Large Open-pit Mine Research Articles

A Stochastic Energy-Efficient Robust Simulation-Based Truck Dispatching Optimization for Simultaneous GHG Mitigation and Operational Excellence in Open-Pit Mines

Almost all currently active large open-pit mines across the globe heavily rely on fleet of shovels and haul trucks for material handling. This material handling system has a significant contribution not only to the production cost of the mine (+50%), but also to its energy consumption (+41%) and greenhouse gas (GHG) emissions (+37%). However, traditionally, operation management in general and truck dispatching, in particular, focused primarily on production targets and operational efficiency, neglecting environmental considerations in open-pit mines. Nowadays, growing awareness of climate change and responsible resource extraction has shifted, however, the focus towards sustainable practices throughout the mining industry, open-pit mining not excluded. The significant contribution of this study lies in the development of an integrated simulation and optimization framework that simultaneously accounts for anthropogenic GHG emissions resulting from energy (fuel) consumption and enhances the operational efficiency of the material handling system, thus yielding direct economic and environmental benefits. The paper fulfills its goals with the aim of simultaneous achievement of four interdependent objectives: minimizing the deviations from target production rates set by strategic plans, minimizing the shovel idle time, minimizing the truck wait time, and minimizing the truck fuel consumption. The performance and the robustness of the proposed framework has been evaluated in a case study at Gol-E-Gohar mine in Iran, demonstrating a successful achievement of up to 6% reduction in fuel consumption per tonne of production leading to a significant overall decrease of up to 20,000 liters in fuel consumption, equivalent to 61,000 carbon dioxide (CO2) emissions, in a 10-day operation with 12 hours of operation per day.

Influence of large open-pit mines on the construction and optimization of urban ecological networks: A case study of Fushun City, China

Influence of large open-pit mines on the construction and optimization of urban ecological networks: A case study of Fushun City, China

Unearthing narratives: an ethnographic lens on the organizational tapestry of massive iron ore mining operations

PurposeOres and minerals are extracted from the earth’s crust depending on the type of deposit. Iron ore mines come under massive deposit patterns and have their own mine development and life cycles. This study aims to depict the development and life cycle of large open-pit iron ore mines and the intertwined organizational design of the departments/sections operated within the industry.Design/methodology/approachPrimary data were collected on the site by participant observation, in-depth interviews of the field staff and executives, and field notes. Secondary data were collected from the literature review to compare and cite similar or previous studies on each mining activity. Finally, interactions were conducted with academic experts and top field executives to validate the findings. An organizational ethnography methodology was employed to study and analyse four large-scale iron ore mines of India’s largest iron-producing state, Odisha, from January to April 2023.FindingsSix stages were observed for development and life cycle, and the operations have been depicted in a schematic diagram for ease of understanding. The intertwined functioning of organizational set-up is also discovered.Originality/valueThe paper will benefit entrepreneurs, mining and geology students, new recruits, and professionals in allied services linked to large iron ore mines. It offers valuable insights for knowledge enhancement, operational manual preparation and further research endeavours.

Response of ecosystem services and environmental dynamics in large open-pit coal mines: A case study in semi-arid areas

Surface coal mining in semi-arid regions has detrimental impacts on the structure and function of surface ecosystems, thereby impeding the attainment of regional sustainable development goals. Moreover, the impact of climate change on ecological restoration in semi-arid mining areas is an inevitable consideration. To elucidate the response of ecosystem services in mining areas to regional climate change, topography, soil, vegetation and socioeconomic development, this study selected six large-scale surface coal mines located in semi-arid regions of China as research objects. In this study, we aimed to assess the main ecosystem services (carbon sequestration, soil conservation, and flow regulation) provided by these mines. In addition, we analysed the spatial and temporal evolution and interrelationships of these ecosystem services. Furthermore, we explored the underlying mechanisms between ecosystem services and environmental factors. The results showed the following: (1) Geospatially, there was a gradual decrease in carbon sequestration and flow regulation from northeast to southwest in the mining areas. However, the soil conservation exhibited an upward trend. Throughout the research period, the carbon sequestration change rate in the six mining areas displayed an initial downward and subsequent upward trend, the rate of soil conservation exhibited a gradual upward trend, and the flow regulation decline rate followed a downward trend. (2) Change rate of carbon sequestration and soil conservation in the six mining areas showed a significant positive correlation (r = 0.51, p < 0.001), with the strongest correlation observed in the Shengli Mining Area (r = 0.64, p < 0.001). (3) Ecosystem service changes in the mining areas were primarily driven by initial conditions (95.0%), followed by meteorological factors (4.2%). Three ecological restoration models were proposed for the different regions based on driver analyses. The findings of this study offer scientific evidence that can be used to inform ecological management, enhance ecological security, and promote regional sustainable development in mining areas.

