Until the construction of the Penzance Promenade, the town ended on a beach where the fishing boats landed their catch. With a number of streams emptying into the Channel it was well known, from the eroded debris, that in the rocks exist some veins that appeared rich in tin and copper.  Although nowadays West Cornwall is renowned for its tin mining industry it is actually rich in lodes of copper and cobalt often found mixed with tin. 

One of these lodes, only visible at very low tide, rises close to the surface around 500 feet out to sea.  In the 18th century, the price of copper and cobalt was extremely high, the industry was booming and there were many speculative ventures.  Perhaps the most challenging was the construction of the Wherry Town Mine, which existed for much of its time underwater.
In the 1780s, Thomas Curtis of Breage spent three years sinking a shaft in the most visible rock, constructed a stone breakwater and a wooden turret.  Not only was the work laborious but it was also extremely time-consuming since it could only be conducted during daytime low tides. 

The work was further complicated by the fact that the shaft filled with water at high tides and so had to be emptied before it could be extended.  The rock was pulverised using dynamite, which in itself was not only extremely dangerous due to the workers' proximity to the explosions in the shaft, but was also time - consuming since dynamite is only of any use when completely dry.
After Curtis’ death, in 1791, the work was continued by another keen group of adventurers who extended a pier from shore to the shaft and installed a steam engine on the shore to pump out the shaft (as pictured above). 

Over its working lifetime the concept was proven to be justified since it is recorded that it produced at least £70,000 of tin.  The value of the copper and cobalt recoveries is not known.

Disaster struck in 1798 when, during a violent storm, an American vessel broke free of its anchor and drifted onto the rock demolishing the turret and much of the pier.  The damage was repaired and the mine was worked until 1816, when the price of the ores collapsed.