TY - THES

T1 - Ventilation on Demand in Metal mine (AngloGold Ashanti, Obuasi)

AU - Bruce, Theophilus

N1 - embargoed until null

PY - 2014

Y1 - 2014

N2 - Underground mines require good ventilation systems to support human life, dissipate and dilute toxic gases and dusts, provide oxygen for the miners and for the operation of internal combustion engines, and in some cases, to provide heated or cooled air for acceptable working conditions. It is therefore incumbent on mining companies to provide adequate ventilation especially for their underground mines, in their quest to explore, develop and mine deeper underground. Currently, the kind of ventilation being employed in the AngloGold Ashanti Obuasi mine is mostly that of the conventional ventilation system. This is characterized by the use of fans and regulators to provide adequate volumes of air in the various phases of the underground mining process. With the conventional system, fans and other devices are left to operate at full power throughout the period the mine is operational irrespective of the number of equipment or personnel working underground. This leads to huge annual electricity costs needed to be paid by the mines so as to sustain operations. Considering the fact that equipment and personnel may not be working in all areas underground at any particular period, it would be economically beneficial if a ventilation system could monitor and determine the amount of ventilation that would be required at specific areas of the underground mine and as a result supply the appropriate volume of air to these areas as and when necessary. The Ventilation on Demand (VOD) system serves such a purpose. The VOD system would ensure the efficient regulation of all fans, regulators, and doors in the mine depending on the required air flow volumes in the various areas of the underground mine. Since these devices are not going to be running at full power all the time, their operating life would also be longer than that of a similar device constantly operating at maximum power in a conventional mine. Technically, this improves the productivity and efficiency of the mine and provides better returns on investment than those in a conventional ventilation system. Consequently, a research study was carried out at the AngloGold Ashanti (AGA) Obuasi underground mine in Ghana and the current energy consumption of the mine, which operates the conventional ventilation system, was calculated. Considering the layout of the mine, the cost of installing a VOD system in the Kwesi Mensah Shaft (KMS) section was determined. The expected energy consumption of the mine once the VOD system was installed was also estimated and a series of analyses was carried out to ascertain the amount of savings that could be made with the VOD system. The analysis showed that if $1.4million is invested in Ventilation on Demand system at the KMS section of the mine, within a period of five years, the pay back will be realised within the first year of which $2 million will be saved. The net present value in five years will be $7.7 million. Such high savings justify the cost of setting up a VOD system in any underground mine, and with the associated benefits of equipment and employee tagging and monitoring that could be derived from such a system, it makes sense economically, technically, and health and safety wise to adopt a VOD system in underground mine operations.

AB - Underground mines require good ventilation systems to support human life, dissipate and dilute toxic gases and dusts, provide oxygen for the miners and for the operation of internal combustion engines, and in some cases, to provide heated or cooled air for acceptable working conditions. It is therefore incumbent on mining companies to provide adequate ventilation especially for their underground mines, in their quest to explore, develop and mine deeper underground. Currently, the kind of ventilation being employed in the AngloGold Ashanti Obuasi mine is mostly that of the conventional ventilation system. This is characterized by the use of fans and regulators to provide adequate volumes of air in the various phases of the underground mining process. With the conventional system, fans and other devices are left to operate at full power throughout the period the mine is operational irrespective of the number of equipment or personnel working underground. This leads to huge annual electricity costs needed to be paid by the mines so as to sustain operations. Considering the fact that equipment and personnel may not be working in all areas underground at any particular period, it would be economically beneficial if a ventilation system could monitor and determine the amount of ventilation that would be required at specific areas of the underground mine and as a result supply the appropriate volume of air to these areas as and when necessary. The Ventilation on Demand (VOD) system serves such a purpose. The VOD system would ensure the efficient regulation of all fans, regulators, and doors in the mine depending on the required air flow volumes in the various areas of the underground mine. Since these devices are not going to be running at full power all the time, their operating life would also be longer than that of a similar device constantly operating at maximum power in a conventional mine. Technically, this improves the productivity and efficiency of the mine and provides better returns on investment than those in a conventional ventilation system. Consequently, a research study was carried out at the AngloGold Ashanti (AGA) Obuasi underground mine in Ghana and the current energy consumption of the mine, which operates the conventional ventilation system, was calculated. Considering the layout of the mine, the cost of installing a VOD system in the Kwesi Mensah Shaft (KMS) section was determined. The expected energy consumption of the mine once the VOD system was installed was also estimated and a series of analyses was carried out to ascertain the amount of savings that could be made with the VOD system. The analysis showed that if $1.4million is invested in Ventilation on Demand system at the KMS section of the mine, within a period of five years, the pay back will be realised within the first year of which $2 million will be saved. The net present value in five years will be $7.7 million. Such high savings justify the cost of setting up a VOD system in any underground mine, and with the associated benefits of equipment and employee tagging and monitoring that could be derived from such a system, it makes sense economically, technically, and health and safety wise to adopt a VOD system in underground mine operations.

M3 - Master's Thesis (University Course)

ER -