The Application of Control Theory to the Management of Sound Emitted from Open-Cut Mining

摘要

This paper shows how the management of sound emissions from the constantly changing environs of a large open-cut mine can be modelled as a closed-loop control system and how using this approach has already been shown to decrease the noise immision levels from an open cut mine. In traditionally control theory, a closed-loop control system (also called a feedback control system) uses a 'set point' as a reference value, to characterise the desired output response of a process. The actual measured 'output response', is compared to the set point and the difference between the two, the error, becomes the input signal to the 'control device'. The measured difference between the set point and the output response of the process can be due to a change in the set point or due to a disturbance to the system. A well-tuned control system is characterised by its stability, its ability to respond to external disturbances and its reliable and repeatable performance. For an open-cut mine the desired output response is to not exceed a specific noise limit while maximising production and minimising any periods of shutdown. To achieve this, the disturbances to the system must be managed. Disturbances to the system include changes to the mine plan, changes in equipment location and changes in the weather. The current control strategy for open cut mines can be insensitive to the error signal and the response to disturbances can be too slow resulting in difficulty bringing the system back under control without enforcing shutdown measures. In this paper it is shown how the management of sound immissions from an open-cut mine can be representated as a closed-loop control system. This has enabled the elements of the control system to be examined using traditional control theory and facilitated the development of a new management tool that is being implemented in a case study in the Hunter Valley.