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21 pages, 16705 KiB

Open AccessArticle

Utilization of Geodetic Methods Results in Small Open-Pit Mine Conditions: A Case Study from Slovakia

by Slavomir Labant, Marcela Bindzarova Gergelova, Zofia Kuzevicova, Stefan Kuzevic, Gabriel Fedorko and Vieroslav Molnar

Minerals 2020, 10(6), 489; https://doi.org/10.3390/min10060489 - 27 May 2020

Cited by 9 | Viewed by 4927

Abstract

Mining, especially surface mining, has a significant impact on the upper part of the soil cover, including fauna and flora. The article deals with the use of geodetic methods to observe the mining process and its possible impact on the environment. The created [...] Read more.

Mining, especially surface mining, has a significant impact on the upper part of the soil cover, including fauna and flora. The article deals with the use of geodetic methods to observe the mining process and its possible impact on the environment. The created model can be used to design the recovery and reclamation of open-pit mines after their closure and mining termination. For the modeling of an open-pit mine, 2151 points from two stages of geodetic measurements were used. Graphical presentations of the geodetic measurements were compared with data from aerial photogrammetry. The measurement and processing results were used to visualize the spatial changes in the open-pit mine, which are necessary to take measures related to the recovery of the landscape affected by mining. Based on the calculation, 145.266 m³ were extracted during the period under exploration. When calculating the average excavated volume per working day, it was found that 188 m³ = 500 tons = 0.5 kilotons per day were extracted between the monitored periods. When comparing the original surface and the generated model of the open-pit mine, it was found that the entire top of the rock massif was permanently removed in the total volume of 3,421,000 m³. To capture the impact of mining on the surrounding environment, multispectral images of Landsat 7 and 8 during the observed period. Focused attention was divided into two factors, land surface temperature, and vegetation condition. The results from the temperature maps show that the open-pit mine is becoming a heat island. Analysis of the vegetative state confirms the rapid change in the health of vegetation, resp. reduction of its condition in the area around the open-pit mine. The presented results show that the selected methods and procedures are applicable in the conditions of the small mining company in Slovakia. Full article

(This article belongs to the Special Issue Selected Papers from the 7th International Symposium on Mining and Environmental Protection)

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14 pages, 7986 KiB

Open AccessArticle

The Use of Precise Survey Techniques to Find the Connection between Discontinuities and Surface Morphologic Features in the Laže Quarry in Slovenia

by Aleš Lazar, Goran Vižintin, Tomaž Beguš and Milivoj Vulić

Minerals 2020, 10(4), 326; https://doi.org/10.3390/min10040326 - 5 Apr 2020

Cited by 6 | Viewed by 2900

Abstract

This paper addresses a stability evaluation of artificial slopes in a quarry located in Slovenia that was affected by a rockslide in March 2019. In order to ensure the safety of further production, measures were taken to restore the slopes. A stability assessment [...] Read more.

This paper addresses a stability evaluation of artificial slopes in a quarry located in Slovenia that was affected by a rockslide in March 2019. In order to ensure the safety of further production, measures were taken to restore the slopes. A stability assessment of the remaining parts of the quarry was conducted. To ensure quality spatial data, an upgraded study based on terrain mapping and aerial photogrammetric imaging using an unmanned aircraft was carried out, in addition to a traditional field survey of the quarry. So that the data were qualitatively useful, a digital terrain and discontinuity model was developed. Projections of the discontinuities occurring in the quarry and in the wider area were determined. The focus of the modeling was finding the main systems of discontinuities and projecting these systems onto the unexcavated parts of the quarry. Full article

(This article belongs to the Special Issue Selected Papers from the 7th International Symposium on Mining and Environmental Protection)

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18 pages, 41847 KiB

Open AccessArticle

Distribution of Uranium and Rare Elements in Radioactive Phosphate-Bearing Anomalies in Southeast Mongolia

by Boris Vakanjac, Neil Rutherford, Vesna Ristić Vakanjac, Tanita Đumić and Suzana Đorđević Milošević

Minerals 2020, 10(4), 307; https://doi.org/10.3390/min10040307 - 30 Mar 2020

Cited by 2 | Viewed by 4564

Abstract

Soviet and Mongolian geologists initiated geological exploration of Mongolia for minerals after World War II (1945). These activities lasted until the breakup of the USSR in 1991. As part of this exploration systematic uranium and rare element exploration was undertaken across Mongolia. New [...] Read more.

