Monitoring Landform Changes in a Mining Area in Mexico Using Geomatic Techniques

Recent technological innovations have led to the available of lightweight Unmanned Aerial Vehicle (UAV) and Structure-from-Motion (SfM) photogrammetry that are successfully applied for 3D topographic surveys. However, application of UAV and SfM for complex topographic areas i.e. open-pit mine areas is still poorly understood. This paper aims to investigate and verify potential application of these techniques for generating Digital Surface Model (DSM) at open-pit coal mine area and assessing its accuracy. For this purpose, the Nui Beo open-pit coal mine located in northeast Vietnam is selected as a case study. Accordingly, a total of 206 photos were captured using DJI Phantom 3 Professional. In addition, 19 ground control points (GCPs) were established using Leica TS09 total station. The accuracy of DSM was assessed using root-mean-square error (RMSE) in X, Y, Z, XY, and XYZ components. The result showed that the DSM model has high accuracy, RMSE on the 12 calibrated GCPs for X, Y, Z, XY, XYZ is 1.1 cm, 1.9 cm, 0.8 cm, 2.2 cm, and 2.3 cm, respectively, whereas RMSE on the 7 checked GCPs is 1.8 cm, 2.4 cm, 3.2 cm, 3.0 cm, and 4.4 cm for X, Y, Z, XY, XYZ components, respectively. We concluded that small UAV and SfM are feasible and valid tools for 3D topographic mapping in complex terrains such as open-pit coal mine areas.

The geomorphological evidences of subsidence in the Nile Delta: Analysis of high resolution topographic DEM and multi-temporal satellite images

Quantifying the spatiotemporal changes of Open Pit Mining Area (OPMA) are of important to understand the influence of mining activities on ecological, environmental and socioeconomic impact assessment procedure. This study uses the morphological mining feature index (MMFI) to identify and map surface mining areas and its dynamic changes in Changting county southeast china during 1998 to 2010, with the specific goal of understanding surface mining activities on vegetation deterioration and recovery. Serials of Landsat datasets during 1988-2010 period were collected, and the spatial distributions and change patterns of OPMA disturbances were detected and mapped. The results indicated that the changes of OPMA in Changting county have shown two stages, where the prior was the out- of-order exploitation of rare earth elements, and the next was dominated by the mining of quarry due to urbanization process in recent years.

The physical and chemical environmental impact in a mining area is inevitable, particularly for open pit mining areas. The impact could affect soil and water quality where mining activities, such as land clearing, blasting and hauling, occur. Thus, environmental monitoring in mining areas should be taken to measure the impact of mining activity for reclamation purposes. The objective of this research focuses on the measure of environmental impact on soil quality in terms of the nutrient content in an abandoned mine area at Jantang village, Lhoong, Aceh Besar. The research was conducted by collecting 15 soil samples, followed by laboratory analysis using atomic absorption spectrophotometry to investigate sampled 'soil's nutrients which are pH, Carbon (C-organic), Nitrogen (N-total), Phosphor (P-availability), and Ferro substance (Fe-concentration). In addition, to estimate the soil properties at locations outside the sampling area, a spatial interpolation method called inverse distance weight with an optimum power was used. The result shows that the soil is acidic, with low C-organic in the range of 0.02%–1.84%, N-total 0.02%–0.16%, and P-availability 0.55%–3.75%. In contrast, the Fe-concentration is very high, at 3000–3400 ppm.

