Search results for: mine revegetation

Authors: Neil Bar, Andrew Heweston

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Probability of failure (PF) often appears alongside factor of safety (FS) in design acceptance criteria for rock slope, underground excavation and open pit mine designs. However, the design acceptance criteria generally provide no guidance relating to how PF should be calculated for homogeneous and heterogeneous rock masses, or what qualifies a ‘reasonable’ PF assessment for a given slope design. Observational and kinematic methods were widely used in the 1990s until advances in computing permitted the routine use of numerical modelling. In the 2000s and early 2010s, PF in numerical models was generally calculated using the point estimate method. More recently, some limit equilibrium analysis software offer statistical parameter inputs along with Monte-Carlo or Latin-Hypercube sampling methods to automatically calculate PF. Factors including rock type and density, weathering and alteration, intact rock strength, rock mass quality and shear strength, the location and orientation of geologic structure, shear strength of geologic structure and groundwater pore pressure influence the stability of rock slopes. Significant engineering and geological judgment, interpretation and data interpolation is usually applied in determining these factors and amalgamating them into a geotechnical model which can then be analysed. Most factors are estimated ‘approximately’ or with allowances for some variability rather than ‘exactly’. When it comes to numerical modelling, some of these factors are then treated deterministically (i.e. as exact values), while others have probabilistic inputs based on the user’s discretion and understanding of the problem being analysed. This paper discusses the importance of understanding the key aspects of slope design for homogeneous and heterogeneous rock masses and how they can be translated into reasonable PF assessments where the data permits. A case study from a large open pit gold mine in a complex geological setting in Western Australia is presented to illustrate how PF can be calculated using different methods and obtain markedly different results. Ultimately sound engineering judgement and logic is often required to decipher the true meaning and significance (if any) of some PF results.

Keywords: probability of failure, point estimate method, Monte-Carlo simulations, sensitivity analysis, slope stability

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Authors: Zh. Karaulova, D. Baizhigitov

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At the Aktogay deposit, the oxidized ore section has been developed since 2015; by now, the reserves of easily enriched ore are decreasing, and a large number of copper-poor, difficult-to-enrich ores has been accumulated in the dumps of the KAZ Minerals Aktogay deposit, which is unprofitable to mine using the traditional mining methods. Hence, another technology needs to be implemented, which will significantly expand the raw material base of copper production in Kazakhstan and ensure the efficient use of natural resources. Heap and dump bacterial recovery are the most acceptable technologies for processing low-grade secondary copper sulfide ores. Test objects were the copper ores of Aktogay deposit and chemolithotrophic bacteria Leptospirillum ferrooxidans (L.f.), Acidithiobacillus caldus (A.c.), Sulfobacillus Acidophilus (S.a.), which are mixed cultures were both used in bacterial oxidation systems. They can stay active in the 20-400C temperature range. These bacteria were the most extensively studied and widely used in sulfide mineral recovery technology. Biocatalytic acceleration was achieved as a result of bacteria oxidizing iron sulfides to form iron sulfate, which subsequently underwent chemical oxidation to become sulfate oxide. The following results have been achieved at the initial stage: the goal was to grow and maintain the life activity of bacterial cultures under laboratory conditions. These bacteria grew the best within the pH 1,2-1,8 range with light stirring and in an aerated environment. The optimal growth temperature was 30-33оC. The growth rate decreased by one-half for each 4-5°C fall in temperature from 30°C. At best, the number of bacteria doubled every 24 hours. Typically, the maximum concentration of cells that can be grown in ferrous solution is about 107/ml. A further step researched in this case was the adaptation of microorganisms to the environment of certain metals. This was followed by mass production of inoculum and maintenance for their further cultivation on a factory scale. This was done by adding sulfide concentrate, allowing the bacteria to convert the ferrous sulfate as indicated by the Eh (>600 mV), then diluting to double the volume and adding concentrate to achieve the same metal level. This process was repeated until the desired metal level and volumes were achieved. The final stage of bacterial recovery was the transportation and irrigation of secondary sulfide copper ores of the oxidized ore section. In conclusion, the project was implemented at the Aktogay mine since the bioleaching process was prolonged. Besides, the method of bacterial recovery might compete well with existing non-biological methods of extraction of metals from ores.

Keywords: bacterial recovery, copper ore, bioleaching, bacterial inoculum

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Authors: Maphuti Georgina Kwata

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Coal mining in Mpumalanga Province is known of contributing to the atmospheric pollution from various activities. Gold mining in North-West Province is known of also contributing to the atmospheric pollution especially with the production of radon gas. In this research directional dust deposition gauge was used to measure source of direction and meteorological data was used to determine the wind rose blowing and the influence of the seasonal changes. Fourteen months of dust collection was undertaken in Witbank Area and Carletonville Area. The results shows that the sources of direction for Ericson Dam its East in February 2010 and Tip Area shows that the source of direction its West in October 2010. In the East direction there were mining operations, power stations which contributed to the East to be the sources of direction. In the West direction there were smelters, power stations and agricultural activities which contributed for the source of direction to be the West direction for Driefontein Mine: East Recreational Village Club. The East of Leslie Williams hospital is the source of direction which also indicated that there dust generating activities such as mining operation, agricultural activities. The meteorological results for Emalahleni Area in summer and winter the wind rose blow with wind speed of 5-10 ms-1 from the East sector. Annual average for the wind rose blow its East South eastern sector with 20 ms-1 and day time the wind rose from northwestern sector with excess of 20 ms-1. The night time wind direction East-eastern direction with a maximum wind speed of 20 ms-1. The meteorogical results for Driefontein Mine show that North-western sector and north-eastern sector wind rose is blowing with 5-10 ms-1 win speed. Day time wind blows from the West sector and night time wind blows from the north sector. In summer the wind blows North-east sector with 5-10 ms-1 and winter wind blows from North-west and it’s also predominant. In spring wind blows from north-east. The conclusion is that not only mining operation where the directional dust deposit gauge were installed contributed to the source of direction also the power stations, smelters, and other activities nearby the mining operation contributed. The recommendations are the dust suppressant for unpaved roads should be used on a regular basis and there should be monitoring of the weather conditions (the wind speed and direction prior to blasting to ensure minimal emissions).

