Environmental campaigners have clashed with a minerals firm over plans to extract tin from the Cornish coastline.
Marine Minerals Ltd (MML) wants to filter valuable tin from a section of the north coast of the county, pumping millions of pounds annually into the UK economy through its use in hi-tech equipment such as mobile phones.
But campaigners from Surfers Against Sewage (SAS) say the work, scheduled to begin as early as 2015, would have significant impact on the region's cherished tourist, surfing and fishing economies, as well as local wildlife.
The mineral firm has rejected these concerns and says any work carried out, 200 metres out to sea from the low tide, would be completed without detriment to existing beach and water users.
The row has re-ignited ahead of an application for an environmental permit from MML to the Marine Management Organisation.
If granted later this year, it would allow MML to assess the likelihood of successfully extracting tin as desired without environmental consequences, eventually paving the way for a licence to carry out the work.
Chris Davies, MML spokesman, said: "The bottom line is that SAS don't know whether the project will or will not cause problems, they are making assumptions based on no evidence.
"The company has made clear that they will only pursue the idea if the valuable tin can be recovered in an environmentally and socially acceptable way, and is seeking a licence to undertake a detailed environmental study to assess all these matters, including the ones SAS raise as 'potentially' a problem.
"Any tin recovery work will be undertaken by one vessel, in one location, at any one time – this is unlikely to cause anything more than temporary minor inconvenience to surfers short-term, and long-term make no difference – other than injecting millions of pounds into the Cornish economy."
He said the process could not be described as "dredging" – something opposed by environmentalists who say the practice, sometimes used in the fishing industry, harms the seabed – because the sand is simply filtered for tin and replaced.
SAS campaign director Andy Cummins said disturbing and removing significant amounts of sediment from the north Cornish coast "has the potential to devastate the fragile and complex environments that support surfing, tourism and fishing".
He added: "SAS are raising these concerns and will continue to engage through the licensing application and we urge any interested parties to do the same.
"There are many potential adverse impacts associated with a proposal of this type, but SAS is especially concerned about threats to vital coastal processes, the marine environment, marine wildlife and local surfing resources.
"The north Cornish coastline is a valuable natural environment, already supporting thousands of jobs and generating millions of pounds for the region."
The tin itself is a remnant of one of the county's long-established industries.