More than 200,000 tonnes of material have passed through the CDE washing plant at Irish Asphalt’s Duleek Quarry, in Co. Meath, since its installation in the summer of 2003. In July 2004 the plant’s ownership will transfer to Irish Asphalt, part of the Lagan Holdings Group, having been operated on a price-pertonne basis by CDE since its installation. The Euro 1.5 million contract represented a major investment for Northern Ireland company CDE, and while their processing systems have previously been chosen for applications ranging from specialist sand classification to quarry-dust washing, the raw material at Duleek provided them with a considerable challenge.
The Lagan Group are one of Ireland’s largest quarry operators with sites both north and south of the border and a combined production capacity of over 2 million tonnes. They are also a major supplier of asphaltic material, and their bitumen division is at the leading edge of binder and emulsion technology. Lough Neagh in Northern Ireland, the largest freshwater lake in the British Isles, is the base for the Group's sand division, while Lagan’s concrete division operates one of the most modern concrete block and brickmaking plants in Europe.
The Duleek site is situated on what is essentially a Carboniferous limestone deposit but bands of heavy and extremely plastic clay are prevalent. Large stockpiles of overburden and clay-bound material had been building up as waste by-products for some time and were seriously compromising the efficiency of the operation. Identifying and responding to this, Lagan’s regional quarry manager, Paul Tuite, initiated discussions with CDE in early 2003. Mr Tuite commented: ‘We demand the highest-quality aggregates for both in-house use and external sales, and it was clear that our existing process could not achieve this. Our partnership with CDE has been rewarded with consistent quality aggregates and production capacity has increased by more than 30% on initial figures.’
Other prominent CDE washing plants and contracts have been established throughout Ireland, the UK and Sweden, and the experience gained from these, together with CDE’s growing reputation for innovation, led to the Lagan Group contract.
The plant born of these negotiations has already attracted numerous visitors from the UK and further afield. What draws them is the consistently high quality of the sand and aggregates produced by the plant, in spite of the poor-quality raw material. Up to 25% of the –90mm raw feed, and often up to 50% of the –5mm fraction, can be less than 75μm. Since final commissioning the plant has consistently supplied clean and dry outputs comprising 20mm, 14mm, 10mm, 6mm and concrete sand, allowing Lagan to offer customers commercial Type 1 and concrete constituents, all from a material previously regarded as waste.