Open Pit Research Articles

Design and development of intelligent unmanned construction system for open-pit mine

China’s huge mineral outputs support the national economy and people’s livelihood. However, the mining operation is rough and the safety accident happens frequently. Consequently, the demand for unmanned mining operations is urgent, which is of great significance to safe production. Facing the complex operation scenarios of open-pit mines, an unmanned construction system framework is proposed based on intelligent construction machinery. On this basis, an unmanned excavation subsystem is designed and developed based on the hydraulic excavator, and an unmanned transportation subsystem is designed and developed based on the mining truck. Equipped with advanced sensors and controllers, the unmanned excavation subsystem and the unmanned transportation subsystem possess sensing, decision-making, and control abilities by using AI algorithms. The experiment of the unmanned construction systems is successfully conducted on the open-pit mine test site. This study provides equipment and technical support for improving the intelligent level of mine construction and ensuring safe production for the open-pit mine.

The evaluation model for factors affecting soil quality in waste dumps open-pit coal waste dumps based on fuzzy mathematics

Taking the Hequ open-pit coal mine waste dump as the research object, using the fuzzy analytic hierarchy process and expert scoring theory, 4 criteria and 25 factors were established, including the evaluation model of soil structure stability, soil water retention capacity, soil fertilizer retention capacity, soil biological activity, and factors affecting soil quality in the waste dumps. Using YAAHP calculation software, the weights of various influencing factors on the soil fertility restoration ability of the waste dumps were determined. Combining a fuzzy comprehensive evaluation method to determine soil nutrient standards, soil quality evaluation is divided into 5 levels, and the main influencing factors of soil restoration ability in open-pit coal mine waste disposal sites are quantitatively analyzed. The results showed that: The weight of soil fertility in the criterion layer of the evaluation model was the largest (0.548), followed by soil water retention capacity (0.198), soil biological activity (0.140), and soil structural stability (0.114). The weight of organic matter F1 in the factor layer was the highest (0.116). Due to the final evaluation score of the soil recovery ability of the target layer open-pit coal mine waste dumps is 53.584, the soil quality and nutrients of the waste dumps are in the middle level. The main factors of soil resilience are soil fertility and soil organic matter content, to provide management strategies for improving soil quality of dump, accelerating soil reconstruction, and promoting soil ecosystem restoration.

Spectrometric borehole logging in mineral exploration and mining

Borehole logging tools based on pulsed neutron technology are used to infer geophysical parameters such as bulk density. If fitted with a gamma-ray spectrometer, they may also measure elemental mass fractions of a variety of formation elements. Spectrometric borehole logging tools of this kind are established in the oil and gas industry. With the demand for mineral resources surging, cost- and time-efficient measurement techniques are increasingly needed in mineral exploration. Their ability to detect multiple elements that are building blocks of minerals makes spectrometric borehole logging tools popular in mineral exploration and mining grade control. In this article, the potential of the OreLog pulsed neutron gamma spectrometric downhole logging tool is demonstrated at Erzberg Mountain (Styria, Austria). Erzberg hosts the largest known siderite deposit in the world, and open-pit mining is used to extract iron ore. The aim was to obtain a more detailed and faster geochemical characterization of iron ore deposits prior to blasting. Elemental logs were acquired with highest accuracies for Fe, Ca, and Mn, followed by Si, Mg, K, and S. The tool mapped a 2D cross section of formation element concentration within a few hours, which agrees with orogenetic fault and geologic contact lines. Mineralogical information retrieved from elemental logs confirmed the interlaced mineralogy of the site. It is dominated by a carbonate body, hosting an intergrowth of Mg-rich siderite (sideroplesite) and a solid solution of dolomite/ankerite/kutnohorite. In addition to the tool's potential for enhanced real-time mining control, the benefit of continuous depth-resolved elemental logs is seen in the possibility to deduce a more refined and reliable geochemical and mineralogical model of the deposit. The information-rich data stream opens applications beyond grade control and exploration, such as data assimilation with gravity models or geologic model building.