The Archaeological Legacy of the Lignite Boom in Upper Lusatia

At the beginning of the 19th century, nobody in the landscape of the heaths and ponds of Lusatia, a small region in the German-Polish border area, would have suspected the lasting effects of the lignite mining boom on the economy, landscape, and the local communities there. The initially small underground mines soon developed into large open-pit mines. 'Industrial cathedrals' were established, new cities were raised out of the heathland, long-distance transport networks were expanded, and industrial centres emerged that gained importance throughout Europe. The local population and culture changed through migration, adaptation and assimilation, the landscape through the huge earth movements caused by lignite mining. This enormous transformation of an entire region has an impact on identity even today, and still influences political processes. It is now the task of archaeology and heritage management organisations to document this recent past as well and to preserve its cultural value.

Biodiversity responses to landscape transformations caused by open-pit coal mining: An assessment on bats and dung beetles in a Colombian tropical dry forest

Mining is a driver for biodiversity loss worldwide. However, studies of its effects on wildlife are scarce, and few involve activities and environmental management carried out by mining companies. We evaluated the effect of mining activity at multiscale landscape approach on the diversity of dung beetles and bats in the largest open-pit mine in Colombia, located in the tropical dry forest (TDF), one of the most threatened ecosystems due to human activities. The landscape scale effect assessment was carried out with a multiscale analysis at 0.2, 0.5, 1, 1.5, and 2 km of radius around sampling points in 2005–2006, 2009–2010, 2012–2013, and 2016–2017. The vegetation cover was measure through remote sensing and fieldwork for the four periods of each scale. Once predictor variables (vegetation cover and mining) were identified at a landscape scale for each buffer. Generalized linear models were run to know the scale of the effect, and to measure the effects of the vegetation transformation by mining activity on diversity (0D, 1D) and abundance. The scale of the effect for dung beetles, and bats corresponded mostly to 0.2 km. Diversity metrics showed positive relationships with the percentage of natural cover but negative with the percentage of non-natural cover. Dung beetles had higher resilience to mining activities than bats. The implementation of environmental management tools such as maintaining natural areas and rehabilitation of disturbed areas is necessary, especially to mitigate the impacts of open-pit coal mining on different groups of fauna in critically endangered ecosystems such as TDF.

Spatial Patterns, Possible Sources, and Risks Assessment of Soil Potentially Toxic Elements in an Open Pit Coal Mining Area in a Typical Arid Region

Intensive mining activities in large-scale opencast coal mines have had a significant impact on the local environment. Elements that are potentially harmful to the environment are brought to the surface from deep underground, altering the geochemical conditions for their transport and redistributing them to the surface, causing serious local pollution. However, in-depth studies of toxic metal contamination in soils of arid coal mining areas have not yet received the attention they deserve. Although previous studies have conducted a great deal of research on heavy metal elements in surface coal mine soils, there are few studies related to the more seriously polluted surface coal mines in the arid regions of Northwest China, and there are no in-depth studies on the ecology of soil heavy metal contamination, health risks and source analysis according to the authors’ knowledge. To make up for this shortcoming, the present study takes Zn, Cu, Cr, Pb, Hg, and As in the surroundings of the tertiary coal mines in the Hongsachuan Mining Area (northern Xinjiang, China) as an example. The health, ecological risks, and pollution sources of heavy metal elements in surface coal mine soils were comprehensively analyzed. The results showed that the average concentrations of Cr, Hg, and As in the soils of open-pit coal mines greatly exceeded the corresponding provincial background values, with the Cr content exceeding China’s soil environmental quality standard Ⅰ and the As content even higher than standard Ⅱ (GB15618-1995). Geostatistical and multivariate statistical results showed that the six metals analyzed in this study can be divided into four groups, as follows. Group 1 included Zn and Cu and was mainly controlled by natural sources related to soil parent materials. Group 2 consisted of Cr and Hg and was associated with industrial practices. Group 3 was explained by As and was mainly from coal combustion during the mining activities. Group 4 was Pb and was dominantly from natural sources, together with vehicular emission during the mining activities, indicating a mixed source. Potential ecological risk index (PER) values exhibited low ecological risk in contaminated soils with Zn, Cu, Pb, and Cr, and only 10% of As samples exhibited moderate risks, while 77% of Hg samples posed ecological risks at different level, implying that Hg was the main contributor for comprehensive risk index (RI). Regardless of non-carcinogenic and carcinogenic health risk assessment, As was the primary risk element followed by Cr, and children tended to have a higher health risk than adults. In this paper, statistical methods, pollution assessment methods, and potential ecological risk models are skillfully combined, and relevant conclusions are drawn based on the human and economic geographical background information of the study area. The results can provide references for the investigation and evaluation of soil heavy metals and quantitative analysis of pollution sources in the same type of areas. In order to grasp the pollution level of potential toxic elements in the soil of large open-pit coal mines in arid areas, effective source-cutting measures are taken to provide data support the sustainable management of coal mines and local soil safety utilization measures.

