N. I. Aziz; I. Porter; F. Sereshki
Abstract
The volumetric changes in the coal matrix (Coal Shrinkage), permeability under various gas environment conditions as well as perographical properties were studied in the laboratory. The shrinkage and permeability of coal were examined with respect to changing gas type and confining pressures. The shrinkage ...
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The volumetric changes in the coal matrix (Coal Shrinkage), permeability under various gas environment conditions as well as perographical properties were studied in the laboratory. The shrinkage and permeability of coal were examined with respect to changing gas type and confining pressures. The shrinkage tests were carried out in high-pressure bombs while the permeability study was conducted in a specially constructed high-pressure chamber. Methane (CH4), carbon dioxide (CO2), nitrogen, (N2) and a 50% -50% volume mixture of CO2/CH4 gas were used in the study. The tests showed that under different pressure levels gas type affected permeability and shrinkage characteristics of coal. This paper presents a case study of Tahmoor Colliery, NSW, Australia and an overall discussion on coal shrinkage, permeability and coal petrography data of Tahmoor that permits a better understanding of the gas regime in this mine. The results are important to the further understanding of the inter-relationship between gas flow, the coal matrix and permeability in ‘normal’ and ‘tight’ coal conditions (locally referred to as disturbed coal).
R. Marandi; F. Doulati Ardejani; H. Amir Afshar
Abstract
The biosorption of heavy metals can be an effective process for the removal of such metal ions from aqueous solutions. In this study, the adsorption properties of nonliving biomass of phanerochaete chrysosporium for Pb (II) and Zn (II) were investigated by the use of batch adsorption techniques. The ...
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The biosorption of heavy metals can be an effective process for the removal of such metal ions from aqueous solutions. In this study, the adsorption properties of nonliving biomass of phanerochaete chrysosporium for Pb (II) and Zn (II) were investigated by the use of batch adsorption techniques. The effects of initial metal ion concentration, initial pH, biosorbent concentration, stirring speed, temperature and contact time on the biosorption efficiency were studied. The experimental results indicated that the uptake capacity and adsorption yield of one the metal ion were reduced by the presence of the other one. The optimum pH was obtained as 6.0. The experimental adsorption data were fitted to both Langmuir and Frundlich adsorption models for Pb (II) and to the Langmuir model for Zn (II) ion. The highest metals uptake values of 57 and 87 mg/g were calculated for Zn (II) and Pb (II) respectively. Desorption of heavy metal ions was performed by 50 mM HNO3 solution. The results indicated that the biomass of phanerochaete chrysosporium is a suitable biosorbent for the removal of heavy metal ions from the aqueous solutions.
M. Ziaii; A. Abedi; M. Ziaei; A. Kamkar Rouhani; A. Zendahdel
Abstract
One of the major strengths of a Geographic Information System (GIS) in geosciences is the ability to integrate and combine multiple layers into mineral potential maps showing areas which are favorable for mineral exploration. These capabilities make GIS an extremely useful tool for mineral exploration. ...
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One of the major strengths of a Geographic Information System (GIS) in geosciences is the ability to integrate and combine multiple layers into mineral potential maps showing areas which are favorable for mineral exploration. These capabilities make GIS an extremely useful tool for mineral exploration. Several spatial modeling techniques can be employed to produce potential maps. However, these methods can be divided into knowledge -and data-driven techniques. The goal of this study is to use GIS in mapping gold deposit potentials in Torud-Chah Shiran area. After collecting relevant exploration data and defining appropriate exploration model for the mineralization zone, several layers including proved mineralization map, geological map, remote sensing derived, alteration map, geochemical and aeromagnetic maps were imported in to GIS environment. For integrated exploration modeling, two methods were used: fuzzy logic and weight of evidence methods. Finally, the results of the two methods were compared. The result of each method had statistical problems but these problems were alleviated using the map of differences that was in a good agreement with reality.
A. Ramezanzadeh; M. Hood
Abstract
The first step in mining activities is rock excavation in both mine development and production. Constant pressure for cost reduction and creating an improved/safe work environment for personnel has naturally resulted in increased use of mechanical excavation systems in many mining operations. Also, mechanical ...
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The first step in mining activities is rock excavation in both mine development and production. Constant pressure for cost reduction and creating an improved/safe work environment for personnel has naturally resulted in increased use of mechanical excavation systems in many mining operations. Also, mechanical excavation and mining is more compatible with automation, meaning possibility of reduction in number of people in the active underground mines. This factor plays a major role in selection of mining systems especially considering the dire shortage of skilled labour in the industry. While these systems are an integral part of mining activities in underground soft rock mining (coal, salt, potash, trona etc.), there is a need for developing new approaches and machinery for use in the underground hard rock mining. This paper will offer a review of current and emerging technologies for mechanical hard rock excavation, including disc cutting technology, drag picks, mini-disc, and activated/oscillating disc cutter. A review of general guidelines for assessment of the potentials of new research and development on this topic and evaluation of emerging technologies for a specific mining application will also be offered.
M. Kor; E. Abkhoshk; Kh. Gharibie; S. Z. Shafaei
Abstract
An attempt has been made in this paper to investigate the effect of particle size distribution on coal flotation kinetics. The effect of particle size (Ps) on kinetics constant (k) and maximum theoretical flotation recovery (RI) was investigated while other operational parameters were kept constant. ...
