Effects of Mine Subsidence, Geology and Surface Topography on Observed Valley Closure Movements and Development of an Updated Valley Closure Prediction Method

This report is provided as a set, comprising C8005, C9067 and C18015.

This report combines information that was presented in project reports C8005, C9067 in 2002 reports, presents new valley closure monitoring data and provides information on field work that was carried out for this project to gather site geological and topographical data from as many of the valley sites as was possible where upsidence and closure had previously been monitored. The report provides a review and analysis of this data to assess the influence of thirty potential geological and topographical factors on the observed valley closure movements. Although, the report discusses the various mechanisms that are believed to cause these observed closure movements, full or complete data sets could not be gathered on all of the complex and interrelated factors that influence the observed valley closure and, hence, this project was not expected to provide a complete understanding of why valley closure movements happen.

The report provides an updated incremental valley closure prediction method that is based on eleven mining, geological and topographical factors with many worked examples and new 'total' valley closure and valley closure strain prediction methods.