Tapping the potential of Imerys' secondary aggregates

For every tonne of china clay produced, Imerys generates nine tonnes of spoil. About one tonne of this is fine mica, a flaky mineral with few uses, but the other eight tonnes comprise useful sand and rock.

Imerys has had some success with its strategy of maximising the reuse of its wastes as secondary aggregates. In 1999, it sold around half a million tonnes of secondary aggregates, mostly for local use. By 2003, sales had increased threefold.

Aggregates manager Clive Kessell says that the aggregates levy, introduced in 2002, was a major driver. Secondary aggregates now account for 75% of the market in Plymouth and Cornwall, about 50% of which is supplied by Imerys. The company believes there is little room for expansion in local sales, which are static at around 1.5 million tonnes per year.

However, the company could go considerably further. "We have three million tonnes a year of useable sand, gravel and aggregate," Mr Kessell says. "The national demand is something like 380 million - so potentially we could supply about 1% of the market."

Imerys is now looking to solve the logistical problems of transporting aggregates further afield. Unfortunately, Cornwall's rail network imposes limitations on transport to the rest of England. Only small trains can cross Brunel's Tamar bridge and traverse the incline on the Devon side, making the operation financially unattractive. Imerys' preferred solution is to develop a rail head at the port of Par to transfer aggregates onto ships.

The company has succeeded in shifting increasing amounts of aggregates through Par without major investment. But to achieve a step change in shipping, it needs to build substantial new facilities.

In 2001, Imerys attempted to secure a freight facilities grant from the Strategic Rail Authority and development funding from the EU to help meet the £17 million cost of building jetties, storage and handling facilities (ENDS Report 323, p 30 ). However, the plan failed when the SRA's funds ran short, leaving a £6 million gap in the budget.

A further blow has been a recent increase in shipping costs. "At the moment we are struggling," Mr Kessell concedes, "Last year we managed 168,000 tonnes [by ship from Par] and this year 236,000 tonnes were planned, but we will not do more than 90,000."

Imerys' ambitious plans to ship 750,000 tonnes by 2006/07 have been scaled back to only 350,000 tonnes. To achieve even this lower level, the company is looking for an increase in the aggregates levy or subsidies aimed at encouraging more sustainable means of transport.

Nevertheless, Mr Kessel is optimistic: "The environmental damage from dredging the sea bed or quarrying are coming increasingly to the fore. We are nationally recognised as the main player in the substitution of primary aggregates, but at the moment we can't seem to get the finance to make it viable."