Ecological environment in mining cities has become an important part of ecological construction. This paper takes Tongling, a mining city, as the research area, and uses Landsat series remote sensing images from 2000 to 2020 as data sources. Using the principal component analysis method and the Remote Sensing Ecological Index (RSEI) integrated with four indexes of greenness, humidity, dryness, and heat, the ecological disturbance of the mining area was evaluated and studied. Meanwhile, the land cover spatiotemporal classification of Tongling city was extracted by the maximum likelihood method. Furthermore, landscape metrics were used, based on the information on open-pit mining areas, to quantitatively analyze the ecological environment quality and its change characteristics in the study area. The results show that (1) RSEI can better characterize the ecological quality of Tongling city, greenness and humidity are positively correlated with it, dryness and heat are negatively correlated with it, and dryness and RSEI have the highest correlation coefficient, indicating that urban expansion will cause ecological environment deterioration to a certain extent. (2) The ecological environment quality of the research area showed a “decline-rising” trend, and the mean value of RSEI decreased from 0.706 to 0.644. Spatially, the areas with poor RSEI are mainly distributed in the central urban area and the open-pit mining area in the south. (3) Land cover change leads to changes in landscape metrics, and most landscape-level metrics are positively or negatively correlated with RSEI. The more concentrated the land cover type distribution is, the smaller the change is, and the more regional RSEI can be improved. (4) The mean value of RESI of the ten open-pit mining areas in Tongling city decreased significantly, with a maximum decrease of 52.73%. Among them, the RESI decline rate in the area around the no.1 open pit mine is 0.034/year. The ecological degradation in Tongling city is attributed to the rapid expansion of built-up areas and the development of the mining industry. The research results can provide a scientific basis for protecting the ecological environment of mining cities.

Atmospheric dustfall is solid air pollutant, has a major impact on the environment and human health. The objective of this study was to investigate the microscopic characteristics and sources of atmospheric dustfall in open-pit mining coal resource-based city in the arid desert area of Northwest China. The characteristics of size and shape factors, variation of shape factors with size distribution, types of individual particles, and sources of atmospheric dustfall, which were collected in the open-pit mining area and surrounding areas, were analyzed by X-ray diffraction (XRD) and scanning electron microscopy coupled with an energy dispersive spectrometer (SEM–EDS) combined with graphical method and shape factors. The results showed that the atmospheric dustfall in all functional areas was dominated by coarse-grained particles. The shape of the atmospheric dustfall deviated from spherical shape, and with decreasing particle size, the difference in shape factors increased in each functional area. The EDS and XRD analyses indicated the presence of 13 types of particles. The sources were mainly local and included soil dust from each functional area; industrial dust, construction dust, biogenic impurities, fossil fuel combustion, wear products of motor vehicle parts, motor vehicle exhaust emissions, and emission and excreta from biological activities in each functional area except the desert area; emissions from a steel plant in the industrial area; coal-associated ore, coal dust, coal gangue emissions, and emissions from the spontaneous combustion of coal gangue in the open-pit mining area; secondary chemical crystallization products in the industrial area and the open-pit mining area; dust generated by vehicles abrading the surface of the off-mine coal road and in the open-pit mining area.

For many years, the high concentration of arsenic (As) in deep groundwater, up to 1.2 mg/L, has posed a health risk to the residents of Zimapán, a mining town in Mexico with a population of about 40,000. Additionally, ore processing, mainly through selective flotation, has resulted in the production of thousands of tons of tailings, which have accumulated in the outskirts of the town, causing damage to soils and shallow wells. To address this environmental issue, Mexican and international scientists have conducted studies focused on various environmental compartments. Since the earliest studies, whose aim was to identify the source of As pollution, the local authorities and people of Zimapán have been involved in the research activities.Three years ago, a collaborative working group was formed, including local authorities, scientific and social researchers from various universities, local social organizations, and individuals who were committed to the environment (Environmental Research Network, REA). Their participation has included support for field activities, communication and exchange of knowledge, and the promotion of alternatives identified by scientific and social efforts to high-level authorities.The outcomes of their work have been significant. They have rehabilitated the As removal treatment plant, which was installed about 15 years earlier as a result of this science-social collaboration. Additionally, they have identified local limestone as an option to treat tainted water and acid mine drainage. They have also supported the municipality in building rain harvesting systems in two schools to provide safe water to students. Moreover, they have interacted with miners to propose alternatives to minimize the impact of the tailings, among other achievements. The quality of drinking water supplied to downtown Zimapán is not yet in line with the national As drinking water standards, which require the arsenic level to be below 0.025 mg/L. The current level of arsenic in the water varies between 0.2 and 0.4 mg/L, which is a significant improvement from the previous level of 1.2 mg/L. However, efforts are still underway to achieve a safe water supply that meets the national standards. The REA has been effective in reducing the arsenic concentration in the water and has proven to be a viable social-scientific method for creating a healthier environment in the locality. It is also a model for other areas in Mexico that are impacted by arsenic contamination.

