 Subjects -> CONSERVATION (Total: 128 journals)
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- Remote sensing and GIS based approach to evaluate the impact of stone
quarrying and crushing activities on land resources
Authors: R. S. Chaurasia et al.
Abstract: The land is one of the most treasures to support life, like food, fibre, medicine, and minerals, etc. Stone quarrying is one of the key elements which supports socio-economic development and industrial expansion. RS and GIS play an important role in environmental assessment to monitor the stone quarries and related activities for time to time. The present study was carried out to evaluate the impact of stone quarrying and crushing activities (SQCA) on land resources. Therefore, matrix change analysis of 2021, 2015, 2008 and 2003 were used for change detection. High-resolution Google Earth Pro images were used for the assessment of spatial as well as temporal changes caused by stone quarries and associated activities, which result in land use/land cover changes. The results show that the temporal changes in and around the quarrying sites over 18 years have contributed to dynamic changes in land use/ land cover. According to the study, damaging mining operations have grown in the area. SQCA are mostly carried out on agricultural land as well as wasteland, which decreases about 18.44% and 59.89% during the study period. Abandoned pits left without reclamation converted to derelict ponds degrading the landscape and becoming dangerous for humans and the ecosystem.
PubDate: Thu, 24 Aug 2023 11:26:06 PDT
- Predictive model of seismic vibrations’ peak value induced by
multi-face blasting
Authors: Krzysztof Fuławka et al.
Abstract: The seismicity level induced by blasting in the Polish copper mines is very important inlight of the efficiency of active rockburst prevention and safe conduct of blasting operations in the vicinity of the mining infrastructure such as shafts, workings, or function chambers (e.g., workshops, storages, etc.). Knowledge of the seismic vibrations’ peak value might be the basis for designing blasting works in a way that ensures desired seismic effect. However, current experiences show that Peak Particle Velocity prediction models developed so far do not apply to multi-face blasting, where there are many vibrations’ sources at the same time dotted across the mining panel. This paper presents the assumptions of a new empirical model with validation data gathered in the underground trials of group blasting. This new method allows for determining the vibration level generated by firing a single face and the value of amplitude amplification resulting from the increased number of faces fired simultaneously in the group. Preliminary analysis shows that this newly developed predictive model is characterized by a high level of reliability and therefore was applied to assess the effectiveness of blasting works in the selected panel in one of the mines belonging to KGHM Polska Miedź S.A.
PubDate: Tue, 22 Aug 2023 09:10:10 PDT
- Managing the rock mass destruction under the explosion
Authors: Maksym Kononenko et al.
Abstract: Using the theory of elasticity and the main provisions of the quasi-static-wave hypothesis of the mechanism of the destruction of a solid medium under the action of an explosion, analytical modelling of the parameters of the formation of crumpling zones and crushing of the rock mass around the charging cavity during its explosive loading was carried out. Analytical models of the radii of the crumpling, intensive fragmentation and fracturing zones formed around the charging cavity in the rock mass during its explosive loading, taking into account the pressure of the explosion products, the limit of tensile-compressive strength of the rocks, their structural composition, fracturing and compaction under the action of rock pressure, were developed. Based on the change in the stress-strain state of the rock mass under the action of the explosion, numerical modelling of the radii of the zones of crumpling, intensive fragmentation and fracturing was performed using the finite element method. According to the simulation results, the power dependence of the change in the radii of the crumpling and fragmentation zones of the rock mass was determined depending on the diameter of the charging cavity, the pressure of the explosion products, and the limit of rock compressive strength. By comparing the results of analytical and numerical modelling for rigid boundary conditions of a homogeneous non-cracked rock mass, the difference in the values of the radii of the defined zones was established as being 4, 8 and 6%, respectively. The resulting analytical models of the radii of crushing zones, intensive fragmentation and fracturing increase the accuracy of estimating the parameters of rock mass destruction by explosion by up to 50% and improve the parameters of drilling and blasting operations when carrying out mining operations, special purpose cavities and rocking of the rock mass.
PubDate: Sun, 13 Aug 2023 13:09:19 PDT
- Application Geological Strength Index (GSI) quantification method on the
characterization of carbonate rock mass
Authors: Singgih Saptono et al.
Abstract: Determining GSI as a representation of the presence of rock mass in slope analysis continues to develop. The development of the quantitative GSI method was carried out because the basic (qualitative) GSI values were deemed too subjective so the results from the use of the quantitative GSIwere expected to be more objective and accurate. The method used is to combine 3 GSI quantitative methods to find GSI based on surface conditions and joint structure. The results showed that the Quantitative GSI value was smaller than the GSI predictive value (qualitative). The GSI approach with RQD and UCS parameters is also presented to describe rock mass conditions due to changes in GSI values, and the third result shows a directly proportional relationship, the greater the GSI value, the greater the RQD and UCS values. The combined application of these three quantification methods is suitable for slopes that have not been properly exposed so that surface and structural conditions can only be seen from visual observations of outcrops and some initial construction slopes.