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An attempt has been made in this paper to investigate the effect of particle size distribution on coal flotation kinetics. The effect of particle size (Ps) on kinetics constant (k) and maximum theoretical flotation recovery (RI) was investigated while other operational parameters were kept constant. The relationship between flotation kinetics constant and theoretical flotation recovery with particle size was estimated with nonlinear equations. Analysis of variance showed that the effect of particle size on the kinetics constant was statistically significant at 95% confidence level. However, it was not significant on maximum theoretical flotation recovery (RI). Different regression methods were conducted in order to model the effect of coal particle size on flotation kinetics. Results indicated that the quadric regression method gave better prediction of the cumulative recovery for different particle size fractions. The correlation coefficient (R2) values of this model were 0.99, 0.996, 0.98, 0.98 and 0.97 for average of particle sizes of 37.5 µm, 112.5 µm, 225 µm, 400 µm and 625 µm respectively.
E. von Sperling; C.A.P. Grandchamp
Abstract
The paper presents the case study of the current formation of a Brazilian pit lake from an iron ore mining activity. The water used for the filling of the lake comes from rain, ground water and the complementary pumpage from a close river. At its final stage, which will be reached around year 2018, Lake ...
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The paper presents the case study of the current formation of a Brazilian pit lake from an iron ore mining activity. The water used for the filling of the lake comes from rain, ground water and the complementary pumpage from a close river. At its final stage, which will be reached around year 2018, Lake Aguas Claras will have a surface area of 0.67 km2 and the depth of 234 m, which will make it the deepest lake in the country. The filling of the lake began in the year 2001 and a monthly monitoring programme (physical, chemical and biological characteristics) is since then in course Theanalyses show that Lake Âguas Claras presents a very good water quality (well oxygenated, low values of colour and turbidity, limited degree of mineralization, pH slightly alkaline, low nutrient concentrations, excellent bacteriological conditions), together with a remarkable shift in the dominance of phytoplanktonic groups, indicating the high instability of lakes that are undergoing a process of formation. One relevant point in the management of this valuable water resource is to create adequate conditions for the protection of the aquatic environment. Considering the very probable maintenance of these favourable characteristics in future years, the possible uses of the lake will be directed to recreation (swimming, diving, sailing and fishing), amenity value and water supply.
M. Koneshloo; Jean-Paul Chiles
Abstract
The kaolinitic clays have been exploited for more than a hundred years, in the western part of the Charentes Basin, France, and belong to a paleo-deltaic network. The recent deposits are relatively richer in alumina in comparison with the older ones. The genesis of the kaolin deposits of the Charentes ...
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The kaolinitic clays have been exploited for more than a hundred years, in the western part of the Charentes Basin, France, and belong to a paleo-deltaic network. The recent deposits are relatively richer in alumina in comparison with the older ones. The genesis of the kaolin deposits of the Charentes Basin follows simple geological rules, but their detailed geometry has a great complexity, reinforced by the fact that one must distinguish very different clay qualities. The exploitation of the complex deposits which are buried in the deeper level needs the more powerful tools. The paper aims at analyzing the adequacy of the traditional method used in the exploitations of the kaolin deposits of the Charentes Basin in comparison with another method based on geostatistics to define criteria of selection and classification of reserves.
R. N. Singh; A.S. Atkins; A.G. Pathan
Abstract
Ground water and surface water create a range of problems in lignite mining utilizing surface mining methods. In order to create a safe and economic mining environment, it is essential to carry out mining after dewatering the rock mass surrounding the lignite mines by advance dewatering techniques. This ...
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Ground water and surface water create a range of problems in lignite mining utilizing surface mining methods. In order to create a safe and economic mining environment, it is essential to carry out mining after dewatering the rock mass surrounding the lignite mines by advance dewatering techniques. This paper briefly describes the ground water regimes including pressure gradients associated with various lignite deposits together with the practical examples of some important lignite deposits in the world. An effective method of controlling ground water in multi-aquifer environment in lignite deposits is to carry out rock mass dewatering using borehole pumps. This approach will help reducing the inflow rates of ground water to the mining excavation and also increase the effective strength of the overburden strata, thus, increasing the slope stability of the mining excavations. The main theme of this paper is to present a case history analysis of Thar lignite deposit in Sindh, Pakistan which has lignite reserves of some 193 billion tonnes. The paper presents a proposed method of dewatering the Thar prospect together with an assessment of the quality of aquifer water which can be used to improve the quality of life of people inhabiting in the Thar Desert area of Sindh, Pakistan. Water samples from three aquifers were collected from nine different locations and were analyzed in the laboratory for evaluating their physical and chemical characteristics. The test results indicated that the aquifer water can be classified as (sodium+ potassium) – chloride type water with a TDS range of 1000 to 20,000 mg/L. Consequently, this ground water is classified as brackish (saline water) requiring treatment before it can be utilised for domestic or industrial consumptions. It should be noted that this ground water does not contain heavy metals and toxic metals including arsenic, mercury and lead or cyanide. However, results indicate that groundwater from a few locations contained traces of silver (<4oppb)Owithozinc0<0.1ppm.
