Billingham Anhydrite Mine

Overview

A mine that existed to feed a chemical works rather than to sell a mineral. ICI dug thirty-three million tons of anhydrite from under Billingham to make sulphuric acid and fertiliser, and when the chemistry changed to natural gas the whole thing was simply sealed and left.

History

Drilling to prove the anhydrite began in 1924 and the sulphuric acid project was launched in 1926. Shaft sinking started that September and bottomed fourteen months later at about 850 feet; the mine went into production in November 1927. The acid plant's first kiln was lit in February 1930, though it took until May 1931 to get acceptable clinker out of it. The mine served the ICI Billingham works — a site of about a thousand acres which in the 1960s was the second largest chemical factory in the world — and by 1953 it had two hundred miles of underground roadways and a square mile of workings. Over forty-four years it yielded more than thirty-three million tons. Production ended in 1971, and the mine was sealed when the shaft was capped in 1978.

Geology

The mine worked a bed of anhydrite five to six metres thick, running 53 to 55 per cent SO3 — an evaporite laid down as the Permian Zechstein sea dried out, the same broad sequence that yields the potash at Boulby and the salt of Cheshire. Anhydrite is calcium sulphate without the water that makes gypsum, and that is exactly what ICI wanted: roasted with coke and clay it gives up sulphur dioxide for sulphuric acid, and leaves behind a calcium silicate clinker that can be ground into Portland cement. The mine's whole existence rested on that one chemical fact.

Geological setting: Evaporite Deposits (well documented example)

Workings

Pillar-and-stall working beneath the plant, over about five square kilometres, with the anhydrite brought up a single shaft of roughly 237 m and taken to the works by belt conveyor. The process used was the Müller-Kühne route, which made sulphuric acid and cement clinker together; the clinker went to the neighbouring cement plant by aerial ropeway for grinding, and the acid kilns produced something like 4.7 million tonnes of it over their life.

Closure

The end came from a change of feedstock rather than exhaustion. Billingham moved to elemental sulphur and to natural gas as both fuel and raw material, and phased out ammonium sulphate as a fertiliser — which left the anhydrite mine with nothing to supply. Production stopped in 1971 and the shaft was capped in 1978.

What remains

Sealed and inaccessible. The workings run about 3 km north to south and up to 1.5 km east to west, between 130 and 280 m below ground — roughly eleven million cubic metres of void. They have been considered for various uses since closure, including at one point as a repository for nuclear waste.

Nothing of the mine at surface; the shaft is capped. The chemical works it was dug to supply is still there in altered form.

Redevelopment

Built over by the continuing industrial estate; the void beneath remains.

Abandoned workings can be dangerous — unstable ground, uncapped shafts, flooding and bad air are common even where a site looks safe from the surface. This entry describes history and general location only; it is not an access guide.

Recorded claims

Individual factual claims, each attached to the source(s) that support it below. Where sources disagree, both are kept.

• Drilling to prove the anhydrite began in 1924; shaft sinking started in September 1926 and bottomed fourteen months later at about 850 ft, with the mine in production from November 1927. ^1,2
• The mine worked a seam of anhydrite 5 to 6 m thick running 53 to 55 per cent SO3, by pillar-and-stall over about 5 km² beneath the plant, reached by a shaft of roughly 237 m. ¹
• The works used the Müller-Kühne process, making sulphuric acid from the anhydrite and Portland cement clinker as a by-product, which went to the neighbouring cement plant by aerial ropeway; the acid kilns produced about 4.7 million tonnes of clinker over their life. ¹
• By 1953 the mine had 200 miles of underground roadways and a square mile of workings; over 44 years more than 33 million tons of anhydrite were extracted. ²
• Production ceased in 1971 and the shaft was capped in 1978, the works having switched to elemental sulphur and natural gas and phased out ammonium sulphate. ^1,2
• The workings run about 3 km north-south and up to 1.5 km east-west, 130 to 280 m below ground — some eleven million cubic metres of void. ²

Photographs & further reading

This page doesn't try to reproduce everything — these are the best original sources found for this mine.

Images

Sources

1. (primary) Billingham — Cement Plants and Kilns in Britain and Ireland — cementkilns.co.uk
2. (secondary) History of the Anhydrite Mine — Picture Stockton Archive
3. (primary) Mine plans SWR2577 and SW209: Hopewell, Wimberry, Cannop and associated gales — British Geological Survey / Mining Remediation Authority mine plans catalogue

Record created: 24 August 2026 · Last researched: 24 August 2026