PubDate: Mon, 07 Aug 2023 03:34:58 PDT
- Nickel recovery from low-grade laterites: study of thermal pre-treatments
to improve the efficiency of the hydrometallurgical process
Authors: Johana Borda et al.
Abstract: The processing of lower-grade laterites to obtain nickel has increased due to the gradual depletion of higher-grade sulphide ore reserves. However, the extraction from laterites has been limited because conventional technologies imply a considerable expense of energy or reagents. In this document, the effect of thermal pre-treatments on a laterite sample is demonstrated to improve nickel leaching under moderate conditions. The influence of agents such as coke, coal and NaCl in the heat treatment was also studied. With the results it is presumed that part of the nickel occluded in the goethite migrates to the iron oxides surface during the heat treatment; this is why the dissolution of nickel is linked to that of iron. The highest extractions (64.7% nickel) were achieved by combining heat treatment and leaching with 1M H2SO4 at ambient conditions. Compared to direct leaching of unpretreated laterite, leaching rates for this metal are increased by 26.5%. The chlorinating calcination and the optimization of the studied variables will be favourable to reach higher metallic extractions.
PubDate: Sun, 30 Jul 2023 22:19:43 PDT
- European feedback on post-mining seismicity
Authors: Isabelle Contrucci et al.
Abstract: Following the Paris Agreement adopted in 2015, Europe has committed to reducing its greenhouse gas emissions. In this context, the abandonment of coal as an energy source, both in terms of consumption and production, will lead to the closure of many mines in the years to come.Mine closure guidelines to manage residual mining risks already exist in European countries. However, they do not include post-mining seismic risk management due to a lack of sufficient studies and knowledge on this subject. After mining closure, the flooding of the mining works leads to hydromechanical loading of the underground and, in the longer term, to diffusion and an increase in the pore pressure. These conditions can lead, in certain situations, to the reactivation of tectonic faults, which may cause seismic events strong enough to be felt on the surface or even produce damage. Events of lower magnitudes, usually attributed to the remobilization of old mining works, are referred to as post-mining seismic hazards.The European RFCS PostMinQuake project, which started in 2020, aims to study this hazard at five mining basins located in France, Germany, Poland and the Czech Republic, known to have experienced significant seismicity during their operation. This analysis, based on the feedback of the partners of the project, aims to frame an inventory of the five studied mining basins, which all encounter post-mining seismicity problem today. Three basins out of five show events with local magnitudes of the order of 3 to 3.5, which took place between nine and thirteen years after the closure of the mines. Even though the magnitudes of these earthquakes are small to moderate, they are felt on the surface as they occur at shallow depths.In all of the considered countries, a national seismological network exists, however, none of them is fully dedicated to post-mining seismic monitoring. These networks generally consist of a sparse mesh of stations, which does not allow the detection of events of magnitude less than 1 and the location of events have high spatial uncertainties. France is not an exception, but it relies on microseismic monitoring to detect early signs of instability at the level of mining structures and to anticipate the possible appearance of surface disorders. Out of the five basins that are studied, the Gardanne basin, which has been monitored since 2008, is the most documented case study of post-mining seismicity. This article also shows the difficulty in identifying the key conditions and factors that can lead to the remobilization of faults.
PubDate: Sun, 30 Jul 2023 22:19:35 PDT
- Influence of cutting parameters on the performance of plough during hard
rock cutting in coal mining
Authors: Sathish Kumar Palaniappan et al.
Abstract: Coal ploughs have proved very successful on many faces in various parts of the world. Recently, there has been a general tendency in longwall working to increase the speed at which the machine progresses along the coal face. An increase in production rate demands enhances either due to depth of penetration or cutting speed. This, in turn, results in increasing power demand and also the force acting on an individual pick. To get maximum efficiency from a cutting machine, a number of parameters need to be investigated. The first and foremost thing of interest is naturally the pick geometry. The cutting force can be expected to depend mainly on the rack angle and clearance angle of the tool. The second parameter is the cutting depth, which when enhanced, increases the rate of advancement and, at the same time, results in enhanced cutting force. This results in large power demand and increases wear of picks. Thirdly, cutting speed, in which higher cutting speed will increase the production rate but at the same time is expected to enhance the power demand and the cutting force. This paper aims at investigating the cutting efficiency of the plough by simulating the coal cutting operation in the laboratory. The effect of three main parameters like pick geometry, cutting depth, and cutting speed, on cutting efficiency have been studied in detail. The cutting force elevates at a faster rate with an increase in depth at higher speeds. The percentage increase in force is nearly 20% for a speed increase of 20%.
