Poldark mining history stolen in scrap metal thefts
Historical artefacts have been stolen from a Cornish mine in a series of metal thefts.
Managers at Poldark Mine near Helston have increased security and installed additional CCTV cameras after the thefts.
It said recently a "unique" Cornish stamp was stolen - formerly used to crush rock - leaving only one original.
Devon and Cornwall Police said it was investigating a number of thefts across the region.
Chief Executive of Poldark Mine, Richard Williams said: "We've had thefts of scrap metal, which are in fact quite important historical artefacts, from the site.
"The sad factor is that some of these items are quite unique."
Insp Dave Meredith, from Devon and Cornwall Police, said: "A lot of offenders involved in the thefts are travelling criminals and they seem to target isolated rural areas, churches, schools, farms."
He said the force carried out Operation Mountain during February where it "identified criminals involved in metal thefts and the vehicles they used and we targeted those vehicles."
Mr Meredith said more than 200 vehicles were stopped and the operation was deemed a "success" although it was too early for the statistics to be made available.