Keywords: directional dust deposition gauge, BS part 5 1747 dust deposit gauge, wind rose, wind blowing

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Authors: Melvin Sethobya, Sithule Xanga, Sechaba Lenong, Lunga Nolakana, Gbenga Adesola

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Mining has been the cornerstone of the South African economy for the last century. Most of the gold mining in South Africa was conducted within the Witwatersrand basin, which contributed to the rapid growth of the city of Johannesburg and capitulated the city to becoming the business and wealth capital of the country. But with gradual depletion of resources, a stoppage in the extraction of underground water from mines and other factors relating to survival of the mining operations over a lengthy period, most of the mines were abandoned and left to pollute the local waterways and groundwater with toxins, heavy metal residue and increased acid mine drainage ensued. The Department of Mineral Resources and Energy commissioned a project whose aim is to monitor, maintain, and mitigate the adverse environmental impacts of polluted water mine water flowing into local streams affecting local ecosystems and livelihoods downstream. As part of mitigation efforts, the diagnosis and monitoring of groundwater or surface water polluted sites has become important. Geophysical surveys, in particular, Resistivity and Magnetics surveys, were selected as some of most suitable techniques for investigation of local ingress points along of one the major streams cutting through the Witwatersrand basin, namely the Blesbokspruit, which is found in the eastern part of the basin. The aim of the surveys was to provide information that could be used to assist in determining possible water loss/ ingress from the Blesbokspriut stream. Modelling of geophysical surveys results offered an in-depth insight into the interaction and pathways of polluted water through mapping of possible ingress channels near the Blesbokspruit. The resistivity - depth profile of the surveyed site exhibit a three(3) layered model with low resistivity values (10 to 200 Ω.m) overburden, which is underlain by a moderate resistivity weathered layer (>300 Ω.m), which sits on a more resistive crystalline bedrock (>500 Ω.m). Two locations of potential ingress channels were mapped across the two traverses at the site. The magnetic survey conducted at the site mapped a major NE-SW trending regional linearment with a strong magnetic signature, which was modeled to depth beyond 100m, with the potential to act as a conduit for dispersion of stream water away from the stream, as it shared a similar orientation with the potential ingress channels as mapped using the resistivity method.

Keywords: eletrictrical resistivity, magnetics survey, blesbokspruit, ingress

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Authors: Juergen Orasche, Vesta Kohlmeier, George C. Dragan, Gert Jakobi, Patricia Forbes, Ralf Zimmermann

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Underground mining poses a difficult environment for both man and machines. At more than 1000 meters underneath the surface of the earth, ores and other mineral resources are still gained by conventional and motorised mining. Adding to the hazards caused by blasting and stone-chipping, the working conditions are best described by the high temperatures of 35-40°C and high humidity, at low air exchange rates. Separate ventilation shafts lead fresh air into a mine and others lead expended air back to the surface. This is essential for humans and machines working deep underground. Nevertheless, mines are widely ramified. Thus the air flow rate at the far end of a tunnel is sensed to be close to zero. In recent years, conventional mining was supplemented by mining with heavy diesel machines. These very flat machines called Load Haul Dump (LHD) vehicles accelerate and ease work in areas favourable for heavy machines. On the other hand, they emit non-filtered diesel exhaust, which constitutes an occupational hazard for the miners. Combined with a low air exchange, high humidity and inorganic dust from the mining it leads to 'black smog' underneath the earth. This work focuses on the air quality in mines employing LHDs. Therefore we performed personal sampling (samplers worn by miners during their work), stationary sampling and aethalometer (Microaeth MA200, Aethlabs) measurements in a platinum mine in around 1000 meters under the earth’s surface. We compared areas of high diesel exhaust emission with areas of conventional mining where no diesel machines were operated. For a better assessment of health risks caused by air pollution we applied a separated gas-/particle-sampling tool (or system), with first denuder section collecting intermediate VOCs. These multi-channel silicone rubber denuders are able to trap IVOCs while allowing particles ranged from 10 nm to 1 µm in diameter to be transmitted with an efficiency of nearly 100%. The second section is represented by a quartz fibre filter collecting particles and adsorbed semi-volatile organic compounds (SVOC). The third part is a graphitized carbon black adsorber – collecting the SVOCs that evaporate from the filter. The compounds collected on these three sections were analyzed in our labs with different thermal desorption techniques coupled with gas chromatography and mass spectrometry (GC-MS). VOCs and IVOCs were measured with a Shimadzu Thermal Desorption Unit (TD20, Shimadzu, Japan) coupled to a GCMS-System QP 2010 Ultra with a quadrupole mass spectrometer (Shimadzu). The GC was equipped with a 30m, BP-20 wax column (0.25mm ID, 0.25µm film) from SGE (Australia). Filters were analyzed with In-situ derivatization thermal desorption gas chromatography time-of-flight-mass spectrometry (IDTD-GC-TOF-MS). The IDTD unit is a modified GL sciences Optic 3 system (GL Sciences, Netherlands). The results showed black carbon concentrations measured with the portable aethalometers up to several mg per m³. The organic chemistry was dominated by very high concentrations of alkanes. Typical diesel engine exhaust markers like alkylated polycyclic aromatic hydrocarbons were detected as well as typical lubrication oil markers like hopanes.