Prediction of rock fragmentation in a fiery seam of an open-pit coal mine in India

Spontaneous combustion of coal increases the temperature in adjoining overburden strata of coal seams and poses a challenge when loading blastholes. This condition, known as hot-hole blasting, is dangerous due to the increased possibility of premature explosions in loaded blastholes. Thus, it is crucial to load the blastholes with an appropriate amount of explosives within a short period to avoid premature detonation caused by high temperatures of blastholes. Additionally, it will help achieve the desired fragment size. This study tried to ascertain the most influencial variables of mean fragment size and their optimum values adopted for blasting in a fiery seam. Data on blast design, rock mass, and fragmentation of 100 blasts in fiery seams of a coal mine were collected and used to develop mean fragmentation prediction models using soft computational techniques. The coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE), mean square error (MSE), variance account for (VAF) and coefficient of efficiency in percentage (CE) were calculated to validate the results. It indicates that the random forest algorithm (RFA) outperforms the artificial neural network (ANN), response surface method (RSM), and decision tree (DT). The values of R2, RMSE, MAE, MSE, VAF, and CE for RFA are 0.94, 0.034, 0.027, 0.001, 93.58, and 93.01, respectively. Multiple parametric sensitivity analyses (MPSAs) of the input variables showed that the Schmidt hammer rebound number and spacing-to-burden ratio are the most influencial variables for the blast fragment size. The analysis was finally used to define the best blast design variables to achieve optimum fragment size from blasting. The optimum factor values for RFA of S/B, ld/B and ls/ld are 1.03, 1.85 and 0.7, respectively.

Bibliometric and Scientometric Assessment of the Environmental Impact and Sustainability of Open Cast Iron Ore Mining: A Comprehensive Analysis

Bibliometric and Scientometric Assessment of the Environmental Impact and Sustainability of Open Cast Iron Ore Mining: A Comprehensive Analysis

2020–2022年环渤海地区8 m分辨率露天采矿区空间分布数据集

With the increase of mining activities in China, the ecological environment around mines is facing unprecedented pressure, leading to a series of resource, ecological and environmental problems, such as air pollution, soil erosion, solid waste pollution, landslides and debris flows. To precisely obtain the spatial distribution data of open-pit mining, scholars and regulatory bodies are actively seeking timely and efficient methods to monitor open-pit mining areas by using the remote sensing, an innovative technology, for this purpose. In this research, we adopted high-resolution optical remote sensing image GF-6 with a resolution of 8m to obtain the open-pit mining dataset in the Bohai Rim through rule-based feature extraction, time-series image discrimination and visual interpretation methods, covering over 8000 open-pit mining areas. The dataset exhibits a high level of accuracy, with an overall accuracy of 95.0%, a producer accuracy of 98.0% and a user accuracy of 92.4%. It effectively reflects the spatial dynamics in the distribution of open-pit mining areas within the Bohai Rim region and reveals the influence of economic growth and policy-making on these changes. Thus, the dataset can offer valuable data support for managing open-pit mining operations and the development of related policies.

Evaluation of overall equipment effectiveness (OEE) for mining equipment (shovel-truck): A case study Manisa-Soma (Turkey) open pit mine

Mining is a costly activity that requires huge investments and large equipment. Therefore, it is crucial to use mining equipment efficiently to maximize productivity. This requires the continuous analysis of equipment efficiency and taking action to reduce negative impacts. Accurately estimating equipment efficiency is essential to increase its effectiveness. One globally recognized and accepted measurement is Overall Equipment Effectiveness (OEE). In this study was conducted to calculate the OEE values of shovels and trucks, which are the primary equipment used in open pit mining. The study presented different loss times and quality values while calculating the OEE values of mining equipment. The OEE values of electric trucks and shovels were found to be consistent with actual work quantities in the Manisa-Soma Lignite open pit operation. This study is the first applied study of OEE analysis in Turkey.

Na krawędzi odkrywki. Praktyki postartystyczne i zaangażowanie klimatyczne na plenerach w Opolnie-Zdroju

The author analyzes the network of activist-artistic practices carried out as part of transdisciplinary gatherings in Opolno-Zdrój, located on the edge of the Turów open-pit coal mine, where the pioneering artistic ecological plein-air event Ziemia Zgorzelecka “Science and art in defense of the natural human environment” took place in 1971. The author describes these activities, conducted by the Office for Post-Artistic Services, using the theory of post-artistic practices and “usology,” and pointing out similarities and differences with related concepts of artivism, socially engaged art, or art with community. Borrowing concepts from the field of environmental humanities and written art theory in the context of the climate crisis, the author shows how those associated with the Office experiment with using art as a tool to enter into relationships and intervene in the reality of Opolno-Zdrój. The post-artistic practices carried out in Opolno-Zdrój are a successful exercise in “ecologizing” the methods and language of art, which allow for meaningful engagement with the issues of the planetary climate and environmental crisis, and provide a valuable tool for expanding imagination, useful speculation, and practical shaping of the future. Key-words: climate, ecology, post-art, post-artistic practices, extractivism, plein-air, Opolno-Zdrój, “Turów” mine

