The following text was produced by the Great Wheal Vor Community and Environment Group:


The Wheal Vor mining district lies in an area of Devonian Slate between two granite masses at Tregonning/Godolphin hills and Carnmanellis. This mining area,  historically known as Great Wheal Vor (GWV) is a compact area of approx 10.5 km  by 6.5 km and is thought to have been mined for tin for the past 1000 years. 

    Fig 1. Basic geology of the Great Wheal Vor district.

The proposal is to locate a new underground tin mine effectively beneath the hamlets of Carleen and Trew in the parish of Breage located in the west of  Cornwall. The mining company known as Cornish Tin Ltd (CTL) have completed an initial exploratory phase of drilling bore holes under a General Permitted  Development Order from Cornwall Council. They are expected to apply for two further phases of bore hole drilling.  

The GWVCEG strongly oppose further development of this site by CTL.  

There were two periods of intensive tin mining in this small historic mining area between 1810 -1848 and 1860 -1874 which were world leading ventures at the time, with over 50 sites excavating down from 3 meters to 540 meters. Thus the area is honeycombed with abandoned shafts and adits, some mapped, some unmapped. 

Fig 2. Map of the recorded workings of Great Wheal Vor – 1847 (based on MRO R137) 

Fig 3. Plan of the shafts, workings and lodes at Wheal Metal. – 1870s  

(based on MRO R137 and 175 and the 1878 O.S. map)  

The above maps show the complexity of known shafts, lodes and adits in the  period between 1840 and 1875 

Fig4.Cross section of the eastern workings of Great Wheal Vor (based on MRO R137) 

The UK’S unique manorial system dating from the 11th century separates the ownership of minerals underground from that of the ownership of the land above ground.  

Traditionally in Cornwall the owners of the various manors became de facto owners of the underground minerals.     

Fig 5 below 

Carleen and Trew existed within the Manor of  Treworlis and formed the area encompassing the Great Wheal Vor mine. (See the various local manors in Fig 5 above.) 

In 1921 the properties and land within the Manor were put up for sale by the Trelawney estate. Sales contained the caveat that all minerals and rights of  access were still in the ownership of the Manor.

Since the closure of mines from 1860 onwards, the area has developed into a quiet  residential community with minimal commercial presence. It is unlikely that any of  the current owners of property and land would have expected the resumption of  mining to become a possibility.  

Many sites in the area have been sterilised by the presence of toxic mine tailings and  it has only been in the last 25 years that there has been a gradual re-wilding of the  landscape.  

Many subsidence events have occurred during the last 75 years despite a number of mines being capped in the interests of Health and Safety”.  

Mine leaching into both north and south running streams continues to pollute the waters with tests showing unacceptable levels of nickel, cadmium and mercury.  

Flooding, particularly from mines in slate bordering onto granite, has caused many problems in the history of Great Wheal Vor. The period of disuse will have made  Cornish Tin’s project expensive and ecologically dangerous. The reputed cost of water removal and filtration from the nearby South Crofty tin mine project is estimated to be in excess of £18 million.  

The Great Wheal Vor Community and Environment Group believe that for the reasons detailed above, the Cornish Tin project is unnecessary, impractical and environmentally unacceptable to our community.  


The IRENA World Energy Transition Outlook Report 2022 is clear that the list of critical metalliferous metals highlighted including the group Rare Earth Elements  (REE)’s does not include tin.  

The British Geological Society’s report of 2021 whose projections did by highly dubious calculations consider the metal as a critical one. However, in the same report, it estimates that recycled tin made a 31% contribution to total production. It noted that production in the UK ranked nil – with no figures available.  

South Crofty Mine, now in the later stages of development, with a legacy of existing mine infrastructure has claimed that by 2026 they will be able to provide enough tin to satisfy UK demand.  

The market growth indices in the British Geological Report take no account of the substitutional effect (for example, through nano technology in solders), changes to vehicle Total Industry Volumes (TIV), alternative power sources or cultural changes in transportation.  

The apparent stalling of the UK’s new battery venture should spur industry and environmentalists into placing greater emphasis on high level recycling.  


We believe the project poses a high risk of failure due to cost escalation – for the following reasons.  

1. It is new in the UK to undertake underground mining beneath an established community setting where the historic mining landscape is known to be unstable. 

2. Exceptional cost of filtration due to water levels and high pollution. 

3. Cornish Tin have pledged that the project will be ‘green’ in all aspects. This inevitably impacts the cost/availability of plant and the use of ‘green’ stabilising slurry if they are to avoid the charge of ‘greenwashing’. 

4. Increasing demands from planners and community for realistic long term financial bonds from miners to indemnify against insolvency, for site landscaping and toxic leaching, etc. 

5. New developments in technologies impacting on tin pricing.  

6 Imminent launch of Government pension !dashboard!”giving more intelligence to  pension savers pursuing ethical investments  


Affected communities and planners will demand proof of the following environmental  measures: Air pollution, Noise pollution, Light pollution, Transportation, Structural  disturbance, Protection of Fauna and Flora, Vibration and, most importantly, water  quality and flood prevention.  

Our community will closely monitor CTL communications to the public as  communication thus far has been lamentable.  

For example, CTL has said to the media from the very start of the project, that there  has not been any meaningful objections to its plan. We disagree – see below

Andrew Brown. January 2023