Open Pit Copper Mine Research Articles

An application of simultaneous stochastic optimisation on an open-pit copper mining complex with supply, recovery, and market uncertainties

ABSTRACT A mining complex is an integrated value chain that consists of multiple mines, stockpiles, processors, waste dumps, and tailing facilities, and where the in-situ materials mined are transformed into products sold to customers. Simultaneous stochastic optimisation provides a strategic mine planning framework that incorporates all components of a mining complex into a single mathematical representation, capitalising on the synergies between components while considering uncertainty. An application of this optimisation framework at a coper mining complex demonstrates that the incorporation of material supply, market demand, and processing recovery uncertainties into the modelling leads to production schedules that yield a higher NPV and metal recovery.

Simultaneous stochastic optimisation of mining complexes with equipment uncertainty: Application at an open-pit copper mining complex

Simultaneous stochastic optimisation of mining complexes with equipment uncertainty: Application at an open-pit copper mining complex

A Systems Engineering Approach to Decarbonizing Mining: Analyzing Electrification and CO2 Emission Reduction Scenarios for Copper Mining Haulage Systems

Due to climate change risks, the public, regulators, and investors require solid actions to minimize the greenhouse gas (GHG) emissions of mineral extraction and metals production. The mining sector considers alternatives to reduce its carbon footprint by transforming the business and adopting new technologies into operations. Given the capital intensity, technical characteristics, and business structure involved, a shift in the mining industry necessitates impartial insights into the trade-offs and risks. Considering the low-carbon transition trade-offs and risks in mining, this study presents the application of system dynamics modeling (SDM) in mining projects to analyze the impact of decarbonization alternatives with respect to carbon footprint and costs. A system dynamics model of an open-pit copper mine is developed to quantify greenhouse gas (GHG) emissions, as well as capital and operational costs, during the project life cycle. The change in GHG emissions in the business-as-usual scenario with diesel equipment haulage versus the alternative scenario with electric overland conveyor haulage is compared concerning GHG emissions and associated costs. The results unequivocally demonstrated that electrifying material mobility offers significant decarbonization in open-pit mining if the on-site electricity has a low emission factor. The findings also indicate that the substantial cost difference between electrification and diesel alternatives is another major obstacle to implementing electrification in an open-pit copper mine. This research proves that implementing SDM in the mining industry can offer impartial insights into decision-making and enable a thorough evaluation of options using quantitative criteria. It effectively assesses and communicates the trade-offs and risks of transitioning to low-carbon alternatives because it analyzes project variables quantitatively and holistically and is easy to run.

An efficient method for modeling and evaluating the bench terrain of open-pit mines

In order to quantitatively analyze the roughness of the bench floor during open-pit mine blasting, this study proposes a real-time measuring method for the three-dimensional terrain of the bench floor during the excavation process. Real-time monitoring is conducted at the boundary and discrete internal points of the workbench floor during electric shovel operation, utilizing real-time kinematic global navigation satellite system (RTK-GNSS) positioning technology. An improved convex hull algorithm is introduced to automatically extract the optimal boundary of discrete point clouds based on their spatial distribution characteristics. This study establishes a digital elevation model (DEM) using five interpolation algorithms for 3D terrain visualization simulation. Through cross-validation, a comparative analysis of the DEM accuracy, the simulation results of the ordinary kriging interpolation algorithm were found to be optimized. The optimized interpolation algorithm is applied to simulate the 3D terrain in the Dexing open-pit copper mine, and the relevant terrain parameters were calculated. This dataset can serve as a precise foundation for the real-time path planning of elevation blasting design and ground leveling operations.

Development a novel empirical approach to control overbreak, surface quality and slope angle of benches following blasting

Overbreak, slope angle and quality of a bench behind the boundary of excavation as attractive subjects for mining and civil engineers are the most crucial consequences of the post-blast. But the breakage mechanism of blasting has not originally been well clarified how a desirable slope angle and quality of a bench can be obtained by common drilling and blasting operations and what parameters can affect such blasting consequences? The breakage mechanism and influence of the blasthole parameters such as hole diameters, explosive weight per hole, burden, spacing, stemming, bench height, powder factor and blastability index on the depth of the overbreak zone (L<sub>OZ</sub>), the difference between hole and bench slope angles (α°-β°) and the width of damaged zone (L<sub>DZ</sub>) in fifteen zones of Sun gun open pit copper mine, Golgohar open pit iron ore mine, Khoy limestone, Rashakan limestone, Bonab silica mine and Evoghli gypsum mine were investigated. New multivariable nonlinear relations between each of L<sub>OZ</sub>, (α°-β°) and L<sub>DZ</sub> with the combination of Φ<sub>h</sub>, Q, B, S, S<sub>t</sub> and K were developed. The new achievements in this study can be new guides to obtain the desirable bench slope angle and bench faces.

