Surface Mining Research Articles

Slope stability of reclaimed coal mines through a new water filling index

A common reclamation practice for closed coal surface mines is filling them with water to form pit lakes. The creation and sustainability of these lakes are significantly affected by the stability of the corresponding slopes. The present study provides a general framework for analyzing the water filling's effect on slope stability based on a new water filling index, which can indirectly consider the factors affecting the process and efficiently quantify the filling speed's influence. The assumptions of the proposed approach are thoroughly discussed, and the range of the water filling index is identified. Furthermore, the safety factor is calculated using the finite element method with the shear strength reduction technique during the filling process for various conditions (soil properties, slope geometry, hydraulic conditions, and water filling speed). Results are presented as normalized stability charts for practical use. During the water filling, the stability gradually decreases until the reservoir reaches a critical level of 10%–40% of the total height; it then increases to even more stable conditions than the initial one. Overall, the present analysis allows for the preliminary stability evaluation of a coal mine during the formation of a pit lake and the appropriate quantification of the water filling's effect.

Инструмент оптимизации выемочных единиц на открытых горных работах для блочных моделей месторождений

The MINEFRAME mining and geological information system features an algorithm and a software module to create bench-wise mining units for surface mining operations, which optimizes losses and dilution with due account for the spatial variability of the ore and gangue rock composition. The software module is based on both wireframe and pure block models, and takes into account a given development direction. The algorithm defines the mineable reserves of the deposit as a set of mining unit models. The module determines the expected levels of rational loss and dilution for each mining units of the bench, for each ore body, for the bench and for the open pit in general. The mining units also become the reference points for the design of blasting operations and the basis for the development of special measures to modify the parameters of the mining system locally. The obtained mineable reserves can be used in defining the pit boundaries and planning mining operations, and the contours of mining units will guide the design of the blast blocks. The algorithm can also be used to clarify the pit boundaries in the footwall of a sloping deposit and for economic comparison of the development options.

Прогнозная оценка устойчивости борта карьера в тектонически напряженном массиве

The article presents an approach to determining the stability of the pit walls and benches using a set of methods. The results of numerical modeling of the stress-and-strain state are presented for the rock mass in vicinities of one of the quarries in the Khibiny Apatite Arc. Calculations were made using elastic approach to a three-dimensional finite-element model which incorporates basic geological, mining engineering and geomechanical data. The impact of gravitational and tectonic stress field is demonstrated on the stability of the pit wall and benches during its development. Potentially unstable areas have been determined in the wall and benches of the open pit design contour. The identified features of the stress-and-strain state of the rock mass in vicinities of the pit wall make it possible to increase the justification level of technical solutions for the development of surface mining operations and to design preventive measures that would ensure the stability of structural elements of the open pit.

Soil in Terms of Industrialization and Mining - Consequences and Soil Recovery

The land resource of Republic of Srpska is subject to damage impact caused by four basic groups of soil process: microbiological contamination, chemical contamination, anthropogenic degradation, and physical destruction or soil disappearance. The most common causes of soil contamination are heavy metals, sulphur solutions, organic pollutants, acid rains, pesticides, mineral fertilizers, radioactive radiation, mineral raw material deposits, various waste dump sites and other. Degradation of soil is reflected in the process of land sliding (erosion) and degradation of soil within the soil profile itself (in situ). Destruction of soil is the heaviest form of soil damage and loss. Surface mining of mineral raw materials appears to have the biggest impact resulting in soil loss. Temporary soil loss is usually defined by surface mining of mineral raw materials. Mining activities have most noticeable impacts on environment (soil, water, air, organisms). Technogenic soils are formed by overburden and interbred disposal and development of mineral raw material mining activities. Soil reclamation and other preventive environmental measures are to be taken to decrease adverse impact of mining activities and improve reclamation of degraded surfaces. Reclamation process covers approximately 10% of technogenic soil in Republic of Srpska at three coal basin locations (Gacko, Ugljevik and Stanari). Technogenic soil falls under VII class and I subclass of automorphic soils. Two types of soil belong to this subclass: Deposol and Rekultisol. Deposol represents interburden material moved to storage area before starting reclamation process. Rekultisol defines technogenic soil in different level and intensity of reclamation. The fertility of deposol, same as most other types of technogenic soil is generally poor. The basic goal of technogenic soil reclamation is surface stabilization and improvement of soil fertility. One of the most important properties of soil in the process of reclamation is organic matter content. Regular monitoring is important for collecting information on state of soils, application of reclamation measures, biogenic and other elements content in crop residue at reclaimed surfaces at the locations nearby mining and industrial utilities.

