No description available.

Acid rock drainage (ARD) is recognised as one of the most serious environmental issues currently facing the mining industry. ARD management strategies rely heavily on the ability to measure the ARD potential of waste materials to ensure strategies are appropriate to the ARD risks. It is apparent that improvements to the understanding of ARD test methods and development of methods to better represent the ARD potential of samples will contribute significantly to the value and reliability of ARD assessment. The research described in this thesis focused on critical assessment and improvement of: ARD test methodology; approach to testing; and interpretation of results for coal mine wastes. Kaltim Prima Coal Mine (KPC) in Kalimantan, Indonesia was selected as a case study site to help focus the research, with the understanding that the broad similarities of coal sequences in general would allow broader application of the findings. / Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2005.

Acid rock drainage (ARD) is recognised as one of the most serious environmental issues currently facing the mining industry. ARD management strategies rely heavily on the ability to measure the ARD potential of waste materials to ensure strategies are appropriate to the ARD risks. It is apparent that improvements to the understanding of ARD test methods and development of methods to better represent the ARD potential of samples will contribute significantly to the value and reliability of ARD assessment. The research described in this thesis focused on critical assessment and improvement of: ARD test methodology; approach to testing; and interpretation of results for coal mine wastes. Kaltim Prima Coal Mine (KPC) in Kalimantan, Indonesia was selected as a case study site to help focus the research, with the understanding that the broad similarities of coal sequences in general would allow broader application of the findings. / Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2005

Acid rock drainage (ARD) is recognised as one of the most serious environmental issues currently facing the mining industry. ARD management strategies rely heavily on the ability to measure the ARD potential of waste materials to ensure strategies are appropriate to the ARD risks. It is apparent that improvements to the understanding of ARD test methods and development of methods to better represent the ARD potential of samples will contribute significantly to the value and reliability of ARD assessment. The research described in this thesis focused on critical assessment and improvement of: ARD test methodology; approach to testing; and interpretation of results for coal mine wastes. Kaltim Prima Coal Mine (KPC) in Kalimantan, Indonesia was selected as a case study site to help focus the research, with the understanding that the broad similarities of coal sequences in general would allow broader application of the findings. / Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2005

Thesis (M. Sc.)--University of Hong Kong, 1998. / Includes bibliographical references.

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 1997. / Due to the extreme costs of establishing new shaft systems in Witwatersrand gold mines it is essential that the resource estimation is optimised, The result of poor Of sub-optimal estimation could be catastrophic even.to the largest of mining companies. This project examines the application of Compound Lognormal Distribution theory and shows the advantages of this distribution model over more traditional models, for the Carbon Leader Reef. The incorporation of information from mined out areas of a deposit in resource estimation is demonstrated. The critical role played by accurate geological modelling is highlighted. The process of Macro Co-Kriging in conjunction with Compound Lognormal Theory is discussed in detail and is shown to be a more accurate estimation technique than traditional techniques using Lognormal theory. Finally the use of the Macro Co-kriged limits are shown to be useful in the classification of Mineral Resources. / AC2017

No description available.

The adjustable-pitch setting on an axial-flow fan is the most common method of controlling airflow for primary coal mine ventilation. With this method, the fan operates at a constant speed dictated by its motor design. The angles of the blades are adjusted to change the amount of airflow and pressure to meet ventilation requirements. Typically, the fan does not operate at its optimum efficiency, which only occurs in a narrow band of air pressures and quantities. The use of variable frequency drives (VFDs), which control fan speed, provides a solution to this problem. VFDs are already used in various similar applications such as pumping and building ventilation. New technology now enables efficient VFD operation in medium voltage (2,300 – 6,900 V) fan applications. The primary benefit of a variable frequency drive is that it allows motors to operate at reduced speeds, and thus at a lower power, without a loss of torque. VFDs also allow for efficient operation over the entire life of the fan. The technical considerations of using a VFD are presented in this work, along with a method for choosing and modeling a variable speed fan to achieve maximum energy savings. As a part of this research, a spreadsheet program was developed that will calculate the optimum fan operating speed based on given fan data and specified operating conditions. A representative room and pillar coal mine is modeled to illustrate the selection and modeling process and as an example of the economic implications of using a VFD. The use of VFDs is shown to potentially yield large energy savings by increasing the fan efficiency over the life of the mine. Although there are definite power savings while using variable speed fans, the magnitude of these savings is specific to an individual mine and the operating conditions encountered. The determination of whether the use of VFDs is economically feasible requires analysis for the specific mine and its operating conditions. This work provides the background and a method for such an evaluation. / Master of Science

