Guinea-based Alufer Mining Limited selected Stefanutti Stocks Coastal to undertake the marine civils work for its Bel Air Mining quarry and the construction of a bauxite export facility, situated six hours from the capital of Conakry on the West Coast of the Republic of Guinea. What drew Alufer Mining’s attention to Stefanutti Stocks in particular was the company’s prior experience in rock revetment construction, its expertise in extracting armour rock, as well as its impeccable safety record.
The project, which commenced on 19 January 2017, will include the construction of a 1.5-kilometre long revetment, a mooring facility for trans-shipment barges, as well as blasting and mining of approximately 1.2-million ton of amour rock required for the revetment.
The commencement of the blasting and mining activities will coincide with the start of the rainy season in Guinea, and over the next three to four months up to four metres of rain can be expected. A further mining consideration is the safe operation of all blasting activity at the quarry located in the vicinity of a populated area, which, for safety reasons, will have to be evacuated prior to each blast.
There is not much marine construction expertise in the coastal countries up the African continent, however Stefanutti Stocks Coastal is required to meet contractual localisation requirements, and therefore will be implementing training programmes, aimed at up-skilling local communities and introducing them to the principles of construction. Stefanutti Stocks’s in-house, custom-developed Solid Foundations course will be offered, which covers a number of modules, relevant to the construction environment including concrete, formwork and reinforcing.
Furthermore, in Guinea, as part of the quarry mining component of the contract, qualifying members of the community will also be trained as ADT drivers and those who are successful in completing their certification, will be employed on site. “The lack of experience of newly trained operators could affect the production targets of the project, however we are confident that the high standards of training provided by Stefanutti Stocks Mining Services will result in operators that are skilled, aware and well-versed in the crucial element of safe operations on site,” says construction manager Abraham Coetzer.
Revetment & mooring facility
The Guinea coastline is very shallow therefore the revetment, or causeway, is being constructed 1.4 kilometres out into the sea. The mooring facility at the end of the revetment includes a pre-cast block wall, made up of 184 reinforced concrete blocks (each weighing 22 ton), which fit together like a large-scale LEGO project. This 100-metre long block wall needs to form a foundation that is accurate to within a few millimetres. The zero visibility within these murky waters means that divers will not be able to monitor the accuracy therefore the foundation concrete must be placed within the tolerance range.
Once completed, a conveyor structure will then be built on top of the causeway, on which the bauxite will be conveyed to moored barges, which in turn will shuttle their loads out to ships waiting at their moorings in deeper water out at sea.
Currently the project’s cargo vessel is en route to Guinea. Once it has landed at Conakry in the Republic of Guinea after a 21-day ship journey from Durban, supplies will still be in transit, on a truck to site for at least another two to three days due to the highly congested pedestrian and vehicular traffic. En route to site, the trucks will have to pass over a bridge crossing a flowing river that cannot bear the load of some of the equipment. To overcome this, some of Stefanutti Stocks’s equipment such as large crawler cranes and long-reach excavators, are being transported in pieces, and will be reassembled again once on site.
“It is evident that the physical site set up cannot be rushed, and this can be frustrating at times,” says Coetzer “We are, however, looking forward to commencing construction operations.”