеу әдістері және нәтижелері келтірілген. Бұдан басқа, ұтымды параметрлерге және эксперименттік жарылыстар үшін ұсынылған параметрлерге сәйкес жарылған жыныстардың гранулометриялық құрамын есептеу жүргізілді One of the main tasks of preparatory work in mineral extraction is the delivery of the required quality and quantity of broken rock mass to the processing plant. The primary method of regulating this process is optimizing the parameters and technologies of drilling and blasting operations. At the Aktogay deposit, a problem has arisen with the increasing hardness of the mined ore as the pit deepens, significantly affecting the performance of the processing plant. The article presents the experience of implementing measures to optimize drilling and blasting operations to improve the performance of the processing plant, specifically to stabilize the primary ore crushing process. The article provides methods for calculating rational parameters and results of drilling and blasting operations. Calculations were made for the rational parameters of drilling and blasting operations, as well as for the granulometric composition of blasted rock under rational parameters and those proposed for experimental blasts

Substantiation of the technology for reducing dilution by changing the direction of water flow in the dredge section

The global demand for gold was considered, as well as the ratio of placer gold to ore. It is revealed that there is an increase in the cost of gold mining. This is due to the fact that deposits with simple mining and geological conditions are currently depleted. The dredge method of developing placer deposits is considered. To reduce the cost, the problem of diluting the tailings of ephel dumps was considered. As a solution, a technology for reducing dilution by changing the direction of water flow is proposed. Modeling was carried out and patterns were identified between variables affecting the technological process. This technology can significantly reduce water turbidity, which has a positive effect on the environmental situation in the dredging area. The justification of the technology is given. Also, to justify the effectiveness of the proposed technology, a calculation example is considered. The given example allows us to identify water contamination under various technology options.

A NIRS-based recognition of coal and rock using convolution-multiview broad learning system

Achieving high production in the top coal caving process from thick coal seams is crucial. Thus, the timely decision of when to stop caving poses an urgent challenge to impact the mining loss rate and cost recovery. To address this issue, an innovative recognition system has been developed using Near-Infrared Spectroscopy (NIRS) technology. It stands out for its on-site usability, it enables rapid data collection and local recognition at the longwall face. Furthermore, to overcome the limitations of existing methods in adapting to variations in spectral data quality during on-site collection and the lack of integration of spectral data across different feature processing stages, a coal-rock recognition method has been developed which can ignore the influence of acquisition factors(granularity, light source angle, and detection sensor angle). This method incorporates the features of convolution and multi-view into the BLS model, the designed model structure exhibits a remarkable recognition accuracy of 99.78 %. The model was deployed into the recognition system, and experimental tests were conducted on the working face. The results showed that the recognition system can effectively identify the entire coal-caving process and achieve a recognition accuracy of 92.3 %. This capability is crucial for determining the optimal point to stop roof caving.

Sand mining governance in post-apartheid South Africa: Interlegalities of resource extraction on the Wild Coast

This viewpoint explores the challenge of the intersection of demand for sand, concerns over its exploitation and its governance in South Africa. Mainly drawing on secondary literature review and direct observations, we highlight the irony of the concern about the environmental cost of sand mining, in the midst of poor sand mining governance. The viewpoint argues that the problem in the Wild Coast is the multiple jurisdictions of sand mining governance, ranging from national, provincial and local government legislation, policies and practices, that combine and create confusion. We call for stronger governance locally, and at other scales, including opening up legal mining opportunities, especially in light of current unauthorized sand mining taking place.