Soviet and Mongolian geologists initiated geological exploration of Mongolia for minerals after World War II (1945). These activities lasted until the breakup of the USSR in 1991. As part of this exploration systematic uranium and rare element exploration was undertaken across Mongolia. New exploration resumed in Mongolia at the beginning of the 21st century for a range of ore and mineral deposit styles including uranium, coal, base and precious metals and Fe-ore. This was generally undertaken by Western-based companies. This paper presents the results from regional reassessment by company exploration in 2011 for uranium radiometric anomalism found during the early Soviet investigations located north of Sainshand Provincial City and the results of preliminary prospecting studies near the town of Mandakh, both in southeastern Mongolia. These radioactive sites are characterized by elevated phosphate–uranium-rare element abundance. The primary company exploration objective of the new study was to confirm and characterize the anomalies and investigate in more detail the concentration of uranium and rare elements at these sites and assess the economic potential for their exploitation. A secondary objective based on the results from radiochemistry and rare element content was to highlight the potential environmental impact on livestock pastoral activities and wellbeing of nomadic families who graze their stock over the anomalous zones in the region. The source of most of the anomalism is considered derived from erosion and subsequent transport in solution or in heavy minerals from extensively eroded granites and mafic magmas of various ages into graben basins and drainage depressions in the windswept arid terrain. The economic potential of the sites explored was considered too low to be of exploration interest. The anomalism does require characterization for environmental health and safety purposes, given sheep, goats, camels and other livestock traditionally bred in Mongolia are grazing on the enriched pasture and nomadic people reside on, or in their vicinity of elevated zones of radiometric anomalism from anomalous uranium, radon and radium held in phosphorus enriched soils. Full article

(This article belongs to the Special Issue Selected Papers from the 7th International Symposium on Mining and Environmental Protection)

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14 pages, 4029 KiB

Open AccessArticle

Investigation of Unmanned Aerial Vehicles-Based Photogrammetry for Large Mine Subsidence Monitoring

by Danijela Ignjatović Stupar, Janez Rošer and Milivoj Vulić

Minerals 2020, 10(2), 196; https://doi.org/10.3390/min10020196 - 21 Feb 2020

Cited by 40 | Viewed by 3921

Abstract

With the exploitation of underground sources, nature receives a huge negative impact on the local environment introducing surface subsidence. A mining region needs to be observed in sequences before, during, and after coal extraction from the coal mine. Different measuring methods exist to [...] Read more.

With the exploitation of underground sources, nature receives a huge negative impact on the local environment introducing surface subsidence. A mining region needs to be observed in sequences before, during, and after coal extraction from the coal mine. Different measuring methods exist to monitor subsidence, and all of them apply various instrumentation. A choice of methodology depends on access to a field of observation and requested accuracy. Obviously, the most accurate results provide geometric leveling, but, many times, the terrain does not allow surveyors to walk over the dangerous outfields. Looking for the most adequate and feasible method, this research did a comparison between observation of the same points, applying statistical analysis of differences between the reference points heights, and tested methods. Monitoring procedure comprised utilization of total stations (TS), global navigation satellite system (GNSS), and unmanned aerial vehicles (UAV). In this paper, the Velenje coal mine was taken as a case study, and observation data were collected during 2017. Full article

(This article belongs to the Special Issue Selected Papers from the 7th International Symposium on Mining and Environmental Protection)

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17 pages, 7786 KiB

Open AccessArticle

Rock-Fill Cofferdam Crest Settlement Behavior Analysis Through Geodetic Monitoring Data

by Andrej Pal, Drago Potočnik and Milivoj Vulić

Minerals 2020, 10(2), 152; https://doi.org/10.3390/min10020152 - 11 Feb 2020

Cited by 1 | Viewed by 2660

Abstract

Construction of rock-fill dams requires extensive preparatory work. The rationality of construction, ecological aspects, and flood safety must be considered. Potential catastrophic consequences of failure or collapse classify dam structures as high-risk objects which are built according to all safety regulations, and their [...] Read more.

