The crushing of general fill particles during compaction, sometimes seem as a problem, often produces a more stable compacted mass. This report considers the use of materials susceptible to crushing during compaction. Such materials include unburnt and burnt colliery spoil, spent oil shale and weak sandstone. The report gives recommendations for their use as general fill and, where appropriate, as more specialised selected fills. The potential for the use of such materials is balanced against both economic and environmental factors.