Review of recent developments in short-term mine planning and IPCC with a research agenda

ABSTRACT In-Pit Crushing and Conveying (IPCC) has gained momentum in recent years to replace trucks partially or fully in large open pit mines because of the shovel-truck system's increasing fuel and labour costs and conveyor systems' low operating costs and less greenhouse gas emissions. This article reviews the most recent literature since 2010 on short-term planning, based on different formulation and solution approaches, and IPCC, based on primary objectives such as optimum crusher location, economic/environmental comparison etc., to find the research gaps and future research opportunities in short-term planning with IPCC. The review reveals that hardly any short-term planning model can generate mine extraction sequences with IPCC integration. Therefore, a short-term planning methodology considering the IPCC system would be a pioneering step in the mine planning literature. Hence, the authors propose a theoretical short-term planning framework with IPCC as a future research direction.

Optimal Intensity Measures for Probabilistic Seismic Stability Assessment of Large Open-Pit Mine Slopes under Different Mining Depths

The dynamic stability of slopes is the key to ensure the safety of a large open-pit mine during and after a strong earthquake. This study was mainly focused on the identification of optimal intensity measures (IMs) for the probabilistic seismic stability assessment of large open-pit mine slopes within the framework of performance-based earthquake engineering (PBEE). To this end, four open-pit slopes with different mining depths were constructed as the reference cases for the numerical investigation. The randomness of input ground motions and the uncertainty of material properties of the slopes were also considered. A total of 96 ground-motion records and 29 common IMs were selected for testing. By a series of nonlinear time-history analyses, the probabilistic seismic demand models (PSDMs) between the minimum factor of safety (FOS) of slopes and all considered IMs were developed. The optimal IMs with respect to FOS were identified based on the evaluation of five criteria: correlation, efficiency, practicality, proficiency, and sufficiency. The impacts on seismic fragility and FOS response hazard of the slopes were discussed when using different IMs. The results reveal that sustained maximum velocity (SMV) and velocity spectrum intensity (VSI) are recognized as the optimal IM for a mining depth of 50 m and 100 m, respectively. However, Housner intensity (HI) is observed to have the best predictability for both the mining depths of 200 m and 300 m. Moreover, for the three most commonly used IMs, peak ground velocity (PGV) is superior to peak ground acceleration (PGA) and spectral acceleration at first mode period (Sa (T1)) for different mining depths. Finally, based on the evaluations of seismic fragility and FOS response hazard, the uncertainty of seismic stability prediction of open-pit slopes can be greatly reduced when using a more appropriate or optimal IM.

Engineering geology and mechanism of multiple landslides in a large open-pit mine: the case of the Copper Mine in Qinghai Province, China

Engineering geology and mechanism of multiple landslides in a large open-pit mine: the case of the Copper Mine in Qinghai Province, China

Research on the Multiobjective and Efficient Ore-Blending Scheduling of Open-Pit Mines Based on Multiagent Deep Reinforcement Learning

In order to solve the problems of a slow solving speed and easily falling into the local optimization of an ore-blending process model (of polymetallic multiobjective open-pit mines), an efficient ore-blending scheduling optimization method based on multiagent deep reinforcement learning is proposed. Firstly, according to the actual production situation of the mine, the optimal control model for ore blending was established with the goal of minimizing deviations in ore grade and lithology. Secondly, the open-pit ore-matching problem was transformed into a partially observable Markov decision process, and the ore supply strategy was continuously optimized according to the feedback of the environmental indicators to obtain the optimal decision-making sequence. Thirdly, a multiagent deep reinforcement learning algorithm was introduced, which was trained continuously and modeled the environment to obtain the optimal strategy. Finally, taking a large open-pit metal mine as an example, the trained multiagent depth reinforcement learning algorithm model was verified via experiments, with the optimal training model displayed on the graphical interface. The experimental results show that the ore-blending optimization model constructed is more in line with the actual production requirements of a mine. When compared with the traditional multiobjective optimization algorithm, the efficiency and accuracy of the solution have been greatly improved, and the calculation results can be obtained in real-time.

