Ripon City Quarry, which adjoins the racecourse off Boroughbridge Road, has operated since 1964, but its permitted reserves will come to an end early in 2009.

Now, Aggregate Industries UK, which operates the quarry under the name Brown and Potter, wants to extract another 1.2 million tonnes of sand and gravel.

The present quarry operation takes place between the River Ure and Ripon Racecourse. The extension covers three separate areas and would use the existing plant and processing site.

The new areas of land on which planning permission is being sought are Canal Field, Bridge Field and Newby Gravel Beds.

Bridge Field is between a small grassed area adjacent to the B6265 and the existing plant site. It is planned that it would be restored to productive agricultural use.

Canal Field is between the current extraction area and the Ripon Canal. The canal is a Site of Importance for Nature Conservation. Canal Field would be restored as an "ecologically valuable wet grassland", which would also provide temporary flood storage for water from the River Ure.

The Yorkshire Wildlife Trust would be responsible for the long term ecological management of the Canal Field site and the current quarry. Together these areas would become a significant new Yorkshire Wildlife Trust reserve.

Newby Gravel Beds would be restored to a lake for use by the White Rose Sailing Club. The land is close to the existing extraction area but separated by the River Ure and it is proposed that they should be joined by a temporary bridge.

Aggregate Industries has told North Yorkshire County Council: "The proposed scheme allows the continued development of a known mineral resource through a quarry that has been supplying material to the North Yorkshire market for many decades."

Brown and Potter would work Bridge Field, Canal Field and Newby Gravel Beds consecutively over a seven year period, extracting 170,000 tonnes per year. The quarry would operate from 7.30am to 6pm Monday to Friday and 7.30pm to 1pm on Saturday. There would be no extraction on Sundays, bank holidays or race days.

British Waterways has progressively restored Ripon Canal, which is now open as far as the basin in the city centre – the most northerly point on the connected inland waterway network. A marina, which provides a base for boat owners and visiting craft, is beside the canal to the west of the racecourse.

The application, which has already been the subject of public consultation with the people of Littlethorpe, will be determined by North Yorkshire's planning committee later in the year.