Proceedings of the 18th Symposium on Environmental Issues and Waste Management in Energy and Mineral Production

Sustainable development requires extraction and utilization of energy resources on a viable basis for the welfare of human beings and global growth. An increased focus on sustainable development and global warming imposes policy-makers and decision-makers to prioritize environmental responsibility while maximizing economic benefits to the industry. Therefore, evaluating environmental aspects and potential impacts associated with energy resources is essential. Turkey, as a signatory of Kyoto protocol, needs to take actions especially in the energy sector to battle emissions. In order to achieve large-scale emission reduction, the current status needs to be placed under closer scrutiny and once the largest emission generating sectors are identified, necessary changes should be involved in accordance with accepted international standards that consider global warming, eco-balance, and sustainability. This paper presents a comparative evaluation of coal production and utilization impacts on carbon dioxide emission in Europe and in Turkey using geographic information systems (GIS).

Self-heating of coal-shales has been reported in some South African coal mines to be one of the causes of spontaneous combustion but not the coal alone. Spontaneous combustion tests were conducted on a series of coal-shale samples collected from affected coal mines using a newly developed liability index referred to as the Wits-CT index. The ash content, volatile matter and the carbon content of the samples were investigated, and their effects towards spontaneous combustion liability were established. The study indicated that as ash content increases, the liability towards spontaneous combustion decreased, while as the volatile matter and carbon content increases, the liability towards spontaneous combustion increased. It was further found that the ash content showed a negative effect on the liability index, while volatile matter and carbon content showed positive effect on the liability index. Coal-shales with low ash content and high volatile matter and carbon content are more likely to be prone to spontaneous combustion.

The spontaneous combustion of coal has been a major problem for the industry, human health and the environment worldwide. The chemical data of two coal samples taken from the Highveld coalfields in the Mpumalanga Province of South Africa was utilized to evaluate the effects of the heat input by the Karoo-aged dolerite intrusions on the coal and consequently, determine the propensity of the coal to spontaneously combust. The coal sampling focused on positions proximal and distal to the intrusion at 0 and 20 m, respectively. The chemical data was represented in terms of ‘area-%’ derived from the chemical compound identification peaks of the chromatographic analyses. Organic compounds detected were grouped into aromatic and aliphatic groups in order to compare their concentration within the sampled coal. The main aromatic compounds present in both coal samples but abundant in proximal coal are benzene, naphthalene, phenanthrene, biphenyl, xanthene, phenol and furan, and the main aliphatic compounds are higher alkanes (n-C10 to n-C31) and ethanol which are abundant in distal coal. Oxidation processes leading to spontaneous combustion will mostly affect the aliphatic-rich coal complexes due to their high reactivity. The aromatic compounds are more stable and have low reactivity. Thus, the propensity of spontaneous combustion increases with increasing distance from the dolerite intrusion.

Increasing the depth of mining operations becomes fundamental due to the depletion of the shallower high-grade orebodies. Besides, technological developments make deep mining operations feasible. Block and panel caving are classified into large-scale production methods applicable to deep low-grade massive deposits. When mining goes deeper, evaluating the rock mass behavior and conditions for caving becomes more complicated during mine planning and design. The limited and poor quality data, unexpected changes in conditions as well as natural variability are the source of all risks in cave mining. Mud inflow is a phenomenon that can plague caving operation with many obstacles such as fatalities, damage, dilution, production delay, or mine closure. In this research, a safety risk assessment framework is presented based on analytic hierarchy process (AHP). Thus, an extensive statistical analysis of all effective parameters in mud inflow was performed at one of the main operation sectors of el Teniente copper mine, Codelco, Chile. The statistical results were used to ranking risk effective parameters in AHP method. The results of this study introduce a robust method for prioritization of safety risk in block caving projects.