Validation of a PGNAA sensor model for bulk material sorting

Global mineral demand is forecast to increase significantly to achieve the transition to renewable energy. Greater volumes of ore of lower grade will have to be mined to meet demand. Techniques to process large volumes of low-grade ore efficiently are being investigated to reduce the cost and impact of mining. One technique is to use sensor information to sort mined material, allowing waste to be discarded early in mineral processing. Prompt gamma neutron activation analysis (PGNAA) is a sensing technique that can provide information on the multi-elemental composition of a bulk sample which can be used for bulk material sorting. This paper presents the development of a Monte Carlo simulation model of a PGNAA sensor for bulk sorting using the Geant4 toolkit. The GEOSCAN sensor (Scantech Australia) was used as a case-study to demonstrate the application of the model. The sensor responses for a range of pure mineral samples (Fe2O3, SiO2, S, Na2CO3 and MnO2) were measured to validate the developed model. The sensitivity of the simulation results to the hadronic and electromagnetic physics models used was tested. It was determined that the PGNAA sensor model can reproduce measurements obtained from the GEOSCAN sensor. In particular, the model can provide a good reproduction of the overall spectral shape and the locations of distinct characteristic peaks. The differences between simulated and experimental results are within 30% on average. It was found that the Geant4 HP neutron model best reproduces the activation peaks observed in experimental measurements. Additionally, the PGNAA spectrum was found to be insensitive to the choice of electromagnetic model for the photon interactions. The validated sensor model provides a useful tool for investigating PGNAA sensor applications including a bulk sorting strategy for new materials, sensor calibration, improvements in signal analysis and optimised sensor design.

Continuous monitoring of coal mine dangers with an automated internet of things system

The safety of mine workers is a major concern in the modern world. The life and health of miners are vulnerable against a few fundamental problems, such as their workplace and its adverse effects. A novel and inventive approach is needed to increase profitability and reduce mining costs while keeping worker safety in mind. For tracking the level of concentration of hazardous gases, semiconductor gas sensors are used. In the mine worker area, air contamination is primarily caused by outflows from particulate matter and gases, such as sulfur dioxide (SO 2), nitrogen dioxide (NO 2), carbon monoxide (CO) furthermore, the goal of this project is to design a real time IOT system that can monitor temperature, humidity, dangerous gasses, and smoke status in an underground mine utilizing sensors with an ODROID-N2+controller and designed a base station to receive data from all coal mines via the ODROID-N2+module. We also built a web-based interface accessible through computers and Android/iOS devices. The suggested system seamlessly integrates surveillance, analysis, and localization strategies using cloud computing, application gateways, real-time operational databases, Internet of Things (IoT), and application program interfaces to enhance the management of safety and prevent injuries in underground coal mines.

Selection of longwall shearers based on the results of research on the mechanical properties of coal

The proper selection of cutting longwall winning machines for specific mining and geological conditions requires the development of an appropriate algorithm. The appropriate selection of a machine (shearer) is closely related to acquiring a high concentration of exploitation from the given longwall. That is indispensable, especially taking into consideration the growing cost of mining, as well as the depth of coal seams. In this article, an algorithm showing the selection of longwall winning machines has been presented. The algorithm has been created based on results of research on the processed coal’s mechanical properties. Analysis of the mining process, especially in difficult conditions, shows that in order to define a drum longwall shearer’s range of usage, the coal’s properties which have a significant impact on the mining process must be determined. The above also influences the technique, technology and effectiveness of mining—they impact the effectiveness of the winning machines. In connection to this, the cutting heads should be chosen and designed based on those factors, as well as any performance forecasts. As representative values the following have been chosen: workability index (WUB), resistance to unidirectional compression (Rc), and energy consumption of the mining process (TE).

Hydrogeology and groundwater control at Chambishi mine, Zambia

The hydrogeological conditions in the Chambishi mine area in Zambia. were investigated. Chambishi is a very wet mine and groundwater discharge costs are high. The research goal was to identify methods to reduce the discharge costs without greatly affecting the mining process. Hydrogeological data was obtained from measurements in drill-holes and from drill cores. The differences in structural deformation in different areas determine whether a layer of rock is an aquifer. In the mine region, the Lower Roan Group ore shale and quartz-sandstone unconformably lie on the basal schist and granite aquifuge. The Upper Roan Group dolomite is continuously distributed over a large area around the orebody. This dolomite is the main target of groundwater control efforts, and its water yield is also influenced by the deformation intensity. Based on the observations, backfilling was gradually adopted to appropriately safeguard the integrity of the aquifuge above the orebody. The overlapping relationship between the aquifer and aquifuge has been utilized to increase mine drainage efficiency. This measure has not only greatly reduced the costs of mine drainage, but also improced protection of the groundwater environment. The old drill-holes that were not sealed after exploration drilling were grouted. Further, possible water-conducting fracture zones were investigated. Cover drilling towards the suspected zone was conducted to prevent the high-pressure groundwater from shallower aquifers from entering stopes in deep areas of the mine.

