Main image: Sikadur-Combiflex® SG-20 – 2mmx200mm on the construction joint, bonded with Sikadur®-31 DW
and sealed with Sikalastic®-152, for additional waterproofing due to small cracks in the substrate.
Fully integrated Sedibelo Platinum Mines Limited (SPM) is involved in the exploration, development, operation and processing of Platinum Group Metals mineral deposits in the Bushveld Complex, South Africa, one of the richest ore deposits in the world. SPM are the owners of the Pilanesberg Platinum Mine in the North-West Province, some 200km west of Johannesburg.
Major loss of water
Major water losses resulted in the 60m diameter tailings thickener at PPM requiring resealing, after which it had to be deemed watertight. Sika was contacted by the main contractors, LEOKA Project Management, for a solution. Con-Solve assisted LEOKA as sub-contractors.
Sedibelo Platinum urged a very quick turnaround time on this project as production losses were substantial. While conscious of the production constraints facing the client, Sika’s approved contractor, Con-Solve Civils, assessed the repair requirements and proposed a workable solution to the client by recommending that the old bandages and joint sealant be removed and totally replaced.
The LEOKA engineering team supported the proposed solution and Sedibelo instructed Con-Solve Civils to proceed with the necessary repairs. Normally this would have been a six-to-eight-week project, but the teams worked day and night shifts enabling Con-Solve Civils to complete the job in just two and a half weeks.
Product mix for success
In terms of product diversity and volume, a wide range of Sika products were specified and used. Sikaflex®-11 FC, a multipurpose elastic adhesive and joint sealant was applied to all construction joints as the secondary seal before installing the Sikadur-Combiflex® SG as the primary joint seal. Forty-seven 6.6litre Sikadur®-31 DW kits were used as the bedding mortar for the bandage system.
Sikadur®-31 DW is a 2-part epoxy structural adhesive that has been specially formulated to meet the requirements for use in contact with drinking water. It was best suited to this time sensitive project as it is easy to mix and apply, has high mechanical strengths and good abrasion & chemical resistance qualities.
No site activation waterproofing
As part of the Sikadur Combiflex® SG System, 188m of Sikadur-Combiflex® SG-20 P – 2mmx 250mm was used to waterproof the wall to floor joint, while 848m of Sikadur-Combiflex® SG
20P – 2mmx 200mm was used to waterproof the floor joints.
SG-20 P is a flexible waterproofing tape based on modified flexible / thermoplastic polyolefin (TPO), with advanced adhesion properties. Other advantages of this product include it not requiring site activation, its high flexibility – a useful property for crack & joint bridging – good resistance to chemicals and UV exposure, and it performs in a broad range of temperatures.
Surface crack waterproofing
Twenty-five kits of Sikalastic®-152, a highly elastic cement-based coating, was applied on the wall joints incorporating a 5 x 5mm plastic-lined glass fibre mesh. It was also used next to the Sikadur-Combiflex® SG on the floor joints for additional waterproofing because of small surface cracks that formed on the concrete. It was also applied over wall construction joints with the applicable plastic-lined glass fibre matt for additional reinforcement.
Sika SA assisted Con-Solve with dedicated technical back-up service and were on constant stand-by for stock requirements meetings, and general client queries.
Con-Solve Civils are to be applauded for their inputs. Despite being 250km from Midrand, Con-Solve staff were on site to inspect the thickener only 4.5 hours after receiving the call from Sika and LEOKA. The subsequent quotation and proposal were submitted to LEOKA five hours after the inspection and the Con-Solve production team were on site within 24 hours of receiving an order.
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