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With the reinforce of the copper mining, the on-site monitoring of the accompanied effluent discharge is highly demanded for the emergency response to minimize the negative effect of the effluent on the surrounding ecosystem. On the basis of the specific interaction between Cu 2+ and l -Cysteine ( l -Cys), which was modified on gold nanoparticles (Au NPs), and the aggregation dependent surface plasmon resonance (SPR) of Au NPs, we developed an easy-on-going paper colorimetric method for the quick evaluating the copper ion concentration in the waste water excreted from the copper mine. The color change of l -Cys modified Au NPs ( l -Cys-Au NPs)immobilized on a filter paper was very sensitive to the Cu 2+ concentration and free of interference from other metal ions typically in waste water. The proposed paper colorimetry has the LOD of 0.09 mg/L and the linear range of 0.1–10 mg/L, respectively, with the RSD ( n = 5) was 6.6% for 1 mg/L Cu 2+ and 3.5% for 5 mg/L Cu 2+ . The quantitative analysis results for the mineral wastewater is in good agreement the China National Environmental Protection Standards HJ485-2009, which indicates the current method could be developed to the on-site detection technique for the emergency response in monitoring Cu 2+ in industrial wastewater or polluted water. [ABSTRACT FROM AUTHOR]

As near-surface mineral resources are being depleted, mining operations are focused on deepening. Rising environmental concerns prefer underground mining methods because their footprint is less than that of surface mining methods. Among the underground mining methods, block caving is a method with low operating costs and comparable production rate to open-pit mines. Mine design and planning optimization is performed to ensure the optimal use of mineral resources with minimal possible extraction costs. Stope boundary optimization is vital in the underground mining planning process, and numerous algorithms have been proposed in that regard. The floating stope algorithm is the most widely used algorithm which is presented for those mining methods where selective mining is possible. This paper tries to apply the floating stope algorithm for stope boundary optimization in the case of block caving. In that regard, a framework is discussed to determine the input parameters of the floating stope algorithm that are suited for block caving including minimum block size, floating ranges, and cutoff grade. These parameters are defined to customize the floating stope algorithm for the block caving method. Then the customized algorithm is applied to optimize the boundary of the underground block caving stope. Then, the corresponding undercut level is determined using the "effective cross-section" heuristic. The procedure is applied in the Songun copper mine. Based on the results, the minable reserve is 617 million tons with an average copper grade of 0.53%. [ABSTRACT FROM AUTHOR]

Loss of copper minerals in the tailings of the rougher and scavenger circuits poses a significant challenge in copper processing plants, diminishing the circuit's efficiency. Part I of this paper identified the causes of copper mineral loss in the scavenger circuit tailings of the Sungun copper concentration plant, situated in northwestern Iran. Changes in feed composition, particularly the ratio of copper oxide to sulfide minerals, along with alterations in the mineralogical properties of the input feed to the scavenger circuit, emerged as pivotal factors contributing to the loss of copper minerals into the tailings. In line with these findings, the objective of the present paper (part II) is to optimize the scavenger circuit by proposing a solution to mitigate the loss of copper minerals to the tailings. Samples were collected from the feed, concentrate, and final tailings, as well as from each cell of the scavenger circuit, followed by comminution and flotation tests on each sample. The results indicate that redirecting the scavenger circuit tailings to the input of the rougher cells, owing to their higher copper grade compared to the tailings of the rougher circuit, can enhance the circuit's recovery by more than 4%. Additionally, employing a combination of sulfide and oxide collectors, along with sulfidation to float the copper oxide minerals in the scavenger circuit, resulted in an overall recovery increase exceeding 11%. Furthermore, adjusting the size of the air bubbles to capture fine copper mineral particles from the scavenger circuit cells proved to be an effective strategy for boosting recovery. Moreover, modifying the grinding circuit to liberate the minerals present in the scavenger circuit feed, predominantly the concentrate of the scavenger circuit itself, led to a recovery increase of approximately 5%. Considering the mineralogical characteristics of the scavenger circuit feed, derived from the tailings of the cleaner cells, implementing changes in the operating conditions of the cleaner circuit—such as employing hybrid bubbles (Nano and coarse bubbles) and utilizing sulfide and oxide collectors—significantly impacted the recovery of fine copper mineral particles and copper oxide minerals to the cleaner concentrate, thereby enhancing the scavenger circuit's performance. [ABSTRACT FROM AUTHOR]

This paper presents the construction of a numerical three-dimensional model of the area of the Żelazny Most Mining Waste Storage Facility (MWSF). In the study area, the difficult geological conditions associated with glaciotectonics are accompanied by a complex hydrotechnical system of sediment deposition and sedimentary water drainage. In order to effectively reflect the water flow paths, a detailed schematization was carried out, using 700,000 boreholes and more than 300 hydrogeological cross-sections. In addition, numerous drainage sections, streams, and ditches were included to reliably assess the amount of saline water entering the underlying aquifers. This research was supported by magnetic resonance sounding (MRS) studies of the reservoir's sediments. The MWSF is currently being expanded, so the work primarily focuses on illustrating changes in the hydrodynamic field resulting from the inclusion of the new southern section. Models of similar facilities have been implemented before, but in the current one, the combination of meticulous analysis of the hydro-structural system, the water balance, a significant amount of data, the size of the facility, and the use of an unstructured discretization grid in the calculations is undoubtedly innovative and will be an important contribution to the development of analogous solutions around the world. [ABSTRACT FROM AUTHOR]

