Walkers approach the ruins of a coastal tin mine at Saint Agnes Head. This was the Wheal Coates Engine House which brought men and tin up from mines which stretched out under the sea. The mines have been sealed off for many years and have only served as a tourist attraction for a glimpse of Cornwall's architectural heritage and industrial past. However in 2021 there has been new interest in the abandoned tin mines as a possible source of lithium in the British Isles. Lithium is in high demand for batteries for electric car and other tech products in the 21st century. There is also research going on in one of the mines with the Deep Geothermal Power Project into using heat from the earth as a domestic power source.