BRITAIN'S only potash mine, in the shadow of the famous quaint fishing village of Staithes on the North Yorkshire coast, is in line for an extension to house a crushing and screening plant.

The development, by Cleveland Potash Ltd at its Boulby Mine, which is some 1.7 km deep, in the North York Moors National Park, is being recommended for approval by the authority's planning committee next Thursday despite warnings by planning officers that it will have an impact on the countryside.

"It will add to the already significant harmful impact on the visual amenity of the area and as such the special qualities of the National Park," says a report to the committee. "But these impacts need to be considered against the beneficial impact on the improved financial sustainability of the mine on the local economy."

Officers say that talks are underway to look at mitigating the new development will have, and to en hance the environment and tourism economy of Staithes, famed for its links as the childhood home of the explorer, Captain James Cook nearly 300 years ago.

"The proposed new building is on an industrial scale and will have additional detrimental impacts on the special qualities of the National Park," says the report.

The mine was established in the 1960's and has production consent until 2023, it adds. "To develop the production line, it is accepted that a new facility within the development is needed.

"The price and demand for potash appears to be rising for the long term and attention is now being focussed on the production of polyhalite form of potash. The main mineral produced from the main currently, is sylvanite forms of potash."

The proposed new building will be nearly 100 metres by 31 metres and 35 metres high.