The No.4 tailings pond of the Dexing Copper Mine is the second largest in Asia. The tailing pond is a dangerous source of man-made debris flow with high potential energy. In view of the lack of effective and low-cost global safety monitoring means in this region, in this paper, the time-series InSAR technology is innovatively introduced to monitor the deformation of tailings dam and significant key findings are obtained. First, the surface deformation information of the tailings pond and its surrounding areas was extracted by using SBAS-InSAR technology and Sentinel-1A data. Second, the cause of deformation is explored by analyzing the deformation rate, deformation accumulation, and three typical deformation rate profiles of the representative observation points on the dam body. Finally, the power function model is used to predict the typical deformation observation points. The results of this paper indicated that: (1) the surface deformation of the tailings dam can be categorized into two directions: the upper portion of the dam moving away from the satellite along the Line of Sight (LOS) at a rate of −40 mm/yr, whereas the bottom portion approaching the satellite along the LOS at a rate of 8 mm/yr; (2) the deformation of the dam body is mainly affected by the inventory deposits and the construction materials of the dam body; (3) according to the current trend, deformation of two typical observation points in the LOS direction will reach the cumulative deformation of 80 mm and −360 mm respectively. The research results can provide data support for safety management of No.4 tailings dam in the Dexing Copper Mine, and provide a method reference for monitoring other similar tailings dams. [ABSTRACT FROM AUTHOR]

Inspired by a paper by Teseletso and Adachi (Miner Econ 8(10):21, 2021), the hypothesis regarding the declining grade of mined copper ore and its possible use as a guide to the future of ultimate recoverable resources (URRs) is tested. As a time axis, cumulative production is taken. Grades can be either grade of cumulative tonnage or annual production grade. Correlation can be linear (grade and tonnage) or semi-logarithmic (grade linear, tonnage logarithmic). We first show that the assumption that the highest correlation is the best guide to the future may be a fallacy. This is the linear correlation between grades of cumulative tonnage and cumulative tonnages since 1959, i.e., 85% of all copper mined historically with a near-perfect correlation approaching one (R2 = 0.97). This leads to implausibly low results of the URR, clearly demonstrating that this trend must shift in the future. Moreover, Teseletso and Adachi's (Miner Econ 8(10):21, 2021) approach using a linear or semi-logarithmic correlation between annual grades with cumulative production leads to erroneous results. Here, the later the calculation of the correlation begins, the lower the extrapolated tonnages are at predetermined, postulated ultimate cutoff grades. This contradicts the accepted knowledge that with lower grades, the resource base is broadened—not narrowed. The only reasonable finding results from the correlation between linear grades of cumulative production with logarithmic cumulative production, i.e., the Lasky relationship, indicating a URR of 7.5 GT Cu, of which 6.7 GT remain to be mined, which is equivalent of close to 325 years of present production. The trend towards declining Cu grades with constant real Cu prices shows the potential for creative solutions for other metal as well. [ABSTRACT FROM AUTHOR]

Rockbursts represent one of the most serious and severe natural hazards emerging in underground copper mines within the Legnica–Glogow Copper District (LGCD) in Poland. The contributing factor determining the scale of this event is mining-induced seismicity of the rock strata. Extensive expertise of the copper mining practitioners clearly indicates that high-energy tremors are the consequence of tectonic disturbances or can be attributed to stress/strain behaviour within the burst-prone roof strata. Apparently, seismic activity is a triggering factor; hence, attempts are made by mine operators to mitigate and control that risk. Underlying the effective rockburst control strategy is a reliable seismicity forecast, taking into account the causes of the registered phenomena. The paper summarises the geomechanics analyses aimed to verify the actual seismic and rockburst hazard levels in one of the panels within the copper mine Rudna (LGCD). Two traverses were designated at the face range and comparative analyses were conducted to establish correlations between the locations of epicentres of registered tremors and anomaly zones obtained via analytical modelling of changes in stress/strain behaviours within the rock strata. The main objective of this study was to evaluate the likelihood of activating carbonate/anhydrite layers within the main roof over the excavation being mined, with an aim to verify the potential causes and conditions which might have triggered the registered high-energy events. Special attention is given to two seismic events giving rise to rockbursts in mine workings. Results seem to confirm the adequacy and effectiveness of solutions provided by mechanics of deformable bodies in the context of forecasting the scale and risk of dynamic phenomena and selecting the appropriate mitigation and control measures in copper mines employing the room-and-pillar mining system. [ABSTRACT FROM AUTHOR]

