An assessment of the 'conservation void' as a management technique for geological conservation in disused quarries

Although nature conservation in Britain is traditionally dominated by wildlife conservation, there is currently a growing awareness of the need to conserve the geological and geomorphological heritage. A significant part of this geological heritage is exposed in rock sections within both active and disused quarries. Conservation is difficult at these sites because they are also valued as repositories for landfill and because of the legal requirement for quarry restoration. One solution to this conflict is to restore quarries with partial landfill to leave a void space adjacent to a rock face of geological interest. In this situation, partial infill ensures that the geological interest of a site remains exposed whilst access is available through the 'conservation void' itself. This paper outlines the history of the 'conservation void' technique and examines the design of such voids for geological conservation schemes. A field survey of existing quarry restoration projects at sites of importance for geological conservation shows that the success of the 'conservation void' method varies with lithology. The method is most successful at sites comprising hard lithologies and least successful at sites comprising soft or unconsolidated rocks and soils. This has important implications for nature conservation policy and for environmental managers dealing with quarry restoration projects.