A New Comprehensive Model for Integrating Environmental, Economic, and Social Performance of Deep and Large-scale Open-Pit Copper Mines

A New Comprehensive Model for Integrating Environmental, Economic, and Social Performance of Deep and Large-scale Open-Pit Copper Mines

Application of Discrete-Event Simulation for Truck Fleet Estimation at an Open-Pit Copper Mine in Peru

With production expansions, studies related to estimating the number of pieces of hauling equipment to be employed in open-pit mines have to be carried out. One of the main challenges comes from the methodology selected since numerous tools are available, including commercial solutions. However, given that some methodologies were complex or required an advanced understanding of programming languages and that, in the case study, the mining company was applying a deterministic approach, a stochastic methodology that involves a discrete-event simulation (DES) was proposed. Such an approach aimed to develop a calibration model whose inputs incorporated random variables, such as fixed times and tonnages loaded to hauling equipment. This model supported the replication of the yearly production plan for an open-pit copper mine in Peru located at 4500 masl that is expanding its operations in 2023 from 100,000 tons per day to 140,000. The results obtained from the stochastic methodology were compared with the deterministic approach, which showed that the stochastic model required additional trucks and that longer cycle times were generated from such an approach. Such outputs are now supporting engineers in anticipating future problems in the mine due to the generation of longer queues.

Thinking Like a Copper Mine: An Ecological Approach to Corporate Ethos and Prosōpon

ABSTRACT This essay uses Aldo Leopold’s essay “Thinking Like a Mountain” as a heuristic for analyzing the rhetorical processes of erasure that have created one of the largest open pit copper mines on the planet: The Bingham Canyon Mine (BCM). Contributing to studies of corporate rhetoric, persona criticism, and nonhuman agencies, I argue that the BCM, and its corporate owner Rio Tinto, is characteristic of Being-in-the-Anthropocene and informs rhetoricians about our extra-human ethos, or manner of dwelling, as an entwinement with corporate actors. Taking Rio Tinto as a synecdoche for corporate personhood and persona (prosōpon), I make the case for an ecological approach to corporate disclosedness that accounts for the earthly resources of corporate rhetorical invention (e.g., copper). Through the later work of Martin Heidegger, I show how the BCM has become a standing reserve within a corporate world picture that is rhetorically apparent in the rhetorical architecture of Salt Lake City, Utah.

Instrumental monitoring of ore stockpile stability in heap leaching area

The current trend in open pit mineral mining is the increased recovery of nonferrous metals by heap leaching of oxidized ore on the shallow horizons. This article presents the case-study of Aktogai open pit copper mine having the project depth to 500 m. To implement heap leaching, ore stockpiling is carried out on ground surface, on a weak clayey and slightly sloped bottom, by layers 12–15 m high. The proposed instrumental monitoring procedure for the stockpiles in the heap leaching area uses a pillar of improved design, arranged below the depth of freezing and outside the potential displacement zone for the installation of an electronic tacheometer and check points with optical reflectors, stiffly bound with the ore stockpile using concrete. The high-precision geodetic measurements allow surveying in a single vertical plane using the check points arranged in the profile cross-section in the area of heap leaching. The values of displacements are determined both in vertical and horizontal planes of the ore stockpile. It is found that the stockpile body undergoes continuous compaction due to the permanent addition of new layers. The deformation mechanism of the stockpile is governed by the continuous stress, which is proved by the displacement values of the check points. In the middle of the stockpile, continuous compaction takes place at a rate up to 7.07 mm/day, while at the slope bottom of the stockpile, slight horizontal displacements toward the support pillar are observed at a rate to 4.90 mm/day. According to the current guidance procedures, such rates of displacement are not hazardous for the production process, as the threshold is 10 mm/day, but continuous instrumental monitoring of the ore stockpile stability in the heap leaching areas is required to reveal maximum allowable displacements and prevent landsliding.