This paper considers the impact of copper mining-influenced water and metallurgical wastewater on the surface water in the Bor area, Serbia. Sampling, realized through the four campaigns (2020–2021), confirmed that both types of water, discharged without appropriate treatment in the Bor River, had a signific impact on the concentration of metal ions, pH and electrical conductivity on the watercourse in the Bor area. The highest concentrations of the following metal ions, Cu—271 mg/L, As—25,991 μg/L, Ni—13,856 μg/L, Cd—2627 μg/L, and Pb—2855 μg/L, were registered in the metallurgical wastewater samples. After changes occurred in the copper production process by stopping the discharge of untreated wastewater into the Bor River, the concentrations of monitored elements were drastically decreased. In the period 2022–2024, the concentration values for Cu, As and Pb ions were below the maximum allowable value, and the concentration values of Ni and Cd ions were also decreased. The values for pH and electrical conductivity were in the maximum allowable range. The return of wastewater to the copper production process would lead to both a reduction in the primary water consumption and reduction in the negative impact on the environment. [ABSTRACT FROM AUTHOR]

Concrete materials are widely used in engineering projects, with fine aggregates (sand) being a key component currently in short supply. Copper tailings sand, a waste by-product of copper mining, accumulates in large quantities in tailings dams. Recycling and reusing this waste sand is crucial for environmental sustainability. This paper investigated the incorporation of copper tailings sand into concrete as a partial replacement for fine aggregates and evaluated its effects on concrete's workability and mechanical properties. The experimental results indicate that the addition of copper tailings sand reduced the workability and compressive strength of concrete. Specifically, at a 60% substitution rate, the slump of the concrete was reduced by 15%, and the axial strength was closest to that of ordinary concrete, with a reduction of 2.5%. As the proportion of copper tailings sand increased from 0% to 80%, the average axial strength decreased from 37.3 MPa to 34.9 MPa, and stiffness decreased by approximately 6.43%. A complete stress–strain curve equation was proposed based on fitting relevant parameters, closely aligning with experimental data. Moderately adding tailings sand can help address the issue of large amounts of waste sand accumulating in tailings dams while maintaining acceptable concrete properties. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Currently, in some domestic and foreign mines, the backfill drilling pipeline experiences a rupture phenomenon even when the wear degree is low. This results in a delay in production due to the filling becoming 'sick'. This paper presents, for the first time, the damage mechanism from a mechanical perspective and re-derives the anti-extrusion strength model of the backfill drilling pipeline. We investigate the influence of the law on the anti-extrusion strength of pipelines from the perspective of strata and cement rings. We then verify the theoretical and simulation results through engineering examples. The results demonstrate that the Mises stress criterion is a suitable modification principle for the anti-extrusion strength model of the backfill drilling pipeline. The anti-extrusion strength of the pipeline is related to the elastic modulus and Poisson's ratio of the stratum, and the thickness of the cement ring. It is negatively affected by the depth of the stratum. For hard strata, a cement ring with a smaller elastic modulus is suitable, while for soft stratum, a cement ring with a larger elastic modulus is recommended. When the missing angle of the cement ring is less than 60°, the stress concentration factor increases up to 2.2. The stress unloading capacity of the cement ring ranges from 32.7% to 37.8%, and optimal performance of the cement ring is achieved when it has high strength and low rigidity. The backfill filling pipeline of a copper mine abroad was destroyed due to external extrusion force exceeding its anti-extrusion strength value. The modified pipeline anti-extrusion strength model is 18.2% higher than the pipeline API strength value. This finding can inform the design of the backfill filling pipeline for China's kilometer-deep wells in the future. [ABSTRACT FROM AUTHOR]

In order to effectively reduce the risk of underground debris flow, surface moraine is solidified and modified by using grouting technology to realize the change in fine-grained moraine from "powder" to "block" to change the source conditions of underground debris flow and to reduce the risk of moraine from the root. In this paper, the effects of grouting pressure, porosity, and pore diameter on the spillability of moraine are investigated experimentally. The results show that the grouting depth increases linearly with increasing sample porosity. For the same sample density, the grouting pressure is proportional to the grouting depth. As the pore diameter of the sample increases, the longitudinal grouting depth of the sample increases, but the transverse diffusion distance decreases. The chemical grout in the moraine is mainly split-infiltration grouting mode. The present research results can provide effective support for the prevention and control of underground debris flow in Pulang Copper Mine. [ABSTRACT FROM AUTHOR]

