The Gamsberg Zinc Project is significant in that it will exploit one of the largest known, undeveloped zinc orebodies in the world. It was discovered almost 40 years ago and held undeveloped in the asset portfolios of various mining companies and subsequently, it was acquired from Anglo American by the Vedanta group in 2011. The Project comprises of an open pit mine and a dedicated processing plant.
A critical feature of Gamsberg’s development is its approach to biodiversity. The Project is being developed in the ecologically sensitive Succulent Karoo Biome, a designated biodiversity “hotspot” and one of just 35 “biodiversity hotspots” in the world. This has required extensive engagement with key stakeholders – government, NGOs and landowners, – which has resulted in a unique biodiversity offset agreement.
At peak, more than 3,400 people were employed by Vedanta Zinc International and business partners being the peak of Gamsberg’s construction. Around 700 people are currently employed permanently at the Gamsberg mine. Recruitment of local community members – in the first instance from local communities such as Pella, Pofadder and Onseepkans, and then from Namakwa District and the rest of the Northern Cape – was an obligation for all of the business partners working on Gamsberg and a priority for Zinc International itself. Of the people already deployed on the project, more than half are from local communities and the Northern Cape.
What was the brief to the architect?
No architect was involved or engaged on the project specifically for the industrial and mining structures. However, Von Bruun Architects were contracted for the LSFB portions of the project which were specifically the laboratory, change house, canteen and administrative buildings. The brief to the architect was to design and develop a system which could be largely fabricated in works off site, transported to the project works and erected with a minimum of on-site work. Given the high cost of skilled labour and erection on site, there was a material advantage to fabricating as much as possible in workshops off site and to limiting on-site work to the erection of modular units.
Was the project envisaged in steel from the start? If not – why was it built in steel in the end?
Preference was given to the use of structural steel as a structural commodity in the process plant design due to the remoteness of the site and limited construction resources available in the vicinity of the site.
This added value thus resulted in high standards of quality and delivery due to the works being undertaken in the controlled environment of the fabricator’s workshop and also reduced the requirement for site based resources.
Give a brief description of the structural framing. What type of sections were used (e.g. hollow, cellular, I beams etc) and why?
As the steelwork structures on this project covered the full spectrum from light lattice and trussed frames for cable and pipe racking to structures supporting large dynamic loads and overhead traveling cranes, from modular overland conveyor sections to a cantilevered stockpile feed conveyor, the project required the use of a very broad range of hot and cold rolled standard sections as well as made up plate girders.
Give a brief description of the cladding process (complexity, difficulty, innovation etc)
Cladding was used extensively to the roofs of substations, conveyor gantry doghouses, roofs and walls of the filter press building, compressor house and the like. In general, the cladding was conventionally applied IBR-profile 0.58mm.
Give a brief description of the Light Steel Frame Building element of the project. (Notable features/ achievements made possible by LSFB)
Due to the remoteness of the Gamsberg site in the Northern Cape and the limited access to construction materials, a clear strategy was adopted to consider alternative solutions for the construction of all non-process related buildings on the project. Through adopting the LSFB solution of the Assay Laboratory, Administration, Canteen and Changehouse, the site based resource requirements were significantly reduced during the construction period thereby improving the safety of the overall construction activities at the site through minimising congestion and interface management.
The LSFB design philosophy also proved to be more flexible in terms of accommodating late changes brought about by the fast track nature of the project. The inherent prefabricated nature of the LSFB reduced the construction time frame associated with the structural frames and opened up parallel working fronts for the installation of the services accommodated in the wall panels.
Were there any challenges in the fabrication of the project from the engineer’s design – if yes, please tell? Tell more about the fabrication and erection process if it was complex, difficult, innovative etc.
The Engineer designed all of the steel structures which was then issued to the various fabricators who also undertook the detailing work prior to manufacture.
It was incumbent on the Engineer and team to check that the detailing had been undertaken to the relevant codes and practices so as to produce complete shop-detailed fabrication drawings.