Although the exploitation of mineral areas brings wealth to society, it inevitably leads to the degradation of the surrounding natural environment. To understand and assess the influences of mining activities on the geological and ecological environment, land cover classification in open-pit mine areas (LCCMA) is of great significance. This research proposes an intelligent classification framework for LCCMA based on an object-oriented method and multitask learning (MTL), named the MTL Classification Framework (MTLCF). With the help of MTL, each land cover type in open-pit mine areas obtains its exclusive and receivable object-oriented feature sets using the model-agnostic method. After that, the feature sets are fused with the original images. EfficientNet, a spatial pyramid pooling module, and a global attention upsample module are assembled as the segmentation models with the structure of the encoder and decoder to classify intelligently each land cover type in open-pit mine areas. Finally, the models were trained, and ablation experiments were performed. The experimental results show that our proposed framework -MTLCF was effective for classification in LCCMA, and the overall accuracy and the mean of F1 score for the MTLCF in LCCMA were 85.6% and 86.06%, respectively.

Mapping ground movements in open pit mining areas using differential SAR interferometry

South Sudan became newest country in Africa after gaining independent in 2011 from the Republic of Sudan after a referendum. Natural resources exploitations have contributed abundantly in socio-economic growth and development of South Sudan. The mining sector in South Sudan consists of both small-scale and large-scale mining, of which anyone has different environmental impacts. This research gives highlights on the environmental impacts of mining activities in South Sudan. The paper generally deliberated on the mining activities in Gorom village, Rejaf County (District) in Central Equatoria State. Primary and secondary data collection was used for the data collection as well as measurement of air quality by portable handheld air and noise devices for environmental assessments of various mining sites in the study area. The findings from the research revealed that mining activities, particularly that emanate from illegal small-scale mining (commonly known as ‘artisanal mining’) deplete natural resources such as the soil, water, the landscape, biodiversity, the ecosystem, among others. The research paper concludes that most important streams in the mining states have been heavily polluted, mainly by illegal small-scale mining. Land around the vicinity of mines has been degraded and vulnerable to severe erosion and loss of viability for agricultural purposes, among other uses. Accelerated clearing of vegetation for mining areas has negatively changed the hydrological regimes and/or patterns in Gorom, Central Equatoria State. Illegal small-scale mining has destroyed some important soil organisms and disrupted stable soil aggregates depriving the soil of organic matter and devoid of macronutrients and soil fertility necessary for plant growth and production. From this research finding, the study concludes by outlining the strengths, weaknesses, opportunities, and threats (SWOT) of the mining in the study area and recommended that there should be effective community participation in environmental decision making to ensure sustainable mining activities; addressing the various weaknesses in the policies and their enforcement in the mining sector; establishment of environmental oversight groups in mining communities; and create environmental awareness campaigns and/or education in mining communities.

Mangrove forests are vital coastal ecosystems that provide a range of ecological, economic, and protective services. However, these ecosystems are increasingly threatened by anthropogenic activities, particularly in resource-rich regions like Rivers State, Nigeria. This study employed Geographic Information System (GIS) and remote sensing techniques to assess the spatio-temporal changes in mangrove forest cover in selected Local Government Areas (LGAs) Gokana, Andoni, Asari-Toru, and Degema from 1995 to 2024. Multi-temporal Landsat satellite images were analyzed using supervised classification to delineate land use/land cover (LULC) categories including mangroves, freshwater vegetation, built-up areas, and water bodies. The results revealed a significant and progressive decline in mangrove coverage across the LGAs, with Gokana and Andoni experiencing a 59.49% loss, and Asari-Toru and Degema a 42.67% loss over the study period. Conversely, built-up areas and freshwater vegetation expanded considerably, indicating growing urbanization and possible ecological succession. The findings strongly suggest that human-induced activities such as infrastructure development, oil exploration, and land reclamation are the primary drivers of mangrove degradation. This study underscores the urgent need for targeted conservation strategies, sustainable land-use planning, and strengthened environmental regulations to preserve the remaining mangrove forests and restore degraded areas.

