The colours of pebbles on the shore range from grey and ochre through green to blue, and the eroded cliff is banded orange and purple and red, like a section through an old volcano.
Pebbles are bubbled with cavities, though not as airy as pumice. We could have been in Iceland, but we were on the shore at Workington – looking at slag.
At Moss Bay, to the south, the 20-metre-high white cliffs that edge the land are man-made. To the north of the town, low rusty-brown cliffs are held back by tumbled blocks of limestone, and reefs of slag spill towards the sea in solid waves, part-hidden by slippery brown fronds of Fucus vesiculatus and F. serratus. Sea-smoothed fragments, greys, greens, blues, all sizes, have drifted over hard pavements of pebbled slag.
It’s a landscape that intrigues and draws you on, further and further along the beach: a man-made landscape, and you can only wonder at the human effort it required, the sequential steps – quarrying, haulage, smelting, and yet more haulage.
West Cumberland has been ideally suited to the production of iron and steel. Haematite and limestone were there to be quarried; and so was coal, both beneath the land and beneath the sea. In 1856 the Workington Haematite Iron Company Ltd, set up to make pig iron from locally-mined haematite ore, had two blast furnaces at Oldside, just north of the town; Bessemer steelmaking commenced there in 1877. In that same year the Workington Moss Bay plant added three Bessemer converters to its own iron-works, and the production of pig-iron and its conversion to steel escalated within the county. Sadly, the story of the industry’s decline is well-known, Cumbria’s iron and steel works closing in the 20th century. The Moss Bay works remained, turning iron into steel for rails until 1974, after which steel ingots were brought in from Teeside. Corus’s rail-making factory closed in 2006.
Nevertheless, the Workington area was a centre of iron and steel production for 100 years, and during these decades, one major unwanted by-product was slag.
Iron ore, limestone, coke. To make iron, you need these three ingredients, plus heat.
‘Coking’, or metallurgical, coal – in contrast to ‘thermal’ coal which is used for generating power – is produced by heating suitable coal to very high temperatures in the absence of oxygen to drive off the impurities such as sulphur and phosphorus and create a hard porous material. Photographs of the now-vanished coke works, furnaces and Bessemer converters are part of the region’s lost industrial heritage. There are valuable photos of the Moss Bay coke works on R W Barnes’ website.
Phil Baggely reproduces a 1908 article on his own website  where the writer notes that “Old coal miners used to say that there is good coking coal lying between Distington and Moss Bay…” Current explorations by West Cumbria Mining in the Haig Pit and Whitehaven area indicate that some of the coal still remaining underground is indeed high-quality coking coal.
Coke, haematite and limestone are introduced into the top of the blast furnace and hot air is blasted into the furnace near the base. As the hot air burns the coke, the resulting carbon monoxide reduces the iron ore to iron. Molten iron is tapped off into a channel with lateral chambers to form iron ‘pigs’ (the pigs can then be converted to steel in a Bessemer converter).
The limestone acts as a flux, combining chemically with coke ash and impurities such as aluminates and silicates from the ore to form slag. The molten slag floats – think of the bubble-cavities in the pebbles – on top of the molten iron. It has to be removed, so it’s tapped off into specially-designed trucks, or ladles, and taken away for disposal.
In Workington, during more than a century of iron-making, this still-molten slag was tipped along the coast, forming artificial hills and cliffs, pavements and reefs.
Phil Baggely has put together a fascinating collection of information and old photos about Workington’s iron and steel works and their locomotives and wagons. Copyrighted material shows a diagram of a slag-ladle, and rare photos of filled ladles being pulled by a locomotive, then tipped and emptied.
Elsewhere, R W Barnes describes the hazardous business of emptying each ladle: “(It) was held in place on the track by ramming a giant wooden wedge – called a ‘Scotch’ – under the wheels. The loco then ran backwards, tensioning a chain attached to the ladle. As the chain tightened, the ladle tipped its load, returning under gravity when empty.” His photograph shows white-hot slag cascading down the tip, and Barnes remembers “standing on the green metal steps of the old Rocket-Brigade station with my Granda – half frightened, half excited – watching this regular, awe-inspiring event. Several tons of white-hot slag racing downwards from above; Workington’s own Vesuvius.”
And thus the beaches are strewn with gaseous pebbles, and rusty iron-bearing material like the smooth and oozing shapes of solidified lava. It is an alien but involving landscape, devoid of marine life except where algae colonise the reefs.
When we visited, it was also a place of alien sounds: the regular scything ‘swish’ of nearby wind-turbines, reminiscent of a samurai sword; a man shouting angrily above the baying and yapping of an intermingling pack of dogs along the shore; the growling of trail-bikes unseen behind the slag-banks.
A short way inland, heath-spotted orchids and wild roses dotted the once-derelict land.
 Phil Baggely has also co-authored, with Neil Sanderson, a very interesting and copiously-illustrated book, A Pictorial Archive of Steel-making at Workington. ISBN 0 9538447 1 4, published 2002 by Richard Byers, Workington