There is an increase in demand for sand in many parts of the world due to rapid economic development. This has led to extensive extraction of sand from rivers and other parts of the land; as a result, sand mining has considerable negative impacts on the fluvial environment and surrounding villagers. This study was carried out in order to identify and assess the environmental impacts of sand mining along Nzhelele River in Nzhelele villages. Geological principles, geotechnical principles, geographical information system (GIS) and remote sensing were used to assess the environmental impacts of sand mining along Nzhelele River Valley. To achieve the objectives of the study, data were collected through field observations, field measurements, soil and water sampling, laboratory analysis (water analysis and sieve analysis), questionnaire survey, the application of GIS methods [multi-temporal images (Landsat ETM + Images) and normalized difference vegetation index (NDVI)] were used. The results of the study have indicated that extensive extraction of sand has resulted into riverbank erosion, depletion in water quality, destruction of the riparian zone, reduction in farms and grazing land and air pollution were the negative impacts associated with sand mining along Nzhelele River. These results were also confirmed by remote sensing and GIS analysis. This research project was sponsored by Thulamela Municipality.

The R523 road links Sibasa to Nzhelele area; it passes through Thathe Vondo and Khalavha. This road presents an important corridor in the area which connects different villages. Sustainable and affordable rural access is a necessary pre-condition for expanding socio-economic opportunities to the different villages. The road is also important to the operation of Thathe Vondo plantation and Tshivhase Tea Estate. Slope failures along busy roads do not only have the potential to cause fatalities and injuries but can also cause serious disruption to traffic. Slope failure of cut-slopes along a road presents a serious problem in most mountainous roads, causing damages to roads, buildings and other structures as well as disrupting the activities of the local people. They also threaten the lives of the people themselves. The road had been excavated using blasting and mechanical operation on the topographically challenging terrain of increasing slope height, inclination and altering slope shape forming an unstable slope, which, along with various other adverse geological conditions, causes slopes to fail during heavy rains, creating damage to property and blocking the road. The road construction has subjected the area to an intensive mass movement. The road construction changes the existing slope geometry and groundwater regime enough to unbalance driving and resisting forces on a slope that was in equilibrium, subjecting the area too unstable conditions. The road has been constructed with insufficient considerations of measures to prevent soil erosion and deposition of silt soil in the water channel. The construction of the road left many cut-slopes, which are difficult to rehabilitate to the original stability condition because the earth material was disturbed. The road also passes through areas of different geological hazards (debris flow, soil erosion and weathered zones). The different environmental factors, such as intensive summer rainfall and human activities, in the study area make the road susceptible to frequent slope failure from time to time.

There is a widespread concern of environmental and social issues in energy and mineral production. Management of these issues in a responsible manner is a big challenge for sustainability of energy and mineral sectors. This paper presents the major environmental issues such as greenhouse gases emissions, acid rain, ground-level ozone disturbance to hydrologic regime, water conservation, acid mine drainage, heavy metals contamination, siltation of productive and agriculture lands, changes in land-use patterns, ecological disturbance coupled with the societal development issues. Application of best management practices (BMPs) in select cases has also been presented to demonstrate the responsible mining in management of environmental and social issues.

Since the introduction of the Council Directive 85/337/EEC in EU, the Environmental Impact Assessment (EIA) has become a required tool to predict and evaluate a wide range of effects on the environment arising from public and private projects. Landscape and Visual Impact Assessment (LVIA) is a separate but closely linked process that operates within the overall framework of EIA. It specifically aims to ensure that all possible effects of change, both on the landscape and on the visual perception of potential observers, are taken into account in decision-making. The Visual Impact Assessment (VIA), in particular, is concerned with how individuals or groups of people may be specifically affected by a change in the landscape’s visual perception. This means assessing changes in specific views and in the general visual amenity experienced by particular people in particular places. The Visual Impact Assessment typically includes the preliminary identification of the viewpoints from which the landscape modification is actually visible and the successive estimation of the visual effect based on direct or indirect criteria. The article deals with the application of a quantitative assessment procedure, which integrates the preliminary identification of the viewpoints from which the modification is visible by means of the Intervisibility Analysis (IA) and the subsequent calculation of the Level of visual impact (Lvi) for each of the selected viewpoints. The article discusses the application of the proposed assessment procedure to the expansion of an existing BRDA (Bauxite Residue Disposal Area) located in the south-west of Sardinia, for which the EIA procedure requires the evaluation of the incremental visual impact deriving from the comparison between the ante- and post-operam states.