The empty-space subsequent filling mining method is the main mining scheme for underground metal mines to achieve large-scale mechanized mining. The stage height, one of the main parameters of this method, affects the various production process aspects of the mine and influences the stability of the goaf. In order to determine the stage height scientifically and rationally in the empty-space subsequent filling mining method, a formula for the stabilized critical safe height of a high goaf in an underground metal mine was derived based on Pu's arch equilibrium theory, Bieniawski's pillar strength limit theory, and the Kastner equation and combined with the results of an orthogonal analysis to rank the importance of the main factors in the formula. A copper mine in Jiangxi Province was used as a case study, with the reliability of the formula verified by numerical simulation and industrial testing. The factors in the formula influencing the critical stabilized safe height of the goaf were, in descending order, the compressive strength of the rock body, the width of the two-step mining pillar, the width of the one-step mining room, the mining height, and the depth of mining. Based on the calculation results, the recommended stage heights are 30 m (−378 m middle section) and 25 m (−478 m middle section) in the area of poor rock body stability and 50 m in the area of better rock body stability. The simulation results show that the goaf is significantly affected by the compressive stress under the condition of a certain rock body stability and that the compressive stress increases with increasing goaf height. The minimum recommended values of the sidewall safety coefficients in areas of poor and better rock stability are 1.04 and 1.06, respectively. The volume deviation coefficients of the three industrial test mines were all controlled within 3%, indicating that no obvious collapse and destabilization phenomenon occurred in the goaf. This paper provides some theoretical and applied guidance for the stage height design of similar underground metal mines using the empty-space subsequent filling mining method. [ABSTRACT FROM AUTHOR]

Nowadays, nonlinear loads are widely employed within the industrial applications that cause harmonic distortions in the network. Passive harmonic filters stand out as the preeminent and cost‐efficient remedy for mitigating the impact of harmonic distortions. Any changes in power system conditions such as load variability and photovoltaic resources uncertainty have a significant impact on the harmonic conditions which can affect the quantity and positioning of passive harmonic filters. Hence, in this paper, a method including an innovative optimization problem is proposed for probabilistic planning of passive harmonic filters considering system conditions variability, which is solved by heuristic methods and multi‐criteria decision‐making techniques. By doing this, a solution is obtained where grid losses and the passive harmonic filter costs are minimized and the power factor and frequency response are improved on selected buses. Also, in this paper, the index that gauges the severity of total harmonic distortion is proposed to determine the worst case of the network in terms of harmonic distortions which is so vital for system operators, especially the systematic approach to designing passive harmonic filters. To indicate the efficiency of the proposed approach, the electrical system of an actual Iranian copper mine of significant scale is employed, featuring the integration of non‐linear loads. [ABSTRACT FROM AUTHOR]

The excavation of large-scale lacustrine soft soil in natural state in the Chengmenshan Copper mine, Jiujiang, China, is a challenging work and is illustrated in this paper. A geometrical model of the lacustrine soft soil was built based on data from more than 150 boreholes. A series of tests were conducted on the natural soft soil including compaction, consolidation and common test, and also remolded samples containing water contents of 10%, 13%, 16%, 21%, 25%, 30% and 37% were tested. Results showed that the cohesion and friction angle decrease rapidly with the increase in water content, but the consolidation pressure played a positive role to the increase in shear strength. To properly manage the soil properties and optimize the surcharge program, settlement and uplift during the infill construction were numerically analyzed by means of SIGMA/W. Based on the test and numerical simulation results, a long term in situ improvement method was proposed and performed. Finally, drilling sampling tests, settlement monitoring and slope stability analysis were conducted to evaluate the overall effects of the surcharge. The properties of the soft soil were improved greatly under the infill surcharge, especially the cohesion and frictional increased by 279.3% and 152.8% and almost reached the value of remolded soil after consolidation under pressure 300 kPa. The settlement rate decreased with the surcharge duration. The safety factor of slope after improvement also met the design requirement. Furthermore, the method proposed in this paper which have given consideration to economic conservation and environmental protection is significant for the soft soil excavation projects. [ABSTRACT FROM AUTHOR]

In the inaugural issue of Past and Present , Eric Hobsbawm cautioned historians against the assumption that a capitalist economy has an inherent tendency to cost-saving and technological innovation, emphasizing that 'It has a bias only towards profit'. Inspired by Hobsbawm, this article shows how a history of profit can elucidate the economic and social history of machines. Beginning with miners' protests at the stoppage of Boulton & Watt steam engines in Cornish copper mines in the late 1780s, it shows that these engines' implications for the people who invested in, and worked, the mines were conditioned by a complex relationship between profit and power: mechanical power, which was crucial to the mining of copper and the costs of its production; imperial power, given fluctuating demand for copper from different parts of the British empire; and market power, since control over price setting on the British copper market was crucial for Cornish mining profits. Understanding what determined mines' profits helps to account for capitalists' decisions to stop their engines as well as copper miners' protests at their actions. More generally, it suggests the potential of studying the economic and social history of new machines through the lens of profit. [ABSTRACT FROM AUTHOR]

In the next decade, the demand for copper is expected to grow by 25%, posing a challenge for mining facilities to increase their production by opening new mines or upgrading existing ones. To optimize the electrical infrastructure of mining facilities, the integration of flexible AC transmission systems (FACTSs) can be instrumental in mitigating voltage stability issues that may arise during the installation of new gearless motor drives (GMDs). The purpose of this paper is to conduct a comparative analysis of the dynamic performance of static VAR systems (SVSs) as a means of enhancing voltage stability in mining expansion projects, particularly in the context of the integration of new GMDs into the system. This paper presents a case study of an existing three crushing-line mine configuration that has been upgraded with two new GMD systems. The primary contribution of this research is a comprehensive methodology designed to enhance the stability of a mining system through the integration of an SVS, which includes the sizing of the SVS system, an analysis of costs, as well as a determination of the required installation surface and optimal placement of the SVS within the system. The simulation results conclusively demonstrate the effectiveness of the SVS systems in reducing the voltage drop by 2% upon activation of new GMDs, as well as mitigating the adverse impact of transient disturbances on the system. Specifically, the first oscillation voltage peak value is improved by 3.5%, following a three-phase short circuit of 1 second duration, while overvoltage is reduced by 1% in response to sudden load changes. When compared with the system without an installed SVS, these findings highlight the significant advantages and benefits of integrating SVSs into mining operations. [ABSTRACT FROM AUTHOR]

