Rehabilitation & Sinkhole Rehabilitation
In January 2012 tragedy struck a mine in Mpumalanga when a fatality occurred involving a sinkhole collapse. Whilst trying to retrieve a bogged down dozer 5 workers fell down a sinkhole that collapsed in the working area, 4 people survived and was rescued but unfortunately 1 passed away.
BB was a contractor at the specific mine when the fatal occurred and was busy with rehabilitation, earth moving and construction work which started in April 2006. We were well known for our expertise in rehabilitating sinkholes around various mining sites, specifically old dumps that was mined or rehabilitated, these dumps were high risk sinkhole areas.
Together with the client, BB came up with a specific procedure to handle and treat exposed and none exposed sinkholes in order to continue mining safely and to prevent another fatality from ever happening again involving sinkholes . Furthermore the process would also help improve production as it supplied a solid base for drilling and it would increase the production rate of the rehabilitation as it involved live placing of topsoil.
Since starting with the procedure BB have treated more than 4 000 000 m² high risk areas and exposed and rehabilitated more than 300 hidden sinkholes which each could have resulted in another fatality, all of this was done whilst contributing to production and rehabilitation.
High Risk Areas – Sinkhole Stabilization
Since the original “roughening up” procedure came into effect back in 2012 a lot has been added and tweaked for the better. A hazard index plan was developed through a Tier 1 and Tier 2 processes and the success of it is undeniable, this will truly be an asset for any opencast mine struggling with high risk underground mined areas.
The hazard index plan indicates high and low risk areas along with the roughening up procedure; this enables the safe approaching of existing sinkholes as well as finding and exposing hidden sinkholes – which are the most dangerous. The normal mining can proceed and drilling can take place knowing that the equipment and people are on stable ground with no hidden tunneling or cavities underneath within the 5 meter specification.
The high amount of previously underground mines within the South-African mining industry is of great concern and remains a huge liability, by making use of this procedure a lot of mines and areas can be rehabilitated or mined out safely following the hazard index plan and the roughening up procedure.
The roughening up procedure has also helped to combat spontaneous combustion in areas where sinkholes have formed by smothering and cladding effected areas, this prevents reserves from burning out and mitigates the risk until further action is taken.
The key effect that the procedure had was educating people about the extreme dangers of sinkholes and the incredible risk that they pose, they should be approached and seen as an extremely dangerous hazard which has the potential for loss of life… no sinkhole, cavity or subsidence should ever be treated without the necessary attention it deserves.
Working in a dangerous and hazardous environment with unpredictability requires extreme caution and focus and all teams are led by an experienced supervisor and site manager who simply has to walk the talk in order to go home safely at the end of the day. Constant communication and planning is the order of the day where all views and inputs are respected and given proper attention.