Stability and Neutralisation Capacity Of Mine Backfill Formed by Neutralisation of Acid Mine Drainage With Fly Ash

The financial benefit of bees to a rehabilitating site could not be modelled with confidence, and a field trial to show direct benefit is hard to configure because so many variables affect rehabilitation. Apiaries suit sites where bee friendly plants are established, the return coming through honey yield rather than measured gains in biodiversity or ground cover, at low establishment cost.

No operating full scale frictional ignition test facility was found anywhere in the world, and building one was judged expensive, impractical and unlikely to justify its cost against laboratory scale testing. Effort should instead go to small scale laboratory equipment using South African rocks, and to expanding geological data such as silica distribution and petrographic analysis.

Geotechnical factors affecting secondary extraction were identified from interviews with collieries already re-mining pillars and with people experienced in stooping, then quantified and ranked against the different aspects of the work. No single factor governs the outcome. Factors interact, so choosing a method and working safely in old workings depends on managing them together across disciplines.