Keywords: diesel emission, personal sampling, aethalometer, mining

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Authors: Ashish Pathak, Dong-Jin Kim, Byoung-Gon Kim

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Biological processes based on oxidation of sulfur compounds by chemolithotrophic microorganisms are emerging as an efficient and eco-friendly technique for removal of sulfur from the coal. In the present article, study was carried out to investigate the potential of biodesulfurization process in removing the sulfur from lignite coal sample collected from a Mongolian coal mine. The batch biodesulfurization experiments were conducted in 2.5 L borosilicate baffle type reactors at 35 ºC using Acidithiobacillus ferrooxidans. The effect of pulp density on efficiency of biodesulfurization was investigated at different solids concentration (1-10%) of coal. The results of the present study suggested that the rate of desulfurization was retarded at higher coal pulp density. The optimum pulp density found 5% at which about 48% of the total sulfur was removed from the coal.

Keywords: biodesulfurization, bioreactor, coal, pyrite

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Authors: Tianle Yang

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As a common mental disorder, depression is a leading cause of various diseases worldwide. Early detection and treatment of depression can dramatically promote remission and prevent relapse. However, conventional ways of depression diagnosis require considerable human effort and cause economic burden, while still being prone to misdiagnosis. On the other hand, recent studies report that physical characteristics are major contributors to the diagnosis of depression, which inspires us to mine the internal relationship by neural networks instead of relying on clinical experiences. In this paper, neural networks are constructed to predict depression from physical characteristics. Two initialization methods are examined - Xaiver and Kaiming initialization. Experimental results show that a 3-layers neural network with Kaiming initialization achieves 83% accuracy.

Keywords: depression, neural network, Xavier initialization, Kaiming initialization

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Authors: Mine Cekin

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Self-regulated learning (SRL), which can be defined as learning that takes place when an individual is an active controller over his cognition, behavior, and motivation in the learning process, seems to be an essential educational goal. However, it is asserted that students need an assistance to become self-regulated learners. Therefore, teachers appear to play an important role in the introduction of SRL. Even though the importance of SRL has been shown by many researchers, the issue of how teachers can introduce it in a classroom environment needs to be investigated thoroughly. When it comes to mathematics learning particularly, it seems really difficult to associate this area with self-regulated learning because of the fact that it is mainly seen as a domain that is overwhelmingly memorizing written notations. As a result, self-regulated learning in mathematics education and what roles teachers have seem to deserve a significant attention. In this study, the significance of SRL and the roles of teachers in promoting SRL in the field of mathematics education particularly with the help of current literature have been highlighted. Some of the roles of teachers are becoming self-regulated learners themselves, facilitating motivation and collaboration with their colleagues in their schools.

Keywords: mathematics education, motivation, self-regulated learning, teacher self-regulation

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Authors: S. Vasailor, C. Rattanakawin

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Electro-winning of copper metal from dilute sulfate solution (13.7 g/L) was performed in a lab electrolytic cell with stainless-steel cathode and lead-alloy anode. The effects of various parameters including cell voltage, electro-winning temperature and time were studied in order to acquire an appropriate current efficiency of copper deposition. The highest efficiency is about 95% obtaining from electro-winning condition of 3V, 55°C and 3,600 s correspondingly. The cathode copper with 95.5% Cu analyzed using atomic absorption spectrometry can be obtained from this single-winning condition. In order to increase the copper grade, solvent extraction should be used to increase the sulfate concentration, say 50 g/L, prior to winning the cathode copper effectively.

Keywords: copper metal, current efficiency, dilute sulfate solution, electro-winning

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Authors: Bagam Venkateswarlu

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NMDC Limited, Indian multinational mining company operates under administrative control of Ministry of Steel, Government of India. This study is undertaken to evaluate how sustainable mining practiced by the company fulfils the provisions of Indian Constitution to secure to its citizen – justice, equality of status and opportunity, promoting social, economic, political, and religious wellbeing. The Constitution of India lays down a road map as to how the goal of being a “Welfare State” shall be achieved. The vision of sustainable mining being practiced is oriented along the constitutional responsibilities on Indian Citizens and the Corporate World. This qualitative study shall be backed by quantitative studies of National Mineral Development Corporation performances in various domains of sustainable mining and ESG, that is, environment, social and governance parameters. For example, Five Star Rating of mine is a comprehensive evaluation system introduced by Ministry of Mines, Govt. of India is one of the methodologies. Corporate Social Responsibilities is one of the thrust areas for securing social well-being. Green energy initiatives in and around the mines has given the title of “Eco-Friendly Miner” to NMDC Limited. While operating fully mechanized large scale iron ore mine (18.8 million tonne per annum capacity) in Bacheli, Chhattisgarh, M/s NMDC Limited caters to the needs of mineral security of State of Chhattisgarh and Indian Union. It preserves forest, wild-life, and environment heritage of richly endowed State of Chhattisgarh. In the remote and far-flung interiors of Chhattisgarh, NMDC empowers the local population by providing world class educational & medical facilities, transportation network, drinking water facilities, irrigational agricultural supports, employment opportunities, establishing religious harmony. All this ultimately results in empowered, educated, and improved awareness in population. Thus, the basic tenets of constitution of India- secularism, democracy, welfare for all, socialism, humanism, decentralization, liberalism, mixed economy, and non-violence is fulfilled. Constitution declares India as a welfare state – for the people, of the people and by the people. The sustainable mining practices by NMDC are in line with the objective. Thus, the purpose of study is fully met with. The potential benefit of the study includes replicating this model in existing or new establishments in various parts of country – especially in the under-privileged interiors and far-flung areas which are yet to see the lights of development.

