The solvent-based fuel was introduced at the works in 1992 but was withdrawn from kiln seven two years ago following local concern about the haze and smell around the site.

A £5 million gas cleaning system has since been installed which Castle Cement says reduces emissions of sulphur dioxide by more than 90 per cent and dust by more than 50 per cent.

Ian Sutheran, Ribblesdale works general manager, said: "We will first carry out trials to demonstrate to the Environment Agency the environmental benefits of burning a mixture of coal and Cemfuel on kiln seven, as opposed to 100 per cent coal."

During the trials stack emissions, fuel and raw materials content, and cement quality will all be carefully monitored.

Castle and the Environment Agency will both carry out wide public consultation and information programme as part of the application.

There will be an exhibition at St Mary Magdalene's church hall on January 7 from 11am to 8pm, and a special newsletter will be sent out to local residents.

The Environment Agency is considering Castle's application and if the firm is given the go-ahead trials will start in spring 1999.