New Insights into the Formation and Properties of Wellbore Skin: Why We Have to Rethink the Concept.

The deposition of fine-grained material of low permeability on the borehole wall during drilling (wellbore skin) is a common problem affecting the operation and efficiency of water wells. Here, we present new data and novel insights from four excavated dewatering wells from a lignite surface mine. All wells have the same age, are of similar construction, and were sampled at two different depths each. The thickness of the skin layer increases with depth. Its composition and permeability is strongly influenced by the surrounding aquifer material. Nonuniform sediments of low permeability result in less permeable wellbore skin deposits. The presence of discontinuities in the skin layer may be a determining feature for the resulting flow to wells, especially with skin layers of low permeability. The presence of naturally occurring swelling clay (smectite) provides the skin layer with a significant self-sealing capacity.

TIME SERIES INSAR ANALYSIS FOR SLOPE STABILITY MONITORING USING SENTINEL-1 IN OPEN PIT MINING

Abstract. Surface mining is an important economic activity in many regions where mineral resources are located close to the surface. The process of ore extraction is characterised by high pit walls with steep slopes. The mining process introduces significant stress and strain changes that could lead to movement on the slope face. Slope failure on the pit walls can occur without warning and can lead to loss of life and disruptions to the mining process. The monitoring of slopes remains the most reliable way to detect movement on unstable slopes. Therefore, slope monitoring programmes have been established to monitor and measure slope movement to help mine management with the stability status of open pit slopes. Conventional monitoring techniques include visual inspections and in situ instrumentation that are point-based, time-consuming, and costly. Open-source remote sensing techniques such as Synthetic Aperture Radar interferometry have been used to monitor slope movements on open-pit mine walls. Time series interferometric Synthetic Aperture Radar (InSAR) can be used to overcome limitations of in-situ monitoring for monitoring slope movements in open-pit mines.

Analysis of the Magnetic Field and Attractive Force of the Electromagnetic Separator Using the Finite Element Method

The paper provides an analysis of the magnetic field and the attractive electromagnetic force of a powerful electromagnet that is used as part of an electromagnetic separator (EMS) to separate metal parts on conveyor belts for coal delivery. The analysis was done using the finite element method using the FEMM 4.2 software package. For the modelling of the EMS magnetic circuit, a two-dimensional axis-symmetric model was defined and one characteristic section was simulated. Since a time-invariant magnetic field originating from a constant direct current is considered, a magnetostatic type of simulation is adopted. The paper presents the simulation results related to the value of the magnetic field induction and the attractive force of the electromagnet for several characteristic distances of interest. The results of the simulation were applied as part of the design if the plant for the detection and extraction of metal parts on the conveyor belt for the delivery of coal from surface mine “Drmno” to the thermal power plant (TPP) "Kostolac".

Design of a GIS Database for Surface Mining

Abstract The mining industry is the branch that provides necessary mineral raw materials for a whole series of economic activities, with the main beneficiaries being the energy industry (through coal consumers), companies specialized in the processing of uranium concentrates, chemical industry, food industry, construction materials industry, non-ferrous metallurgical industry, etc. Thus, in accordance with the Romanian mining industry strategy 2017-2035, one of the objectives of the industrial policy in the mining field in Romania is the development and implementation of a database system for the mining sector. Specifically, the goal consists in a development of a tool for tracking and implementing the Mining Law, which allows the collection, storage, administration, modification and analysis of data regarding licenses and permits. At the same time, the development of a visualization and geographic information system (GIS) of mining exploration and exploitation perimeters, as support for the promotion of concessions for mineral resources, is being pursued. In this way, there is a tendency towards the automated and computerized management of the production processes. The development of such systems with practical applicability requires the design, development, and implementation of specific models and databases. The structure and quality of the designed data models directly influence the exploitability and analytical capability of the systems. This paper analyzes the possibilities of designing and implementing a database for the management of the surface mining activities. In the first part of the paper, the basic principles regarding the design and population of databases are presented, as well as their correlation with user requirements and exploitation needs. In the second part, a data model was proposed for the management of mining activities, in accordance with the main stages in the life cycle of a mining operation. In the end, several scenarios for the exploitation of GIS databases were presented, as well as their interconnection with data sources external to the system.