Understanding key mineral supply chain dynamics using economics‐informed material flow analysis and Bayesian optimization

AbstractThe low‐carbon energy transition requires significant increases in production for many mineral commodities. Understanding demand, technological requirements, and prices associated with this production increase requires understanding the supply chain dynamics of many minerals simultaneously, and via a consistent framework. A generalized economics‐informed material flow method, global materials modeling using Bayesian optimization, captures the market dynamics of key mineral commodities. The method relies only on a limited set of widely available historical data as input, enabling quantification of economic relationships (elasticities) for supply chain components where data are sparse, and relationships cannot be obtained via traditional statistical approaches. Building upon established material flow analysis (MFA) and economic modeling techniques, Bayesian optimization was applied to fit an economics‐informed MFA model to global historical demand, supply, and price for aluminum, copper, gold, lead, nickel, silver, iron, tin, and zinc. This approach enables estimates for the evolution of ore grades, mine costs, refining charges, sector‐specific demand, and scrap collection for each commodity. Economic relationships were quantified and compared with a database compiled from the literature, including 1333 values from 213 analyses across 65 publications. Discrepancies in methods and limited coverage make use of these parameters in modeling efforts difficult. This work provides a single, homogeneous, probabilistic approach to identifying economic relationships across mineral supply chains, with uncertainty quantification, a literature database for comparison, and a modeling framework in which to use them. This article met the requirements for a Gold‐Gold JIE data openness badge described at http://jie.click/badges.

Effect and mechanism of time-dependent and economical expansion materials in improving the active roof-contact for cemented paste backfill

During the backfilling process, there is often a problem of no roof-contact, and the time and state of roof-contact cannot be predicted, seriously affecting the backfilling safety and efficiency. Therefore, the expansion effect, mechanism, and time dependence of the expansion agents used to achieve roof-contact were studied through expansion ratio tests, strength tests, and microscopic analysis. The expansion ratio of the MgO-type expansion agent (MEA) can meet the requirement of backfilling, and the unconfined compressive strength (UCS) of the expansive cemented paste backfill (ECPB) was attenuated compared to that of ordinary cemented paste backfill (CPB). Through scanning electron microscope (SEM) and mercury intrusion porosimetry (MIP) of the MgO-type ECPB, it is found that the ECB produces Mg(OH)2 crystals, which improves the compensation space inside the ECPB. MIP analysis results also show that the ECPB has higher porosity and more macropores, which is the reason for the strength attenuation of the ECPB. It is found that the expansion ratio and sedimentation ratio of fresh ECPB are time-dependent, and they both conform to logarithmic function. Afterwards, through the dynamic relationship between the sedimentation and expansion of fresh ECPB, the synthetic criterion of roof-contact based on the time-dependent model of expansion ratio and sedimentation ratio was established. The theoretical shortest roof-contact time of different experimental groups was obtained. Finally, through a comparative analysis of backfilling costs, the lowest cost and reasonable backfilling scheme were obtained. It is of great value for judging the effectiveness of roof contact, optimizing the backfilling proportion scheme, ensuring backfilling safety, and saving backfilling and mining costs.

