Noise is a major component of the environmental impact assessment of surface mining operations and the minimization of noise impact requires proper assessment and management of noise generation and propagation. Comprehensive noise impact assessments allow actual and potential noise problems to be identified and evaluated and provide a means of deciding on any necessary mitigation measures.The APPRAISAL-Environmental system is a prototype knowledge-and geographical information-based environmental impact assessment system for surface mining and quarrying projects. The methodology and techniques used and the various components of the system are described with particular reference to the modelling and analysis of noise generation, propagation and impact. Noise impact problems are assessed in two steps: scoping exercises (qualitative assessment) and technical assessment (quantitative). The scoping exercises use stored expertise to identify the source of noise problems and then to analyse noise propagation and its impact on surrounding areas; when a significant adverse impact is identified the system provides mitigation advice. Scoping exercises can be conducted repeatedly to assess the effects of different mitigation measures and/or to assess properties in different locations. At the same time the scoping exercise gathers information that is subsequently used for the technical assessment. The technical assessment employs numerical models of noise transmission together with a geographical model of the mine and surrounding area to quantify impacts in neighbouring, environmentally sensitive areas. The results of the overall noise impact assessment are presented as an environmental impact statement in text format and as geographical images. Scoping exercises and technical assessments can be conducted separately at the user's discretion.Ways in which knowledge-based systems, geographical information systems and numerical modelling techniques can be integrated and applied in the environmental impact assessment of surface mining and quarrying projects are also explored.

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