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- Spatio-Temporal Changes in the Gravity And Post-Mining Seismic Activity in
Abandoned Deep Coal Mine Kazimierz-Juliusz During Flooding
Authors: Andrzej Kotyrba et al.
Abstract: The flooding of an underground hard coal mine, resulting in the filling of post-mining voids (workings and goafs) and the repeated saturation of pore and interstitial spaces of the adjacent rock with water, change the mass and its distribution in the near-surface part of the earth’s crust. This process is slow and lasts many years. As a result, the local gravity field undergoes dynamic changes. It depends on the surface morphology and the density of geological strata, which is related to their water content. Changes in the local gravity field can be monitored by periodic gravity surveys performed in the area of the flooded mine using portable spring gravimeters. This paper presents the results of gravity monitoring surveys conducted in the area of the abandoned coal mine Kazimierz-Juliusz (K-J) in Poland, which is in the process of flooding. Gravity surveys were conducted at yearly intervals spanning 2021–2023. We used a high-precision CG-6 gravity meter manufactured by Scintrex LTD, allowing for relative gravity measurement with an accuracy of order 0.005 mGal. In the collected data set, the rates of annual gravity change ranged from -0.04 mGal to 0.04 mGal. The K-J mine was closed in 2016, and since then, the rock mass in the zone between the deepest workings (about 750 m) and the surface has been undergoing repeated water saturation. In 2021–2023, the water table in carboniferous rock mass was located at an estimated depth of 380 m and moved up to a depth of 330 m. An average yearly increase of the water table level oscillated around 18 m per year. During this period, over 50 seismic tremors of local magnitude ranging from 0.6–2 and ground deformations on the surface were recorded in the K-J mine’s area. Surface deformations recorded in this area by GNSS surveys had a form of subsidence and uplifts. The annual rates of surface movements ranged between –11 cm (subsiding regions) and +3 cm (uplifting regions). The main objective of this paper is to identify the relationship between seismic phenomena and observed variations in the local gravity field distribution, factoring in the mining activity performed and changes in terrain relief. However, the data presented in the article indicate that in the coal mines, in the process of flooding, there are threats to the surface similar to those during the mining period (surface deformations and soil vibrations). In view of the collected data, their intensity is lower than of those observed during the mine’s operation. As the gravity field is the primary factor shaping the dynamics of a geological medium, the research results indicate that gravity monitoring is essential in studies of safety in post-mining lands.Keywords: coal, mines, liquidation, flooding, gravity, seismicity
PubDate: Fri, 02 Aug 2024 03:36:46 PDT
- Enhancing fuel injection system reliability through Weibull family
functions analysis
Authors: Ali Nouri Qarahasanlou et al.
Abstract: The efficient operation of heavy machinery is crucial to the success of mining and civil construction operations. To guarantee this performance, equipment performance is assessed using the Reliability Index, which analyzes failures to study the ability of a system to carry out its intended functions under predetermined conditions. On the other hand, the failure rate and operational environmental condition (such as management decisions, maintenance performance, etc., that are defined as “risk factors”) over the life cycle of industrial systems pose a significant challenge to reliability analysis. This paper proposes an approach to address these challenges by extending Weibull family functions with regression models. Then, the effectiveness of this approach using 12-month failure data from the Komatsu 785-5 dump-truck engine refueling system is demonstrated. The most appropriate reliability function for two scenarios with different environmental conditions over the performance interval is fitted. The results indicate that both scenarios exhibit lower reliability than the baseline, highlighting the influence of environmental conditions on equipment reliability.Keywords: Mining Truck, Reliability, Weibull distribution family, Proportional hazard model, Fuel injection system
PubDate: Wed, 31 Jul 2024 10:11:09 PDT
- Influence of the moisture on fumes derived from the ANFO detonation
Authors: Andrzej Biessikirski et al.