Close liaison with the fabricators afforded the Engineer greater control over the quantity and measure of steelwork.
Interfacing the details into the Tekla models resulted in significant time savings to the project. Conceptual designs in-house, allowed the Engineer to tailor the fabrication of steelwork to suit the erection on site with specific emphasis on minimising small-piece assembly.
The two primary measures of the success of this process are the minimal requirement for site modification of fabricated steelwork and virtually zero interface errors to civil work and mechanical plant, then this process results unequivocally in success.
What is special/ unusual/ innovative/ aesthetic about the steelwork/cladding in this project?
The project gave great scope to structural designers to carry out innovative and creative work. At the dictate of a somewhat fluid project schedule, designs often had to be adapted to retrofitting or to constructability with restricted access or to speed of fabrication and erection. One particular case in point being the design, detailing and erection (often retrofitting to structures already completed) of pipe and cable racks (latticed and framed or box trussed) as these were to a great extent site-run services which crossed already completed works or vehicle access ways.
How did the project team work together (e.g. contractor involved early, challenges/ ease of communication etc.)
The project setup was unique in that it comprised four distinct centres of execution across the subcontinent, including China, India and South Africa. The centre of gravity moved progressively from Beijing, where the process and basic engineering design was undertaken, Johannesburg where the detailed engineering to South African norms and standards was completed and all procurement undertaken, and finally to the Northern Cape during the construction phase. The engagement and involvement of the Owner’s Engineering team based in India formed an integral communication link throughout the project execution phase. The greatest lesson learnt in terms of communication across continents is the necessity of early engagement and team building across the broader project stakeholders, to gain a better understanding of cultural differences and approaches to engineering solutions and establish a common base of mutual respect and understand early on.
|Completion date of steelwork||Final installation of structural steelwork – September 2018.|
|Completion date of full project||Operational Completion – 6 December 2018.|
|Tons of structural steel used||2 177t.|
|Structural profiles used||SA hot-rolled sections S355JR:
· RSA, RSC, PFC, UB, UC
· Plate Girders
· CRLC purlins & girts
· Chutes, bins, hoppers
|Completion date of cladding||Approximately October 2018|
|Cladding profile/ type used||0,56 / 0,8 IBR Chromadek: Kingfisher Blue N01029|
|Cladding area/ coverage and tonnage||8 142 m²|
|LSFB / LIGHT STEEL FRAME BUILDING WORK|
|Completion date of LSFB work||Final building completed in October 2018.|
|Completion date of full project||Operational Completion – 6 December 2018.|
|Tons of LSF used||Approx. 60 tons.|
|Span of trusses and Kg/m2 (if applicable)||Longest span 12m span
Varies between 18 to 22kg/m2
|Profiles used||Z200 galvansied 550MPa 0.8mm flat sheet rolled on Framemaster profiler roll-former.|
|Type of cladding||· Lamnaboard from Rigifoam with Terraco render
· 15mm fIrec.heck boards from Knaus.
· Internal 3mm rhinolite and washable paint.
· Internal walls 102mm cavity batt from Isover.
· Roof – 80mm polyurethane by Dalucon on 30mm purlins 0.58mm 550MPa.
|PROJECT TEAM ROLE||COMPANY|
|Nominator||ELB Engineering Services|
|Client/ Developer||Vedanta Resources|
|Engineer||ELB Engineering Services|
|Quantity Surveyor||CD Venter Land Surveyors|
|Project Manager||ELB Engineering Services|
|Main Contractor||ELB Construction (Pty) Ltd|
|Steelwork Contractor||Louwill Lefa (Pty) Ltd|
|Steel Erector||ELB Construction|
|Cladding Manufacturer||Arcelor Mittal South Africa|
|Cladding Supplier||Global Roofing Solutions|
|Cladding Contractor||Abraham Hansen|
|Louwill Lefa (Pty) Ltd|