Examining the immunotoxicity of oil sands process affected waters using a human macrophage cell line

Oil sands process affected water (OSPW) is produced during the surface mining of the oil sands bitumen deposits in Northern Alberta. OSPW contains variable quantities of organic and inorganic components causing toxic effects on living organisms. Advanced Oxidation Processes (AOPs) are widely used to degrade toxic organic components from OSPW including naphthenic acids (NAs). However, there is no established biological procedure to assess the effectiveness of the remediation processes. Our previous study showed that human macrophage cells (THP-1) can be used as a bioindicator system to evaluate the effectiveness of OSPW treatments through examining the proinflammatory gene transcription levels. In the present study, we investigated the immunotoxicological changes in THP-1 cells following exposure to untreated and AOP-treated OSPW. Specifically, using proinflammatory cytokine protein secretion assays we showed that AOP treatment significantly abrogates the ability of OSPW to induce the secretion of IL-1β, IL-6, IL-8, TNF-α, IL-1Ra and MCP-1. By measuring transcriptional activity as well as surface protein expression levels, we also showed that two select immune cell surface markers, CD40 and CD54, were significantly elevated following OSPW exposure. However, AOP treatments abolished the immunostimulatory properties of OSPW to enhance the surface expression of these immune proteins. Finally, a transcriptome-based approach was used to examine the proinflammatory effects of OSPW as well as the abrogation of immunotoxicity following AOP treatments. Overall, this research shows how a human macrophage cell-based biomonitoring system serves as an effective in vitro tool to study the immunotoxicity of OSPW samples before and after targeted remediation strategies.

Characteristics of miners’ working conditions in the surface mine of the mining and chemical complex in the Arctic region of the Russian Federation: cross-sectional (simultaneous) study

INTRODUCTION. The development of rich mineral resources in the Arctic region of the Russian Federation (ARRF) is a strategic direction for the further economic development of the country. The study of the working conditions to prevent the development of an occupational disease and to preserve the health of workers, employed in the ARRF economy, are fully aligned with national priorities of the state policy.
 OBJECTIVE. To assess miner’s working conditions in the surface mine, located in the Arctic region of the Russian Federation.
 MATERIALS AND METHODS. Working conditions of mining dump truck, bulldozer, drilling machine, excavator drivers and blasting teams in the ARRF surface mine were examined with the use of sanitary description method as well as physical and chemical ones.
 RESULTS. Natural and climatic conditions around mining sites are adverse with some extremeness. Miners’ working conditions сcorrespond to class 2 and 3 of 1-2 degree of harmfulness on physical and chemical factors. Maximum permissible levels are most exceeded on noise and vibration ones as well as on the content of nitric oxide and formaldehyde in the cabin of dump bulldozers, and least – in the workplace of drilling machine drivers.
 CONCLUSION. To improve miners’ working conditions and preserve their health, it is necessary to develop and implement a comprehensive program of measures, adapted to the Arctic conditions, aimed at preventing occupational diseases and providing for the solution of sanitary-technological and medical preventive issues.

The uncertain future of mountaintop-removal-mined landscapes 1: How mining changes erosion processes and variables