Copyright of Mineral Resources Management / Gospodarka Surowcami Mineralnymi is the property of Mineral & Energy Economy Research Institute of the Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Despite the high cost and low efficiency, compressed air is mostly used in underground mining for ore extraction, hoisting, and mineral processing operations. Failures of compressed air systems not only threaten the health and safety of workers but also contribute to inefficient control of airflow and stopped all equipment that operates by compressed air. In such uncertain conditions, mine managers are faced with the big challenge to supply enough compressed air, and therefore, the reliability evaluation of these systems is essential. This paper aims to analyze the reliability of the compressed air system using the Markov modeling approach as a case study, Qaleh-Zari Copper Mine, Iran. To achieve this, the state space diagram was constructed considering all relevant states for all compressors in the main compressor house of the mine. The failure and repair rate of all main and reserve compressors were calculated for all possible transitions between states to obtain the probability of being of the system in each of the states. Moreover, the probability of failure at any time period was considered to study the reliability behavior. The results of this study show that there is 31.5% probability that the compressed air supplying system is in operating condition with two main and one standby compressors. The system probability that two main compressors are remain in the operation without failure for one months is 92.32%. Furthermore, the lifetime of the system is estimated 33 months when at least one main compressor is active. [ABSTRACT FROM AUTHOR]

The hazards of gaseous geodynamic phenomena and rockbursts are among the most challenging to assess and classify. This perception arises from both a review of the literature and an examination of available instructions and regulations in underground mining facilities. The hazard of gaseous geodynamic phenomena in Polish copper ore mines only appeared in 2009, whereas these phenomena occur and are commonly described in other mining countries. In Polish copper ore mines, due to the room and pillar system in fields with lengths of about 460 m, very often parallel to neighboring fields, which together give a length of about 900 m, it is difficult to identify the location of gas traps due to the large size of the area. This paper presents an analysis of the influence of the velocity of the excavation on the possibility of escalating or reducing the described mining hazards. An analysis of the impact of excavation velocity on the state of gaseous geodynamic and roof fall hazards was conducted for two mining fields. For the considered mining fields, the hypothesis was formulated that an excavation velocity greater than or equal to 17 m/month positively influences a reduction in both gaseous geodynamic and roof fall hazards. [ABSTRACT FROM AUTHOR]

Valorization of high-volume mine tailings could be achieved by the development of new geopolymers with a low CO2 footprint. Materials rich in aluminum and silicon with appropriate solubility in an alkaline medium can be used to obtain a geopolymer. This paper presents a study of copper mine tailings from Bulgaria as precursors for geopolymers. Particle size distribution, chemical and mineralogical composition, as well as alkaline reactivity, acidity and electroconductivity of aqueous slurry are studied. The heavy metal content and their mobility are studied by leaching tests. Sequential extraction was applied to determine the geochemical phase distribution of heavy metals. The studied samples were characterized by high alkalinity, which could favor the geopolymerization process. The water-soluble sulphates were less than 4%. The Si/Al ratio in mine tailing was found to be 3. The alkaline reactivity depended more so on the time of extraction than on the concentration of NaOH solution. The main part of the heavy metals was found in the residual fraction; hence, in high alkaline medium during the geopolymerization process, they will stay fixed. Thus, the obtained geopolymers could be expected to exert low environmental impact. The presented results revealed that studied copper mine tailing is a suitable precursor for geopolymerization. [ABSTRACT FROM AUTHOR]

The paper presents the results of work on the numerical hydrogeological model of the mines of the Legnica-Głogów Copper District (LGCD) in Poland. Due to the extensive impact on the rock mass and the multilayer depression cone caused by drainage, the model covers an area of 3,049 km2. The complicated, mutual hydraulic connections of the multi-aquifer hydrogeological system required the model to cover the area beyond the range of mining areas, and to separate 17 numerical layers. The research was carried out in the GMS software environment using Modflow computing modules. The model was updated successively, since its structure, parameters, and boundary conditions are subject to change. It was also additionally calibrated based on new data from measurements in piezometers and changes recorded in inflows to the excavations. The simulations made it possible to determine the exact water balance, with a particular emphasis on the Sieroszowice mining area, where sudden unexpected inflows were noted. Subsequently, two prognostic simulations were performed to estimate dynamic water inflows to mine workings in the years 2020 and 2025. [ABSTRACT FROM AUTHOR]