Keywords: ESG values, Indian constitution, NMDC limited, sustainable mining, CSR, green energy

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Authors: C. Rattanakawin, S. Vasailor

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Acid leaching of flotation concentrate of oxide copper ore containing mainly of malachite was performed in a standard agitation tank with various parameters. The effects of solid to liquid ratio, sulfuric acid concentration, agitation speed, leaching temperature and time were examined to get proper conditions. The best conditions are 1:8 solid to liquid ratio, 10% concentration by weight, 250 rev/min, 30 ^oC and 5-min leaching time in respect. About 20% Cu grade assayed by atomic absorption technique with 98% copper recovery was obtained from these combined optimum conditions. Dissolution kinetics of the concentrate was approximated as a logarithmic function. As a result, the first-order reaction rate is suggested from this leaching study.

Keywords: agitation leaching, dissolution kinetics, flotation concentrate, oxide copper ore, sulfuric acid

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Authors: Rachida Malaoui, Leila Arabet , Asma Benbouza

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The use of mining waste rock as a material for construction is one of the biggest concerns grabbing the attention of many mining countries. As these materials are abandoned, more effective solutions have been made to offset some of the building materials, and to avoid environmental pollution. The sands of the Djemi Djema deposit mines of the Djebel Onk mines are sedimentary materials of several varieties of layers with varying thicknesses and are worth far more than 300m deep. The sands from the Djemi Djema business area are medium to coarse and are discharged and accumulated, generating a huge estimated quantity of more than 77424250 tonnes. This state of "resource" is of great importance so as to be oriented towards the fields of public works and civil engineering after having reached the acceptable properties of this resource

Keywords: reuse, sands, shear tests, waste rock

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Authors: Mehmet Salih Bayraktutan

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Geomechanical properties of Rock Salt Deposits in Tuzluca Salt Mine Area (Eastern Turkey) are studied for modeling the operation- excavation strategy. The purpose of this research focused on calculating the critical value of span height- which will meet the safety requirements. The Mine Site Tuzluca Hills consist of alternating parallel bedding of Salt ( NaCl ) and Gypsum ( CaS04 + 2 H20) rocks. Rock Salt beds are more resistant than narrow Gypsum interlayers. Rock Salt beds formed almost 97 percent of the total height of the Hill. Therefore, the geotechnical safety of Galleries depends on the mechanical criteria of Rock Salt Cores. General deposition of Tuzluca Basin was finally completed by Tuzluca Evaporites, as for the uppermost stratigraphic unit. They are currently running mining operations performed by classic mechanical excavation, room and pillar method. Rooms and Pillars are currently experiencing an initial stage of fracturing in places. Geotechnical safety of the whole mining area evaluated by Rock Mass Rating (RMR), Rock Quality Designation (RQD) spacing of joints, and the interaction of groundwater and fracture system. In general, bedded rock salt Show large lateral deformation capacity (while deformation modulus stays in relative small values, here E= 9.86 GPa). In such litho-stratigraphic environments, creep is a critical mechanism in failure. Rock Salt creep rate in steady-state is greater than interbedding layers. Under long-lasted compressive stresses, creep may cause shear displacements, partly using bedding planes. Eventually, steady-state creep in time returns to accelerated stages. Uniaxial compression creep tests on specimens were performed to have an idea of rock salt strength. To give an idea, on Rock Salt cores, average axial strength and strain are found as 18 - 24 MPa and 0.43-0.45 %, respectively. Uniaxial Compressive strength of 26- 32 MPa, from bedded rock salt cores. Elastic modulus is comparatively low, but lateral deformation of the rock salt is high under the uniaxial compression stress state. Poisson ratio = 0.44, break load = 156 kN, cohesion c= 12.8 kg/cm2, specific gravity SG=2.17 gr/cm3. Fracture System; spacing of fractures, joints, faults, offsets are evaluated under acting geodynamic mechanism. Two sand beds, each 4-6 m thick, exist near to upper level and at the top of the evaporating sequence. They act as aquifers and keep infiltrated water on top for a long duration, which may result in the failure of roofs or pillars. Two major active seismic ( N30W and N70E ) striking Fault Planes and parallel fracture strands have seismically triggered moderate risk of structural deformation of rock salt bedding sequence. Earthquakes and Floods are two prevailing sources of geohazards in this region—the seismotectonic activity of the Mine Site based on the crossing framework of Kagizman Faults and Igdir Faults. Dominant Hazard Risk sources include; a) Weak mechanical properties of rock salt, gypsum, anhydrite beds-creep. b) Physical discontinuities cutting across the thick parallel layers of Evaporite Mass, c) Intercalated beds of weak cemented or loose sand, clayey sandy sediments. On the other hand, absorbing the effects of salt-gyps parallel bedded deposits on seismic wave amplitudes has a reducing effect on the Rock Mass.

