Woodsmith Mine Tunnel

The Woodsmith Mine Tunnel (also known as a Mineral Transport System [MTS]) is a 23-mile (37 km) long tunnel that will stretch between Woodsmith Mine at Sneatonthorpe near Whitby in North Yorkshire and the Wilton International complex on Teesside, England. The tunnel has been in development since 2016, but cutting of the tunnel bore did not start until April 2019, with an expected finish date of 2021. By the end of July 2020, over 4 miles (6.4 km) of tunnel had been dug out.

Woodsmith Mine Tunnel
Lockwood Beck site
Overview
Official nameMineral Transport System (MTS)
LocationNorth Yorkshire
Coordinates54.4942°N 0.9002°W / 54.4942; -0.9002
StatusUnder construction
Crosses
StartWoodsmith Mine
(Sneatonthorpe)
(54.4350°N 0.6216°W / 54.4350; -0.6216 (Woodsmith Mine Portal))
EndWilton
(54.5977°N 1.1051°W / 54.5977; -1.1051 (Wilton Portal))
Operation
Work begunApril 2019
Constructed2019–2021
Opens2021 (projected)
OwnerSirius Minerals
TrafficPolyhalite
CharacterMineral transport
Technical
Design engineerStrabag
Length23 miles (37 km)
No. of tracks1 (Maintenance train)
Operating speed13 miles per hour (21 km/h)
Highest elevation390 feet (120 m)
Lowest elevation1,180 feet (360 m)
Tunnel clearance20 feet (6 m)
Width20 feet (6 m)

When finished, the tunnel will be the longest tunnel in the United Kingdom and will also house the longest conveyor in the UK.[note 1][1][2] The estimated cost of the tunnel in November 2018 was £1.1 billion.

Background

York Potash Ltd[note 2] put forward the idea of mining potash and polyhalite on the moors above Whitby in 2010. Originally, three options for moving the mineral out were considered; a pipeline, a tunnel or a railway. Whilst the intended end location is Wilton (for delivery to the Redcar Bulk Terminal [RBT]), the developers also considered the Ports of Hull and of Immingham to the south. However the geology south through the Yorkshire Wolds was prohibitive for tunnelling as the chalk bedrock carries aquifers that are important for the region and would also need extra access/ventilation shafts, create more overburden and be of a significant extra cost than a shorter tunnel to Teesside.[3] A tunnel to Hull would stretch for 60 miles (97 km) and need an extra 62% of tunnelling effort, time and expense.[4]

Transporting the product out via a railway line involved crossing the River Esk at Larpool Viaduct, and then along the Esk Valley Line via two reversals in Whitby to gain the route towards Middlesbrough.[5]

A pipeline would have involved turning the potash and polyhalite into a slurry[6] which would have required a more labour and technically enhanced process at both ends of the transport system.[7] A pipeline would also be above ground and cause a lot of environmental damage.[8]

Both the pipeline and rail options were dropped in favour of a tunnel with conveyors in it during the planning stages, and through various submissions, the accepted plan was approved in June 2015.[9] The company, now Sirius Minerals, agreed to pay £130 million to the North York Moors National Park Authority to "protect and enhance the environment". This would be over the whole life of the project.[10]

To avoid damaging aquifers across the route, the tunnel is designed to stay deep within the Redcar Mudstone Formation.[11] The Redcar Mudstone Formation is less permeable to water and the route also avoids any former ironstone workings in the Redcar and Cleveland area.[12]

The cost of the tunnel was estimated at £1.1 billion in November 2018,[13] and when complete, the tunnel will be the longest that is wholly within the United Kingdom.[14] The conveyor will be robust enough to transport between 10 and 20 million tonnes of polyhalite when the mine is in full production with the raw mineral being transported to Teesside for granulation and onward shipping.[15][16][17]