Short-term planning typically involves optimising different mining complex components individually, preventing unlocking value from intercorrelated activities. This paper proposes an integrated framework that defines diglines and shovel allocation decisions to improve the operation's financial performance. This involves a clustering approach, defining diglines and material destination; a simulator of the mining complex operations, forecasting the material flow from benches to processors; and an actor-critic reinforcement learning approach, assigning shovels to mining areas given operating requirements. A case study at a copper mining complex shows 27% cash flow improvements compared to a non-adaptive baseline approach provided by recent advances in the field. [ABSTRACT FROM AUTHOR]

Copyright of Oltenia, Studii si Comunicari Seria Stiintele Naturii is the property of Museum of Oltenia Craiova and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Unmanned Aerial Vehicle (UAV) oblique photogrammetry has been extensively employed in mining, albeit predominantly for reconstructing three-dimensional scenes and detecting changes within mining sites, lacking predictive capabilities. Leveraging 3D real scene model data, this study presents a two-stage prediction model, merging the probabilistic integral method with recurrent neural network (PIMF-RNN), to mitigate the impact of internal and external factors on surface subsidence, thereby enhancing predictive accuracy. Building upon this framework, a methodology was developed to forecast the maximum surface subsidence height and affected area under the block caving method, offering crucial data support for mitigating hazards associated with this mining technique. Analysis of surface data from Pulang copper mine during 2018–2020 demonstrates a prediction accuracy of 91.47% for maximum surface subsidence height and 87.52% for subsidence area. This research expands the potential applications of UAV oblique photogrammetry techniques within mining contexts. Furthermore, it establishes a cost-effective and efficient operational procedure for predicting mine surface subsidence. [ABSTRACT FROM AUTHOR]

Rock and gas outbursts occur most frequently in coal mining. Gas-induced geodynamic events in dolomite are a new and unexplored phenomenon. In the last time, two outbursts of gas and dolomite have occurred in the Legnica-Głogów Copper Region in southwestern Poland, which is one of the world's largest copper ore mining regions. Gas-induced geodynamic events are dependent on the co-occurrence of two factors: rock porosity, and the presence of gas under significant pressure in the pores and crevices of the rock. This paper presents a condensed energy balance for the phenomenon of outbursts of dolomites and gases. The quantity of energy depends on the type of transformation taking place during decompression. The work produced enables first the disintegration of the rock, and then its transportation along the mine working space. This paper has focused on the estimation of the energy required to disintegrate the rock. It has been estimated that 0.38 MJ is needed for the size reduction of 1 m3 of ejected mass. Highlights: In the case of a dolomite outburst, the energy is accumulated primarily in the form of compressed gas present in the porous structure of the rock and causes the rock to disintegrate and its transport along the mine working space. Gas decompression during a gas-induced geodynamic phenomena can be between isothermal and adiabatic. Existing disintegration theories: Rittinger's, Kick's and Bond's are based consists chiefly of crushing, compression or abrasion, caused by the action of external factors. Author's theory of disintegration of research on tensile stress and is based on Brazilian tests. The disintegration of 1 m3 of rock requires the production of energy of approximately 0.38 MJ. [ABSTRACT FROM AUTHOR]

This paper focuses on the lives and circumstances of Chinese laborers in the copper mines of Lepanto in Northern Luzon from 1856 until the American occupation of the Philippines in 1898. While Filipino laborers were also employed by the Spanish Cantabro-Filipina Company, Chinese laborers were preferred when it came to opening up and exploiting large areas in the "mineral belt" of Luzon. This preference was due mainly to Chinese workers' mining skills and the availability of inexpensive Chinese labor contracted to open up resource frontiers in Southeast Asia and elsewhere. In addition to these factors, the hazardous nature of mining and the Spaniards' negative stereotypical view of Chinese as dangerous albeit "necessary outsiders" made the latter the most suitable labor force for mining. The conditions in the mines, and the abuses committed against the Chinese laborers, caused many workers to run away. This paper has two parts. The first part discusses the importance of Chinese labor in Philippine mining prior to the nineteenth century. It demonstrates how the Spaniards preferred to employ Chinese labor as Filipinos were viewed to lack the skills and enterprise necessary to exploit the colony's mineral resources. The second part focuses on Chinese laborers in the Lepanto copper mines in the midnineteenth century. It describes and analyzes the laborers' working and living conditions in relation to the prevailing labor hierarchy and system of management implemented by the Cantabro-Filipina Company. It also describes the limited interactions between Chinese laborers and non-Chinese employees in the mines. [ABSTRACT FROM AUTHOR]

