Drilling equipment has appeared at Dean Quarry near St Keverne as the owners plan to carry out blasting this week despite campaigners' claims that such work is unauthorised.

A drilling rig was spotted being taken into the coastal quarry by residents on Monday morning, with members of campaign group Cornwall Against Dean Superquarry (CADS) using a long lens to take photographs of it being put into place.

CADS spokesperson Alison McGregor said the pictures "clearly show a drilling rig at work in the overburden zone preparing holes for the explosives to be inserted."

She said: "This is unauthorised schedule two development in an AONB. Cornwall Council have been given repeated notice that a claim for judicial review will be made this week unless a stop notice is served by their enforcement team. CADS will now also be asking Cornwall Council to serve an injunction on Shire Oak Quarries to prevent any further blasting taking place."

But quarry owner Shire Oak has said it plans to carry out one single blast this week, and claims the activity is covered by existing consent to operate Dean Quarry.

The company said in a statement: "A drilling rig has arrived on site in preparation for a single blast that is planned to take place this week. Vibration monitors will be installed in the vicinity of nearby properties.

"The blast itself will last just one second. Security guards will be on site throughout this week, including overnight."

A spokesperson for Cornwall Council confirmed that planning consent "remains in force" for quarrying activities at the site.

Shire Oak has been told it has until October 8 to resume "substantive" levels of quarrying work at the site, or face permanent closure and the task of restoring the quarry to its natural state.

However this has been complicated by the fact that to be able to quarry such an amount of stone, the company needs to have submitted an environmental impact assessment (EIA) - something it failed to do ahead of a planning application last year. That application, which would have seen several new buildings go up on the site and an increase in quarrying, was overturned at a high court appeal.

CADS has also claimed that the quarrying work cannot go ahead until a perimeter fence is completed at the site, but said any fence would be illegal without planning permission and an EIA, however Shire oak has submitted a retrospective planning application for a current fence and requested an EIA screening opinion.

And CADS has also said it has tried contacting Cornwall Council's legal and enforcement teams, but was told that officers were currently on holiday. The council has yet to issue a response.

The group has urged locals to record any activity, including blasting, with times and dates, but not to trespass or carry out any other criminal activity.