First publishedin Aggregates Business Europe
Natural sand is a limited resource but one Norwegian quarry operator is offering an alternative with industrial sand, which it claims is better than the real thing. Claire Symes visited Velde Pukk to find out more
If you arrive at Norway's Stavanger Airport right now, you may think you are on a building site, rather than an airport but the work marks a step change in the approach to concrete in Norway.
Part of the work includes construction of a 27,000m2 car park by precast manufacturer and contractor Spencon and it is the first project in the country to use manufactured sand in place of natural sand. This landmark project is the result of a far-sighted investment by the Velde Gruppen to create a new product that could become a necessary resource as sand reserves are depleted.
"With natural sand you work with the gradings that are available but industrial sand can be engineered to meet customer need," said Velde production manager Sven-Henrik Norman.
In order to meet the demand for sand now, and in the future, the company has recently installed a new Metso Minerals
Barmac VSI crushing system with Buell air classifiers to manufacture industrial sand at Velde Pukk near Stavanger. The air classifiers separate the 0-2mm material into three products - coarse sand, medium filler which is the 63 to 500µm fraction and 0-63µm sand.
This fine sand is also used to give natural sand a better gradation curve to replace cement that is currently used for this purpose. The machined sand is a cheaper alternative.
Velde Gruppen also said that the use of machined sand is helping the company to gain asphalt market share based on quality but it is not yet able to command a higher market price. The main benefit is for concrete with minimal variation between mixes, which is especially important for self compacting concrete and flooring applications. It is also possible to customise the mix design and create smoother faces. Industrial sand is also used by the stone paving manufacturing industry.
This latest venture is part of the company's continued investment and expansion plan. The quarry produces 1million tonnes of material per year and has another 40million tonnes of reserves. The quarry was started by the three Velde brother's father in 1984 after his construction business needed aggregates for a specific project.
Velde Gruppen used to just produce construction aggregates but in the last four years the brothers have expanded the products produced at the quarry to include asphalt with the installation of a 1000tonnes per hour Benninghoven
plant in 2006 and a 110m3 per hour Skako Apollo 3000 planetary plant last year. The business also moved into the asphalt paving business in 2008 and is already the largest contractor in the Rogaland/Greater Stavanger region with 40 employees. The business area is limited by geography rather than by commercial ambition.
The turnover of the company has grown in line with the level of investment going from NOK72million in 2006 to an anticipated NOK250million this year. In the same period the company has invested NOK200million and the number of employees has expanded from 40 to 90 people.
The company does its own drill and blast work at the quarry using a mix of Atlas Copco
and Tamrock rigs and also carries out drill and blast work for other quarries in the region. Blasting is down twice a month at Velde Pukk with around 50tonnes blasted in each session.
The quarry operates 15m benches and blasts 3.5" diameter holes laid out to a 7.5 to 8m2 spacing using slurry explosives from Orica. The blast is deigned to produce material suited to the crusher inlet with a maximum size of 1.6m.
The quarry has one common control room for the crushing and screening operations, asphalt plant and concrete plant. With 6000tonnes of storage in the silos, the delivery of material to the truck loading, asphalt mixing and concrete plant is all automated. There are 10 silos in total, each with 600tonnes capacity to store eight products - 0-63µm, 63µ m-0.2mm, 0.2-2mm, 2-5mm, 5-8mm, 8-11mm, 11-16mm and 16-18mm. Recipes for standard mixes are stored to help with the automated selection process.