Construction

Above ground works at the Lockwood Beck site for the Woodsmith Mine tunnel

In July 2016, the UK Government awarded Sirius Minerals a Development Consent Order[18] for the harbour facilities on Teesside. At that time, a different developer was shortlisted for the work on the tunnel which was also envisaged as needing five TBMs.[19] This was later downgraded to three TBMs.[20]

Whilst preparatory work was started in 2016, a ceremony to "break ground" at the Wilton site was held in June 2018 with Jake Berry, the MP for the Northern Powerhouse project.[21][22] In February 2019, the first of three Tunnel Boring Machines (TBMs) was delivered to the Wilton site via Teesport. The first TBM, named Stella Rose after a naming competition with local schoolchildren, started boring in early April 2019.[note 3][23] A spokesperson for Sirius Minerals commented on the tunnel stating that "we’re actually tunnelling in a rock that is relatively easy to cut, from a tunnelling point of view. It’s also relatively stable, and we’re not going through any cross measures; we’re not going from one geological horizon to another, which is where tunnels normally have more issues."[8] By September 2019, progress had extended to 1-mile (1.6 km) of complete tunnelling with rails, connections and concrete interiors.[24]

The tunnelling contract was split into three sections; Drive 1 was from Wilton to Lockwood Beck, Drive 2 was from Lockwood Beck southwards and Drive 3 was from Woodsmith Mine to Lockwood Beck northwards.[25] Initially, an Austrian company, Strabag, were awarded the first tunnelling contract for the 8.1-mile (13 km) section from Wilton to Lockwood Beck. This would involve 490 feet (150 m) of cut and cover, 2,600 feet (800 m) of conventional tunnelling and 7.4 miles (11.9 km) of using a TBM in a south easterly direction.[26] In November 2018, it was revealed that Strabag had been awarded the contract for the other two sections (nominally 7.5 miles (12 km) per section on average), and so would be the sole contracting company for the tunnel project.[20] The TBMs will process through the route tunnelling at the front of the machine, whilst the middle and rear sections, add concrete lining to the tunnel walls.[27]

The first TBM, Stella Rose, weighs 1,800 tonnes (2,000 tons) and is 738 feet (225 m) long. The concrete segments are 4 feet 11 inches (1.5 m) in length and a special concreting plant has been built to supply the TBMs as they progress through the tunnel, lining the route with over 150,000 concrete segments.[28][29]

Three ventilation shafts will be constructed at Lady Cross Plantation, near Egton, Lockwood Beck and at Tocketts Lythe. Lady Cross Plantation is within the North York Moors National Park whilst the other two sites are outside the park and are located within Redcar and Cleveland.[30] The access and ventilation shafts are planned to be 30 feet (9 m) in diameter.[11]

Location Coords Distance[lower-alpha 1] Depth Notes
Woodsmith Mine 54.4350°N 0.6216°W / 54.4350; -0.6216 0 4,921 feet (1,500 m)[lower-alpha 2] [31]
Lady Cross Plantation 54.4590°N 0.7433°W / 54.4590; -0.7433 5 miles (8 km) 1,181 feet (360 m) Site would host a crossover for the railway and conveyors[31][32]
Lockwood Beck 54.5182°N 0.9599°W / 54.5182; -0.9599 15 miles (24 km) 886 feet (270 m) Site would host a crossover for the railway and conveyors[31][32]
Tocketts Lythe 54.5478°N 1.0278°W / 54.5478; -1.0278 18 miles (29.5 km) 394 feet (120 m) [31]
Wilton 54.5977°N 1.1051°W / 54.5977; -1.1051 23 miles (36.5 km) Ground level at Wilton [31]
  1. From Woodsmith Mine site
  2. Conveyor into tunnel is estimated to be about 1,181 feet (360 m) in depth

The shaft at Tocketts Lythe will be smaller than the others as it is not envisaged to have a conveyor transfer. Lockwood Beck and Lady Cross plantation will be larger caverns to accommodate the crossover in conveyors and for the passing of maintenance trains. Lockwood Beck would also need a larger diameter shaft as it will be a setting off site for one of the TBMs.[32]