Surface mining may be humanity's most tangible impact on Earth's surface and will become more prevalent as the energy transition progresses. Prediction of post-mining landscape change can help mitigate environmental damage, but requires understanding how mining changes geomorphic processes and variables. Here we investigate surface mining's complex influence on surface processes in a case study of mountaintop removal/valley fill (MTR/VF) coal mining in the Appalachian Coalfields, USA. The future of MTR/VF landscapes is unclear because mining's effects on geomorphic processes are poorly understood. We use geospatial analysis—leveraging the existence of pre- and post-MTR/VF elevation models—and synthesis of literature to ask how MTR/VF alters topography, hydrology, and land-surface erodibility and how these changes could be incorporated into numerical models of post-MTR/VF landscape evolution.MTR/VF reduces slope and area–slope product, and rearranges drainage divides. Creation of closed depressions alters flow routing and casts doubt on the utility of models that assume steady flow. MTR/VF creates two contrasting hydrologic domains, one in which overland flow is generated efficiently due to a lack of infiltration capacity, and one in which waste rock deposits act as extensive subsurface reservoirs. This dichotomy creates localized hotspots of overland flow and erosion. Loss of forest cover probably reduces cohesion in near-surface soils for at least the timescale of vegetation recovery, while waste rock fills and minesoils also likely experience reduced erosion resistance. Our analysis suggests three necessary ingredients for numerical modeling of post-MTR/VF landscape change: 1) accurate routing and accumulation of unsteady overland flow and accompanying sediment across low-gradient, depression-rich, engineered landscapes, 2) separation of the landscape into cut, filled, and unmined regions, and 3) incorporation of vegetation recovery trajectories. Improved modeling of post-mining landscape evolution will mitigate environmental degradation from past mining and reduce the impacts of future mining that supports the energy transition.

The uncertain future of mountaintop-removal-mined landscapes 2: Modeling the influence of topography and vegetation

Erosion following human disturbance threatens ecosystem health and inhibits effective land use. Mountaintop removal/valley fill (MTR/VF) mined landscapes of the Appalachian Coalfields region, USA, provide a unique opportunity to quantify the geomorphic trajectory of disturbed lands. Here we assess how MTR/VF-induced changes to topography and vegetation influence spatiotemporal erosion patterns in five mined watersheds. We use landscape evolution models starting from pre- and post-MTR/VF topographic data to isolate the influence of mining-induced topographic change. We then constrain ranges of erodibility from incision depths of gully features on mine margins, and use those estimates to model the influence of vegetation recovery trends on erosion.Topographic alterations alone reduce total sediment export from mined catchments. Model runs that incorporate the disturbance and recovery of vegetation in mined watersheds show that complete vegetation recovery keeps millennial sediment export from mined catchments within the range of unmined catchments. If vegetation recovery is anything less than complete, vegetation disturbance drives greater total sediment export from mined catchments than unmined catchments. Full vegetation recovery causes sediment fluxes to decline over millennia beyond the recovery period, while watersheds without full recovery experience fluxes that increase over the same time period. Spatiotemporal erosion trends depend on 1) the extent of vegetation recovery and 2) the extent to which MTR/VF creates slope–area disequilibrium. Valley fills and mine scarps experience erosion rates several times higher than those found in the unmined landscapes. Rapid erosion of mined areas drives deposition in colluvial hollows, headwater stream valleys, and below scarps. Our experiments suggest that reclamation focused on maximizing vegetation recovery and reducing hotspots of slope–area disequilibrium would reduce MTR's influence on Appalachian watersheds both during and long after the vegetation recovery period. Insights from MTR/VF-influenced landscapes can inform mined land management as the renewable energy transition drives increased surface mining.

Sources, spatial-distributions and fluxes of PAH-contaminated dusts in the Athabasca oil sands region

Atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) has increased in northern Alberta, Canada, due to industrial development in the Athabasca oil sands region (AOSR). However, the sources, summertime deposition fluxes and associated spatial patterns are poorly characterized, and the magnitude of contamination has not been directly contrasted with comparable measurements around large Canadian cities. PAHs were measured in Sphagnum moss collected from 30 bogs in the AOSR and compared with reference moss collected from various remote, rural and near-urban sites in Alberta and Ontario. At all 39 locations, strong correlations between depositional fluxes of PAHs and accumulation rates of ash (n = 117, r = 0.877, p < 0.001) implied that the main source of PAHs to moss was atmospheric deposition of particles. Average PAH concentrations at near-field AOSR sites (mean [SD], 62.4 [24.3] ng/g) were significantly higher than at far-field AOSR sites (44.9 [20.8] ng/g; p = 0.038) or the 7 reference sites in Alberta (20.6 [3.5] ng/g; p < 0.001). In fact, average PAH concentrations across the entire AOSR (7,850 km2) were approximately twice as high as in London, Ontario, or near petroleum upgrading and major traffic corridors in Edmonton, Alberta. A chemical mass balance model estimated that both delayed petcoke (33 % of PAHs) and fine tailings (38 % of PAHs) were the major sources of PAHs in the AOSR. Over the 2015 summer growing season, we estimate that 101–110 kg of PAHs (on 14,300–17,300 tonnes of PAH-containing dusts) were deposited to the AOSR within a 50 km radius of surface mining. Given that the highest PAH deposition was to the northern quadrant of the AOSR, which includes the First Nations community of Fort MacKay, further dust control measures should be considered to protect human and environmental health in the region.