Keywords: bedded rock salt, creep, failure mechanism, geotechnical safety

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Authors: Dmitry Kukushkin

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Lineaments form complex grids on Earth's surface. Currently, one particular object of study for many researchers is the analysis and geological interpretation of maps of lineament density in an attempt to locate various geological structures. But lineament grids are made up of global, regional and local components, and this superimposition of lineament grids of various scales (global, regional, and local) renders this method less effective. Besides, the erosion processes and the erosional resistance of rocks lying on the surface play a significant role in the formation of lineament grids. Therefore, specific lineament density map is characterized by poor contrast (most anomalies do not exceed the average values by more than 30%) and unstable relation with local geological structures. Our method allows to confidently determine the location and boundaries of local geological structures that are likely to contain mineral deposits. Maps of the fields of lineament distortion (residual specific density) created by our method are characterized by high contrast with anomalies exceeding the average by upward of 200%, and stable correlation to local geological structures containing mineral deposits. Our method considers a lineament grid as a general lineaments field – surface manifestation of stress and strain fields of Earth associated with geological structures of global, regional and local scales. Each of these structures has its own field of brittle dislocations that appears on the surface of its lineament field. Our method allows singling out local components by suppressing global and regional components of the general lineaments field. The remaining local lineament field is an indicator of local geological structures.The following are some of the examples of the method application: 1. Srednevilyuiskoye gas condensate field (Yakutia) - a direct proof of the effectiveness of methodology; 2. Structure of Astronomy (Taimyr) - confirmed by the seismic survey; 3. Active gold mine of Kadara (Chita Region) – confirmed by geochemistry; 4. Active gold mine of Davenda (Yakutia) - determined the boundaries of the granite massif that controls mineralization; 5. Object, promising to search for hydrocarbons in the north of Algeria - correlated with the results of geological, geochemical and geophysical surveys. For both Kadara and Davenda, the method demonstrated that the intensive anomalies of the local lineament fields are consistent with the geochemical anomalies and indicate the presence of the gold content at commercial levels. Our method of suppression of global and regional components results in isolating a local lineament field. In early stages of a geological exploration for oil and gas, this allows determining boundaries of various geological structures with very high reliability. Therefore, our method allows optimization of placement of seismic profile and exploratory drilling equipment, and this leads to a reduction of costs of prospecting and exploration of deposits, as well as acceleration of its commissioning.

Keywords: lineaments, mineral exploration, oil and gas, remote sensing

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Authors: A. Ali, V. Strezov, P. Davies, I. Wright, T. Kan

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The environmental impacts arising from mining activities affect the air, water, and soil quality. Impacts may result in unexpected and adverse environmental outcomes. This study reports on the impact of coal production on sediment in Sydney region of Australia. The sediment samples upstream and downstream from the discharge points from three mines were taken, and 80 parameters were tested. The results were assessed against sediment quality based on presence of metals. The study revealed the increment of metal content in the sediment downstream of the reference locations. In many cases, the sediment was above the Australia and New Zealand Environment Conservation Council and international sediment quality guidelines value (SQGV). The major outliers to the guidelines were nickel (Ni) and zinc (Zn).

Keywords: coal mine, environmental impact, produced water, sediment quality guidelines value (SQGV)

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Authors: M. Tang, S. M. Wen, D. W. Liu

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This paper presents the influences on the entrainment of serpentines by grinding and reagents during copper–nickel sulfide flotation. The previous bench flotation tests were performed to extract the metallic values from the ore in Yunnan Mine, China and the relatively satisfied results with recoveries of 86.92% Cu, 54.92% Ni, and 74.73% Pt+Pd in the concentrate were harvested at their grades of 4.02%, 3.24% and 76.61 g/t, respectively. However, the content of MgO in the concentrate was still more than 19%. Micro-flotation tests were conducted with the objective of figuring out the influences on the entrainment of serpentines into the concentrate by particle size, flocculants or depressants and collectors, as well as visual observations in suspension by OLYMPUS camera. All the tests results pointed to the presences of both “entrapped-in” serpentines and its coating on the hydrophobic flocs resulted from strong collectors (combination of butyl xanthate, butyl ammonium dithophosphate, even after adding carboxymethyl cellulose as effective depressant. And fine grinding may escalate the entrainment of serpentines in the concentrate.

Keywords: serpentine, copper and nickel sulfides, flotation, entrainment

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Authors: Victor Siahaan

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Coal still become the most important energy source for electricity generation known for its contribution which take the biggest portion of energy mix that a country has, for example Indonesia. The low cost of electricity generation and quite a lot of resources make this energy still be the first choice to fill the portion of base load power. To realize its significance to produce electricity, it is necessary to know the amount of coal (volume) needed to ensure that all coal power plants (CPP) in a country can operate properly. To secure the volume of coal, in this study, discussion was carried out regarding the identification of coal mining sources in Indonesia, classification of coal typical from each coal mining sources, and determination of the port of loading. By using data above, the sources of coal mining are then selected to feed certain CPP based on the compatibility of the coal typical and the lowest transport cost.

Keywords: merit order, Indonesian coal mine, electricity, power plant

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Authors: Zulkifli Yusop

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The severity of December 2014 flood on the east coast of Peninsular Malaysia has raised concern over the adequacy of existing land use practices and policies. This article assesses flood responses to selective logging, plantation establishment (oil palm and rubber) and their subsequent management regimes. The hydrological impacts were evaluated on two levels: on-site (mostly in the upstream) and off-site to reflect the cumulative impact at downstream. Results of experimental catchment studies suggest that on-site impact of flood could be kept to a minimum when selecting logging strictly adhere to the existing guidelines. However, increases in flood potential and sedimentation rate were observed with logging intensity and slope steepness. Forest conversion to plantation show the highest impacts. Except on the heavily compacted surfaces, the ground revegetation is usually rapid within two years upon the cessation of the logging operation. The hydrological impacts of plantation opening and replanting could be significantly reduced once the cover crop has fully established which normally takes between three to six months after sowing. However, as oil palms become taller and the canopy gets closer, the cover crop tends to die off due to light competition, and its protecting function gradually diminishes. The exposed soil is further compacted by harvesting machinery which subsequently leads to greater overland flow and erosion rates. As such, the hydrological properties of matured oil palm plantations are generally poorer than in young plantation. In hilly area, the undergrowth in rubber plantation is usually denser compared to under oil palm. The soil under rubber trees is also less compacted as latex collection is done manually. By considering the cumulative effects of land-use over space and time, selective logging seems to pose the least impact on flood potential, followed by planting rubber for latex, oil palm and Latex Timber Clone (LTC). The cumulative hydrological impact of LTC plantation is the most severe because of its shortest replanting rotation (12 to 15 years) compared to oil palm (25 years) and rubber for latex (35 years). Furthermore, the areas gazetted for LTC are mostly located on steeper slopes which are more susceptible to landslide and erosion. Forest has limited capability to store excess rainfall and is only effective in attenuating regular floods. Once the hydrologic storage is exceeded, the excess rainfall will appear as flood water. Therefore, for big floods, rainfall regime has a much bigger influence than land use.