A re-assessment of metal pollution in the Dexing mining area in Jiangxi province, China: current status, hydro-geochemical controls, and effectiveness of remediation practices

This study re-assess the environmental impacts of the Dexing copper mine (the largest open-pit copper mine in Asia) on the Lean river and its two tributaries (the Dawu river and Jishui river) in the Jiangxi province, China, with particular focus on metal pollution as well as the effectiveness and side-effects of remediation activities. Results show that the Dawu river and its mixing zone with the Lean river were still heavily influenced by acid mine drainage (AMD) and loaded with elevated levels of metals, in particular Mn, Ni, and Al whose concentrations were frequently above the health-based guideline values. Manganese and Ni in the AMD-impacted waters were predicted to occur as free ions or sulfate and carbonate complexes, and thus highly-toxic to living organisms. Although Al in the AMD-impacted waters was predicted to exist largely as colloidal hydroxides with low bioavailability, abundant formation of such nano-sized particles could impair the respiratory and circulatory systems of aquatic macro-invertebrates. The integration and comparison of the results from the current and previous studies show that the concentrations of several metals (Cu, Zn, and Cd) in the Dawu river decreased significantly after 2011–2012, during which several remediation practices were implemented (e.g., AMD neutralization, excavation of contaminated sediments in impounded rivers, and rehabilitation of mine tailings and open-pit slopes). This provides evidence that these remediation practices have effectively limited the dispersion of metals from the mining area. However, AMD neutralization greatly enhanced the release of sulfate, making the mining area an even more important sulfate source.

Slope failure and stability investigations for an open pit copper mine in Turkey

Slope failure and stability investigations for an open pit copper mine in Turkey

Application of the method for prediction of the failure location and time based on monitoring of a slope using synthetic aperture radar

Synthetic aperture radar (SAR) technology has been widely used in landslide deformation monitoring in the past decade. It has the advantages of high monitoring accuracy, a wide range, and flexibility allowing all-weather continuous monitoring. The self-developed S-SAR synthetic aperture radar (slope radar) is the first completely domestic-made radar used in slope deformation monitoring equipment in China, and its performance and technical parameters are equal to or better than similar products made abroad. The characteristics of deformation data collected by S-SAR slope radar deployed in the front open pit mine are analyzed to further develop a spatio-temporal landslide prediction method which is applicable to the massive monitoring data within the monitoring range of slope radar. The intersection points of short-term moving average velocity curve and long-term moving average velocity curve of slope deformation, which are onset of acceleration (OOA) and termination of acceleration (TOA). When OOA occurs, the deformation will accelerate, and when TOA occurs, the deformation will tend to stabilize. The OOA can identify areas at risk in the monitored area before failure, so that the spatial position prediction of landslide early warning can be realized. Based on the assumptions of the inverse velocity method, a T-log (t) logarithmic model is established, and the updated monitoring data are corrected to approximate the time of failure, thus improving the accuracy of landslide location and time prediction. In an open-pit copper mine in Serbia, the accurate prediction of landslide location and time has been successfully applied, guaranteeing safe mining.

Fragmentation calculation method for blast muck piles in open-pit copper mines based on three-dimensional laser point cloud data

The current calculation methods for the blast fragmentation of muck piles (BFMP) do not consider three-dimensional (3D) feature information, such as concavity and convexity. Thus, their calculation results are inaccurate. In this work, 3D laser scanning technology with high precision, high efficiency, and real-time digitization is used to calculate fragmentation of blast muck piles in open-pit copper mines. The voxel cloud connectivity segmentation (VCCS) algorithm and locally convex connected patches (LCCP) algorithm are used to calculate BFMP from 3D laser point cloud data (3D LPCD). Meanwhile, an improved VCCS algorithm based on discrete features is proposed to solve the segmentation problem of 3D LPCD of small blast muck piles, which cannot be effectively segmented and thus greatly influence the 3D LPCD of large blast muck piles. An improved LCCP algorithm based on plane fitting solves the incorrect segmentation of the surface of large fragments into small pieces of fragments. Dexing Copper Mine, the largest open-pit copper mine in China, is taken as the research object. Results show that the accuracy of the calculation results is about 80% when the fragment sizes are 0.1–0.5 m. Moreover, almost all BFMP can be correctly calculated when the fragment size exceeds 0.5 m.

Optimization of truck-shovel allocation in open-pit mines under uncertainty: a chance-constrained goal programming approach

ABSTRACT The truck allocation problem is an important section of the transportation system in open-pit mines. Most available models for the truck scheduling problem do not directly address the stochastic nature of truck-shovel systems by using multi-objective optimization techniques. This paper presents a chance-constrained goal programming (CCGP) model based on four important goals to estimate the impacts of the uncertainty on the efficiency of truck-shovel systems. The proposed model has been implemented using 11 schedule scenarios and different confidence levels (CLs) for loader’s production to determine the best allocation of trucks in an open-pit copper mine. The results display that the model can handle the quality and quantity of material required to achieve the objectives of the short-term production schedule of the mine in all CLs, even in the highest risk level. This model has a remarkable ability to meet the required objectives in terms of uncertainty in mining operations.