Spatiotemporal variation of vegetation cover in mining areas of Dexing City, China

Dexing City is an important mining city in China, abounding in copper ore, lead ore, zinc ore, and other metal resources, and there are two large open-pit mines in its territory, Dexing Copper Mine and Yinshan Mine. The two open-pit mines have been expanding their mining production scale since 2005, with frequent mining activities; and the expansion of the pits and the discharge of solid waste will undoubtedly increase the land use and cause the destruction of vegetation. Therefore, we plan to visualize the change in vegetation cover in Dexing City from 2005 to 2020 and the expansion of the two open-pit mines by calculating changes of the Fractional Vegetation Cover (FVC) in the mining area using remote sensing technology. In this study, we calculated the FVC of Dexing City in 2005, 2010, 2015 and 2020 using data from NASA Landsat Database via ENVI image analysis software, plotted the FVC reclassified maps via ArcGIS, and conducted field investigations in the mining areas of Dexing City. In this way, we can visualize the spatial and temporal changes of vegetation cover in Dexing City from 2005 to 2020, and appreciate the situation of mining expansion and its solid waste discharge in Dexing City. The results of this study showed that the vegetation cover of Dexing City remained stable from 2005 to 2020, as the expansion of mining scale and mine pits was accompanied by active environmental management and land reclamation, setting a positive example for other mining cities.

Characterization of Blighia sapida seed extracts.

Blighia sapida, commonly known as the ackee, is a member of the Sapindaceae family. The tree is native to the forests of West Africa and was brought to the Caribbean and later Florida, where it is cultivated as an orchard crop in some areas. Arilli of the fruit are processed to make canned ackee in brine whereas the seeds, raphe and pods are discarded. Physiochemical studies were conducted on extracts of the seed. Qualitative analysis detected the presence of phenolics and reducing sugars. Aqueous extracts of the seeds (ASE) exhibited free radical scavenging activity and had an inhibitory concentration of 2.59 mg/mL. Gas chromatography mass spectrometry led to the identification of several metabolites including amino acids and fatty acids. Hypoglycin B was isolated utilizing ion exchange chromatography. Fourier transform infrared spectroscopy of hypoglycin B detected a band resonating at 3070 cm-1 which may be attributed to the methylenecyclopropane moiety of hypoglycin B. The seeds had a lipid content of 5.72 ± 0.25 % (w/w). The ackee seed oil (ASO) had a saponification value of 152.07 ± 37 and a carotenoid content of 23.7 ± 1.8 mg/kg. The ackee seeds are a source of bioactive components.

Effect of spatial variation of spoil material properties on slope displacements under rapid drawndown of pit lakes

In many European countries, lignite or brown coal is used as a fuel source in steam-electric power generation. Upon completion of mining activities, a reclamation plan is imperative to ensure environmental and social prosperity of local areas. Abandoned mine pits are often reclaimed by creating a pit lake. Reclamation of large lignite open pit mine sites may use large amounts of previous overburden materials or “spoils” to create the slopes of the pit lake. Spoils are anthropogenic materials with large spatial variation in properties, hence, considering mean values of shear strength and hydraulic parameters to assess stability and seasonal displacements will not fully simulate actual field conditions. This paper considers the effect of spatial variation on slope stability and ground movements during rapid drawdown events (a critical case) using coupled flow-deformation 2D finite element analyses, incorporating unsaturated soil suctions above the phreatic surface. Effects of heterogeneity and randomness of spoils on the response of the slope are considered through random field modelling and the Monte-Carlo simulation technique. Four lognormally distributed random variables (spoil cohesion, friction angle, void ratio, and permeability coefficient) are examined. The effect of spatial variability of spoils is shown to be important; a significant number of the random field analyses resulted in larger displacements compared to a benchmark deterministic analysis adopting uniform mean parameter values.

Stability Analysis of a Steep Rock Slope in a Large Open-Pit Mine in a High-Intensity Area: A Case Study of the Yejiagou Boron Iron Mine

The slope stability of open-pit mines has always been a major problem affecting the safe production of resources from open-pit step mines. At present, slope excavation in open-pit mines is difficult and slope instability problems are becoming increasingly prominent. In this study, an open-pit bench rock slope in Liaoning Province was taken as the research object. The physical parameters of the rock mass in the area were obtained through engineering drilling and large-scale direct shear tests. Based on the determination of the dominant group of the slope’s structural plane, the seepage deformation failure and maximum stress deformation of the slope were analyzed to explore the stability of high and steep rocky slopes in large open-pit mines. The results show that there is a group of dominant structural planes at the no. 1~3 observation points whose dip angle is steep and consistent with the slope inclination. The dip angle is slightly lesser at the slope toe, and the slope is basically a stable structure. The Janbu method was used to calculate the seepage stability of the slope and it is found that section 4-4 is in a dangerous area. In the stress nephogram, the maximum principal stress is located inside the slope, and the minimum principal stress is located at the surface of the free surface.