Abstract: ANFO is one of the most commonly used explosives in open-pit mining, usually produced by mixing systems on the blast site. One of the problems usually not considered is the moisture”s influence on the stored ammonium nitrate(V). The influence of moisture on fumes and the detonation process has been investigated by placing ammonium nitrate(V) prills in the climatic chamber. In the investigation, the influence was evaluated for ANFO samples which were produced based on the two types of fuel oils. It was concluded that the 3.0% moisture level resulted in the lowest NOx content in both case studies. Further increased moisture resulted in blending problems (water absorption instead of fuel oils). An additional evaluation was made to stimulate the influence of wetted boreholes. The data showed that the equivalent mass of water present in the borehole would generate more fumes compared with the explosive produced from wetted ammonium nitrate(V) prill. Moreover, it was established that the second type of fuel oil can be applied as a fuel component, especially in the winter season.Keywords: explosives, ANFO, moisture, fumes, ammonium nitrate(V)
PubDate: Wed, 03 Jul 2024 05:05:34 PDT
- Modified method for assessing the required expenditures and estimated time
of hard coal mine liquidation
Authors: Andrzej Chmiela et al.
Abstract: The restructuring of hard coal mining requires significant budgetary expenditures. A comprehensive scientific approach may facilitate the rationalisation and minimisation of mine closure costs. This study proposes a method for the preliminary estimation of the costs and time required for the potential liquidation of a hard coal mine. In addition to a literature review, a statistical analysis and a case study, personal interviews were conducted with individuals with direct management over the restructuring, reclamation and liquidation processes pertaining to mines undergoing closure.The assessment method is based on an analysis of the mine liquidation costs, divided into successive years of the course of the aforementioned processes. The method does not pertain directly to the specific liquidation processes conducted at SRK S.A., but it can also be employed by any entity conducting mine liquidation as a comparative tool for the detailed and multi-criterial estimation of the costs of planned mine closure.
PubDate: Thu, 13 Jun 2024 06:30:32 PDT
- Study on law and influencing factors of air leakage in isolated island
working face with large burial depth
Authors: Gang Wang et al.
Abstract: During the mining of a single coal seam isolated island work surface with large burial depth, the high mine pressures can crush and break the protective coal pillars, causing serious air leakages in the rear goaf. Herein, we use the analytic hierarchy process(AHP) to determine the main influencing factors of air leakage in island mining face. The air leakage source and sink in goaf were determined by measuring the differential pressures between the island mining face and the adjacent goaf using the energy level measurement method. The air volumes in the roadways were monitored on site to quantitatively analyze the specific changes of the air leakage in the isolated island work surface. Finally, the air leakage prevention measures were evaluated for the air leakage reduction efficiency in the island mining face and the goaf. Research shows that: (1) The fissure development in the roadway wall is the main influencing element of the air leakage in the isolated island work surface; (2) The differential pressure causes the air leakage volume of 37-40 m3/ min from the goaf to the island mining face; (3) Shotcrete in the gob-side roadway of the isolated island work surface can reduce the air leakage by 78%.
PubDate: Wed, 05 Jun 2024 12:05:27 PDT
- Prototype device for measuring the dustiness of stone and lime dust used
in explosion prevention
Authors: Adrian Toman et al.
Abstract: This paper presents the prototype of a device for measuring the dustiness of powdered materials by means of a new measurement method. The currently employed stationary laboratory device, utilised in KD “Barbara”, uses the attenuation of a radiant flux transmitted through a dust cloud induced by a manually generated air blast. The new device uses the same measurement method, but it includes modern elements based on a microprocessor, a laser line generator instead of an LED diode, and a precise multi-channel detector. The generated quantity of the mixture (dust and air) is strictly determined and precisely dosed via buffer containers, pressure sensors, and high-speed solenoid valves. Utilising the new solutions will make it possible to improve the repeatability of the air blast parameters and the detection of the dispersed dust cloud, which will enable a better evaluation of the tested dust quality. The paper presents a prototype of a device for measuring the dustiness of stone and lime dusts. The device can also be used to determine the dustiness of other powdered materials.