Impact of mine pit lake on metal mobility in groundwater

Open pit mines are potential source of metal contamination. Three types of open pit mines, i.e. copper, quartzite and granite were selected to understand the mobility and behaviour of metals. Metal contamination due to abandoned open pit copper mines (Average Cu = 64.57 ± 90 µg/L) is observed more comparative to quartzite (Average Cu = 20.42 ± 34.39 µg/L) and granite mines (Average Cu = 9.67 ± 7.94 µg/L). Acid mine drainage (AMD) from copper mines result in dissolution of metals and contaminates groundwater in the downstream direction. Correlation used for source assessment confirms the influence of anthropogenic or abandoned pit mine on metal concentration in groundwater. It is observed that the impact of abandoned pit mine is more compared to tailings and overburden dumps. Dissolution and precipitation process control the metal abundance in downstream groundwater. Precipitation dominates dissolution process with distance and results in decrease in metal concentration. It also confirms the self-neutralisation and self-attenuation capacity of the aquifer. The study recommends restoration of abandoned open pit mines to their natural conditions to avoid metal contamination in downstream.

Characterizations of heavy metal contamination, microbial community, and resistance genes in a tailing of the largest copper mine in China.

Copper mine tailings are causing great environmental concern nowadays due to their high contents of heavy metals. These hazards may release to air, water, and soil, posing great threat to the living organisms in the surroundings. In the present work, we profiled the heavy metal contents, microbiome and resistome of a mine tailing in Dexing Copper Mine, which is the largest open-pit copper mine in China. A total of 39.75Gb clean data was generated by metagenomics sequencing and taxonomy analysis revealed Actinobacteria, Proteobacteria, Acidobacteria, Euryarchaeota, and Nitrospirae as the most abundant phylum in this tailing. In general, 76 heavy metal resistance genes (HMRGs) and 194 antimicrobial resistance genes (ARGs) were identified with merA and rpoB2 as the most abundant HMRG and ARG, respectively. We also compared the differences of heavy metal concentrations among the six sampling sites in the same tailing and found that significant differences exited in copper and zinc. Hierarchical cluster analysis showed that the samples from the six sampling sites were clustering in two groups based on heavy metal concentrations. Accordingly, clustering based on microbial composition and relative abundances of resistance genes exhibited the same clustering pattern, indicating a possible shaping influence of heavy metals on the microbiome and resistome in this tailing. Our work presented heavy metal contents, microbial composition and resistance genes in a copper mine tailing of the largest copper mine in China, and these data will of great use in the surveillance, maintenance, and remediation of this tailing.

Physicochemical factors affecting the wettability of copper mine blasting dust

To investigate the factors affecting the wettability of copper mine blasting dust, the primary blasting dust was collected from an open-pit copper mine and separated into hydrophilic blasting dust (HLBD) and hydrophobic blasting dust (HBBD) using water flotation method. The physicochemical properties of HLBD and HBBD were measured and compared with each other. The properties included particle size distributions (PSDs), micromorphologies, pore structures, mineral components and surface organic carbon functional groups. The results show that particle size and pore structure of the blasting dust are the main factors affecting its wettability. Specifically, particle size of HBBD is smaller than that of HLBD, and their respiratory dust (less than 10 µm) accounts for 61.74 vol% and 53.00 vol%, respectively. The pore structure of HBBD is more developed, and the total pore volume of HBBD is 1.66 times larger than that of HLBD. The identical mineral compositions were detected in HLBD and HBBD by X-rays diffraction (XRD); however, the surface organic hydrophobic component of HBBD is slightly larger than that of HLBD, this may be the reason for the poor wettability of HBBD. This study is significant to understand the effects of physicochemical properties of copper mine blasting dust on its wettability.

A New Approach to Represent Impact of Discontinuity Spacing and Rock Mass Description on the Median Fragment Size of Blasted Rocks Using Image Analysis of Rock Mass