Оценка направлений использования техногенных ресурсов при отработке различных видов минерального сырья

The paper reviews the issues related to closure of the Korkinsky coal mine in the Chelyabinsk Region. The authors describe the directions to utilize such man-made resources as open-pit excavation, overburden, and tailings generated during mining of coal and newly developed copper ore deposits. An assessment of possible ways to use man-made resources is provided in relation to abandonment of the worked-out Korkinsky coal mine. Backfilling with copper ore dressing tailings has been justified as the most rational way to abandon the worked-out coal strip mine. The paper describes the process of the backfill material production and its transportation to the discharge point. Backfilling of the Korkinsky coal mine with backfill material will help to solve environmental and social challenges of the region.

Постановка многокритериальной задачи анализа и прогнозирования гранулометрического состава взорванных горных пород

Changes in the mining and geological characteristics of solid mineral deposits, a sharp decrease in the ore grades in many ore fields as well as the intensification of surface mining methods define the need to develop scientific, theoretical and methodological foundations for improving the efficiency of the interaction between the technological elements within the Mine-to-Mill' (M2M) concept, which can be adapted to each specific mining operation and will help to streamline the operating costs. Drilling and blasting is the main technological operation to break the rock off the rock mass and crush it when mining solid minerals. The main purpose of drilling and blasting operations is to create rock material that has the necessary properties for smooth and efficient handling by mining equipment at the subsequent stages of the field development with due account of the technical and economic costs. Formation of the muck pile affects the subsequent technological processes of the mining operation, and consequently, the cost of the end product of the mining company. The purpose of the study was to develop a mathematical model for forecasting and analyzing the particle size distribution of rocks in the muck pile within the 'Mine-to-Mill' system. Methods used. The study is based on a comprehensive approach, which includes scientific analysis and generalization of previously published research results. From the methodological point of view, the study was based on the system analysis methods, as well as on the use of information technologies.

Intelligent Fleet Management Systems in Surface Mining: Status, Threats, and Opportunities

Intelligent Fleet Management Systems in Surface Mining: Status, Threats, and Opportunities

Геотехнологический потенциал открыто-подземной разработки угольных месторождений Кузбасса

The combination of surface and underground mining with the use of common industrial infrastructure at operating open-pit mines and those under construction is defined by the geotechnological potential of the integrated development of Kuzbass coalmines using the combined mining method. The description of key characteristics of technological solutions for coal deposits development by the surface, underground and combined methods are introduced in the article. The novelty of this work lies in developing the priority directions for combining open-cast and underground geotechnologies in a single mining method with the advantage of using unified industrial infrastructure for development of mineral deposits. The application area of open-pit coalmine opening and development schemes based on modular mining and technological structure of the combined method covers the range of conditions in operating, designated and prospective open-pit coalmines in flat-lying coal seams of Kuzbass.

Hydrochemical Characteristics and Control Factors of Surface Water in Kuaize River Basin at the Upper Pearl River