PubDate: Sat, 01 Jun 2024 01:21:04 PDT
- Tracking mining company electric vehicles for sustainable development
optimization using Distributed Ledger Technologies
Authors: Teodora Hristova
Abstract: It is established that based on the industrial revolutions towards Industry 5.0, the population of the Earth and its well-being are increasing. To preserve and improve living conditions the development in all spheres of life is by the paradigm of sustainable development. Through the prism of the mining industry, one step could be the introduction of circular economy measures for digitized tracking of materials, repairs, consumed electricity, safety, and finances. Implementing of electric cars is an option to achieve this goal through automation, manageability, and data traceability via Industry 4.0 technologies. Such are blockchain technologies, IoT, V2V, and others. For this purpose, the appropriate types of power supplies for electric vehicles for the mining sector have been identified and information flows have been defined. They are quantity of material, consumed electricity, state of the fleet, charging of batteries and operation of charging stations, and finances. For their implementation, Hyperledger Fabric was chosen as a suitable DLT platform ([1], [2]). Based on Hyperledger Fabric, a conceptual model for tracking material quantities as a step of the circular economy is proposed. A method of communication is shown in the presence of two channels - material and repairs for an electric car.
PubDate: Sat, 01 Jun 2024 01:20:56 PDT
- Double acting liberation of Ni and Co in the pre-treatment process to
increase recovery of nickel from low-grade nickel laterite
Authors: Eni Febriana et al.
Abstract: This study highlights the effectiveness of employing double-acting liberation to release Ni and Co from the complex phases of the low-grade nickel laterite. It includes the addition of concentrated sulphuric acid and NaF as well as the heat treatment prior to roasting and leaching processes to improve the destruction of the complex phases contained. The finding describes that dehydration of iron sulfate and decomposition of the lizardite at a lower temperature, 270°C, were occurred in the pre-treatment process, followed by hematite formation in the roasting process. It subsequently accelerated Ni and Co extraction in the pregnant solution and omitted Fe as the water-insoluble hematite in the residue when the leaching process was employed. The optimum leaching percentages of nickel and cobalt are 71.3% and 98.8%, serially, and were obtained at a roasting temperature of 700°C for 30 minutes with the addition of 3 wt.% sodium fluoride. This research provides essential contributions to the optimization of decomposition process for complex phases of in the low-grade nickel laterite at a lower temperature and to upsurge leaching percentage of Ni and Co by strictly suppressing Fe dissolution.
PubDate: Sat, 25 May 2024 13:25:22 PDT
- Bibliometric review of the landscape and thematic structure of research on
sustainable mining in ASEAN, 1942–2022
Authors: Nathatai Janjirawatna et al.
Abstract: This bibliometric review addressed the lack of consolidated information on the current state of sustainable mining in the ASEAN region. The review analyzed bibliographic data associated with 539 Scopus-indexed documents on sustainable mining in ASEAN nations published through the end of 2022. Descriptive statistics identified a great disparity in the scope of research on sustainable mining practices across the ASEAN countries. Surprisingly, a significant portion of the extant research on sustainable mining in the region has been authored by scholars from outside of ASEAN. Keyword analyses highlighted several emerging research topics including life cycle assessment, conservation of natural resources, climate change, and artisanal and small-scale mining. Findings from the review emphasize the need to develop and implement more comprehensive and standardized frameworks for sustainable mining within ASEAN. The findings also suggest a potential for greater coordination and more focused attention to regional regulations and policies. Several directions for future research are also proposed.
PubDate: Tue, 07 May 2024 21:54:35 PDT
- Environmental health impacts of small-scale gold mining in East Indonesia:
mercury pollution and nature conservation
Authors: Tri Edhi Budhi Soesilo et al.
Abstract: The expansion of small-scale gold mining impacts environmental health and socioeconomic. Research in Bombana District, one of the gold mining centers in eastern Indonesia, was conducted to explore perceptions of the impact of small-scale gold mining on human health and attitudes towards environmental conservation activities related to small-scale gold mining activities. This research uses a quantitative approach with univariate tests to identify respondent characteristics, bivariate tests (Chi-square) to test relationships and frequency differences, and multivariate analysis (regression) to test the direction and magnitude of the relationship. The perception of the impact of small-scale gold mining on human health was not significantly related (p=0.576) to community participation in environmental conservation activities. Attitude variables related to nature conservation are partially significantly related to community participation in environmental conservation activities (p=0.001). Respondents with a poor attitude regarding environmental conservation activities are 17.1 times more likely to not participate in environmental conservation activities than respondents with a good attitude. Although mining activities benefit several sectors, it is undeniably detrimental to the environmental health sector, where one of the critical impacts is the mercury content in the soil and water in the environment around mining. Therefore, local people should take advantage of locally-based nature conservation.