Batch studies are frequently used to understand the behavior of soils, sediments, and wastes exposed to different environmental conditions. This study exposed steel slag to 0.11 M acetic acid and a mixture of 0.128 M sodium dithionite, 0.3 M sodium citrate, and 0.1 M sodium bicarbonate extraction solutions. Steel slag is going to be used as a synthetic (top) soil for mine rehabilitation. Synthetic soil is an innovative and economical alternative method to dispose of industrial wastes and by-products. When used in mine rehabilitation, synthetic (top) soil would get exposed to different environmental conditions. Hence, understanding the behavior of slag under a range of soil conditions before its use as a synthetic soil is important. To understand the mobility of metal ions from steel slag under different environmental conditions, a batch study was performed on the end-over-end mixer at 30 rpm for 48 h. Results depicted that slag on being exposed to 0.11 M acetic acid and solution of 0.128 M sodium dithionite, 0.3 M sodium citrate, and 0.1 M sodium bicarbonate enhanced the mobility of heavy metals. In acidic conditions, metal concentration trend was Mn > Pb > Al > Ba > Cr > Zn > Ni > Cd > Cu and Mn > Al > Ba > Cr > Zn > Pb > Cu > Ni > Cd in sodium-rich (saline) conditions. Concentrations of Al, Ba, Cr, Fe, Mn, and Zn are more in saline conditions compared to acidic fractions. These results will assist in predicting the environmental impact and fate of toxic metals released into the system. This paper will discuss the possible reasons and environmental risks associated with steel slag used for synthetic soil.

The production of electricity by burning coal produces huge amount of fly ash and bottom ash; hence, with the increase in the quantum of the thermal power generation, the production of the fly ash also rises to the top. The hanging of the by-product of the coal is considered to be the problematic issue at Matimba power station. The objectives of this investigation were to investigate the geotechnical properties of fly and bottom ash to establish their possible utilisation as a construction material, to determine the grain size distribution, therefore, to analyse the consistency of coal fly ash and bottom ash and perform comparative analysis of the geotechnical properties for suitability of the material as a building material, as well as to identify geotechnical constraints that may have an adverse effect on the project. The methodology used included preliminary studies, reconnaissance survey, soil sampling and laboratory tests. This involved determination of Atterberg limits, sieve analysis, moisture content and soil classification. Results of the laboratory tests indicate that the material of coal fly ash is mainly clay, while bottom ash is mainly silty. The coal fly ash was found to have low plasticity, low liquid limit as well as low plasticity index with low moisture content. The bottom ash on the other hand had considerable plastic limit and liquid limit with high moisture content. The plastering sand was determined to have low plastic limit, considerable liquid limit with low plasticity index. In comparison with the mixture of ashes with plastering sand, the material can be used as plastering material for building purposes.

The paper illustrates and discusses an innovative approach in the reclamation of old mining areas, which is inspired by the circular economy principle and considers the waste of old mining and mineral processing activities as secondary potential raw materials. The European Union legislation has been encouraging this type of practice, which is receiving full recognition from the international scientific literature as well. The application of the mining waste treatment as a reclamation technique is mostly based on the flotation technique that proved to be useful for separating the remaining minerals from the gangue. This provides both an environmental benefit and an economic advantage, which in some cases repays the re-processing costs, even though several difficulties could be encountered in the application of flotation to mining waste. The paper presents the results of the experimental laboratory batch tests, which proved to be encouraging in the case of the Montevecchio mining district (SW Sardinia). Nevertheless, future work is needed to clarify that they are valid for the different situations present on the site.