Construction of rock-fill dams requires extensive preparatory work. The rationality of construction, ecological aspects, and flood safety must be considered. Potential catastrophic consequences of failure or collapse classify dam structures as high-risk objects which are built according to all safety regulations, and their conditions must be monitored. In this study, we focus on the settlement behavior of a cofferdam crest by analyzing the obtained monitoring data with a non-exponential modified sigmoid function, developed at the Faculty of Natural Sciences and Engineering (FNSE model). Furthermore, monitoring adjustment is introduced, and future settlement is estimated based on verification with actual values. Full article

(This article belongs to the Special Issue Selected Papers from the 7th International Symposium on Mining and Environmental Protection)

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22 pages, 10010 KiB

Open AccessArticle

Predicting the Spatial Distributions of Elements in Former Military Operation Area Using Linear and Nonlinear Methods Across the Stavnja Valley, Bosnia and Herzegovina

by Jasminka Alijagić and Robert Šajn

Minerals 2020, 10(2), 120; https://doi.org/10.3390/min10020120 - 30 Jan 2020

Cited by 3 | Viewed by 2956

Abstract

This study has the purpose of developing a realistic soil prediction maps of the spatial distribution of elements by evaluating and comparing different modelling techniques: Kriging, artificial neural network-multilayer perceptron (ANN-MLP) and multiple polynomial regressions (MPR). The Stavnja Valley was selected as a [...] Read more.

This study has the purpose of developing a realistic soil prediction maps of the spatial distribution of elements by evaluating and comparing different modelling techniques: Kriging, artificial neural network-multilayer perceptron (ANN-MLP) and multiple polynomial regressions (MPR). The Stavnja Valley was selected as a test area due to the following reasons: (1) intensive metal ore mining and metallurgical processing; (2) peculiar geomorphological natural features; (3) regular geological setting, and (4) the remaining minefields. Geospatial parameters from digital elevation models (DEM) are used as an input to advanced prediction modelling techniques: ANN-MLP and MPR. Soil measurements, land use data, and remote sensing are applied, developed, and finally incorporated into the models of spatial distribution in the form of 2D or 3D maps. In order to reconstruct the different processes that influenced the entire study area simultaneously, we used novel approaches to modelling. This comprehensive approach not only represents an innovation in contamination mapping, but developed prediction models also help in the reconstruction of main distribution pathways, assess the real size of the affected area, and improve the data interpretation. Full article

(This article belongs to the Special Issue Selected Papers from the 7th International Symposium on Mining and Environmental Protection)

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Graphical abstract

20 pages, 12437 KiB

Open AccessArticle

Surface Subsidence Prognosis above an Underground Longwall Excavation and Based on 3D Point Cloud Analysis

by Andrej Pal, Janez Rošer and Milivoj Vulić

Minerals 2020, 10(1), 82; https://doi.org/10.3390/min10010082 - 20 Jan 2020

Cited by 23 | Viewed by 3815

Abstract

Impacts of underground mining have been reduced by continuous environmental endeavors, scientific, and engineering research activities, whose main object is the behavior and control of the undermined rock mass and the subsequent surface subsidence. In the presented Velenje case of underground sublevel longwall [...] Read more.