PubDate: Thu, 18 Apr 2024 09:34:52 PDT
- Critical raw material in mineral elements found in fly ashes from the
Czech Republic power plant
Authors: Agnieszka Klupa
Abstract: The economic development of EU countries is limited due to limited access to a number of mineral raw materials, which necessitates actions aimed at securing the supply of CRM. For this reason, CRMs constitute elements of particular importance for the EU. The aim of the study was to assess the content of CRMs as a potential source of REY in fly ash resulting from the coal combustion in one of the power plants in the Czech Republic. In the tested ash the main phases are: glassy phase, mullite and quartz. The chemical composition of the tested fly ashes showed dominance of SiO2 and Al2O3. The CRM included Co, Sb, W, Be, Nb, Ga, lanthanides and Y, as well as Cr and In. Light elements have the largest share among REE, while heavy elements have the smallest share. In the tested fly ash, the share of critical elements, the content of uncritical elements and the content of excessive elements in the total REY content were also determined. Based on the analyzed results, the value of the Coutl prospective coefficient was calculated, which assesses the profitability of obtaining CRM from fly ash as an alternative source of these metals.
PubDate: Wed, 17 Apr 2024 13:30:33 PDT
- Induced oxidation effects on physical and mechanical properties of lignite
from Tempoku, Hokkaido, Japan for sustainable mining via subsurface
cultivation and gasification method
Authors: AKM Badrul Alam et al.
Abstract: The lignite resource has been under consideration for the subsurface cultivation and gasification (SCG) method to produce biomethane from lignite in Hokkaido, Japan. The primary phase of the method entails initiating the oxidative transformation of lignite using an H2O2 solution, resulting in the formation of dissolved organic carbon (DOC), a pivotal component. To examine the effects of induced oxidation on lignite's mechanical properties, artificial oxidation tests were conducted to form DOC. While there was a slight decrease in P-wave velocity and density, the uniaxial compression and indirect tensile strengths, as well as stiffness, did not decrease. These results were obtained at room temperature and atmospheric pressure. Therefore, further examination of the results under pore and confining pressures and at a higher temperature is necessary. However, it is expected that a significant strength decrease due to H2O2 oxidation would not need to be considered in the SCG method. This would lead to a reasonable design of the SCG site, saving time and costs. Moreover, DOC, strengths, and Young’s modulus showed positive correlations with P-wave velocity. Its measurement could be an effective tool for designing the site and predicting the performance of the SCG method.
PubDate: Tue, 16 Apr 2024 09:40:54 PDT
- A biocompatible hybrid approach for the selection of gas drainage methods
Authors: Amir Jafarpour et al.
Abstract: Methane drainage is one of the main steps in underground coal mining projects. The operation of methane extraction from coal mines/seams is important from the safety, economic, and technical points of view. Selecting the appropriate method for methane drainage is very difficult, and if the method is not chosen correctly, it will lead to environmental problems. The relationship between different influencing factors, parameters, and methods (and how they affect) is significant in choosing the method of gas drainage. In the current study, a hybrid algorithm is presented based on an Analytic Network Process (ANP) and a method based on the mathematical model (BWM). In the presented approach, the weighting of criteria by the BWM method and ranking of alternatives based on effective criteria is performed using the network analysis-based method. “Operating and capital costs” were the most effective criteria, and “in-situ stress” was the least effective factor in the selection process. The results show that the “post‐drainage method using cross-measure boreholes” was ranked first with the highest score (0.249). Applying the selected method in the Tabas coal mine (case study) indicates that the proposed algorithm is compatible with real-world conditions and can have various applications in multi-criteria decision-making problems.
PubDate: Fri, 12 Apr 2024 02:25:22 PDT
- Analysis of the key performance indicators between lithologies on Mine to
Crusher
Authors: Janine Figueiredo et al.