Rice husk-based flotation reagent was produced as alternative of modern expensive universal flotation reagents. Its collective properties were estimated in a comparison with modern collector named TM 067 Danafloat. It was determined that the collector consisting of 50% of TM 067 Danafloat and 50% of the new flotation reagent allows increasing the content of the lead to 0.20% in the lead concentrate and zinc to 0.38% in the zinc concentrate during the increase of metal recovery. The use of the new flotation agent even in the composition with TM 067 Danafloat will lead to a significant economic effect taking into account the ratio of their cost and the productivity of the concentrated factory.

Various difficulties can be encountered in mining activities. One of the most important of these is environmental issues associated with tailings storage. In this context, laboratory-scale research has been carried out to study the effects of adding cement to various layers of a surface paste tailings storage. Different storage designs have been developed to evaluate the SPD method, and variations of paste material have been measured for volumetric water content, oxygen consumption and matric suction. Especially when the middle layers are examined, it has been determined that the volumetric water content is lower than 50% in the reference design; however, it is well above the saturation limit in other designs with cemented layers. In addition, matric suction in the cemented layers reached ~ 86–87 kPa in about a week, whereas a maximum of only ~18 kPa was achieved in the reference layers. The results indicate that the cemented layers act as barriers which may reduce the potential for the development of acid mine drainage.

Mine tailings may cause important environmental problems. There are some tailing disposal methods which have been applied in the mining industry for a long time. Tailing dams that are generally used in the disposal of mine tailing also bring about many problems in terms of cost, environment and human health. In this study, a risk analysis of a tailing dam was carried out based on soil stability using the finite element method for a Pb-Zn tailing mine. Firstly, considering the topographic features of the tailing dam site, the geographical area of the dam was determined. Secondly, physical and geomechanical characteristics of tailing such as grain size distribution were determined in the laboratory by taking representative samples at various depths from different regions such as tailing and grounds of tailing dam. Lastly, by using this data, tailing area was modelled by finite element method and the distribution of stresses and displacements occurring in the tailing stream were shown. Risk zones of barriers have been identified in terms of stability. In addition, due to its location in the earthquake zone, the behaviour of dam against the earthquake loads was investigated and damages of dam were determined in a possible earthquake. Accordingly, the measurements carried out showed that maximum displacement and stresses in the dam spread from the tailing to the shed, when the duration of the earthquake is 3 s and 30° slope angle, the maximum displacement value for upstream design is calculated as 0.01 m and for downstream design as 0.05 m. For 35° slope angle, maximum displacement values have significantly increased by increasing the duration of the earthquake. This increase has been more limited for designs of 25° and 30°. Accordingly, it can be said that the border slope angle value is 30° in terms of seismic loads.

Mining and subsequent processing of phosphate rock for phosphate-bearing mineral recovery result in the large production of waste material, also known as tailings material. At the studied phosphate mine, the waste tailings are processed into slurry at a tailings plant, which is eventually pumped out to its final location, the tailings dam. At this point, the material poses environmental challenges, including consumption of surface land, dust hazard, potential for surface and subsurface water pollutant. The main objective of this study was to evaluate in situ mechanical properties of phosphate tailings, with the scope of exploring their reuse potential, through determination of material’s bearing capacity, penetration indices, as well as overall mechanical strength capabilities. The field dynamic cone penetrometer (DCP) tests were conducted to obtain material’s in situ California bearing ratio (CBR), bearing pressures and penetration indices. As a complementary measure, material’s gradation tests were performed at the laboratory to give further insight into material’s mechanical strength. The resultant data collected through these tests revealed that the material exhibits low bearing strength and low penetration resistance, which were accompanied by uniform-graded particle distribution. Observed penetration indices were well above the 10 mm/blow mark, at some points going as high as 90 mm/blow. CBR values were found to be very low, with some as low as 02–20. This corresponded with the low values of bearing capacities, with most values falling below 100 kPa and some as low as 20–40 kPa. Sieve analysis revealed that material consists mostly of sand-sized particles, with a coefficient of uniformity of 3. From the assessment and understanding of this data, it was concluded that the tailings are of poor mechanical strength, and for this reason, they could not be reused readily for engineering purposes. Hence, it is advisable that before any attempt to reuse the material for such purposes, innovative measures must be explored to enhance tailings mechanical strength. The work presented in this paper forms part of the mini-dissertation submitted by the first author to the Department of Mining and Environmental Geology, School of Environmental sciences, University of Venda, Thohoyandou, South Africa.