Shallow Failure of Weak Slopes in Bayan Obo West Mine.

The slope stability of large open-pit mines has always been a concern and the analysis of large-scale slope landslides is a focus. However, shallow failure in soft rock slopes also has a serious impact on safe production. The northern slope of Baiyunebo West Mine has many shallow landslides in the final slope, resulting in damage of the maintenance channel of the belt transportation system, which has a serious impact on the safety of production. In order to reduce the shallow failure in weak rock slope, it is necessary to analyze the behavior and characteristics of shallow failure in weak rock. Firstly, the mechanical parameters of the intact rock were obtained by using the exploration data; secondly, through the analysis of blasting-damage range, the distribution characteristics of fractures after the failure of weak rock were obtained. Finally, through theoretical analysis, numerical simulation, surface displacement monitoring and on-site shallow-failure case analysis, the deformation and characteristics of shallow failure of weak rock slope in West Mine were obtained. It was found that the mechanical parameters of rock mass strength on the surface of weak rock slope and the original rock were quite different after mining disturbance. The mode of failure of shallow weak rock slope in the West Mine was creep-cracking; the numerical modelling analysis was carried out by using the assignment method of shallow lithology weakening and gradual change, which is more in line with the deformation characteristics of weak rock slope in West Mine. The lower deformation of the soft rock slope in West Mine is 3–5 times that of the upper deformation. The research results are helpful to understand the influence of blasting on the stability of soft rock slope. At present, West Mine has started to adjust blasting parameters according to the research results, so as to reduce the excessive damage of blasting to rock mass, so the stability of the slope is improved.

A stochastic mine planning approach to determine the optimal open pit to underground mining transition depth – case study at the Geita gold mine, Tanzania

ABSTRACT Several of the world’s largest open-pit mines are expected to consider making a transition to underground mining because of the opportunity to access an increased amount of reserves and extend a mine’s life. A case study exploring the optimal transition depth from open pit to underground mining at AngloGold Ashanti’s Geita gold mine in Tanzania is presented herein. The approach considered assesses the problem by evaluating the profits of a set of candidate transition depths, which have been identified by the mining operation as viable opportunities. An accurate valuation for each candidate’s transition depth is derived by producing yearly mine plans based on uncertainty, which outline expected yearly cash flows. Compared with the conventional deterministic approach, the results of this study show a 23% net present value increase for the stochastic mine plans, as well as an improved production performance and the ability to meet mill requirements throughout the life-of-mine.

Study on Complexity Planning Model of Pumped Storage in Abandoned Open-Pit Mine: A Case Study of Fushun Open-Pit Mine

Open-pit mining is one of the main exploiting methods for solid mineral resources. After more than 100 years of high-intensity development, there are a large number of abandoned open-pit mines and related mining relics in the world. The reconstruction of Pumped Hydraulic Energy Storage systems (PHES) from abandoned open-pit mines is an effective utilization mode of the abandoned underground space in recent years. The project planning of PHES should consider not only the technical and economic feasibility of PHES power station but also a series of problems, such as comprehensive utilization of mine dump, slope treatment, industrial heritage and cultural inheritance, ecological environment restoration of mining area, and transformation and matching of nearby resource-exhausted cities. This constitutes a complex planning problem of pumped storage in abandoned open-pit mines. This paper takes Fushun open-pit mine, the second largest open-pit mine in the world, as the analysis object and abstracts a variety of application modes of pumped storage in abandoned open-pit mines with the model research method. On this basis, the modes abstracted such as the single-pit oil–water co-storage mode, single-pit gravity dam reinforcement mode, multi-pit linkage energy storage mode, and multi-pit and dump linkage energy storage mode are all carefully studied in this paper. A series of supporting integrated programs are proposed for each mode with regard to ecological restoration, multi-energy complementary, cultural tourism governance, etc. In addition, based on the PHES with abandoned open-pit mine, this paper also explores the sustainable development of resource-exhausted cities and the transmission of their core industries.

A new approach for evaluation of slope stability in large open-pit mines: a case study at the Dexing Copper Mine, China

A new approach for evaluation of slope stability in large open-pit mines: a case study at the Dexing Copper Mine, China

Risk Management and Control of Blasting Operation in Large Open-pit Coal Mine

Risk Management and Control of Blasting Operation in Large Open-pit Coal Mine