Abstract: The evolution of the mineral economy requires greater technological developments to find a better use of resources and reserves through the relationships between the characteristics of the rocks and the need to enable the entire mining enterprise. This study focuses on the development of new rock blasting technologies that result in a more optimized fragmentation according to the lithology in the feed of the primary crusher. This methodology is known as Mine to Crusher, through which it becomes possible to minimize costs in the future prospecting of the mine and maximize productivity. For this methodology to be developed, it was necessary to implement the Mine to Crusher model. Through this project, the key performance indicators (KPIs), such as average productivity, availability and utilization of the equipment, and a nominal capacity observed in the crushing circuit, were analyzed. Furthermore, by observing the results, it became possible to evaluate the KPIs must be adjusted for better equipment performance and better development and planning of the mining project. Through this project, it was possible to carry out a probabilistic analysis of the project's KPIs using a Monte Carlo simulation. At the end of the work, it became possible to verify the relationship between more compact and less compact lithologies, where there is a difference in results depending on the lithology and properties evaluated. At the end of the evaluations, a difference in the penetration rate and productivity between the CI and FI lithologies of 26.99% and 26.78% respectively was verified. It is also possible to verify that when carrying out sensitivity tests for lithologies, friable lithologies require a reduction in a fixed time of 6%, whereas more compact lithologies require an increase of up to 2% in their time.
PubDate: Fri, 05 Apr 2024 10:55:02 PDT
- Review on quarrying methods suitable for space mining missions
Authors: Daniel Chpolianski et al.
Abstract: In this review paper, existing mining techniques and technologies are scrutinized for the purpose of superterrestrial use. Different aspects and challenges of a space mining mission are examined in light of the viable iron-nickel quarry operation on M-Type (metallic) asteroids. The research and findings presented in this work cover different disciplines of science and engineering, including Geology, Rock Engineering, Space Exploration, and Explosives Engineering. The particular focus of this study is on the application of shaped charge explosives in military munitions, oil well perforations, tunneling, open-pit mines, and bolder fracturing that could be deployed in asteroid mining missions. The central proposal of this research is a methodology to carve out a solid iron-nickel quarry slab, properly shaped to enter Earth’s atmosphere and land independently, without spacecraft or landing capsule, thus offering an economically feasible solution to space mining.
PubDate: Fri, 29 Mar 2024 01:20:34 PDT
- Municipal waste management based on geomechanical assessments of the
landfill site slope – a case study in southern Poland
Authors: Tomasz Janoszek et al.
Abstract: Over time, municipal waste landfills tend to go higher and become larger. The stability of the municipal landfill slope is one of the basic geotechnical tasks. This task ensures continuous waste deposition on the landfill surface and safety in its surroundings. With the increasing height and volume of the landfill, it is difficult to estimate the available area of the municipal landfill, where more waste can be safely deposited due to a number of variable factors, such as the geotechnical conditions of the municipal landfill, the morphological composition, age, and degree of compaction and decomposition of the deposited waste.This paper presents an attempt to determine the available area of a landfill where municipal waste can be safely deposited for further operation. For this purpose, a numerical slope stability analysis was carried out using the finite difference method code FLAC3D, presenting the actual geomechanical conditions of a landfill located in southern Poland. Based on the numerical results, options for municipal waste storage were presented and discussed. The proposed design chart aims to help landfill owners/managers make an adequate decision in terms of landfill planning and design.
PubDate: Thu, 28 Mar 2024 00:45:54 PDT
- Difficulties of hydrofracturing in sandstone – experimental study
Authors: S Vikram et al.
Abstract: Hydrofracturing in sandstone is not an easy task. Sandstone is porous; fluid dissipation is common hence unable to obtain breakdown pressures in certain flow rates (0.0000005–0.0001 m3/s). The higher flow rate (0.00025 m3/s) is ascertained to determine the fracturing pressures. Due to this, fracture propagation and delineation are observed [1]. To enhance, an experimental method is adopted by carrying out 6 Hydrofracturing tests in a borehole comprising sandstone. A high flow rate of 0.00025 m3/s and viscosity 0.001 Pascal second is applied. Later, the fracture simulation was run on 12 core samples collected from the same depths in a lab. The fluid flow rates of 0.0000005–0.0000015 m3/s, viscosity 0.27 Pascal-second, pore pressure of 4 MPa, confining pressures in vertical-12 MPa and horizontal 6, 18, 24, 30 MPa is applied. The fracture traces and the stress results exhibit a difference of 80 to 300 observed in both cases. The major principle stress orientation obtained in the borehole is 20 and 40. In lab tests with confining horizontal pressures at 6 and 18 MPa, it is 120 and 130, and at 24 and 30 MPa is 20. This indicated that there is fracture delineation occurred. It is observed in the higher flow rate and confining pressures.
