Boulby Mine

In 1939, potash was discovered in the area at Aislaby when prospectors were drilling to look for oil. The reserves were investigated in the 1950s but appeared too deep to exploit economically. Solution mining was considered from 1962, but not pursued. The first shaft was begun in 1968 and Imperial Chemical Industries (ICI) began construction on the mine in 1969, with potash being produced from one shaft in 1973. Full production of the mine commenced in 1976. The mine was the source of all UK-produced potash – around 55 percent of the total UK market. The ore horizon occurs between below ground with an average seam thickness of . The mine did not achieve profitability until 1984. In April 2011, the mine began the world's first commercial production of polyhalite, a rare mineral that has been found in large quantities in a seam out to sea from the mine, with total resources estimated at over a billion tonnes lying more than offshore. The mineral has commercial potential as an inorganic fertiliser. In April 2014, Cleveland Potash was awarded a £4.9 million government grant to support the mining of polyhalite at the Boulby site and parent company Israel Chemicals Ltd has pledged to invest £300 million in the area before 2018. crystals from the Boulby Mine. Size: 4.0 × 2.4 × 2.0 cm Plans include extending the mine to the east and upgrading facilities to increase production capacity. Environmental groups have raised concerns that the development could have an intrusive effect on the local area. and can produce up to one million tonnes of potash each year. At deep, it is the second deepest mine of any kind in Europe, and has a network of underground roads extending under the North Sea, totalling in length. Due to the mine's depth it takes workers seven minutes travelling in a lift to reach the bottom of the mine. Cleveland Potash Limited had a reported turnover of £194 million in 2013, up from £162 million the year before. However, despite the increased turnover, the company suffered a total pre-tax loss of £194 million. This was the result of a huge £200 million impairment charge arising from a significant fall in potash prices. By the end of 2018, the company had 470 employees after a round of job cuts related to the switch from mining potash to polyhalite. In 2023, the mine produced of polyhalite, an increase on the 2022 production of . ==Transport==

Much of the output from the mine is transported by rail, as the site is located east of Loftus along the route of the former WRMU (Whitby Redcar and Middlesbrough Union Railway), which was closed on 5 May 1958. The line remains open from Saltburn to Boulby for goods traffic. Teesport handles most of the bulk cargo export from the mine, via a specific potash and rock salt terminal. ==Underground laboratory==

Because of its depth, Boulby Mine is the site of the Boulby Underground Laboratory below the surface (2800 metre water equivalent). Part of the laboratory is called Palmer Lab (subterranean) and the laboratory's surface facilities are sometimes called the John Barton surface facility. Work being carried out at the underground laboratory includes the UK Centre for Astrobiology study of extremophile organisms that can survive in a salt-rich environment. The site is also used for testing NASA Mars rovers. In October 2017, the European Space Agency (ESA) sent astronaut Matthias Maurer as part of the fifth Mine Analogue Research sortie. It is thought that the brines present in the mine may be able to support extremophiles, and be like similar sites in caves on other planets. Extant testing and recording programmes at the laboratory include: • BUGS or BUGs (Boulby Underground Germanium Suite; also used to be called Boulby-Ge): Ultra-low background material screening of germanium for development of dark matter experiments • UltraLO-1800 equipment: For study of radioactivity of the surface layers of materials (surface screening) with aim to aid in development of dark matter experiments • SELLR (Subsurface Experiment of Life in Low Radiation): an experiment studying the effect of low-radiation environment to biological systems • Deep Carbon, MuScan, Muon-Tides (3 experiments): Muon Tomography • DRIFT-II (Directional Recoil Identification From Tracks): dark matter experiment. One of the experiments detectors, the DRIFT-IIb, is located at Boulby. A low pressure negative ion time projection chamber (NITPC) designed to detect weakly interacting massive particles (WIMPs, a prime dark matter candidate), a second detector (DRIFT-IIc) is located on the surface at Occidental College, Los Angeles, California, USA. Previous, now completed experiments include: • ZEPLIN: dark matter experiment(s). The final ZEPLIN experiment, ZEPLIN-III finished in 2011. • DRIFT-I: dark matter experiment • DM-Ice: dark matter experiment • ERSaB: Environmental gamma spectroscopy • SKY, SKY ZERO (multiple experiments in the same SKY-experiment series): study if ionisation by cosmic rays induced aerosol nucleation & growth • UK Dark Matter Collaboration: dark matter experiment • NAIAD: dark matter experiment ==Health and safety==

Since the year 2000, there have been several incidents at the mine. Cleveland Potash Limited has been served with 11 notices for breaches of health and safety procedures by the Health and Safety Executive since 2012. They include not taking appropriate measures to protect workers from the risks of explosion, falling ground and inadvertent entry into the mine shaft. Other incidents include; • 2001 – an electrician suffered severe burns to his face during routine maintenance work. • 2012 – a 50-year-old man suffered chest injuries when a hose burst and forced him against a skip. • April 2014 – there was a collapse at the mine caused by a falling boulder. • June 2014 – an employment tribunal revealed that the Boulby mine would have been unable to cope in an emergency. A former rescue team coordinator, Steve Angus, was fired after failing to ensure enough safety officers were trained to respond. He was also accused of failing to maintain the required standard of breathing apparatus. • 13 April 2016 – Seven workers were hospitalised for smoke inhalation when polystyrene blocks caught fire under the sea and from land. • 17 June 2016 – a miner, 55-year-old John Anderson, was killed in a "gas blow-out" while working in the mine. ==See also==