An experimental mine simulator was constructed which will be used to conduct tracer gas experiments in the laboratory. The test apparatus simulates a mine in a tabular deposit and is modular and simple and can be easily rearranged to represent a variety of mine geometries. The apparatus is appropriate for the use of tracer gases by being both airtight and open-circuit (exhausting to the atmosphere) and by maintaining turbulent flow throughout the model, ensuring the tracer gas is fully dispersed. The model features ports for injection and sampling of tracer gases, which represent boreholes present in an actual mine. The model is designed, in part, for the practice of tracer gas release and sampling methods in the laboratory. Valves on the apparatus represent ventilation controls, such as stoppings or regulators, or changing resistances in a mine, such an increase in resistance due to a roof fall or a decrease in resistance due to stoppings being destroyed. The relative resistances of airways can be changed by changing the status of the valves to represent different states of the ventilation controls. The mine simulator should serve as a tool for identifying and investigating novel tracer gases, developing a procedure for performing ventilation surveys using multiple tracer gases, and eventually developing a method for remotely inferring ventilation changes using tracer gases. / Master of Science

Acid mine drainage (AMD) at Stockton Coal Mine, located near Westport, New Zealand, is generated from the oxidation of pyrite within sedimentary overburden exposed during surface mining. The pyrite oxidation releases significant acidity, Fe, and sulphate together with trace metals to the receiving environment. Aluminium is also elevated in drainage waters due to acid leaching from overburden materials. Thirteen AMD seeps emanating from waste rock dumps, and associated sediment ponds were monitored at Stockton Coal Mine to characterise water chemistry, delineate their spatial and temporal variability, and quantify metal loads. Dissolved metal concentrations ranged from 0.05-1430 mg/L Fe, 0.200-627 mg/L Al, 0.0024-0.594 mg/L Cu, 0.0052-4.21 mg/L Ni, 0.019- 18.8 mg/L Zn, <0.00005-0.0232 mg/L Cd, 0.0007-0.0028 mg/L Pb, <0.001-0.154 mg/L As and 0.103- 29.3 mg/L Mn and the pH ranged from 2.04-4.31. Currently this AMD is treated further downstream by a number of water treatment plants employing a combination of ultra fine limestone and calcium hydroxide; however, in the interest of assessing more cost-effective technologies, passive treatment systems were investigated for their treatment and hydraulic efficacy and as potential cost-effective options. Biogeochemical reactors (BGCRs) were selected as the most appropriate passive treatment system for ameliorating AMD at Stockton Coal Mine. Results of mesocosm-scale treatability tests showed that BGCRs incorporating mussel shells, Pinus radiata bark, wood fragments (post peel), and compost increased pH to ≥6.7 and sequestered ≥98.2% of the metal load from the Manchester Seep located within the Mangatini Stream catchment. The following design criteria were recommended for BGCRs incorporating 20-30 vol. % mussel shells as an alkalinity amendment: 1) 0.3 mol sulphate /m3 substrate/day for sulphate removal (mean of 94.1% removal (range of 87.6-98.0%)); 2) 0.4 mol metals/m3/day for metal (mean of 99.0% removal (range of 98.5-99.9%)) and partial sulphate (mean of 46.0% removal (range of 39.6-57.8%)) removal; and 3) 0.8 mol metals/m3/day for metal (mean of 98.4% removal (range of 98.2-98.6%) and minimal sulphate (mean of 16.6% removal (range of 11.9- 19.2%)) removal. At the maximum recommended loading rate of 0.8 mol total metals/m3/day an average of 20.0 kg/day (7.30 tonnes/year) of metals and 85.2 kg acidity as CaCO3/day could be removed from the Manchester Seep AMD by employing BGCRs. The design hydraulic residence time (HRT) would be 3.64 days. On an acidity areal loading basis, a design criterion of 65 g/m2/day was recommended. Tracer studies conducted on the BGCRs indicated ideal flow characteristics for cylindrical drumshaped reactors and non-ideal flow conditions for trapezoidal-shaped reactors indicative of shortcircuiting, channelised flow paths and internal recirculation. Consequently, this resulted in compromised treatment performance in the trapezoidal-shaped reactors. The relaxed tanks in series (TIS) model could be successfully applied to model the treatment performance of drum-shaped reactors; however, the model was unsuccessful for trapezoidal-shaped reactors. Because most pilot and full-scaled vertical flow wetlands (VFWs) have consisted of trapezoidal-prism basins excavated into the ground, the rate-removal methods previously recommended (e.g. mol metals/m3/day) should be applied to BGCR design, evaluation and operation rather than results of hydraulic and reactor modelling. Overall, a staged passive treatment approach is recommended. The first stage should consist of a sedimentation basin to remove sediment, the second stage a BGCR to remove acidity and metals and the third an aerobic wetland to provide oxygenation and tertiary treatment of metals (primarily Fe) from BGCR effluent. Preliminary analysis indicates that BGCRs are potentially a more cost-effective means of treating AMD at Stockton Coal Mine compared with the current active lime-dosing plant by over $125/tonne of acidity ($197/tonne for BGCRs versus $324/tonne for lime dosing (60% efficient)); however, their successful implementation would need to recognise current treatment goals, required areal footprint and inherent maintenance requirements.