PubDate: Sat, 09 Mar 2024 00:45:15 PST
- Contribution of mine water and uranium ore rocks to the 222Rn-induced
radiation dose received by the mine workers in a low-ore grade underground
uranium mine, India
Authors: Imran Athar Beg et al.
Abstract: More than 50% of the radiation dose received by underground mine workers is mainly due to the inhalation of radon (222Rn) gas and its decay products in an underground mine working space. Monitoring and controlling of 222Rn exhalation in the underground mine working plays a vital role in minimizing the radiation risk hazards to the mine-workers. This study discusses the contribution of mine water and uranium ore to 222Rn activity concentration in mine air and its health risk assessment. The annual effective radiation dose (ERn) due to inhalation of 222Rn for mine workers is estimated 0.10 mSv/y. Furthermore, the estimated Excess lifetime cancer risk (ELCR) and radoninduced lung cancer per million per person (RnLCC) is found to be 0.3 x 10-3 and 0.002 x 10-6. The estimated results of ERn and RnLCC due to the inhalation of 222Rn are well within the prescribed limits of the International regulatory agencies.
PubDate: Thu, 22 Feb 2024 01:35:23 PST
- Development of an empirical ground-motion model for post-mining induced
seismicity near Gardanne, France
Authors: Pierre Gehl et al.
Abstract: Since the closure of mining activities in 2003, the coal basin of Gardanne in South-East France has experienced thousands of small-magnitude earthquake events, mostly triggered by the flooding of mine workings. Some of these events have been powerful enough to be strongly felt by the population, generating nuisance and concern about potential damage to buildings. The aim of this study is to improve the characterisation of the level of ground motion at the surface, by developing a ground-motion model for post-mining induced seismicity, based on several years of recorded data. A Bayesian-based method is applied to the data in order to account for uncertainties in the estimation of moment magnitude. Station-to-station ground-motion site terms are also quantified for the nine recording stations in the area, thus providing additional information on the local site conditions. The developed model is compared to existing prediction equations for seismicity induced by other types of anthropic activities, confirming the need for a specific model in the case of post-mining induced seismicity. Finally, the Gardanne ground-motion model is also integrated with a shake-map procedure, showing how this predictive model may be merged with recorded data in order to generate rapid estimates of shaking levels in the area.
PubDate: Sun, 18 Feb 2024 22:00:26 PST
- Hydraulic Borehole Mining (HBM) technology employed in lignite mining –
technical, economic and market aspects
Authors: Bartłomiej Jura et al.
Abstract: The results of a cost-effectiveness and economic efficiency assessment of the Hydraulic Borehole Mining (HBM) technology applied to lignite mining are presented. The Dynamic Generation Cost, the Net Present Value, and the Internal Rate of Return were calculated for the extraction of lignite at a rate of about 3.44 million Mg/year from a mining parcel of 1 2.5 km, taking into account CAPEX and OPEX. The cost of mining 1 Mg of lignite using the HBM technology was reported to be lower than its market prices before the energy crisis in Europe caused by the war in Ukraine. The values of the NPV and IRR confirm that the HBM technology may be economically effective in lignite mining. The greatest influence on the cost-effectiveness of the HBM technology was caused by the price of backfill and the diameter of the mining cavern. The NPV is affected by changes in lignite prices. The capital expenditures required by the HBM technology have the least impact on the results in contrary to the open-pit mining technology. Lignite mining using the HBM technology is possible at a level similar to the current level of mining by open-pit technology in Polish conditions.
PubDate: Fri, 16 Feb 2024 07:55:28 PST
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