Several in-situ rock mass properties and blasthole parameters can affect the rock fragmentation. Because of the complexity of the variables affecting the fragmentation results of blasted rocks, to predict a proper value of the median fragment size has long been a difficult task. The blastability index (BI) represents the effect of five parameters of rock mass description (RMD), joint plane spacing (JPS), joint plane orientation, specific gravity and uniaxial compressive strength on the rock fragmentation. The median discontinuity spacing significantly varies with varying the scanline direction and an acceptable value of the median discontinuity spacing will not be expected in practice. The JPS rating also has a constant value of 20 for a wide range of joint spacing values between 0.1 and 1 m, whereas joint spacing can be in this range for most cases. A new method using image analysis of the in-situ rock mass was applied to represent JPS and RMD (belonging to one of the cases: friable, blocky and massive) as an alternative solution. The images contain the details of all individual discontinuities and interlocked in-situ small and large rock blocks. BI, rock strength factor, blasthole parameters, powder factor, fragment size distribution of blasted rock and in-situ block size distribution using image analysis technique were assessed in 15 zones of Sungun open pit copper mine, Angouran lead and zinc open pit mine, Bonab silica mine, Soufian limestone mine and Rashakan limestone mine. The results for rock mass properties and blasthole patterns cover a wide range using different mines. The fragment size distribution was assessed by Split Desktop program with proper delineating images using the Pixler software and blasting was carried out with electric delay detonators. The relations between fragment size and parameters such as in-situ block size (F50), σc, rating of joint plane orientation, powder factor (q), ϕh, Q and Lc were analyzed. The relations with high correlations were achieved by applying the new approach for the defined conditions. Not only the problem of assessing discontinuity spacing has been improved using this method but also the lower number of parameters that properly represent the factors affecting the rock fragmentation have been used. The results were also analyzed by the Sanchidrian and Ouchterlony model and modified Kuz–Ram models. The fragment size obtained by the new method in this study, Sanchidrian and Ouchterlony model and extended modified Kuz–Ram model by Cunningham (in: Proceedings of 3rd world conference on explosives and blasting, Brighton, 2005) after using correction factor [c(A)] significantly better fitted to the results than the modified Kuz–Ram models by Cunningham (in: Fourney, Dick (eds) Proceedings of 2nd international symposium on rock fragmentation by blasting, Keystone, 1987) and Gheibie et al. (Int J Rock Mech Min 46(6):967–973, 2009).

Accounting for Water Footprint of an Open-Pit Copper Mine

Water is a crucial input for any production system, and mining is no exception. A huge amount of water is being used in the various phases of mining activities. In the coming decades, the competition in using a sufficient amount of fresh water will become a major hurdle for the mining industry. Water footprint (WF), an accounting framework for tracking the amount of water used to produce a unit of product, can be useful to the mining companies by quantifying their water resource appropriation and identifying ways to reduce the consumption. In this study, we accounted for the green, blue, and grey water footprint of an open-pit copper mine that is located in Laos. The input–output water flows of the mine are also developed from the inventory of water use. Moreover, we have calculated the uncertainty in the water footprint accounting to check the robustness of the findings. According to the results, the green, blue, and grey WF of the studied mine are 52.04, 988.83, and 69.78 m3/tonne of copper concentrate, respectively. After the installation of a passive effluent treatment system in 2013, the calculated grey WF of the mine was 13.64 m3/tonne, a fivefold decrease than before. The uncertainty in the footprint ranges between 8% to 11% which shows the robustness of the analysis. Although green WF is ignored by most studies, we suggest incorporating it into the accounting. The responsible share of a supply-chain WF to the total blue WF is about 98%, which is quite huge. Water embedded in the hydroelectricity is mainly responsible for such a huge amount of blue WF. Evidently, the use of electricity from hydropower results in the consumption of a large amount of water in exchange for a reduction in carbon emissions. Thus, the article attempts to demonstrate the escalating importance of WF accounting of this mine.

Tele-production of miningscapes in the open-pit era: The case of low-grade copper, Bingham Canyon, US and Chuquicamata, Chile (1903–1923)

In 1906, the Guggenheim Exploration Company (GUGGENEX), financed the low-grade copper project that Daniel Cowen Jackling had started three years earlier at Bingham Canyon (Utah, US). With GUGGENEX's investment, the exploitation of copper entered into the open-pit mining era. Nine years later, the Guggenheims applied the industrial experience acquired in Bingham Canyon in the opening of the Chuquicamata Mine (northern Chile). In both cases, all the crucial decisions about the mining were made in Manhattan, New York, while the local territories faced these projects' outcomes. From a geohistorical standpoint, and through the analysis of several archives, in this paper, we explore how the extractive territories associated with these mines were remotely produced, transformed, and redefined; becoming “teleconnected miningscapes”. We aimed to visualize how the cross-sector partnership between large economic groups—GUGGENEX—and scientific personalities was essential in the emergence of open-pit copper mining. We argue that the miningscapes produced in Bingham Canyon and Chuquicamata mines are an entanglement of scientific discourses, research (geology and metallurgy), materialities (capital and technology), human bodies (workers) and nature (copper porphyries, water, air, etc.) that were unevenly and remotely produced from the headquarters of GUGGENEX.