Keywords: selective logging, plantation, extreme rainfall, debris flow

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Authors: B. Merdas

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The Guelma region constitutes a vast geothermal field whose local geothermal gradient is very high. Indeed, various thermal and thermo sources emerging in the region, including some at relatively high temperatures. In the mio Pliocene Hammam N'bails, basin emerges a hot spring that leaves develop a thick series of thermal travertine linked to it. Near the thermal emergences has settled a very special mineralization antimony and zinc and lead. The results of analyses of the thermal waters of the source of Hammam N'bails and the associated travertine, show abnormal values in Pb, Sb, Zn, As, and other metals, demonstrating the genetic link between those waters and mineralization. Hammam N'bails mineralizations by their mineral assembling represented and their association with the hot springs, are very similar to epithermal deposits with precious metals (gold and silver) like Senator mine in Turkey or ‘Carlin-type’ in Nevada (USA).

Keywords: hot springs, mineralization; basement faults, Guelma, NE Algeria

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Authors: Alejandro Ruiz-Olivares, M. del Carmen González-Chávez, Rogelio Carrillo-González, Martha Reyes-Ramos, Javier Suárez Espinosa

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Use of automobiles has increased and proportionally, the demand for batteries to impulse them. When the device is aged, all the battery materials are reused through lead acid battery recycling (LABR). Importation of used lead acid batteries in Mexico has increased in the last years since many recycling factories have been settled in the country. Inadequate disposal of lead-acid battery recycling (LABR) wastes left soil severely polluted with Pb, Cu, and salts (Na+, SO2− 4, PO3− 4). Soil organic amendments may contribute with essential nutrients and sequester (scavenger compounds) metals to allow plant establishment. The objective of this research was to revegetate a former lead-acid battery recycling site aided with organic amendments. Seven tree species (Acacia farnesiana, Casuarina equisetifolia, Cupressus lusitanica, Eucalyptus obliqua, Fraxinus excelsior, Prosopis laevigata and Pinus greggii) and two organic amendments (vermicompost and vermicompost + sawdust mixture) were tested for phytoremediation of a defunct LABR site. Plants were irrigated during the dry season. Monitoring of the soils was carried out during the experiment: Available metals, salts concentrations and their spatial pattern in soil were analyzed. Plant species and amendments were compared through analysis of covariance and longitudinal analysis. High concentrations of extractable (DTPA-TEA-CaCl₂) metals (up to 15,685 mg kg⁻¹ and 478 mg kg⁻¹ for Pb and Cu) and soluble salts (292 mg kg-1 and 23,578 mg kg-1 for PO3− 4and SO2− 4) were found in the soil after three and six months of setting up the experiment. Lead and Cu concentrations were depleted in the rhizosphere after amendments addition. Spatial pattern of PO3− 4, SO2− 4 and DTPA-extractable Pb and Cu changed slightly through time. In spite of extreme soil conditions the plant species planted: A. farnesiana, E. obliqua, C. equisetifolia and F. excelsior had 100% of survival. Available metals and salts differently affected each species. In addition, negative effect on growth due to Pb accumulated in shoots was observed only in C. lusitanica. Many specimens accumulated high concentrations of Pb ( > 1000 mg kg-1) in shoots. C. equisetifolia and C. lusitanica had the best rate of growth. Based on the results, all the evaluated species may be useful for revegetation of Pb-polluted soils. Besides their use in phytoremediation, some ecosystem services can be obtained from the woodland such as encourage wildlife, wood production, and carbon sequestration. Further research should be conducted to analyze these services.

Keywords: heavy metals, inadequate disposal, organic amendments, phytoremediation with trees

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Authors: Yıldırım I. Tosun, Halim Cevizci, Hakan Ceylan

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By GEO5 FEM program with four rockfill slope modeling and stability analysis was performed for S1, S2, S3 and S4 slopes where landslides of the shalefills were limited. Effective angle of internal friction (φ'°) 17°-22.5°, the effective cohesion (c') from 0.5 to 1.8 kPa, saturated unit weight 1.78-2.43 g/cm3, natural unit weight 1.9-2.35 g/cm3, dry unit weight 1.97-2.40 g/cm3, the permeability coefficient of 1x10-4 - 6.5x10-4 cm/s. In cross-sections of the slope, GEO 5 FEM program possible critical surface tension was examined. Rockfill dump design was made to prevent sliding slopes. Bulk material designated geotechnical properties using also GEO5 programs FEM and stability program via a safety factor determined and calculated according to the values S3 and S4 No. slopes are stable S1 and S2 No. slopes were close to stable state that has been found to be risk. GEO5 programs with limestone rock fill dump through FEM program was found to exhibit stability.