Forecasting the cost and volume of uranium mining for different world nuclear energy development scenarios

Forecasting the cost and volume of uranium mining for different world nuclear energy development scenarios

Geo-mechanical classification of the Ighrem Aousser rock mass mining site of the Touissit Mining Company

Purpose. The paper aims to classify the rock mass of the Ighrem Aousser (I/A) mine and analyze its fracturing to determine the appropriate excavation supports. Methods. The study begins with a geo-mechanical classification of the mass using widely used methods: Rock Quality Designation (RQD), Rock Mass Rating (RMR), Q-Barton, and Geological Strength Index (GSI). Fracturing surveys were then conducted to identify the main fracture families using DIPS software. Finally, UNWEDGE software was used to measure the support systems. Findings. The study provides a comprehensive geological study, including field observations, core drilling analysis, and structural analysis with DIPS software. Results indicate that the I/A mine rock mass is highly fractured and altered, as confirmed by mechanical tests at the Mohammadia School of Engineers' laboratory and empirical classifications. Based on these findings, appropriate support systems were identified using UNWEDGE software. Originality. This study provides a detailed classification and structural analysis of the I/A rock mass to propose and measure excavation supports. Integrated approach not only advances understanding of rock mass behavior, but also ensures optimized safety, stability, and productivity of mining operations, setting a new standard in sustainable mining development. Practical implications. In the mining industry, classifying rock masses and designing excavation supports enhances safety, increases site productivity by reducing contamination and lowering mining costs.

Dispatcher: Resource-aware Nakamoto Blockchain via Hierarchical Topology and Adaptive Incentives

Mainstream blockchain systems such as Bitcoin and Ethereum are revolutionizing the financial industry by adopting the Nakamoto consensus protocol, i.e., Proof-of-Work (PoW). Only nodes with sufficient computing resources can work out the PoW difficulties, thereby increasing the mining cost of malicious attackers and ensuring the security of blockchain systems. Such an assumption of having abundant resources leads to drawbacks of low throughput and risk of centralization. In this article, we present Dispatcher, a novel distributed consensus protocol that takes resource heterogeneity into account to ensure resource-aware PoW with high efficiency. Dispatcher introduces a hierarchical topology to offer flexible PoW difficulties tailored for different nodes’ resources. In particular, it utilizes the limited resource of each node to jointly maximize the performance by concurrent mining. Moreover, we design an adaptive incentive mechanism to fit the available resource of blockchain nodes to rewards. Our experiments show that Dispatcher enjoys a substantial performance margin over the state-of-the-art. We can achieve a 50% throughput improvement compared with OHIE.

A New CRITIC-GRA Model for Stope Dimension Optimization Considering Open Stoping Stability, Mining Capacity and Costs

In the long-hole stage open stoping with subsequent backfill mining of underground metal mines, the selection or optimization of stope dimension parameters is significant for safe and economic mining operations. To analyze the optimal stope sizes, the Mathews empirical graph method and FLAC3D numerical method can be used, but the analyzed safety results of the two methods are generally independent from each other. More importantly, economic indicators including production capacity and mining costs should be considered simultaneously to optimize the stope dimension which was mostly ignored in previous reports. In this paper, a new CRITIC-GRA model was proposed for the first time to build up a multi-factor quantitative optimization for stope dimension, which allows for a comprehensive analysis with preset influential safety and economic indicators. The indicators considered include the safety indicators such as stability probability for the side walls and roof of the open stope via the updated Mathews graph method, maximum displacement, plastic zones volume and maximum principal stress via FLAC3D simulations, as well as economic indicators such as mining costs and stope production capacity in mine operations. The model was then illustrated in an underground iron mine. With the given rockmass quality in the mine, the overall stability of the open stope can be improved instead of reduced to enlarge the single stage stope height (60 m) to a double stage height (120 m) by reducing the stope width from 20 m to 15 m, thereby significantly increasing the mineable ore amount and improving the stope safety. An integrated evaluation of open stope stability, mining capacity and costs objectively determined that scheme No. 10, with a slope length of 50 m, a width of 15 m and a height of 120 m, was the optimum out of the 20 preset schemes. The new CRITIC-GRA model offers a dependable reference tool for determining the optimal stope dimensions in similar underground mines.

