An investigation into the life cycle costs of a two-flight conveyor versus a single-flight conveyor by analysis of the system reliability, availability, maintainability and overall economic viability

• Main Author: Nkomonde, Noxolo
• Published: 2014
• Subjects: Belt conveyors; Conveying machinery; Bulk solids handling
• Online Access: http://hdl.handle.net/10210/10998

M.Ing. (Engineering Management) === In a tender bid to energy and chemical company Sasol, a request to offer a technical solution for a two-flight overland conveyor system whose function is to transport coal from a 15 000 tonne bunker into an external stockpile storage facility in the plant was made. This conveyor consisted of two conveyor flight sections of lengths 18 423m and 8 537m each. The prospect of combining the two flights of conveyors to form one, super-efficient conveyor structure with additional cost saving benefits was identified. It was found that this occurrence was not unique to the individual project as other researching engineers have been faced with similar problems before [18]. This then lead the researcher into believing that there could be some advantage in investigating the possible benefits to the overall cost, maintainability and scheduling of the fabrication and erection activities for the entire project of combining the multiple flight conveyors into a single-flight conveyor. It is also the conviction of the researcher that the achieved outcomes will prove beneficial to the bulk materials handling industry as a whole. The problem is traditionally short, multiple flight conveyors have always been used for performing the function of transporting bulk material from one location in a mining plant to another hence; long, single-flight overland conveyors of lengths exceeding 26 km have not been commonly installed. In this dissertation the possibility of employing a single-flight overland as opposed to a two-flight conveyor in the Sasol Impumelelo coal plant is investigated. This is done against the work of other researchers who have conducted similar studies in the field as well as by utilizing project-specific data using applicable industry standards as well as Engineering Management course theory. By employing actual project procurement and engineering design data; the investigation is done by calculating and comparing the individual capital and operational costs that encompass the total cost of ownership (TCO) for both conveyor systems as well as the two systems’ reliability, availability and maintainability to establish each system’s complete life cycle costs. It is the opinion of the researcher that the investigation method is valid as it is in line with the guidelines given by The Miami University of Ohio [24] as well as J Hanek [25] and thus provides the researcher with a plausible technique for establishing which between the single-flight overland conveyor and two-flight overland conveyor configurations is overall the more superior system to install. It was found that even though its initial capital and operational costs are higher; the single-flight conveyor system is more reliable, readily available and cheaper to run and sustain over the 30 year expected life-span of the plant. It also is less labour intensive to perform maintenance on, yields less material degradation and results in less material spillage because of the elimination of additional transfer points and transfer towers. These results can be taken as valid on a global scale, for any mining plant, not restricted to any specific material as they are not subject to South African temperature, altitude or seismic conditions nor are they constrained to the type of bulk material being mined.