Mapping open-pit mining area in complex mining and mixed land cover zone using Landsat imagery

The monitoring of open-pit mining and reclamation activities is an important part of ecological protection across various countries. Among the many methods of monitoring open-pit mining areas, satellite remote sensing is the most widely used and effective. However, few works have been conducted to map open-pit mines over a larger geographical scale, or have considered complex land cover types, or a wide variety of mine properties. This work proposes a framework for mapping open-pit mines for areas over complex land cover and mining properties, including preprocessing, classification, and postprocessing steps. First, the pixels that did not contain mines were masked, second the mines were divided into two categories according to their spectral characteristics, then the selected samples and classified to obtain the classification results of mines, and third mis-classified pixels were removed. This work used Landsat images and Google Earth Engine to map the open-pit mines over Shanxi in 5-year steps from 2000 to 2020. The average producer and user accuracy of the results was found to be 79.4% and 83.2% respectively. The experimental results showed that open-pit mining areas in Shanxi first increased and subsequently decreased over the past twenty years. Additionally, the new preprocessing, classification, and postprocessing workflow was found to be effective, especially in environments with more vegetative cover.

Optimization of cycle time for loading and hauling trucks in open-pit mining

Purpose. The purpose of the paper is to provide open-pit mining operations with practical strategies and insights to optimize truck loading and hauling cycles, ultimately leading to enhanced productivity and economic advantages. Methods. The objectives are to minimize loading time, optimize the haul road network, enhance truck performance, and optimize dumping and return time. By diligently implementing these methods and achieving these objectives, open-pit mining operations can significantly reduce the truck cycle times, resulting in increased productivity, lower costs and improved profitability. Findings. In this case, the total loading time of the excavator and shovel is determined to be 3.98 and 2.92 minutes, respectively, while the hauling time for total loading of the open-pit floor depends mainly on the average distance and speed of 239 m and 10.1 km/hour, which results in 1.53 minutes. Originality. As a result, the total cycle time for open-pit mining is 19.765 minutes, resulting from the total loading time, hauling time for total loading, total dumping time, and total return time for empty transport of 4.265, 8.46, 0.86 and 6.18 minutes, respectively. Practical implications. By combining theoretical analysis with practical insights and site-specific considerations, the paper aims to provide a comprehensive and applicable framework for optimizing truck cycle time in open-pit mining, resulting in improved efficiency and profitability of mining operations.

Influence of Structural Discontinuity on Slope Stability using Numerical Modelling and Sirovision

The rock mass consists of heterogeneous and anisotropic materials, with smaller and larger blocks of rock, and the presence of structural discontinuities is a significant concern. Characterising the rock mass is crucial for the success of engineering excavations in such areas. A detailed study of joints, their orientation, and discontinuities in the exposed rock mass is crucial as they greatly influence stability and fragmentation. Existing rock mass classifications like Rock Mass Rating (RMR) and Q-classification require various geological parameters and physico-mechanical properties of the rock. However, determining these parameters conventionally can be time-consuming, requiring careful on-site measurements. The number of opencast coal mines is increasing compared to underground mines due to shorter gestation periods, higher productivity, and quicker returns. However, opencast mining raises environmental concerns such as air and water pollution, solid waste management, land degradation, and socio-economic issues. Additionally, many opencast coal mines, regardless of size, are reaching greater depths, making analysing bench slopes and ultimate pit slope design crucial. Slope failure in these mines leads to production loss, additional costs for recovery and handling of failed material, pit dewatering, sometimes mine abandonment or premature closure, and loss of life. A study was conducted at Prakash Khani Opencast Mine – IV, Manuguru area, M/s The Singereni Company Collieries Limited (SCCL), to investigate the influence of structural discontinuities on slope stability. SIROVISION software was used to assess rock mass characterisation, while PLAXIS-2D software was employed to analyse the influence of structural discontinuities on slope stability. A comparative conclusion was drawn based on the results obtained from SIROVISION and PLAXIS-2D analyses. The study revealed that the RMR of the mine ranged from very poor to fair due to numerous discontinuities. It was also found that discontinuities in the slope decrease the Factor of Safety (FOS), indicating an impact on slope stability.

