Yorkshire's Grand Canyon
One of the most striking features of the North York Moors is the cleft of the Cleveland Dyke, seen at its most dramatic south-east of Grosmont.
The excavated chasm runs over open access land for 1¼ miles, from beside the mysterious Arundel Hill (NZ837035) to cross the Goathland road (where the ancient Sil Howe tumulus seems to be forever buried under piles of road chippings), to the A169.
The 1:25000 Ordnance Survey map labels the feature "Whinstone Ridge", the name by which it is best known to walkers and locals.
Whinstone is not, however, a geologically precise name, but a general term applied by miners to extremely hard rock. "Whin" is a folk name for gorse, but it has been suggested that in this case, it refers to the sound made when the rock is struck.
The seam of whinstone exposed near Goathland is the southern end of a deposit that extends in a remarkably straight line for about 450 miles to the Isle of Skye, where it forms the Cuillin Hills, before disappearing under the sea. En route, it is responsible for High Force waterfall on the River Tees, and the foundations of a stretch of Hadrian's Wall.
It was formed 26 million years ago, when a volcanic eruption close to what is now the Isle of Arran injected unimaginable volumes of molten rock into three radiating seams left behind by a complex earthquake.
The most significant seam headed for Yorkshire, halting near Blea Hill on Sneaton High Moor (NZ900006).
The quarries near Grosmont have been worked since at least the early 19th Century, mainly for roadstone. Because of the weight of the stone, originally it was used only locally, but the opening of a horse-drawn railway to Whitby opened new markets.
Instability in the neighbouring rock meant that the seam, which is 30-40ft wide, could not be excavated at an angle greater than about 60 degrees, and when work reached a depth of about 60ft, it became uneconomic to mine the fast-narrowing accessible vein.
So towards the end of the 19th Century, a horizontal tunnel was driven almost 600 yards into the whinstone from the moor, to open a mine that could exploit the 140ft of rock above it.
A tramway ran from the level to Goathland Station, with the full trucks hurtling down under gravity, and the empty ones hauled up by pony. (In much later days, an old Ford Popular was adapted to run on the tracks to replace the ponies.)
A shaft in the chasm also lowered quarried stone into the mine, so that it could be transported on the tramway.
The stone is so hard that it is very difficult to shape it, but originally, men wearing wire-mesh goggles to protect their eyes became skilled at hitting it at an angle, to exploit lines of weakness, producing cobbles with sides of about two inches. (If a stone was alleged to be too large, the workman could prove that it was acceptable if he was able to fit it into his mouth.)
Eventually, a steam-driven stone-crushing plant was built at the station, and few cobbles were then produced. Instead, large chunks of stone were ground down to provide road dressing.
The engine driving the crusher burnt out, so water pouring out of the mine was diverted to a reservoir, then an 8-inch pipe led downhill to drive a water wheel. This was not powerful enough, so a Pelton wheel (a type of water-driven turbine) was installed, and auxiliary reservoirs were dug to maintain a greater head of water.
During World War II, a jettisoned bomb from a German aircraft destroyed the mine building - the crater is still visible - and the building and portal were replaced.
The mine continued briefly in operation after the war. Annual production declined from 19,250 tons in 1900 to 3,850 tons in 1949, so closure became inevitable, despite the huge resources that remain.
The drift entrance is now sealed, and a planning application to re-open the mine for show to the public was turned down in 1978.
Badly stained, sludgy water still leaves the level, and a settling pond has been built near the portal.
Extensive mining of the dike also took place south of Roseberry Topping.
Leeds City Council made great use of stone from the area, and once operated three quarries to ensure a supply.
BELOW: Ordnance Survey map from 1910, showing the quarries, the mine ("level") entrance, the tramway and the crushing plant at Goathland Station.
Harry notes: This is a first attempt to produce a very brief summary of a complex and highly fascinating topic, to which I could never really do justice.
If anyone is interested in learning more, I suggest reading initially The Mines and Miners of Goathland, Beck Hole and Greenend, by Peter Wainwright, published by Peter Tuffs in the Cleveland Mining Series (no ISBN) available from moorebooks.co.uk, and relevant chapters in Great Ayton - A History of the Village, by Dan O'Sullivan (no ISBN), excerpts quoted on the internet.