The upstream segment of the minerals supply chain (MiSC) is the backbone for achieving the transition to clean energy by securing the supply of minerals. Recently, the MiSC has been disrupted, affecting mineral supply and generating uncertainty among clean energy producers. Supply chain (SC) mapping addresses this uncertainty, providing a holistic end-to-end view. However, MiSC mapping studies mainly focus on the downstream segment, leaving aside the upstream segment. In this context, the fundamental gap is the lack of standardized modelling frameworks that can accurately represent the upstream segment dynamics and, at the same time, seamlessly integrate with the downstream segment. This paper bridges this gap, designing a model for the MiSC upstream segment (MiSCOR). Framed within design science research methodology, MiSCOR is built by adapting two reference models, the Exploration and Mining Business Reference Model (EM) and the Supply Chain Operations Reference Model (SCOR), focusing on the commodity-making process. The MiSCOR demonstrates its applicability and robustness in real operational scenarios of one of the largest copper producers. MiSCOR provides a management tool for practitioners and decision-makers in the MISC's upstream segment, offering blueprints to throw functional silos, foster collaboration, and a standardized framework that integrates seamlessly with the downstream segment. [ABSTRACT FROM AUTHOR]

Short-term production planning in industrial mining complexes involves defining daily, weekly or monthly decisions that aim to achieve production targets established by long-term planning. Operational requirements must be considered when defining fleet allocation and production scheduling decisions. Thus, this paper presents an actor-critic reinforcement learning (RL) method to make mining equipment allocation and production scheduling decisions that maximize the profitability of a mining operation. Two RL agents are proposed. The first agent allocates shovels to mining fronts by considering some operational requirements. The second agent defines the processing destination and the number of trucks required for transportation. A simulator of mining complex operations is proposed to forecast the material flow from the mining fronts to the destinations. This simulator provides new states and rewards to the RL agents, so shovel allocation and production scheduling decisions can be improved. Additionally, as the mining complex operates, sensors collect ore quality data, which are used to update the uncertainty associated with the orebody models. The improvement in material supply characterization allows the RL agents to make more informed decisions. A case study applied at a copper mining complex highlights the method's ability to make informed decisions while collecting new data. The results show a 47% improvement in cash flow by adapting the shovel and truck allocation and material destination compared to a base case with predefined fleet assignments. [ABSTRACT FROM AUTHOR]

In recent years, Pulang Copper Deposit has experienced multiple occurrences of debris flow, of varying magnitudes, which have significantly impacted the safety of mining operations. Debris flow has become a major safety hazard of natural caving mining in Pulang Copper Deposit. To address the issues of the formation of debris flow due to the collapse of glacial debris in the Pulang Copper Deposit, this paper proposes new composite curing agents for grouting and curing glacial debris. The study investigates the influence of curing agents' proportions on the mechanical property, water stability, and permeability of solidified glacial debris. Hydration and consolidation mechanisms were analyzed based on XRD and SEM test results. The results indicate that the mechanical properties of solidified glacial debris with the new composite curing agents A, B, and C are superior to those with cement. The permeability coefficients of the solidified glacial debris with 7% dosage of the new composite curing agents A, B and C are both less than 1 × 10−6 cm/s. The reaction between the new composite curing agents and the glacial debris generates crystalline product ettringite (AFt) and gel-like hydration product calcium silicate hydrate (C-S-H). These products enhance interparticle bonding and fill the voids among the glacial debris, which is the main source of strength for the solidified glacial debris. These new composite curing agents provide important reference value for addressing and preventing surface glacial debris collapse. [ABSTRACT FROM AUTHOR]

Fleet management systems in open pit mines make two important semi-dynamic and dynamic decisions to maximize utilization of available equipment: the decision of allocation and the decision of dispatching the trucks to the shovels. In this paper, we propose a bi-objective mathematical model that incorporates the minimization of carbon emission into the allocation optimization model. We also consider different inputs that might impact upon truck allocation decisions such as the fleet size, truck velocity, truck age groups, etc. The presented mathematical model is examined using two different case studies from an iron mine and a copper mine containing a different number of shovels, dumps, and trucks. The results reveal that the developed model enhances the production performance while controlling emissions. It is indicated that the average truck velocity and, the age of trucks are among the critical factors, which can highly affect the amount of carbon emissions. [ABSTRACT FROM AUTHOR]

This paper presents the results of a numerical analysis of the impact of rock mass geomechanical parameters on the stability of preparatory headings located within the Legnica-Glogow Copper District. The paper shows the results of numerical calculations prepared for headings driven in two rock mass types with different strength and deformation parameters, which allow illustrating their influence on the safety of mining performed in underground copper ore mines. Numerical modeling was performed using the Examine2D 7.0 software, in the plane strain state. Numerical simulations were performed for an isotropic and for a homogenous medium. The rock medium was described with an elastic model. The parameters of the rock mass for numerical modeling were calculated using the Hoek–Brown classification. The Coulomb–Mohr strength criterion was adopted as a measure for assessing the rock mass effort. Numerical simulations confirmed the dependance between the stability of the analyzed excavations and rock mass geomechanical parameters. [ABSTRACT FROM AUTHOR]

