South Africa has a long history when it comes to mining. It is an industry that forms the backbone of the South African economy. Anglo American Coal has been a key catalyst in helping create a stronger, safer, healthier and more sustainable South Africa since 1917.
One of the key requirements of a mine is to ensure that provisions are made for adequate ventilation. This includes airways for the air to flow down the mine to the working areas. The primary ventilation system consists of an intake (downcasts) through which the fresh air passes to the mine working areas and an exhaust (or upcasts where the air passes after having been ventilated. Any interference with the ventilation system would have a direct impact on the safety and operational capacity of the mine.
The Goedehoop Colliery Block 7 mine ventilation downcast shaft is approximately 60m (approx. 196 ft) deep and was constructed in the 1980s. The shaft consists of a segmented ring liner arrangement with an interlocking joint connection between the different shaft segments. The shaft had experienced an ingress of water over the last 35 years with a notable increase in recent years through the joint interface, posing potential flooding and deterioration to the existing concrete shaft liner. To run the mine on a normal schedule, excessive leaks were being pumped out on a daily bases as a routine operation.
Over the years, the underground water levels increased, exacerbating the potential for significant leakage and flooding of the underground mining levels.
Early in 2017, the underground build-up of water broke through the concrete ventilation shaft, allowing excessive water penetration into the mine. A solution to the excessive water penetration into the shaft (approximately 7000 liters per minute was required, failing which the possibility of closing the shafts was nothing short of inevitable.
Hired to repair the mine, Sanika Waterproofing Specialists, the exclusive distributors for Kryton products in South Africa found it critical that the entire structure is accurately rejuvenated, repaired and waterproofed using Kryton’s Crystalline Technology, which has a proven record of success in similar projects worldwide for the last 40 years.
The inspection and preparation of the site were imperative to this project. A bore-hole was equipped with a camera and sunk into the ingress to accurately investigate the ingress from the positive side. A scan of the affected concrete was conducted with GPRS equipment to ensure that the safety and integrity of the structure were still intact. With the information gathered, the Krytonite™ Swelling Waterstop was identified as the best solution to reduce water flow on the positive side to a manageable condition. Kryton’s Leak Repair System was identified as the best course of action for a project of this magnitude.
In order to prepare the site for the application of Kryton products, the damaged sections of concrete had to be cleaned and prepared using a dustless sandblasting and ultra-high pressure cleaning system. Concrete cutting machines and chisels were used to chip chases along the entire length of all water ingress points, construction joints, and cracks.
Kryton’s Krystol Plug and Krytonite Swelling WaterStop complement each other and were used to effectively waterproof cold joints. While Krytonite Swelling WaterStop swells up to 1000% on contact with water, Kryton’s Krystol Grout effectively blocks the flow of water around the Krytonite.
Once Krystol Repair Grout and Krytonite had been applied, Krystol T1 Concrete Waterproofing was used on the surface, which would result in the growth of crystals throughout the concrete mass, preventing any further flow of water throughout the concrete’s surface. Krystol technology turns concrete into a waterproof barrier.
The growth of these interlocking needle-shaped crystals into concrete will stop any further deterioration of concrete, substantially extending the lifespan of the structure. The final result is a safe, dry, impermeable and reusable structure.
Krystol Bari-Cote is a high-strength crystalline concrete waterproofing top coat used to resurface and repair concrete or masonry.
As part of the Krystol Leak Repair System, Krystol Repair Grout is a crystalline concrete waterproofing product that stops the flow of water to permanently repair leaking cracks, holes and joints in concrete, and can also be used to resurface and waterproof defective, damaged or deteriorating concrete. The grout employs advanced fiber technology and shrinkage controlling additives to prevent cracking.