Fully integrated Sedibelo Platinum Mines Limited (SPM) is involved in the exploration, development, operation, and processing of Platinum Group Metals (PGM) mineral deposits in the Bushveld Complex (BC), South Africa – one of the richest ore deposits in the world. SPM are the owners of the Pilanesberg Platinum Mine (PPM) in the North-West Province, some 200km west of Johannesburg. Due to major water losses, the 60m diameter tailings thickener at PPM required resealing, after which it had to be deemed watertight. Sika were contacted by LEOKA Project Management, the main contractors, for a solution. In turn, Con-Solve were asked by Sika to assist LEOKA as sub-contractors.
Sedibelo Platinum had urged a very quick turnaround time on this project as the thickener is the ‘heartbeat’ of the mine and 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. Under normal circumstances this would have been an approximate six- to eight-week project, but by working twelve-hour day and night shifts, Con-Solve Civils completed it in just 2.5 weeks.
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 6.6lt Sikadur-31 DW kits were used as the bedding mortar for the bandage system. Sikadur-31 DW is a two-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 and chemical resistance qualities.
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 floor joints. Sikadur-Combiflex SG-20 P is a flexible waterproofing tape based on modified flexible/thermoplastic polyolefin (TPO), with advanced adhesion properties. Other advantages in the use of this product include not requiring site activation, high flexibility – a useful property for crack and joint bridging – good resistance to chemicals and UV exposure, and it performs in a broad range of temperatures.
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, as well as next to the Sikadur-Combiflex SG on the floor joints for additional waterproofing, due to small surface cracks that formed on the concrete. Its purpose: an additional waterproofing and concrete protection due to hairline cracks. It was also applied over wall construction joints with applicable plastic-lined glass fibre matt for additional reinforcement. Sika SA are proud to have had their products recognised by the engineers and contractors as part of the solution to this project. Sika SA assisted Con-Solve with dedicated technical back-up service and 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.
As with any project, this one was not without its challenges. The supply, organising and transport of materials was a constant stress for all parties; though, through a collective understanding of the products and the nature of the project, success prevailed. One month after the thickener was filled, the structure was certified watertight. To do a job correctly the first time around requires the teamwork and support of a multitude of other divisions and external parties. Sedibelo are positive towards future projects involving Sika and Con-Solve Civils.