1. Koornfontein Coal Mine (Blinkpan)
This designed decline box-cut has a life of around 20 years, therefore a designed stabilisation of the vertical rock faces and horizontal benches was done by Rock Mechanical Engineers, this being rockbolting, meshing and lacing along with sprayed concrete. The support work was carried out as the excavation of the box-cut proceeded, with a final depth of 40m.
Strict safety measures had to be implemented at all times.
As in one of our previous contracts the brief was to stabilise the rock mountain face against any further rock-falls, this is done by installing rockbolts in strategic positions and installing specialised rock-fall drapery mesh. A further protection method is the installation of catch fences to provide barriers for any loose falling rock releasing from higher places on the mountain face. The work has to be carried out using abseilers working at heights, once again high safety measures are put in place.
3. Kasese (Uganda)
This project involved the drilling, blasting, rockbolting and guniting of a 200 meter long intake tunnel. The contract was successfully completed within the allowable programme. guncrete was recommended for this project by a Norwegian civil contractor who guncrete had previously worked on a project within Mozambique.
The purpose of the designed lateral support on this project was to prevent slippage of existing earth embankment going on to the rail tracks, the advantage here of using sprayed concrete as opposed to other methods was access due to the overhead live electrical wires and limited access to the work face from street level. The combination of self-drilling anchors and a mesh reinforced gunite lining was used for the installation of the support work.
5. Zimplats Platinum Mine (Zimbabewe)
R.O.M.(raw ore silos) that have been in use for over ten years have suffered fatigue in the constant loading and off-loading of the ore, to such an extent that the existing reinforcing was being exposed and a possible structural failure taking place. The first step in this rehabilitation was to reinstate the silo walls back to original profile and replacing of any missing reinforcement, this was followed by the installation of a reinforced highly abrasive lining with strengths of up to 70 mpa, the purpose of the lining being to provide protection of the existing concrete substrate and increase the longevity of the silos.
6. Sir Lowry’s Pass
guncrete were awarded the contract to provide rock-fall protection to various sections of the pass. Our brief was to install both mesh netting along with rock-bolts, as well as catch fences. The work was carried out at great heights and guncrete used innovative access and drilling solutions to complete the works, while taking into consideration both the environmental impact and the busy traffic flow of this infamous pass.
7. Kwa-Kopi Pass
Due to recent dangerous rock-falls, this pass needed rock-fall support work done urgently at great heights. guncrete were able to provide this service using specially fabricated working platforms to allow drilling of up to 12m long bolts to be installed. This method proved successful and the project is due for completion by the end of 2014.
8. Kakamas Water Channel
The original design of this canal was the placing of no fine concrete using a sliding formwork set-up. However this proved to be impractical and an alternative design using rock-bolting and sprayed concrete was offered and approved. The contract was behind schedule at that time, but adopting this method allowed the contractor to catch up on its original programme.
9. N3 – MOOI RIVER
Existing embankments adjacent to the N3 Toll road near Mooi River were made up of a composite that when exposed to air and water they would start to disintegrate and fall onto the highway. guncrete carried out the application of a fibre reinforced gunite lining to provide erosion protection.
10. Gateway Umhlanga
guncrete were contracted by a piling company (VNA Piling) to carry out the reinforced gunite infilling between piles in order to complete the designed lateral support for basement parking to this office complex.
11. Teekloof Pass
Certain section of the outside lane on this pass started showing signs of slipping. guncrete were appointed by the roads contractor to provide lateral support to the inside lane, while the outside lane was being re-done. This entailed working in very restricted areas, but with innovative access platforms and plant they were able to overcome this problem.