The main requirement for permanent shaft sealing and capping projects is to ensure full compliance with the Mine Health and Safety Act
The most effective means of ensuring that redundant shafts are protected from occupation by illegal miners is to seal them permanently below natural ground level (NGL), typically after filling the shaft barrel. Here is where specialist demolition contractor Jet Demolition stands to play a vital role.
Another challenge is that various shafts are often interconnected, such as a live shaft and redundant shafts linking together hundreds of meters below NGL. “It is thus critical to ensure that we understand the network we are operating within, so that our capping and sealing activities do not influence or adversely affect miners underground in a neighbouring shaft,” comments Jet Demolition Contracts Manager André Botes (N. Dip. Mechanical Engineering).
Its turnkey service offering for the mining industry includes backfilling shaft barrels, designing permanent caps, installing caps at a defined depth below NGL, and recording the final position and depth of caps, followed by the backfill and reinstatement of the natural material over cap tops.
Mining houses typically require such a turnkey service for two main scenarios: Firstly, to seal the shaft permanently as a mitigating factor, thereby preventing unauthorised access by illegal miners or, secondly, to rehabilitate the mining footprint fully, rendering the area safe for public use.
The main requirement for permanent shaft sealing and capping projects is to ensure full compliance with the Mine Health and Safety Act, the provisions of the Department of Mineral Resources, the approved Environmental Management Plan, as well as any client-specific requirements.
The natural surrounding environment also has to be taken into account, paying special attention to natural water courses and stormwater management. This could mean rerouting natural water courses slightly, while ensuring there is no subsequent negative downstream effect. All material used to fill shafts must be clean and uncontaminated. This is vital to ensure that no groundwater contamination will occur after sealing.
Jet Demolition pays particular attention to health and safety, especially when working over an open shaft that could extend a few kilometres underground. “It is absolutely critical to protect plant and personnel from falling,” Botes stresses. Hence certified lifelines are installed prior to any work commencing, providing personnel with anchoring points during shaft sealing. Larger machines are also typically used for increased reach, and, in some instances, remote-controlled machines could be deployed to ensure the safety of persons.