Nearly 90 people took part in a protest against exploratory drilling for tin in the Great Wheal Vor area, near Breage.

Organised by a group called Protect Wheal Vor, they are concerned that the first phase of drilling 33 boreholes to be sunk next spring by Cornish Tin Ltd could potentially disturb toxic mine wastes that currently lie dormant – something denied by the CEO of Cornish Tin.

The mining company has been given the rights to explore for tin by drilling holes around 200 metres in depth in a triangular area marked by Carleen, Wheal Vor and Poldown.

A spokesman for the protest group, Jamie Lovekin, said: “We already know that cadmium, nickel, arsenic, mercury and other carcinogens leach through from disused mines in this area down into Porthleven Stream.

"Cornish Tin have been granted a planning order which allows the company to monitor the boreholes themselves, and if the company pack up and disappear there are no plans for the protection of streams and groundwater in the years following abandonment.

"People are very angry.”

Jamie went on to add: “The Great Wheal Vor area has slowly begun to heal its visible scars and the poisons have settled, more or less. People have found other forms of employment now, or set up businesses which could be jeopardised if drilling goes ahead in spring.

"Protect Wheal Vor demand an environmental assessment of Porthleven Stream prior to the start of drilling, and we want Cornish Tin to know that, should planning permission for extractive mining be sought at any time in the future, we will formally object.”

In response to the concerns over water quality, Sally Norcross-Webb, the CEO of Cornish Tin, said: “As set out in full in the planning application, for which we have been granted planning consent by Cornwall Council, the drilling method is a closed loop system, is non-toxic, and uses tap water which is recycled using a closed loop system, and returned to surface for re-use.

“The Environment Agency has statutory responsibility for the protection of the environment and we have been working with them, and will continue to do so, to ensure that all the requirements of the EA are complied with. All this information is freely available to everyone, in the planning consent on Cornwall Council website.”

She said Cornish Tin’s exploration drilling programme had been confirmed as “very low risk from the EA’s perspective".

She added: "The name 'Protect Wheal Vor' has now appeared as a 'group' but we have no information that it represents a majority of the people who actually live in the area.

"We have during the last year had a very constructive dialogue with many local residents. We have held two public meetings by Zoom and a further public meeting is being scheduled for November. We will always remain keen to engage with local residents and answer questions, and I hope that Mr Lovekin will agree to talk with us as we have asked."

Ms Norcross-Webb said the plan was to begin drilling in spring next year, describing it as "optimal timing to enable us to implement the many ecological and environmental protections we wish to carry out."