Impacts of underground mining have been reduced by continuous environmental endeavors, scientific, and engineering research activities, whose main object is the behavior and control of the undermined rock mass and the subsequent surface subsidence. In the presented Velenje case of underground sublevel longwall mining where coal is being exploited both horizontal and vertical, backfilling processes and accompanying fracturing in the coal layer, and rock mass are causing uncontrolled subsidence of the surface above. 3D point clouds of the study were acquired in ten epochs and at excavation heights on the front were measured at the same epochs. By establishing a sectors layout in the observational area, smaller point clouds were obtained, to which planes were fitted and centroids of these planes then calculated. Centroid heights were analyzed with the FNSE model to estimate the time of consolidation and modified according to excavation parameters to determine total subsidence after a certain period. Proposed prognosis approaches for estimating consolidation of active subsidence and long term surface environmental protection measures have been proposed and presented. The C2C analysis of distances between acquired 3D point clouds was used for identification of surface subsidence, reclamation areas and sink holes, and for validation of feasibility and effectiveness of the proposed prognosis. Full article

(This article belongs to the Special Issue Selected Papers from the 7th International Symposium on Mining and Environmental Protection)

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12 pages, 1559 KiB

Open AccessArticle

An Assessment of Natural Radioactivity in the Namxe Rare Earth Deposit, Laichau Province, Vietnam

by Quang Van Phan, Trung Thanh Dao, Phuong Nguyen, Dinh Huan Trinh and Thomas Heinig

Minerals 2019, 9(10), 602; https://doi.org/10.3390/min9100602 - 30 Sep 2019

Cited by 13 | Viewed by 5418

Abstract

The Namxe rare earth deposit belongs to Namxe commune, Phongtho district, Laichau province, which has a large resource of rare earth metals in Vietnam. The case study presents an assessment of the naturally occurring radioactivity for the rare earth prospect Namxe for future [...] Read more.

The Namxe rare earth deposit belongs to Namxe commune, Phongtho district, Laichau province, which has a large resource of rare earth metals in Vietnam. The case study presents an assessment of the naturally occurring radioactivity for the rare earth prospect Namxe for future monitoring purpose, especially for the case of an actual mine in the area. The investigation included determination of radioactivity in the air, soil, water, and plants. The results showed that although the water usage is harmless, radioactive materials were found in soils and plants in considerable amounts. The mapping of these features revealed two zones of elevated radioactivity, one of which even bearing health risks according to several health standards. These zones correspond well with the rare earth deposit area. From the study, safety, health, and environmental issues could be deduced, including a risk assessment for the area and the intended mining site. Full article

(This article belongs to the Special Issue Selected Papers from the 7th International Symposium on Mining and Environmental Protection)

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Review

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29 pages, 3675 KiB

Open AccessFeature PaperReview

Deep Underground Injection of Waste from Drilling Activities—An Overview

by Nediljka Gaurina-Međimurec, Borivoje Pašić, Petar Mijić and Igor Medved

Minerals 2020, 10(4), 303; https://doi.org/10.3390/min10040303 - 27 Mar 2020

Cited by 22 | Viewed by 12915

Abstract

Oil and gas exploration and production activities generate large amounts of waste material, especially during well drilling and completion activities. Waste material from drilling activities to the greatest extent consists of drilled cuttings and used drilling mud with a smaller portion of other [...] Read more.

Oil and gas exploration and production activities generate large amounts of waste material, especially during well drilling and completion activities. Waste material from drilling activities to the greatest extent consists of drilled cuttings and used drilling mud with a smaller portion of other materials (wastewater, produced hydrocarbons during well testing, spent stimulation fluid, etc.). Nowadays, growing concerns for environmental protections and new strict regulations encourage companies to improve methods for the reduction of waste material, as well as improve existing and develop new waste disposal methods that are more environmentally friendly and safer from the aspect of human health. The main advantages of the waste injection method into suitable deep geological formations over other waste disposal methods (biodegradation, thermal treatment, etc.) are minimizing potentially harmful impacts on groundwater, reducing the required surface area for waste disposal, reducing the negative impact on the air and long-term risks for the entire environment. This paper gives a comprehensive overview of the underground waste injection technology, criteria for the selection of the injection zone and methods required for process monitoring, as well as a comprehensive literature overview of significant past or ongoing projects from all over the world. Full article

(This article belongs to the Special Issue Selected Papers from the 7th International Symposium on Mining and Environmental Protection)

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