Boulby Mine

Boulby Mine has been part of ICL Group, as ICL UK, since 2002. Its history, however, stretches back to 1968. Following a Public Inquiry, planning permission was granted to Cleveland Potash Ltd for the underground working of minerals – potash and salt – in an area that extended from Brotton into the National Park in East Cleveland, a range of approximately 8,200 hectares. Permission was granted for buildings, machinery and plant in Boulby to accompany the underground ‘world’. Creating Boulby Mine as we know it today began in 1969 when the two mine shafts were erected at the site.

A part of the community for over 40 years

Planning permission for the mine was obtained by Imperial Chemical Industries (ICI) in 1968 and they began work the following year. Under ICI, Cleveland Potash Ltd was a wholly owned subsidiary. ICI jointly owned the mine with Anglo American, and then with De Beers, before ownership was transferred to Israeli Chemicals Ltd in 2002. Since, Boulby mine has been known as ICL UK and has continued to be the largest employer in the area at any given time.

UK’s deepest mine

In 1973, the first potash was extracted from the mine, and structured production and supplying has been ongoing ever since. Since that time, Boulby Mine has been successfully supplying customers around the world with potash products, mined and refined on site. In addition to potash, Boulby mine is responsible for supplying around half of the de-icing rock salt used on the UK road system during the winter, removing the need for importation of salt into the UK. Recently, ICL UK became the first mine in the world to mine polyhalite, a fertilizer carrying the benefits of sulphur, potassium, magnesium and calcium. Sold only by ICL as Polysulphate, this 4-in-1 mineral has become a key player in the fertilizer market.


It isn’t just about mining Polysulphatepotash and salt at ICL UK. Through the years, we have sponsored, funded and hosted a variety of PhD theses on topics such as ground surface deformation, stability and design of excavations, and mining and microbial ecology. Boulby Mine has proved to be a special case study for research projects and literature on these areas of research.

We’ve carried out a large amount of observations and research into potash mining subsidence, and subsidence monitoring information is shown in the annual reports produced for us by Durham University. We also host the Science and Technology Facilities Council’s underground laboratory projects governed by Dr Sean Paling. The 1,100 metres deep laboratory provides a special environment free of background radiation in which particular science projects benefit, including the search for Dark Matter.