Crank Caverns is the common name of what is in fact the remains of the Rainford Delph Quarry. It is a network of underground tunnels and caverns, as well as an extensive woodland. Information in the St. Helens local history archives states that mining began here as early as 1730, with a small stone quarry known as Rainford Delph. As the quarry expanded, cost of purchasing land in order to open cast mine it increased, so it was decided to opt for a different method. Instead of quarrying out the stone, they would mine it out, following a seam of decent stone until it ran out. This resulted in the network of caves, tunnels and shafts we see today. Mining ceased in 1865, and the woods and caverns were used as a game reserve by the Earl of Derby until 1939, when they became a storage facility for ammunition for the Anti Aircraft position at Crank. After the war, the caverns ceased use as a game reserve and have instead remained open to the public.