Some of the largest and deepest mines in the world are situated in South Africa. Underground temperatures and humidity can be controlled by means of complex chilled water reticulation system. A cascade pumping system is used to pump the used water from the underground levels back to the surface. The dewatering process is energy intensive. Large volumes of water are used during the general mine drilling periods (06:00 to 12:00). During blasting periods (15:00 to 18:00) a minimum amount of personnel are underground, yet large volumes of water are still sent underground due to a lack of control. Reducing the water sent underground, will reduce the amount of water pumped back to the surface; resulting in significant energy savings. Water flow and pressure can be managed by installing control valves at appropriate positions throughout the water reticulation system. Selecting a control valve is typically governed by constraints such as cavitation, water hammer, flashing, safety ratings and control range. A basic set of calculations can be used to determine whether a valve conforms to a specific scenario. However, scenarios calculated by engineers are not indicative of all applied system scenarios. When control valves are installed, to optimise the operation of a system, it affects the system’s characteristics. Sampled system data will therefore no longer provide adequate readings to help with selecting the correct control valve. An analytical control valve selection method has been developed and implemented. The case study shows the results and practical implications of applying this method in the mining industry. Implementing the analytical valve selection method is shown to be viable, realising electrical energy cost savings for the mine by reducing power requirements from Eskom. Analytical control valve selection for mine water reticulation systems / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013.

Some of the largest and deepest mines in the world are situated in South Africa. Underground temperatures and humidity can be controlled by means of complex chilled water reticulation system. A cascade pumping system is used to pump the used water from the underground levels back to the surface. The dewatering process is energy intensive. Large volumes of water are used during the general mine drilling periods (06:00 to 12:00). During blasting periods (15:00 to 18:00) a minimum amount of personnel are underground, yet large volumes of water are still sent underground due to a lack of control. Reducing the water sent underground, will reduce the amount of water pumped back to the surface; resulting in significant energy savings. Water flow and pressure can be managed by installing control valves at appropriate positions throughout the water reticulation system. Selecting a control valve is typically governed by constraints such as cavitation, water hammer, flashing, safety ratings and control range. A basic set of calculations can be used to determine whether a valve conforms to a specific scenario. However, scenarios calculated by engineers are not indicative of all applied system scenarios. When control valves are installed, to optimise the operation of a system, it affects the system’s characteristics. Sampled system data will therefore no longer provide adequate readings to help with selecting the correct control valve. An analytical control valve selection method has been developed and implemented. The case study shows the results and practical implications of applying this method in the mining industry. Implementing the analytical valve selection method is shown to be viable, realising electrical energy cost savings for the mine by reducing power requirements from Eskom. Analytical control valve selection for mine water reticulation systems / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013.

Energy shortage, escalation of energy cost and climate change have led to an increased focus on energy conservation worldwide. In order to curb the increase in electricity demand, Eskom has introduced demand-side management (DSM) to improve energy efficiency and to shift peak-time load to off-peak periods in order to postpone additional capacity requirements. In the past, several mine DSM projects have been implemented without the use of system simulations as part of the analysis of project planning. Many of these projects are characterised by contractual energy saving targets that have not been met, projects that are delayed, potential energy savings projects that have been overlooked and additional savings that have not realised. This study demonstrates the potential of simulations to plan new and correct implemented DSM solutions. This is done by allowing analysis of energy consumption in complex technical systems and quantification of the savings potential of DSM interventions to inform design changes in order to attain energy savings. In applying simulations to a well-instrumented compressed air system, it was possible to compare the theoretical and measured values for system parameters. The simulation was fine-tuned for low-pressure operation (with the system operating well within design constraints) by incorporating estimated flow losses. By simulating high-pressure operation in which the system operates closer to design limits, the constraints that were experienced, were revealed. This application exemplifies the approach that has been adopted in the case studies to follow. The value of the use of simulation models for mine DSM projects Simulations that have been applied to four case studies demonstrate the use in improving existing DSM projects as well as in planning new DSM projects. Two case studies demonstrate the use of simulations in rectifying problems that have been encountered during the implementation of existing mine DSM projects. Simulations have been employed to propose corrections to these project implementations; this demonstrates significant value for the customer. In two additional case studies, the value of simulation models is demonstrated where simulations have been developed prior to the implementation of DSM projects. It demonstrates that projects can be implemented with less effort, in a shorter time span and at a reduced cost (both capital and man-hours) by using simulations in the planning phases of DSM projects. / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013.

Energy shortage, escalation of energy cost and climate change have led to an increased focus on energy conservation worldwide. In order to curb the increase in electricity demand, Eskom has introduced demand-side management (DSM) to improve energy efficiency and to shift peak-time load to off-peak periods in order to postpone additional capacity requirements. In the past, several mine DSM projects have been implemented without the use of system simulations as part of the analysis of project planning. Many of these projects are characterised by contractual energy saving targets that have not been met, projects that are delayed, potential energy savings projects that have been overlooked and additional savings that have not realised. This study demonstrates the potential of simulations to plan new and correct implemented DSM solutions. This is done by allowing analysis of energy consumption in complex technical systems and quantification of the savings potential of DSM interventions to inform design changes in order to attain energy savings. In applying simulations to a well-instrumented compressed air system, it was possible to compare the theoretical and measured values for system parameters. The simulation was fine-tuned for low-pressure operation (with the system operating well within design constraints) by incorporating estimated flow losses. By simulating high-pressure operation in which the system operates closer to design limits, the constraints that were experienced, were revealed. This application exemplifies the approach that has been adopted in the case studies to follow. The value of the use of simulation models for mine DSM projects Simulations that have been applied to four case studies demonstrate the use in improving existing DSM projects as well as in planning new DSM projects. Two case studies demonstrate the use of simulations in rectifying problems that have been encountered during the implementation of existing mine DSM projects. Simulations have been employed to propose corrections to these project implementations; this demonstrates significant value for the customer. In two additional case studies, the value of simulation models is demonstrated where simulations have been developed prior to the implementation of DSM projects. It demonstrates that projects can be implemented with less effort, in a shorter time span and at a reduced cost (both capital and man-hours) by using simulations in the planning phases of DSM projects. / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013.

Please read the abstract in the section 00front of this document / Dissertation (M Eng (Electrical Engineering))--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / unrestricted