Crushed Rock (available at LS Quarry only) 20mm: 4: Top layer resheet (gravel roads) or fill on gravel roads: Driveways and tracks: Driveways and tracks: Crushed Rock: 40mm: 3: Road base and sub base: Sub base on tracks, gateways and around stock troughs or stock high traffic areas, shed sites, hard stands: Site access for wet sites: Crushed Rock: 40mm: 4