The Kuaize River is a small typical karst watershed in the source area of the Pearl River as well as an important coal mining area in Eastern Yunnan with a fragile ecological environment. Strengthening the research on the water environment in the region plays an important role in supporting the comprehensive management of the ecological environment and water resources in the source region of the Pearl River. Through the systematic collection of surface water, karst groundwater, and mine water samples, mathematical statistics analysis, correlation analysis, ion ratio analysis, absolute principal component scores multiple linear regression(APCS-MLR), and other methods were used to study the characteristics of hydrochemical evolution and control factors in Kuaize River Basin. The results showed that the average pH value of surface water in Kuaize River Basin was 7.8, which was weakly alkaline. The main cations were Ca2+ and Na+, showing the characteristics of Ca2+>Na+>Mg2+>K+. The main anions were HCO3- and SO42-, showing the characteristics of HCO3->SO42->NO3->Cl-. The variation coefficients of Na+, SO42-, and NO3- in surface water were high, showing strong spatial variability. The water chemical type of the trunk stream was mainly HCO3-Ca, whereas the water chemical type of the tributary was relatively complex, mainly HCO3-Ca, HCO3-Ca·Na, and HCO3·SO4-Ca·Na. The chemical composition of surface water was mainly affected by rock weathering, cation exchange, and human activities. Ca2+, Mg2+, Na+, and HCO3- in surface water mainly came from the weathering of carbonate rock and silicate rock; SO42- mainly came from the oxidation of sulfide, such as pyrite in coal seams; K+, Cl-, and NO3- mainly came from domestic sewage and agricultural activities. The APCS-MLR receptor model analysis results showed that the surface water in the Kuaize River Basin was mainly affected by sulfide oxidation, carbonate weathering, weathering of silicate rock in mine water, domestic sewage, agricultural activities, and unknown sources. In general, the contribution rate of human activities such as mining, domestic sewage, and agricultural activities to the surface water reached 47.17%, indicating that human activities were the key driving factor of surface water chemistry in the Kuaize River Basin.

Determination of long-term deformation behaviours with InSAR data at a dump site of an open-pit coal mine in Turkey

Dump sites with broken overburden layers in surface mines have the risk of instability due to their loose bulk structures. In this study, deformations at a dump site of the Kangal/Kalburçayırı open-pit coal mine and their long-term behaviours were revealed with InSAR data for a total period of 4.5 years. Firstly, 9-periods involving different time ranges were created considering the presence of LiCSAR products. Then, the deformation velocities of each period were calculated by LiCSBAS software using LiCSAR products. The area where high deformations were concentrated from the LiCSBAS result products was determined and divided into 4 zones for more detailed evaluations. At the final stage, the period-deformation velocity graphs were drawn separately for each zone with the data obtained using two different approaches from the deformation velocities of all periods, and long-term deformation behaviours were determined. More reliable future behaviour projections could be made considering the current increasing or decreasing trend of deformation behaviours. It was revealed that vertical deformations at the dump site had an increasing trend in the first periods and a decreasing trend in the later periods. Maximum vertical deformation velocities ranging between −111.4 mm/year and −178.0 mm/year in the first 4 months reached the highest values (ranging from −141.9 mm/year to −261.8 mm/year) at the end of two years and decreased to values ranging from −33.0 mm/year to −44.3 mm/year in the later periods. It was found that horizontal deformation velocities ranged between +0.5 mm/year and +55.4 mm/year in the east–west direction and between −7.0 mm/year and −56.8 mm/year in the west-east direction, were approximately 5 times lower than vertical velocities and did not have a constantly increasing or decreasing trend in any direction. It was observed that deformations exhibited a behaviour resulting from the structural property of the dump bulk material. The results of the evaluations showed that the risk of instability gradually decreased at the dump site. The methodology of this study can enable the determination of similar areas that may pose a threat in a short time, the prioritization of risky areas, the planning of more detailed studies, and taking the necessary measures in a timely manner.

INVESTIGATING THE REASONS FOR QUARRY SHUT-DOWN IN PLATEAU STATE, NIGERIA: A CASE STUDY OF AFRI-MINE QUARRY AND JOLEX CONSTRUCTION

Background: Quarry operation is one of the surface mining activity carried out in Nigeria. It involves different stages of operation such as blasting, crushing and lots more but due to financial loss, many quarry business has shut down while very few is still in operation. This research aim at identifying the reason(s) behind the incessant folding up of quarry business in Nigeria through comparative study between Afrimine Quarry and Jolex Construction. Results: Data was obtained through interactive interview with the staff in the quarry and after collation and data analysis, the following results were observed. Afrimine sells her granite within the price range of N3,300 to N5,200 for sizes of 1/2 inch, 3/4 inch, 3/8 inch, stone dust and makes a monthly profit of N36, 484,859.375 with a total volume of 15,000 tons per month and a unit price of N2,291.61/ton while Jolex Construction sells her granite within the prices of N7,500 to N8,000 and makes a monthly profit of N58, 295,000 at total volume of 9,000 tons per month with a unit price of N1022.78/ton. Conclusions: Quarry business is quite capital intensive but with the right managerial scheme, it can be a very profiting business.