This paper discusses the spatial trends of urban physical growth of several cities in Java. Six cities in Java (Jakarta, Bandung, Semarang, Yogyakarta, Surabaya, and Malang) were chosen as samples to represent the characteristics of cities in Java based on their geographic settings, including their topography, size, population density, and history of their development. The objectives of this study were: (1) to understand the variations in physical growth of cities in Java; and (2) to explain the spatial trends of urban physical growth of these cities based on their geographic settings. Multi-temporal Landsat satellite images were chosen as data sources to identify urban morphological development processes. Based on results of analysis, it was found that the physical growth of cities in Java has had relatively diverse variations in the aspects of urban settlements, infrastructure, and urban functions. However, the diversity of urban physical growth can be simplified into four types based on the dominant form of physical development. These four types were found to be (1) a compact-rounded city that is formed by the domination of a densification process; (2) a spread-elongated city formed by the dominance of an extensification process; (3) a compact fan-shaped city that is formed by natural physical conditions; and (4) a scattered-random city formed by the domination of a leapfrogging process.

Coastal and landuse changes of Burullus Lake, Egypt: A comparison using Landsat and Sentinel-2 satellite images

<p><strong>Abstract</strong></p><p>The Remance gold mine, in Veraguas (central Panama), had its last mining operation in 1999, using the cyanidation process for Au separation. As a result of this activity, three waste tailings were exposed to the weather, in addition to mine dumps and the open pit mining areas. Currently the area is inhabited by peasants who develop subsistence agriculture and livestock. Therefore, the objective of this study has been to evaluate the environmental and human health risks that this area represents. The total concentrations of potentially toxic elements (PTEs) such as As, Cu, Zn, Ba, Sb and Hg were determined in mining process areas, surrounding soils and edible and inedible plants in the area; in addition to the cyanide species and the enzymatic activity by dehydrogenase (DHA) in soils. The accumulated contamination index (PLI) and potential ecological risk (RI) were calculated, the carcinogenic (CR) and non-carcinogenic (HQ) risk to human health represented by soils and edible plants was estimated.</p><p>Regarding the degree of contamination, it is observed that the contamination is considerable in the tailings and the sediments of the pithead, and it spreads to the surroundings mainly in the sediments of the streams and their terraces, and, to a lesser degree, to the soils around it, showing that the main route of dissemination is through runoff; the same trend is followed by the potential ecological risk, being extreme in the sediments of the pithead, serious in the tailings and terrace sediments, high in the stream sediments and medium in the surrounding soils. The enzymatic activity by DHA tells us that the health of the surrounding soils is better than that of the stream sediments and terrace sediments, but less than in other sites affected by mining activity in Spain. Cyanide species are linked to DHA and this in turn is favoured by organic matter (OM). On the other hand, it was observed that cyanide elutes from the tailing’s piles in a complex cyanide way, favouring the transport of PTEs associated with it to the stream sediments.</p><p>Regarding the risks to human health in soils, As and Cu concentrations exceed the limits for non-carcinogenic and carcinogenic risk in both children and adults, with the residential scenario being the worst scenario, and for adults also the agricultural scenario. In edible plants such as rice, corn, cassava and tea leaves, Sb exceeds the limit for non-carcinogenic risk, and Cu and As for carcinogenic risk. Due to the potential ecological and human health risks that the area represents, actions must be taken to reduce them.</p><p><strong>Keywords</strong>: potentially toxic elements (PTEs), gold mine, risk assessment, edible plants, human health.</p>

Seasonal and spatial variations in lead concentrations in soil and plants and lead-tolerant plant species diversity were studied in a closed open-pit Bo Ngam lead mine area. Two different sampling sites at the open pit mine area, the pond site and land site, were observed. Lead content in soil and plants was seasonally dependent. The lowest lead concentrations in soils were found in July during the wet season (0.6%) and highest in October during the dry season (> 11%). Most plants had the highest lead content during the wet season (May to September) and the lowest during the dry season (October to April). Most plants examined were perennials (16 species) with some annuals (6 species). Twelve species were common to both sampling sites. There were a total of 17 plant species that had lead accumulation in shoots > 1 g/kg, though only six species (Ageratum conyzoides, Buddleja asiatica, Chromolaena odoratum, Conyza sumatrensis, Mimosa pudica, and Sonchus arvensis) showed a translocation factor > 1. These plant species have a high potential for remediating the lead mine area.