These rare flash photographs show topless Victorian miners without helmets toil deep underground on rickety scaffolding, in an age before 'health and safety'.
Workers with blackened faces are pictured drilling, climbing rickety ladders and propping up shafts with flimsy poles in these fascinating images from the 1890s.
They were caught on camera by some of the earliest flash photography ever attempted in Britain.
Covered in dirt and without any sort of protective clothing - some shirtless - their methods look precarious by modern standards but were actually state of the art at the end of the 19th century.
Some of the workers can been seen carrying explosives while others snatch some down time and snack on a Cornish pasty for their lunch.
Pioneering photographer J.C.Burrow was commissioned by Cornwall's tin mine owners to showcase their technology in a series of illustrated guides.
But faced with trying to take pictures in complete darkness, hundreds of feet underground, Burrow had to employ a few new tricks of his own.
Using the latest flash photography methods, he rigged up a system of lamps filled with highly flammable magnesium powder.
He then assembled a team of fearless volunteers to ignite the magnesium while he waited for the brilliant white flash to illuminate his cloth-capped subjects.
The process was painstaking and time-consuming and after a year's worth of tinkering, Burrow considered only 24 of his 100 plates worthy of publication in 1893.
In an accompanying text he described his many difficulties and apologised for the "incompleteness of the series".
He wrote: "It is a rather disheartening experience to find the results of a whole days work with an energetic band of helpers are not 'printable', but such experience was mine on more than one occasion.
"The work, however is so full of interest, and its performance so productive of welcome enlightenment on many critical points, that I have no intention of allowing it to remain where it is.
"I hope that at no distant date, the present attempt may be followed by another and more successful one."
Despite Burrow's reservations, his book - "Mongst Mines and Miners:Underground Scenes by Flash-Light" - was well received by Camborne Mining school, who used it as an educational tool.
Cornwall was once a global mining powerhouse thanks to its abundant natural deposits of tin, copper, zinc and arsenic, with more than 2,000 operational pits in its heyday.
Overseas competition began to kill the industry towards the end of the 20th century, however, and the few remaining pits were closed after the price of tin collapsed in 1985.
A copy of Burrow's volume is expected to fetch £2,250 at this year's PBFA London International Antiquarian Book Fair from May 23 to 24.
Bookseller Michael Kemp said: "Mr Burrow was attempting to showcase the mining technology of his age, but in doing so he devised some pretty groundbreaking methods of his own.
"Using explosive materials in the open air would be challenging enough back in 1893, but to do it in the pitch dark confines of an underground mine shaft seems unthinkable.
"Evidently our late Victorian counterparts did not share our modern day obsession with health and safety."