PubDate: Mon, 17 Jul 2023 12:00:45 PDT
- Geophysical imprint of mining-induced rock mass deformation in the area of
construction disaster in Bytom (Poland)
Authors: Andrzej Kotyrba et al.
Abstract: The paper presents the analysis of the results of geophysical surveys conducted in the mining area located in Bytom – Karb (USCB, Poland) in the aspect of identifying the causes of significant damage to the complex of inhabited tenement houses which occurred in 2011. The surveys were carried out by microgravimetric and GPR methods. The construction disaster was caused by the exploitation of one of the hard coal seams at a depth of about 800 m along the mining longwall running underneath the settlement. The terrain deformation parameters exceeded the forecasted values, and in several places discontinuities took linear forms along the diagonal directions to the front lines of the longwall. In addition to the sliding movement, the rotational movement appeared in the ground. As a consequence of spatially complex ground movements, some buildings suffered significant damage. The extent of the damage turned out to be catastrophic and immediate relocation of the inhabitants and demolition of the buildings became necessary. The article is an attempt to explain the nature and the causes of excessive terrain deformations in relation to those modeled on the basis of analysis and interpretation of geophysical data from the current measurements as well as archival maps and geological and mining cartography data.
PubDate: Fri, 14 Jul 2023 09:25:05 PDT
- Status and prospects of fully mechanized mining technology in Vietnam coal
mines from 2005 to 2020
Authors: Hai Duong Duc et al.
Abstract: This paper analyzes the achievement and the failures of applying the mechanized mining method in underground coal mines by the Vietnam National Coal – Mineral Industries Holding Corporation Ltd. (VINACOMIN) for 15 years (from 2005 to 2020). It also proposes the recommendations for developing mechanized mining in order to improve coal production, productivity and safety management for the sustainable development of Vietnam’s underground coal mining in the period 2021-2025
PubDate: Thu, 29 Jun 2023 04:59:09 PDT
- Evaluating the impacts of the transition from open-pit to underground
mining on sustainable development indexes
Authors: Naser Badakhshan et al.
Abstract: Sustainable development is about creating a balance between development and environment, and it consists of three essential principles: environment, society, and economy. Today, one of the most important challenges in deep open pit mines is the transition from open pit to underground, which has positive and negative impacts on sustainable development indexes. In order to reduce these adverse impacts, the impact of various parts of the transition operation on these indexes should be evaluated and corrective and preventive measures should be implemented. In this study, using a hybrid semi-quantitative approach, the effects of the transition in the Songun copper mine were evaluated. The obtained results showed that the transition in Songun copper mine has the greatest impact on the economic index of sustainable development with a value of 67.72 percent. In addition, the amount of impact of transition in this mine on environmental and social index is 41.74 and 39.84% respectively. In the meantime, the most significant impact was determined on components such as production rate and productivity, mine life, operation and capital cost, mineral value and income per ton of ore, mine closure (and reclamation) cost, Initial investment rate of returns, post–mining land use type.
PubDate: Wed, 28 Jun 2023 09:05:00 PDT
- Applications of UAVs in mine industry: A scoping review
Authors: Dang Tuyet Minh et al.
Abstract: In recent years, a variety of technologies have improved mining operations. One of them is the Unmanned Aerial Vehicles (UAVs), the emerging technology that has been changing the mining process, boosting mining safety and productivity. The main purpose of this paper is to review the applications of UAVs in the mining industry based on the results of 113 research papers over the past twelve years, from 2010 to May 2022. The potential applications of UAVs in the mining industry are broad. Based on the paper identified, eight categories are used to classify UAV applications in the mining sector. The reviewed literature revealed that UAVs are an excellent tool for multitasking at any stage of a mining project and in any type of mine. The findings of this study may serve as some guidelines for developing the necessary requirements for the use of UAV technology in mine sites.
PubDate: Tue, 27 Jun 2023 04:29:11 PDT
- Research on stability of rock mass and +30 level surface construction
works when re-exploiting the seam H10 at Mong Duong Coal Mine, Vietnam
Authors: Tien Trung Vu et al.