Integration of ground geophysical methods to characterize near‐surface aquifer zones within an active mine

AbstractUnderstanding near‐surface groundwater storage, flow patterns, surface and groundwater interactions in mining areas can assist in making mining more efficient and profitable. This is especially important in opencast mines affected by water inflows that may negatively affect production and increase mining costs. We map and characterize the near‐surface aquifer zones at the opencast site of Tharisa Minerals, located in the southwestern region of the Bushveld Complex (South Africa). The main goal is to infer pit water inflow at the mine site and determine how it may be better controlled. The Bushveld Complex hosts partially connected and unconfined alluvial, shallow‐weathered and crystalline bedrock aquifers, which are often connected by small‐scale permeable zones. Seismic refraction tomography, multichannel analysis of surface waves, electrical resistivity tomography and borehole data are used to map and understand the different aquifer zones in the vicinity of the mine, as well as infer their relation to water inflow in the mine pits. The geophysical surveys map the overburden, weathered bedrock aquifer zone, and the top of the crystalline aquifer rock zone reasonably well. They reveal extensive and deep weathering, and possible high hydraulic conductivity in the vicinity of the mine. The results provide a better understanding of the mine's near‐surface environment, which could be used to implement effective and targeted dewatering techniques, thus enabling better pit inflow water control to improve mine working conditions and production.

The Influence of Geotechnical, Geological and Mining Factors on the Formation of Sinkholes at Lubambe Mine, Zambia

Mining-induced sinkholes are a common feature in underground mines. Sinkholes usually disrupt mining operations and associated infrastructure when they occur. This paper presents a case study of the Lubambe copper mine, where nine (9) sinkholes have been reported on the eastern and southern limbs. The development of sinkholes has resulted in increased mining costs due to the closure of the 182 mL decline on the eastern limb and the 175 mL truck route on the southern limb. This study establishes the influence that poor ground formation, rock stability, geological structures, and inappropriate mining practices have on the formation of surface sinkholes. Assessment of ground condition was done by core logging, and borehole analysis was conducted using GEM4D-BasRock software to classify the rock mass quality based on RQD, RMR, Q-System and GIS. Assessment of the mining operational environment was focused on the effects of varying stope designs and sequencing on ground stability. Results of the study indicate that the formation of surface-induced sinkholes is attributed to historical mining in weak rock formation and weathered rock coupled with subsequent failure of unsupported stopes with stope height between 8 and 25 metres and less stand-up time of 7 days.

Does Mining Fuel Bubbles? An Experimental Study on Cryptocurrency Markets

We investigate how key features associated with the Proof-of-Work consensus mechanism of Bitcoin (commonly referred to as mining) affect pricing. In a controlled laboratory experiment, we observe that price bubble formation can be attributed to mining. Moreover, overpricing is more pronounced if the mining capacity is centralized to a small group of individuals. The order book data reveal that miners seem to play a crucial role in bubble formation. Further probing the mechanism in a second study, we find that both mining costs and decisions jointly with the sluggish rate of supply of the asset contribute to the bubble formation. Our results demonstrate that erratic pricing is an inherent feature of cryptocurrencies based on a mining protocol, thus seriously limiting any prospects for such assets becoming a medium of exchange. This paper was accepted by Yan Chen, behavioral economics and decision analysis. Funding: The funding provided by the University of Heidelberg, Hanken Foundation [Grant 271-6250], and Durham University is gratefully acknowledged. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2022.01238 .