Adding to work on environmental decision making, decoloniality, and rhetorics of social protest, this paper analyzes a troubling case of resource colonialism at Oak Flat, AZ where mining corporations Rio Tinto and BHP seek to execute decade-old plans to turn land sacred to many Western Apache into one of the largest copper mines in the US (Resolution Mine). This paper studies how members and supporters of the group Apache Stronghold "talk back" in ways that consummate decolonial identities. Taking up the process-oriented nature of this exigency, I study indecorous protest rhetorics at six public hearings about the mine's Environmental Impact Statement (Draft) in 2019. I argue Apache Stronghold uses place, time, and memory as topoi of decolonial dissensus. While the Resolution Mine may be foregone conclusion, Apache Stronghold shows how (de)coloniality can delink environmental public participation processes from regimes of colonial capitalism. [ABSTRACT FROM AUTHOR]

Due to industrialization, copper demand has increased over the last decades. Recycling rate of copper is high and its scrap requires less energy than primary production, so sustainable closed-loop supply chain network design is considered a primary decision. Besides, the uneven distribution of copper has exaggerated the destructive effects of natural disasters such as earthquakes on mines. To the best of the authors' knowledge, there is no research about copper supply chain network design. In this paper, a copper network is designed and backup suppliers are used as a resilience strategy to reduce the effects of earthquakes on mining operations. Without backup model and with backup model are presented as multi-objective and are compared with each other. In each model, the economic objective is to maximize the supply chain profit; the environmental objective is to minimize water consumption and air pollutants; and the social objective is to maximize social desirability by considering security and unemployment rates. The models are formulated using mixed-integer linear programming and they are solved by ε -constraint and weighted sum methods. Results show that, with backup model increases the supply chain responsiveness. Also, the model is able to improve the economic and social performances of the supply chain. But in environmental aspect, it performs worse than without backup model. This is because the backup suppliers are added to the supply chain and their exploitation will create negative environmental effects. In addition, using copper scraps saves costs, energy and the consumption of this non-renewable metal. [ABSTRACT FROM AUTHOR]

An important element of numerical modeling for specific mining issues is the selection of model parameters. The incorrect determination of geomechanical parameters can result in significant calculation errors carried throughout the entire problem. This paper presents a method for determining effective geomechanical parameters for technological and residual pillars through the use of numerical modeling, specifically, back-calculation. This is based on the results of numerical simulations, measurement data (e.g., excavation convergence measurements), and statistical methods (a non-linear regression model with "dummy" variables). The result is that appropriate parameters of pillars are set out iteratively so that the displacements of selected points in the numerical model correspond (with some approximation) to the results of mine measurements. The procedure of determining pillar parameters is presented using a case study of one mining field in an underground copper mine, where the deposit is mined using the room and pillar system. Numerical calculations were performed using a Phase2 v. 8.0 program (Rocscience, Toronto, Canada), while statistical calculations used a Statistica computer program. The results of excavation convergence measurements performed in the analyzed mine have been applied. This paper shows that for the presented method, the resulting matching of theoretical values of convergence determined numerically for specified pillar parameters to in-situ results of convergence measurements, is very good (R2 = 0.9896). This work exemplifies a set of the parameters of pillars for an elastic model of rock mass, but this method can also be applied to other models. [ABSTRACT FROM AUTHOR]

Nowadays, nonlinear loads such as load commutated inverter (LCI) drives are being used by industrial sector throughout the world. However, despite the LCI drive uses low-cost thyristors and their corresponding controllers, which have high efficiency and low manufacturing cost, there are concerns regarding the use of LCI drives which are two-fold: (i) they generate harmonics and (ii) they are sensitive to voltage sags occurring at their PCC. In the literature, passive harmonic filters have been suggested to address the former concern and therefore various filter designing techniques have been introduced. However, the need to elaborate a cost-effective filter to address both concerns regarding LCI drive operation has been neglected. Therefore, this paper presents an innovative approach for designing passive filters which can decrease the harmonic distortions generated by LCI drives while ensuring more reliable annual operation of these equipment. Besides, other aspects of passive filter designing, such as eliminating detuning effects, resonance elimination and harmonic loading of capacitors, have been taken into account to provide a general and practical filter designing approach for real industrial applications. In order to evaluate the innovative proposed approach, a passive filter is designed for LCI drive used in an Iranian large copper mine company. [ABSTRACT FROM AUTHOR]

Mongolia is in the midst of one of the world's largest mining boom and the Gobi Desert is the construction site of what is expected to become the World's third‐largest gold‐copper mine: Oyu Tolgoi. The paper follows the case of Oyu Tolgoi to analyse how a complex array of global norms are being domesticated in the particular context of Mongolia. Building on data gathered in the course of three field visits to Mongolia and the literature rooted in critical political economy, it is argued that in Mongolia, the domestication of market‐oriented norms in extractive governance have taken precedence over any other international norms championed for the sector. In such light, and this is the second argument of the paper, this hierarchy embedded in the complex array of international norms that impact the mining sector has compelled the State to strategically cede some of its former roles and responsibilities to the private sector, leaving civil society elements—in the case of Oyu Tolgoi mine, local nomadic communities—with little recourse to address what is now a highly asymmetric relationship with Rio Tinto, the main shareholder of the mine. [ABSTRACT FROM AUTHOR]

The original publication of this paper contains a mistake. [ABSTRACT FROM AUTHOR]