Bubbling sinkhole re-appears on Cornish beach
Watch the sinkhole appear on a beach in Cornwall
A bubbling sinkhole has reappeared on a Cornish beach - much to the bemusement of visitors.
The strange sight appeared at Porthminster beach in St Ives in March.
It is the second time in four months a sinkhole has opened on the beach, prompting a safety warning from a local tour guide.
Billy Nason explained: “The one in the middle is the subterranean stream that goes underground on the edge of Tregenna Castle grounds up the valley.
“The black stuff you are seeing is alluvial tin (cassiterite) as this valley was once mined for its alluvial tin, and mineralisation still occurs, and after heavy rain, this can get washed out.
“The other sinkhole, further south, is actually a pipe that can be seen after sand is stripped in a storm, and forms part of the drainage that is connected to a stream on Hain walk.
In January 2020, safety fencing around the soft sand area was damaged by storms and started to sink into the sand.
At the time, Cornwall Council urged people to stay away and keep their distance.
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