St Austell Bay
Marine Alluvial Dredging for Tin
Indonesia is the World’s largest tin producer country with the majority of their production of circa 75,000mt per annum coming from dredging drowned beach terraces at sea off the islands of Bangka and Belitung. Similar deposits are found off the coast of Cornwall but have never been exploited.
1980's Work in St Austell Bay
Previous work by Billiton Exploration in the early 1980’s identified over 20km of channels, with an average width of 200m within St Austell bay. These channels are the courses taken by the rivers Par and Pentewan during the last ice age when sea levels were up to 120m below current levels. These two rivers are two of the most productive and heavily exploited resources of alluvial tin to be mined on-shore in Cornwall. Some limited drilling was undertaken by Billiton just prior to the 1985 tin crash, giving grades of between 500ppm and 4000ppm tin in the basal gravels. Economic grades in Indonesia can be as low as 150ppm so these channels represent an attractive exploration target with the potential for +15,000mt contained tin.
Licence Application and Proposed Work Programme
In the UK the sea floor is owned by the Crown Estate. Treliver has been progressing a licence application for this area over the last 18 months and expects an exploration licence to be granted in Q2 2015. This will be followed by a geophysics survey to accurately map the palaeo-channels in 3D and then by the taking and analysis of a bulk sample