Green supply chain for steel raw materials under price and demand uncertainty

The scientific formulation of procurement and inventory plans is an important topic in the steel industry, when considering both economic and environmental impacts in an uncertain market environment. Robust optimization methods offer an effective solution to this problem. This study has investigated a multi-echelon and multi-period front-end supply chain centered on a steel enterprise under uncertain purchase prices and demand. The goal is to minimize the costs associated with mining, processing, transportation, procurement, and inventory along with the corresponding carbon emission costs. To address this issue, we present a robust rolling horizon model (RRHM) that considers the inventory capacity constraints of steel enterprise and incorporates ore grade requirements. Subsequently, the RRHM was reformulated into a solvable mixed-integer linear programming model, and the relationship between the robust model and a specific deterministic model was established. Finally, the model was validated by generating instances based on real scenarios. The results demonstrate that the robust rolling horizon model proposed in this paper outperforms both the Sample Average Approximation (SAA) strategy and the (s, S) strategy in terms of cost and robustness. In addition, a sensitivity analysis of the key parameters was conducted. The findings reveal that the unit inventory, mining, and carbon emission costs have a limited impact on the total cost, highlighting the robustness of the model. These findings provide valuable insights into the green and sustainable development of the steel industry, enabling the formulation of effective strategies to mitigate the impacts of uncertainties.

Preparation and Properties of Expansive Backfill Material Based on Municipal Solid Waste Incineration Fly Ash and Coal Gangue

To realize the large-scale utilization of municipal solid waste incineration (MSWI) fly ash in the field of building materials and to reduce the cost of coal mine backfill mining, the effects of the mixing ratio of cementitious materials, the particle size distribution of aggregates, and the amount and mass concentration of cementitious materials on the properties of backfill materials were experimentally investigated, and the microstructure of the hydration products was analyzed. The results showed that as the mass ratio of MSWI fly ash to bottom ash increased, the rate of expansion of the cementitious system continued to increase, and the compressive strength of the cementitious system continued to decrease. The Al (aluminum) and AlN (aluminum nitride) in the fly ash reacted with water to generate gas, causing the expansion of the cementitious materials; NaOH increased the alkalinity of the solution, which promoted the formation of more bubbles, thereby improving the expansion performance of the cementitious material. When the content of NaOH was 0.9%, the sample rate of expansion could reach 15.9%. The addition of CaCl2 promoted the early hydration reaction of the cementitious material, forming a dense microstructure, thus improving the early strength and rate of expansion of the cementitious material. The compressive strength of the backfill body increased as the fractal dimension of the aggregate particles increased, and the particle grading scheme of group S1 was optimal. The 1-day, 3-day, and 28-day strengths of the backfill body of group S1 reached 0.72 MPa, 1.43 MPa, and 3.26 MPa, respectively. It is recommended to choose a backfill paste concentration ranging between 78.5% and 80% and a reasonable amount of cementitious material between 20% and 25%. After the MSWI fly ash was prepared as a backfill material, the leaching of potentially harmful elements in the fly ash was greatly reduced, and the concentration of dioxin was reduced to 13 ng TEQ/kg. This was attributed to the dilution of the cement, the physical encapsulation of gel products, and the isomorphous replacement of Ca2+ in calcium aluminate chloride hydrate.

Cost Benefit Analysis of Re-Developing the Defunct Panguna Copper Deposit in Autonomous Region of Bougainville

The Autonomous Bougainville Government (ABG) has been obliged to devise socially inclusive mining legislation and policies that were realised through enactment of Mining Act (2015). It recognises community ownership of minerals found in predominantly maternal system of land ownership. The enactment of a separate mining legislation from that of Papua New Guinea (PNG) was a response to socio-political and environmental legacies associated with former Panguna mine. The cost benefit analysis (CBA) study was conducted using historical data from former Panguna mine and conceptual model of redeveloping the defunct Panguna resource. The results show redevelopment of the remaining copper resource could exceed the net benefits of the former mine. The historical and conceptual efficiency ratios (CBR) being greater than 1 depicted that monetary benefits could exceed production and opportunity costs of mining. Despite excluding social and environmental costs of mining, the positive NPV and IRR create opportunities to forge workable partnerships to enhance low-risk options to reduce net costs and maximize the benefits of mining. A major finding of the CBA study was that despite the local ownership of minerals, the mining lease permits and land access are competitive, similar to regalian ownership system. Also, the benefit redistribution structure was found to be similar to PNG’s regalian system where local ownership of minerals may not be a direct form of nationalisation.