Archaeologists are battling against time to unearth clues about one of the UK's earliest chemical industries before a historic quarry falls victim to the sea.
It is a matter of time before the quarry is claimed by the sea
A team from English Heritage have begun work surveying an early-19th century alum quarry at Loftus, in east Cleveland
Aerial photography of the site has already been completed to identify inaccessible and dangerous locations.
So unstable is the crumbling Loftus site that archaeologists have been trained in the use of ropes and harnesses to complete the task.
Last year a similar site nearby at Kettleness was also mapped as part of the project before it too is consumed by the North Sea.
Alum shale occurs in abundance around the Whitby area.
In the Middle Ages it was discovered to be a rich source of aluminium sulphate - a crucial raw material used as a fixing agent in dyeing cloth.
Around 20 alum sites, some dating back almost 400 years, are known on the North Yorkshire coast.
Surviving remains at the Loftus site include quays and rutways for wagons, which ran between the foreshore and boats, are still visible at low tide below the old workings.
Abby Hunt, archaeological Investigator with English Heritage, said: "There are lots of unanswered questions about how the quarries actually worked.
"In the case of Loftus we are also racing against the clock to find answers because of coastal erosion.
"We can't do anything about its imminent destruction - but we can make sure that, along with Kettleness, it is fully recorded in the history books.
"The landscape still looks very industrial to the expert eye, but many walkers on the beach probably think the features are natural."
Survey work could take up to eight weeks to complete with many months of painstaking interpretation by archaeologists to follow.