Numerical Investigation into Factors Affecting Stability of Opencast Coal Mine's Rise Side Highwall Slope

Open-pit coal mining accounts for 93% of India's total coal production, playing a significant role in meeting the nation's substantial energy needs. The success of an open-pit mine hinges on maintaining the steepest and deepest slopes that remain stable over the mine's lifespan. However, slope failure is a complex issue influenced by numerous factors. In the context of openpit coal mines, the rise side highwall involves cutting through a rock mass containing various elements like an unconsolidated weathered mantle of sandstone, sandy clay, clay, carbonaceous shale and coal. Some opencast mines within the Godavari Valley Coal Field (GVCF), India have encountered significant pit slope failures. This paper uses a numerical modelling approach aimed at effectively assessing the stability of the rise side highwall, leveraging available geotechnical data from one of GVCF's largest opencast coal mines. The research investigates the impact of seven detrimental factors on slope stability, including dynamic loading due to blasting, employing a methodical One-Factor-At-A-Time (OFAT) approach. The study utilises Rocscience Phase2 version 9.0, a Finite Element Method (FEM) based numerical modelling software to gauge the sensitivity of each factor on the Factor of Safety (FoS). The numerical modelling results indicate that there is a linear decrease in FoS corresponding to the reduction in cohesion and an exponential increase in the FoS as the angle of internal friction rises. Furthermore, the analysis reveals significant impacts on the FoS due to groundwater and seismic loading from the blasting. This approach aims to comprehensively analyse and understand the intricacies of slope stability in the specific context of open-pit coal mining.

A novel model for sustainable production scheduling of an open-pit mining complex considering waste encapsulation

This work presents a novel mixed integer programming model for simultaneous optimisation of ore production and waste dumping schedule for an open-pit mining complex. The model maximises net present value and generates an optimal flow of materials from multiple sources (open pits, stockpiles) to destinations (processing streams, stockpiles, waste dumps) within the supply chain of a mining complex. In addition, the proposed model implements sustainable mining practices as it ensures the responsible disposal of potentially acid forming waste. An application of the new simultaneous and the traditional two-step (or sequential) methods confirms that the proposed method derives higher net present value and reflects a distinct advantage in addressing the acid mine drainage problem through encapsulation of potentially acid forming wastes. In addition, the results reveal that the new model requires less waste haulage work leading to a significant reduction in greenhouse gas emissions.

Slope Monitoring Techniques in Opencast Mines: A Review of Recent Advances

The process of excavating rock mass induces changes in the stress distribution within the slope, rendering it prone to deformation over a specific duration. The potential consequence of movements along the weak planes is the ultimate breakdown of the slope. Various monitoring techniques, including visual inspection, laser scanning, Lidar scanning, total stations, Global Positioning Systems (GPS), state-of-the-art radar scanning, and micro-seismic monitoring, are currently employed in mining environments to forecast slope failure and deformation rate. This article will discuss the need to implement a continuous slope monitoring system, including categorizing such systems and an overview of the current state of existing slope monitoring technologies. The paper also discusses the applications of UAVs (Unmanned Aerial Vehicles) in slope monitoring. The research proposes implementing a consistent and continuous slope monitoring strategy grounded on empirical data when planning big and deep opencast mines. This approach is crucial for guaranteeing optimal safety measures and enhanced productivity levels.

Application of Mining Width-Constrained Open Pit Mine Production Scheduling Problem to the Medium-Term Planning of Radomiro Tomic Mine: A Case Study

Application of Mining Width-Constrained Open Pit Mine Production Scheduling Problem to the Medium-Term Planning of Radomiro Tomic Mine: A Case Study

Evaluation of rock stability challenges affecting the formation of sustainable pit lake towards mine closure following crown pillar extraction in open pit-underground mines

The extraction of high-grade ore from the crown pillar (CP) in open pit-underground mines poses stability challenges and potential environmental risks. While an open pit has the potential to transition into a pit lake, the extraction of CP can induce failure in the surrounding walls, preventing the formation of the lake. There is also a concern that the backfilling material may not effectively confine toxic water within the pit, thereby risking contamination of the underground environment. To address these issues, a case study was conducted using FLAC3D and 3DEC models to evaluate the extent of failure caused by CP extraction. On-site observation, along with modelling, has revealed rock damage, including deformation stretching about 4 m from the pit wall and extending vertically from the pit floor to the ramp. The study identified three primary factors leading to pit wall failure or damage: steep pit slopes reaching approximately 70° near the pit floor, an underestimated CP thickness by about 4 m, and the concurrent extraction of ore from the pit wall alongside CP. Based on these findings, rehabilitation measures are suggested, including excavation of the deformed wall and cantilever, as well as partial pit backfilling. There is a substantial increase in the volume of backfill material as the extent of failure increases, which raise concerns about the decision-making process regarding CP extraction. Therefore, this article aims to raise environmental awareness and evaluate whether the benefits of ore extraction outweigh the considerations for pit wall support and the rehabilitation efforts during mine closure.