Water is considered to be the most precious and important (resource) of all the natural resources. Groundwater plays a vital role in sustaining the livelihood of most people staying in the rural areas of South Africa owing to the fact that rural water supply is limited due to insufficient pipe-borne water supply. Salinity is regarded as one of the major contributors to water pollution, not only in rural areas but throughout South Africa. The main aim of this study was to assess the quality of groundwater in Tshivhase villages. The investigation of groundwater quality involved analysis of physical water quality parameters such as pH, electrical conductivity, turbidity, salinity, and geostatistical analysis. Water samples were collected from seven different boreholes a period of four months. EC, pH, and TDS meter were used to measure the physical parameters and turbidity was measured using a turbidity meter. The results show that the pH values for the boreholes ranged between 6.61 and 8.26 meaning that the water in all the boreholes was slightly acidic to alkaline. The EC of the boreholes ranged from 947 to 2350 µs/cm, and the concentrations of EC were found to be above the recommended standard for water quality. The turbidity of all the boreholes was found to be within the range of 1–5 NTU indicating that all the boreholes were within required standard. Lastly, the TDS of the sampled water ranged from 660 to 1790 mg/l; meanwhile, the salinity was ranged from 465 to 1120 ppm. Both the TDS and the salinity were found to be relatively higher compared to the recommended standard by DWAF.

Waste of the special coke production called special coke fines was investigated as a raw material to produce a carbon adsorbent. The results of a study of the technical characteristics, X-ray diffraction phase composition, and structure of the special coke fines showed it is formed of the carbon and mineral dense non-porous particles and the carbon particles of a graphite-like structure. The carbon component was derived from coke fines varying the elutriation method parameters. The influence of steam–gas activation with live water steam on the sorption properties of the special coke fines and derived carbon materials was studied. The experiments showed that the best results were achieved using a two-stage activation process of carbon materials with live water steam. It was determined that prepared special coke-based carbon adsorbents had a high adsorption activity toward rhenium (VII) ions. The method of the production of the adsorbent based on the special coke fines is recommended, which includes separation of the special coke fines into carbon and mineral parts by means of elutriation in the mixture of kerosene and water with the subsequent two-stage activation of the carbon material with live water steam.

Abandonment of underground mines of a complex multi-level structure is usually done in a stepwise way. At each stage, the performance of the ventilation system must be adjusted to current structure of workings and the liquidation of related activities. The ventilation system must not only provide relevant working conditions of the liquidation but also ensure safety, taking into account issues like the fan operation stability or gas and fire hazards. The basic objective of the article is to present the plan of mine workings liquidation taking into account natural hazards and to analyse the air flows during the progressing liquidation of the mine workings system. Performance of the above analysis requires the knowledge of the following data: schedule of mine workings liquidation, structure of the considered ventilation system, values of parameters describing the air flow in the workings system, characteristics of working fans. To obtain the data, partially via ‘in situ’ measurements in the mine workings allows using a modern computing tool, which is ventilation engineer’s software system Ventgraph. Computer programs of this system are used in numerous Polish mines and in some mines worldwide. The results obtained from their application are useful for the determination of ventilation system safety objectives. The computer database held by the mine ventilation department was used for the study. Because of the fire hazard, the article pays particular attention to the pressure (aerodynamic potential) distribution in the ventilation nodes for the sequence of stages of the ‘S’ mine ventilation structures of mine workings liquidation. Results of the case study incorporating 14 variants simulated with the Ventgraph software have been presented in the forms of graphs and tables. In conclusion, some guidelines for general rules of such gradual liquidation have been outlined.