Abstract: The re-exploitation of coal seams located near the ground is one of the solutions to increase output, reduce mining investment costs, and avoid wasting coal resources. The re-exploitation of coal seams will also cause instability of the surrounding rock mass and may affect surface construction works. Through the process of re-exploiting the longwall in seam H10 at Mong Duong Coal Mine, the authors have studied and evaluated the stability of the rock mass and +30 level surface works (including fan station and gateroad). To achieve the results in this study, the numerical simulation model method and the analytical method were applied. The model analysis results have determined that the displacement and deformation areas of the rock mass around the mining area correspond to the length of the cut in the strike direction of the longwall H10. The analysis and calculation results from the model show that the longwall in seam H10 can be re-exploited when leaving a protective coal pillar about 50 m from the center of the +30 fan station at the east side; this distance ensures the stability of the rock mass that located near the ground and the surface works at +30.
PubDate: Thu, 22 Jun 2023 23:49:37 PDT
- Evaluating the post-mining land uses of former mine sites for sustainable
purposes in South Africa
Authors: Sphiwe E Mhlongo
Abstract: This paper uses a case study of an abandoned magnesite mine in the Limpopo Province of South Africa to find ways of identifying post-mining land used from the current uses of the abandoned mine sites or features. The approach used involved carrying out a field characterization of the mine site and documentation of the current uses of the features of the abandoned mine site. The technique used to identify the internal and external factors of the land uses involved analyzing their Strength, Weakness, Opportunities, and Threats. The Analytic Hierarchy Process (AHP) technique was used for further ranking of the land uses to identify the most post-mining or rehabilitation land uses for the different parts of the mine. Lastly, the earthwork requirement in reshaping the terrain of the mine to support the selected land uses was estimated from the 3D-terrain models generated from height data collected using a Real-Time Kinematic Geographical Positioning System. The results of the study identified land use that needs further surface development as the most appropriate for the abandoned Nyala Mine. These land uses demonstrated the potential of addressing the hazards of the mine with the clear promise of improving the socio-economic status of the host communities.
PubDate: Thu, 22 Jun 2023 03:15:58 PDT
- Time variability of methane extraction from hard coal deposits in the
Upper Silesian Coal Basin (Poland) in relation to geological and mining
conditions
Authors: Sławomir Kędzior et al.
Abstract: The extraction and economical use of methane from coal mines in the Upper Silesian Coal Basin, Poland (USCB) have shown a variable tendency in recent decades, with numerous fluctuations from year to year. In 2021, approximately 286 million m3 of methane was collected from coal mines, which accounted for approximately 40% of the total emissions of this gas to mine workings. Due to the fact that the economical use of coal mine methane brings environmental, economic and work safety benefits, increasing its extraction is an urgent need. Trends in changes in the amount of mined methane in the entire USCB and in the deposits where the most methane was extracted in the last 25 years were analysed. The most important potential factors influencing the variability of coal mine gas extraction were taken into account, i.e. elements of the geological structure, coal extraction, methane emissions, mining and technical conditions, etc. The directions for using the collected methane and the main consumers were discussed. The aim is to indicate the most important problems faced by coal mining in terms of the capture and management of methane over the last 25 years and to outline possible solutions.
PubDate: Tue, 20 Jun 2023 09:10:05 PDT
- Diagnostic gold deportment studies and leaching behaviour of small-scale
gold mining tailings from Eastern Region, Ghana
Authors: Ishmael Quaicoe et al.
Abstract: Artisanal and small-scale gold mining (ASGM) sector employs about 80% of the mining workforce but only contributes about 20-30% of Ghana’s gold production. The low gold production is linked to low recoveries associated with the activities because ofinadequate understanding of the chemical, mineralogical and metallurgical characteristics of the ores. This study examined the metallurgical characteristics of typical small-scale gold mining tailings to understand their grinding characteristics, gold deportment and cyanidation behaviour. The gold deportment results showed that 96.1% of the gold in the samples is free milling (can be leached directly with cyanide and recovered through carbon adsorption), whilst the remaining 3.9% of the gold in the samples is associated/locked up with other mineral phases (carbonates, sulphides, carbonaceous matter and quartz). The gold-by-size distribution also indicated that 73.1% of the gold is contained in coarser size fractions (+150 µm), 14.96% isfrom–150 µm to +75 µm size range, and 11.83% is contained in the finer size distribution (–75 µm). This suggests that incorporating a gravity recovery system during processing will be highly advantageous. The leaching kinetics results showed that gold recoveries achieved within 8, 16 and 24 h were 68, 73.8 and 76.4%, respectively. The corresponding total cyanide consumption rates after 8, 16 and 24 h of leaching were 550, 580 and 600 ppm, respectively. Generally, the gold recoveries and the cyanide consumption rates agree with industrial practices/results. Overall, the outcomes of the study support the view that some small-scale gold mining tailings are economically viable, and hence can be re-processed through efficient processes such as carbon-in-leach/carbon-in-pulp.
