Over a kilometre under the North Sea - 8 miles from dry land - sits a Spelsberg GRP enclosure. It is installed at the face of the UK's deepest mine as part of an Air Spectrum dust suppression system - this an environment so alien that NASA rovers, dark matter experiments and underground labs all call this place home. This is Boulby Mine, the frontline of Cleveland Potash Limited's polyhalite mining operations.
Boulby Mine varies in depth between 1100 and 1400metres, which equates to over four stacked Eiffel Towers. A former potash mine, Boulby Mine now primarily produces polyhalite, a rare earth mineral that can be used as fertiliser. Underground laboratories also form part of the site: researching the big questions surrounding dark matter and providing a proving ground for NASA space rovers.
In 2018, 450,000 tonnes of polyhalite was extracted from Boulby Mine, with operators Cleveland Potash looking to expand operations and output over the coming years. Mining at this extreme depth under the sea presents challenges: darkness, equipment reliability, access, ventilation and of - pertinence to this application - dust.
As polyhalite is mined at the face, the auger produces large amounts of airborne dust. Failure to suppress this dust can cause it to spread down the shaft, presenting safety risks to miners and potentially harming equipment. To ensure that dust is suitably controlled at the face, Cleveland Potash approached Air Spectrum, a leading provider of dust control systems, to deliver a solution.
Matt Edmonds, Operations & Engineering Manager at Air Spectrum, explains the system: "Our dust suppression system constitutes a series of 12 air and water atomising nozzles that spray above the auger as it mines. Water is pumped into each nozzle along with compressed air, mixed in a secondary chamber to form a very fine mist, then fired out of the nozzle in a cone. The reliability of the system is paramount, as mining cannot continue without it. Therefore, we knew that when it came to choosing an enclosure for the system, we needed an optimum solution."
With Boulby Mine looking to improve output, keeping the mine running is paramount in meeting exacting targets. Commodities are susceptible to price fluctuations, so insure against this requires Cleveland Potash to continually extract large quantities of polyhalite to protect profit margins. Due to the remoteness of the face, it also takes time for maintenance crews to reach stricken equipment, which adds further urgency to the reliability requirements. Therefore, ensuring equipment can operate reliably between scheduled maintenance checks is incredibly important.
Chris Smith, Area Sales Manager at Spelsberg, took the call from Air Spectrum: "Spelsberg is synonymous with enclosures for challenging application areas. From stealth ships to fire-resistant electrical infrastructure in tunnels - our boxes are designed to offer reliability. This experience meant that we were able to understand Air Spectrum's requirements for this particularly harsh environment."
In conjunction with Air Spectrum, Spelsberg selected a highly durable GRP (glass-reinforced polymer) enclosure measuring over a metre high. Available with an ingress rating of IP68, the enclosure was well suited for resisting dust and moisture off the shelf; especially important as it was installed within 10m off the face itself. Well within the range of the auger cutting through the seabed, this exceptional environmental resistance ensures electricals are not at risk from the grime produced as part of the mining process. Its durable chassis also meant that the harsh conditions of mining do not compromise its integrity.
Matt Edmonds continues: "The enclosure offered a good IP rating, increased durability, correct specification and the right size to accommodate everything we needed. Overall, it ticked all the boxes, while also offering value. We've tried other enclosures in this application, but Spelsberg offered a high level of technical proficiency right out of the box, which is what we need for these specialised systems. We carried out the installation of the enclosure at the face ourselves and it has been operating well ever since."
Chris concludes: "We hold a lot of stock in the UK ready for rapid delivery. In this case, we could take a specialised GRP enclosure straight off the shelf and deliver it to Air Spectrum on a reduced lead time. We also offer customisation services to Air Spectrum if a standard solution doesn't fit, so we can be flexible in terms of meeting their requirements - even if that's providing a solution for over 1km below the sea."
Learn more about the Spelsberg GRP enclosure and other products at www.spelsberg.co.uk.