Keywords: slope stability, stability analysis, rockfills, sock stability

Procedia PDF Downloads 483

Authors: Sukran Acikel, Mehmet Ekmekci, Otgonbayar Namkhai

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Lignite coal fields in western Turkey generally occurs in tensional Neogene basins bordered by major faults. Karacahisar coal field in Mugla province of western Turkey is a large Neogene basin filled with alternation of silisic and calcerous layers. The basement of the basin is composed of mainly karstified carbonate rocks of Mesozoic and schists of Paleozoic age. The basement rocks are exposed at highlands surrounding the basin. The basin fill deposits forms shallow, low yield and local aquifers whereas karstic carbonate rock masses forms the major aquifer in the region. The karstic aquifer discharges through a spring zone issuing at intersection of two major faults. Municipal water demand in Bodrum city, a touristic attraction area is almost totally supplied by boreholes tapping the karstic aquifer. A well field has been constructed on the eastern edge of the coal basin, which forms a ridge separating two Neogene basins. A major concern was raised about the plausible impact of mining activities on groundwater system in general and on water supply well field in particular. The hydrogeological studies carried out in the area revealed that the coal seam is located below the groundwater level. Mining operations will be affected by groundwater inflow to the pits, which will require dewatering measures. Dewatering activities in mine sites have two-sided effects: a) lowers the groundwater level at and around the pit for a safe and effective mining operation, b) continuous dewatering causes expansion of cone of depression to reach a spring, stream and/or well being utilized by local people, capturing their water. Plausible effect of mining operations on the flow of the spring zone was another issue of concern. Therefore, a detailed representative hydrogeological conceptual model of the site was developed on the basis of available data and field work. According to the hydrogeological conceptual model, dewatering of Neogene layers will not hydraulically affect the water supply wells, however, the ultimate perimeter of the open pit will expand to intersect the well field. According to the conceptual model, the coal seam is separated from the bottom by a thick impervious clay layer sitting on the carbonate basement. Therefore, the hydrostratigraphy does not allow a hydraulic interaction between the mine pit and the karstic carbonate rock aquifer. However, the structural setting in the basin suggests that deep faults intersecting the basement and the Neogene sequence will most probably carry the deep groundwater up to a level above the bottom of the pit. This will require taking necessary measure to lower the piezometric level of the carbonate rock aquifer along the faults. Dewatering the carbonate rock aquifer will reduce the flow to the spring zone. All findings were put together to recommend a strategy for safe and effective mining operation.

Keywords: conceptual model, dewatering, groundwater, mining operation

Procedia PDF Downloads 400

Authors: J. BalaRaju, M. Govinda Raj, C. S. N. Murthy

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Every organization in the competitive world tends to improve its economy by increasing their production and productivity rates. Unequivocally, the production in Indian underground mines over the years is not satisfactory, due to a variety of reasons. There are manifold of avenues for the betterment of production, and one such approach is through enhanced utilization of mechanized equipment such as Load Haul Dumper (LHD). This is used as loading and hauling purpose in underground mines. In view of the aforementioned facts, this paper delves into identification of the key influencing factors such as LHDs maintenance effectiveness, vehicle condition, operator skill and utilization of the machines on performance of LHDs. An attempt has been made for improvement of performance of the equipment through evaluation of Overall Equipment Effectiveness (OEE). Two different approaches for evaluation of OEE have been adopted and compared under various operating conditions. The use of OEE calculation in terms of percentage availability, performance and quality and the hitherto existing situation of the underground mine production is evaluated. Necessary recommendations are suggested to mining industry on the basis of OEE.

Keywords: utilization, maintenance, availability, performance and quality

Procedia PDF Downloads 222

Authors: Nurcan Tugrul, Funda Demir, Hilal Ozkan, Nur Olgun, Emek Derun

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Geopolymers are aluminosilicate-containing materials. The raw materials of the geopolymerization can be natural material such as kaolinite, metakaolin (calcined kaolinite), clay, diatomite, rock powder or can also be industrial by-products such as fly ash, silica fume, blast furnace slag, rice-husk ash, mine tailing, red mud, waste slag, etc. Reactivity of raw materials in geopolymer production is very important for achieving high reaction grade. Fly ash used in geopolymer production has been calcined to obtain tetrahedral SiO₂ and Al₂O₃ structures. In this study, fly ash calcined at different temperatures (700, 800 and 900 °C), and Al₂O₃ addition (Al₂O₃ at min (0%) and max (100%)) were used to produce geopolymers. HCl dissolution method was applied to determine the geopolymerization percentage of samples and Fourier Transform Infrared (FTIR) Spectroscopy was used to find out the optimum calcination temperature for geopolymerization. According to obtained results, the highest geopolymerization percentage (0% alumina added geopolymer equal to 35.789%; 100% alumina added geopolymer equal to 40.546%) was obtained in samples using fly ash calcined at 800 °C.

Keywords: geopolymer, fly ash, Al₂O₃ addition, calcination

Procedia PDF Downloads 176

Authors: A. Mavrikos, N. Petsas, E. Kaltsi, D. Kaliampakos

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The lignite-fired power plants in the Western Macedonia Lignite Center produce more than 8 106 t of fly ash per year. Approximately 90% of this quantity is used for restoration-reclamation of exhausted open-cast lignite mines and slope stabilization of the overburden. The purpose of this work is to evaluate the environmental behavior of the mixture of waste rock and fly ash that is being used in the external deposition site of the South Field lignite mine. For this reason, a borehole was made within the site and 86 samples were taken and subjected to chemical analyses and leaching tests. The results showed very limited leaching of trace elements and heavy metals from this mixture. Moreover, when compared to the limit values set for waste acceptable in inert waste landfills, only few excesses were observed, indicating only minor risk for groundwater pollution. However, due to the complexity of both the leaching process and the contaminant pathway, more boreholes and analyses should be made in nearby locations and a systematic groundwater monitoring program should be implemented both downstream and within the external deposition site.