Nowadays, some of the raw materials are extracted from deposits in so-called deep mines. Mining technology used for this process has not changed significantly; however, environment becomes more and more harsh. It directly influences the comfort of people performing their tasks, especially in close distance to relatively poorly ventilate mining faces. Environmental conditions in the underground corridors might change relatively quickly. In addition, each person might be sensitive to given conditions at various levels, which can also vary in time. In general, the problem of difficult working conditions might be associated with human fatigue and it has a direct link to safety issues, which is one of the most important aspects of mine operation in recent decades. Solving such a problem is a complex task. In this paper, we describe a portable monitoring system for an individual miner, which can measure location of an employee, his/her activity (walk, work, sitting, standing, etc.), basic physiological parameters (temperature, pulse), and environmental parameters (temperature, humidity, gas presence). This information can be stored locally. Black-box-type purpose of the system allows to transfer recorded data to higher-level database after each shift. In the context of analyzing human activity, it is essential to investigate long-term trends in acquired data rather than local disturbances. Most of data analysis is planned to be done in offline mode. However, for safety reason, some crucial parameters, such as H₂S or CO presence, should be analyzed in real time to provide information about gas concentration in given mining cavity. The system should be lightweight, reliable, and non-disturbing for miners. Authors propose to deploy the system using Arduino platform, which is inexpensive and commonly available. Moreover, miniaturization in sensor technology helps making the system as unnoticeable and comfortable for the miner as possible.

Mining is an equipment-intensive industry that utilizes machinery both in production and mineral processing. As an essential part of sustainable development, mining is subject to environmental management from many aspects. The decision-making process integrated into all stages of mining has to be based on reliable data. Available technology enables to track and monitor the production stages in mining by using various sensors and systems. Data related to mining and mineral processing activities have different characteristics and therefore might be handled in different IT infrastructures. However, the integration of these different data infrastructures is of key importance for management. Mineral processing plant equipment is potentially a data source of process type of data, unique by its volume and frequency. Analyzing process type of data, such as sensors, is a challenging task for engineers that work in a dynamic work environment. Belt conveyors located in the mineral processing plants transport material between different stages such as crushing and grinding which are monitored by sensor systems. The data collected by these sensors is commonly visualized on SCADA screens and can provide real-time data about the operation. This study focuses on the available sensor data of belt conveyors in a mineral processing plant with an aim to manage the dust generated during material transportation. The belt conveyors and the water spraying systems are equipped with tags that provide data for daily management. A data integration tool was developed to create an alarm system to track whether the dust suppression systems were active during material was conveyed in the mineral processing plant. As a result, violations of dust suppression were identified, and the alarm system was integrated into the environmental management system of the operation.

The raw material extraction has increased rapidly since the last century. At the same time, each year billion tonnes of waste containing useful materials (e.g., glass, plastics, and metals) are disposed of in uncontrolled and controlled landfills. One option to tackle this problem is to follow the landfill mining (LFM) approach, which could be the chance not only to transform landfills into the new “mines,” but also to enhance the image of mining sector in the society. Provided, however, that the economic factors associated with LFM are numerous and complex, this paper aims at estimating the economic feasibility of LFM projects by means of a modern management approach, namely the Real Option Valuation (ROV). For the purpose of the analysis, a hypothetical “typical” landfill site is examined and different alternatives are formed. The proposed project is examined via conventional DCF and ROV, taking into account multiple sources of uncertainties. The results indicate that the DCF approach results may be questionable. On the other hand, ROV analysis reveals through the passage of time events and appropriate actions to be taken and assists in identifying and capturing a higher economic value for the investment.