PubDate: Thu, 30 Mar 2023 13:33:48 PDT
- Acknowledgments of Reviewers
PubDate: Mon, 16 Jan 2023 03:07:53 PST
- Hitting two birds with one emissions-based maintenance stone – a
literature review on improving overall productivity of underground diesel
fleets
Authors: Johannes Deon Swanepoel et al.
Abstract: Many industries regard occupational health and safety as a core value and an integral component to maintaining high productivity, and, thus, shareholder value. Diesel fleets’ engine maintenance is instrumental in ensuring affected workplaces meet production requirements while controlling health and safety hazards that these fleets introduce to the workplace. This systematic literature review focuses on production and occupational health and safety advantages associated with the implementation and adherence to an emissions-based maintenance (EBM) program. The literature review was conducted across eight databases relevant to workplace health and engineering. To be eligible for inclusion, the publication had to contain maintenance interventions that were informed by diesel engine emissions (DEE) data. Eight publications met the inclusion criteria. The quality of evidence was evaluated by applying the Authority, Accuracy, Coverage, Objectivity, Date, and Significance (AACODS) checklist [1]. There is a paucity in peer-reviewed EBM literature. Available research show evidence for productivity gains such as reduced DEE at the source, reduced fuel consumption, reduced worker exposure, and anecdotal evidence for extended exhaust aftertreatment (EAT) service life. There was no evidence that EBM improved fleet management (measured as fleet availability and reliability) or resulted in reduced underground dilution ventilation delivery.
PubDate: Mon, 09 Jan 2023 07:13:48 PST
- Research on vibration-based early diagnostic system for excavator motor
bearing using 1-D CNN
Authors: Dorjsuren Yandagsuren et al.
Abstract: In mining, super-large machines such as rope excavators are used to perform the main mining operations. A rope excavator is equipped with motors that drive mechanisms. Motors are easily damaged as a result of harsh mining conditions. Bearings are important parts in a motor; bearing failure accounts for approximately half of all motor failures. Failure reduces work efficiency and increases maintenance costs. In practice, reactive, preventive, and predictive maintenance are used to minimize failures. Predictive maintenance can prevent failures and is more effective than other maintenance. For effective predictive maintenance, a good diagnosis is required to accurately determine motor-bearing health. In this study, vibration-based diagnosis and a one-dimensional convolutional neural network (1-D CNN) were used to evaluate bearing deterioration levels. The system allows for early diagnosis of bearing failures. Normal and failure-bearing vibrations were measured. Spectral and wavelet analyses were performed to determine the normal and failure vibration features. The measured signals were used to generate new data to represent bearing deterioration in increments of 10%. A reliable diagnosis system was proposed. The proposed system could determine bearing health deterioration at eleven levels with considerable accuracy. Moreover, a new data mixing method was applied.
PubDate: Mon, 09 Jan 2023 07:13:39 PST
- Predicting Young’s modulus of Indian coal measure rock using multiple
regression and artificial neutral network
Authors: Sayantan Chakraborty et al.
Abstract: Accurate information on Young’s modulus (E) is required for simulating rock deformation in mines; on the other hand, it is very cumbersome to obtain in the laboratory and collecting drilled cores in sufficient amounts, especially in the case of soft rocks, is quite impossible. Empirical equations were deducted for E from easily determinable rock properties, and the final model was selected through different statistical strength parameter tests. The generalization of the equation was verified through the normal distribution tests of residues of the equation. R2 came to be 0.609 and was validated using an artificial neural network with an improved value of 0.73
PubDate: Sun, 01 Jan 2023 07:47:59 PST
- Gravity and electrostatic separation of unburned coal from a selected fly
ash
Authors: Krzysztof Wierzchowski et al.
Abstract: Unburned coal grains make it difficult to use fly ash economically, which causes energy losses in the fuel. The article presents the possibilities of separating unburned coal from selected fly ash. In order to assess the possibility of separation of unburned carbon, the analysis of grain density and ash composition was used. Unburned coal was separated by four methods – one wet gravity and three dry methods. It has been found that despite very fine ash grains, the quality and quantity of separation products are significantly dependent on the separation method used and the separated grains’ qualitative characteristics. The analysis of the coal grains under an electron microscope has revealed that they contain mineral inclusions. Their presence enables selective separation of carbon without first grinding the middling grains. The most advantageous results of the separation of unburned coal were obtained by the electrostatic separation method. Separated coal can be used in high-value carbon applications.
PubDate: Sun, 01 Jan 2023 07:47:52 PST
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