Secure and Sustainable Final Slopes for SME Aggregate Quarries     ISBN 0897766882

A handbook prepared for the Office of the Deputy Prime Minister and the Mineral Industry Research Organisation by the Geoffrey Walton Practice* and David Jarvis Associates.

This handbook deals with the need for, and methods of obtaining, secure and sustainable final slopes in SME quarries. These small and medium sized firms rarely have in-house geotechnical or landscape personnel and often need to know where to go for information and technical advice. The issues and interested parties are noted. The parties include the HSE and the Quarries Regulations 1999, Mineral Planning Authorities, English Nature (with Geological Sites of Special Scientific Interest) and local interest groups (concerned with Regionally Important Geological Sites). Different types of quarries and their settings are outlined; these include hilltop, valley bottom, hillside and coastal quarries in all the main aggregate types worked in SME operations. General approaches to slope treatment are then discussed including landform replication, restoration blasting, ground preparation and excavation, the use of quarry waste materials and vegetation and planting within the context of the design, construction and management of final slopes.

A simplified outline of stability and safety is then provided having regard to the range of after-uses at the end of quarrying. Final slopes need to be consistent with intended after-uses. The factors affecting different types of slope failure are noted and different modes of failure are described. Approaches to the design of slopes are then briefly mentioned with regard to the legal requirement for slope design and the assessment of geotechnical risk in those slopes that represent significant hazards. Rockfall is seen as the principal concern at most final slopes and methods of its assessment, control and management are outlined.

A more specific review is given of different ways to treat, construct and manage the various elements of final quarry slopes. Advice is given regarding slope crests, bench faces, benches and the toes of overall slopes. Examples are shown in photographs of good and unsatisfactory practice with respect to the slope elements.

The concluding sections of the handbook cover the general findings of landscape management at these quarries. A number of generic mistakes and missed opportunities are listed and also some of the high spots in terms of current SME practice. The geotechnical conclusions cover the use and sizing of benches, the significance and avoidance of rockfall and the widespread need for improved face scaling. There is also a need to re-appraise access arrangements to geological SSSIs in quarries having regard to increasing levels of safety awareness. In general it is considered that the Quarries Regulations are beneficially impacting on the safety and configuration of final quarry slopes.

Appendices include references and further reading, pro formas that SMEs can use to appraise hazards within their final slopes and the visual impacts of these faces in the local landscape setting. A sequential checklist of steps to be followed in designing, constructing and managing final slopes is also provided together with a glossary of terms.

To review the contents of the handbook and download a copy, click HERE.

*  The Geoffrey Walton Practice is a former name of GWP Consultants LLP.