Keywords: co-deposition, fly ash, leaching tests, lignite, waste rock

Procedia PDF Downloads 238

Authors: Kristine Dzagnidze

Abstract:

The paper equally centers on both the structural and cognitive linguistics in light of phraseologism and its emotional implication. Accordingly, the methods elaborated within the framework of both the systematic-structural and linguo-cognitive theories are identically relevant to the research of mine. In other words, through studying the negotiation process, our attention is drawn upon defining negotiations’ peculiarities, emotion, style and specifics of cognition, motives, aims, contextual characterizations and the quality of cultural context and integration. Besides, the totality of the concepts and methods is also referred to, which is connected with the stage of the development of the emotional linguistic thinking. The latter contextually correlates with the dominance of anthropocentric–communicative paradigm. The synthesis of structuralistic and cognitive perspectives has turned out to be relevant to our research, carried out in the form of intellectual action, that is, on the one hand, the adequacy of the research purpose to the expected results. On the other hand, the validity of methodology for formulating the objective conclusions needed for emotional connotation beyond phraseologism. The mechanism mentioned does not make a claim about a discovery of a new truth. Though, it gives the possibility of a novel interpretation of the content in existence.

Keywords: cognitivism, communication, implication, negotiation

Procedia PDF Downloads 264

Authors: Blessing Olamide Taiwo, Andrew Palangio, Chirag Savaliya, Jenil Patel

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Oversized material resulting from blasting presents a notable drawback in the transportation of run-off-mine material due to increased expenses associated with handling, decreased efficiency in loading, and greater wear on digging equipment. Its irregular size and weight demand additional resources and time for secondary breakage, impacting overall productivity and profitability. This paper addresses the limitations of interpreting image analysis software results and applying them to the assessment of blast-generated oversized materials. This comprehensive guide utilizes both ortho mosaic and digital photos to provide critical approaches for optimizing fragmentation analysis and improving decision-making in mining operations. It briefly covers post-blast assessment, blast block heat map interpretation, and material loading decision-making recommendations.

Keywords: blast result assessment, WipFrag, oversize identification, orthomosaic images, production optimization

Procedia PDF Downloads 39

Authors: Yu Zhang, Pedro Desouza

Abstract:

Since big data has become substantially more accessible and manageable due to the development of powerful tools for dealing with unstructured data, people are eager to mine information from social media resources that could not be handled in the past. Sentiment analysis, as a novel branch of text mining, has in the last decade become increasingly important in marketing analysis, customer risk prediction and other fields. Scientists and researchers have undertaken significant work in creating and improving their sentiment models. In this paper, we present a concept of selecting appropriate classifiers based on the features and qualities of data sources by comparing the performances of five classifiers with three popular social media data sources: Twitter, Amazon Customer Reviews, and Movie Reviews. We introduced a couple of innovative models that outperform traditional sentiment classifiers for these data sources, and provide insights on how to further improve the predictive power of sentiment analysis. The modelling and testing work was done in R and Greenplum in-database analytic tools.

Keywords: sentiment analysis, social media, Twitter, Amazon, data mining, machine learning, text mining

Procedia PDF Downloads 352

Authors: Anurag Savarnya

Abstract:

The reliability of the various parts of electric mining shovel has been assessed through the application of Weibull Model. The study was initiated to find reliability of components of electric mining shovel. The paper aims to optimize the reliability of components and increase the life cycle of component. A multilevel decomposition of the electric mining shovel was done and maintenance records were used to evaluate the failure data and appropriate system characterization was done to model the system in terms of reasonable number of components. The approach used develops a mathematical model to assess the reliability of the electric mining shovel components. The model can be used to predict reliability of components of the hydraulic mining shovel and system performance. Reliability is an inherent attribute to a system. When the life-cycle costs of a system are being analyzed, reliability plays an important role as a major driver of these costs and has considerable influence on system performance. It is an iterative process that begins with specification of reliability goals consistent with cost and performance objectives. The data were collected from an Indian open cast coal mine and the reliability of various components of the electric mining shovel has been assessed by following a Weibull Model.

Keywords: reliability, Weibull model, electric mining shovel

Procedia PDF Downloads 512

Authors: Franky Michael Hamonangan Siagian, Affan Maulana, Himawan Tri Bayu Murti Petrus, Widi Astuti

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In this study, the feasibility of the direct electrowinning method was used to produce zero-valent iron from red mud. The bauxite residue sample came from the Tayan mine, Indonesia, which contains high hematite (Fe₂O₃). Before electrolysis, the samples were characterized by various analytical techniques (ICP-AES, SEM, XRD) to determine their chemical composition and mineralogy. The direct electrowinning method of red mud suspended in NaOH was introduced at low temperatures ranging from 30 - 110 °C. Variations of current density, red mud: NaOH ratio and temperature were carried out to determine the optimum operation of the direct electrowinning process. Cathode deposits and residues in electrochemical cells were analyzed using XRD, XRF, and SEM to determine the chemical composition and current recovery. The low-temperature electrolysis current efficiency on Redmud can reach 20% recovery at a current density of 920,945 A/m². The moderate performance of the process was investigated with red mud, which was attributed to the troublesome adsorption of red mud particles on the cathode, making the reduction far less efficient than that with hematite.

Keywords: red mud, electrochemical reduction, Iron production, hematite

Procedia PDF Downloads 75