Metagenomic analysis reveals the effect of revegetation types on the function of soil microorganisms in carbon and nitrogen metabolism in the open-cast mining area

Metagenomic analysis reveals the effect of revegetation types on the function of soil microorganisms in carbon and nitrogen metabolism in the open-cast mining area

Evaluation of Coarse Gold-Bearing Conglomerate Mineralisation at Beatons Creek, Pilbara, Western Australia: Sampling for Resource Development and Grade Control

Many styles of gold mineralisation are challenging to sample because of the presence of coarse gold and a high spatial heterogeneity. The coarse gold-bearing conglomerates of the Beatons Creek deposit provide some challenges related to the presence of gold particles up to 8 mm and gold particle clusters (up to 500 mm3) at low in situ grades (<2 g/t Au). Novo has attempted to address these issues over the last six years of exploration, resource development and mining. The Beatons Creek open pit operation was the first Pilbara conglomerate-hosted gold deposit to go into production. Between January 2021 and September 2022, it produced 2.5 Mt at 1.2 g/t Au for 87,300 oz Au recovered. Gold is present within a matrix of multiple, narrow-stacked oxide and fresh (sulphide) conglomeritic reef horizons, which are interbedded with unmineralised conglomerate, sandstones and grits. It is strongly associated with detrital pyrite and authigenic nodules. Several sampling techniques have been applied across the project, including diamond core and RC drilling, trench channel sampling and bulk sampling. Assay methods applied include fire assay, screen fire assay, LeachWELL™ and more recently PhotonAssay™. The dominant sampling protocol applied for resource development and grade control utilised 0.5 m length RC samples; a 50% rig split (c. 8.5 kg) and laboratory crushing to 3 mm, followed by a 2.5 kg split and total assay via PhotonAssay™. For part of the 2022 RC programme, the detectORE™ technique was used to screen primary RC samples and reduce the feed to the laboratory. Novo operated a sampling and assay programme that aimed to reduce the impact of coarse gold on sample and assay preparation biases and to improve estimation.

New findings of gymnosperms in the Middle Jurassic of the East European platform

The plant-bearing layers in the Stoilensky open mine (Belgorod Region, Russia) are dated to the middle Bathonian–early Callovian based on the dinoflagellate cysts and spore-pollen assemblages, and in the Mikhailovsky open mine (Kursk Region, Russia) – to the middle–late Bathonian based on palynological data. Representatives of Pseudotorellia are recorded in the Middle Jurassic of the Belgorod and Kursk regions for the first time. A new species, Pseudotorellia oskolica, is described from the Stoilensky open mine based on the unique morphological and epidermal features. Leaves of this species are very narrow, they are characterized by the presence of stomata on the adaxial leaf surface. The type material of Czekanowskia europea from the Middle Jurassic of the Pripyat depression in Belarus was restudied. The diagnosis for C. europea is provided, since only a description of this species was given in the original publication. Czekanowskia leaves are recorded from the Belgorod and Kursk regions for the first time. They are determined as C. europea based on the similar epidermal features as in the type leaves. A shoot of Pagiophyllum sp. and numerous leaf fragments of Podozamites sp. were found in association with C. europea in the Pripyat depression. These genera are recorded in Belarus for the first time. Findings of Pseudotorellia, Czekanowskia and Podozamites leaves in the Middle Jurassic floras of the East European platform are discussed.

Extraction of sand from the complex matrix of coal mining dump waste: A sustainable approach in Indian context

Dump waste generated by open cast coal mining industry is a significant global source of environmental pollution, land degradation and possesses threats to the environmental sustainability. After conducting pilot study, experimental investigations were conducted to study the reuse of waste rocks coming from mining as fine aggregates as a possible replacement of river sand. Physical, chemical and mechanical tests have been carried out in order to analyze in detail the interaction whether extracted sand is suitable in construction sector or not. The present study focuses on utilizing the overburden of the Sasti open cast coal mine of Western Coal Limited in the Chandrapur District of Maharashtra state, India for extraction of sand. Extracted sand contains minerals mainly quartz, alumina, and satisfies the prescribed permissible limit as per the Indian coal provisions for its use in construction work and observed to be equivalent to river sand. The compressive strength obtained with extracted OB sand after 28 days of curing was 29.294 MPa as compared to 33.153 MPa for the river sand for M25 grade of concrete. The focus of the study is on the reclaimed sand and its possible usages and not on the other components like clay of dump waste.