On the UK’s wild and beautiful southern tip, a rebellion is growing. People on Cornwall’s Lizard Peninsula have been fighting the reopening and expansion of Dean Quarry which was mothballed in 2008.

Shire Oak Quarries Ltd wants to extract 6.3 million tonnes of high density gabbro rock, over two decades, to supply a tidal lagoon proposed for Swansea Bay, as well as similar future developments. These could, in turn, boost the UK’s renewable energy supply and energy security.

Shire Oak says that the quarry could generate between £140m and £190m for the Cornish economy, but the Community Against Dean Super Quarry (CADS) group say the proposed ‘super quarry’ is a threat to the environment and local businesses.

Tidal Lagoon Swansea Bay plc has a commitment to sourcing half of all elements for the lagoon from the UK and would prefer a domestic source for the rock. But, they say, Dean Quarry is just one of the places being considered and the ultimate decision is down to marine contractors.

Although Tidal Lagoon Swansea Bay is controlled by a board, CADS have questioned the link with Shire Oak as the two companies share the same chief executive, Mark Shorrock.

The plans for Dean Quarry involve building jetties and a breakwater within the Manacles Marine Conservation Zone, home to a diverse range of habitats and species including spiny lobster, stalked jellyfish, sea fan anemones and delicate maerl seaweed.

Joan Edwards, head of Living Seas for the Wildlife Trusts, explains that the potential disturbance could put these things at risk: “The structure and the quarrying could create sediment which could smother the communities that live on the reef.”

Dean Quarry could test what MCZ designation actually means in practice. The first MCZ was designated in 2010 and there are now 50 in England and Wales. “The whole regulatory system associated with MCZs is brand new so we’re all learning how it’s going to work,” says Edwards.

“We don’t want to stop people developing in the sea but we don’t want the features of the MCZ to be damaged in any way.”

 CADS campaigners celebrated earlier this year when the High Court ruled planning permission, which had been granted by Cornwall Council for ancillary works at Dean Quarry, was unlawful.

 The judicial review was spearheaded by Silke Roskilly of Roskilly’s Organic Farm, a long-standing business next to the quarry site which employs 45 people – around 60 in the summer. She is worried about the impact of dust, increased noise and traffic for hers and other businesses in the area, including Cornish Sea Salt.

“We all depend on clean seas and the whole vegetation of the area is completable unspoiled,” she says. “I don’t feel that we would be able to continue our business model as we are doing it now if the quarry was to open.”

The Lizard is within an Area of Outstanding Natural Beauty and has many other international designations, including several sites of Special Scientific Interest.

Tidal Lagoon says that the project at Swansea Bay could produce clean, renewable energy to power over 155,000 homes for 120 years, as well as up to 1,900 jobs during its construction.

CADS has defended itself against accusations of NIMBYism, saying its members support renewable energy and would support the reopening of the quarry in a sustainable manner, but only at the level of previous activity.

“Suddenly bringing Dean Quarry back to life, not just doing that but super-sizing it… it’s like wanting to put up a skyscraper on Dartmoor,” says Alison McGregor of the CADS committee who runs a holiday cottage business on the Lizard.

CADS argues that there would be other more practical sources of rock for tidal lagoons from already established quarries, particularly in Norway.

“We truly believe that there are more sustainable sources of rock which will be better value for the tax payer,” says McGregor. “Norway is just set up and ready to go… It’s a proven, reliable source. It’s like ordering a pizza.”

 The CADS campaigners are keeping a close eye on an independent review into the value for money of tidal lagoons which could put a stop to the Swansea Bay and other proposed projects for larger lagoons in South Wales. The Swansea project, which is estimated to cost £1 billion has been dogged with criticisms over costs and has struggled to get the government subsidies they want.

“I don’t think it’s an answer for energy security because one, Swansea will not provide a lot of energy and two, it will be the most expensive in the world,” says Edwards. “Forgetting the environment if you’re looking at the economics then it makes no sense at all.”

There are also some environmental concerns around the lagoons, particularly the impact on fish, although many green groups, including Friends of the Earth, have welcomed the project.

 “At the moment we have been quite supportive of Swansea because it’s a small lagoon,” says Edwards. “We always say the right renewable in the right place, the right technology in the right place. We don’t believe large lagoons are the right technology but we do agree we should looking at harnessing the energy that’s there in the Severn Estuary but not at the cost to the environment.”

 There has been no decision on whether Dean Quarry would be the source of rock if the lagoons went ahead, but Shire Oak still intend to reopen the quarry, even it it involves selling to other markets.

CADS has said they will closely monitor any planning developments at Dean Quarry and want a full Environmental Impact Assessment to take place before any work happens.

“I’m very very proud of the beauty of our area,” says McGregor. “We’re going to fight it tooth and nail and are determined to see it out. We’ve done a year and a half and it think there’s another decade in us yet.”