By the end of July 2020, the length of tunnel that had been dug out had reached 4.5 miles (7.2 km).[33] Concrete segments to line the tunnel were produced in a special factory inside the Wilton International Complex, however, at least 3,000 segments needed to be imported due to the tunnel boring machine making greater progress than anticipated for.[34] By early December 2020, 7 miles (11 km) had been tunneled, and the company was looking to start on building the shafts.[35]

Route

The tunnel will run in a north westerly direction from the Woodsmith Mine site, passing under the River Esk, the Esk Valley railway line, the A169 and then up across the Esk Valley to its first ventilation/access Point at Lady Cross Plantation. It then crosses moorland and runs alongside the A171 road for some distance crossing under it just south of Lockwood Beck reservoir where the second access point is. It then turns in a more north/north westerly direction through Tocketts Wood and under first the A173 road and then the A174 until it arrives at the Materials Handling Facility (MHF) at Wilton.[36] After granulation, the finished product will be taken on another conveyor (this time above ground) to the export site at Redcar Bulk Terminal.[37]

Sirius Minerals claim that the entire route does not travel under any housing, but it does come close to some barns.[38]

Details

Proposed cross-section of tunnel for Woodsmith Mine MTS (Mineral Transport System)[39] This is representational only and is not to scale
  • Length - 23 miles (37 km)
  • Overall diameter - 20 feet (6 m)
  • Internal diameter - 16 feet (4.9 m)
  • Minimum depth - 390 feet (120 m)
  • Average depth - 820 feet (250 m)
  • Maximum depth - 1,180 feet (360 m)
  • Width of conveyor belt - 47 inches (1,200 mm)
  • Speed of conveyor - 13 miles per hour (21 km/h)[note 4][40]
  • Gauge of maintenance railway - 2 feet 11.44 inches (900 mm)

The original plans detailed a tunnel with an internal diameter that was 14 feet (4.4 m) with a tunnel lining of 9.8 inches (250 mm). This was increased to a diameter of 16 feet (4.9 m) with a tunnel lining of 14 inches (350 mm). The overall diameter of the tunnel will be 20 feet (6 m).[20] This also increased the cost of the whole project (including sinking the mineshafts) from £3.6 billion to £4.2 billion.[41] The increase in diameter has also led to a slower progress rate than before; the TBMs tunnelling would be reduced from covering 66 feet (20 m) to 56 feet (17 m) per day.[42] The average depth of the tunnel will be 820 feet (250 m) as it makes its way north eastwards towards Wilton. The company stated that this will allow for minimal visual and environmental impact as well as avoiding any significant construction obstacles on the way.[43]

The 47-inch (1,200 mm) wide conveyor[40] will transport the mineral at the rate of 13 miles per hour (21 km/h) with a changeover between conveyors at the Lockwood Access Site.[38] The Mineral Transport System (MTS)[43] will consist of the longest underground conveyor in the world.[44] The tunnel will also include an access railway for maintenance crews, an 11 kilovolt power system for the conveyor, fibre optic cables, a pumping main and a 66 kilovolt feeder cable to supply the mine site from Wilton.[39][45] This is needed as there are no National Grid powers sources near to the mine site.[46]

Planning documents assume the gauge of the railway to be 2 feet 11.44 inches (900 mm), and the caverns where the crossovers are located will also be furnished with sidings.[47] A train maintenance depot will be sited at the Wilton end of the tunnel.[48]

See also

Notes

  1. Whilst the Channel Tunnel is underground for 35 miles (56 km), it is not wholly within United Kingdom. Additionally, the twin-bore Crossrail Tunnels stretch for 13 miles (21 km) across London, and are regularly listed as being 26 miles (42 km), when this is in fact the total amount of tunnel mileage across the two tunnels.
  2. YPL became part of Sirius Minerals in 2011.
  3. Stella Rose was so named after Stella meaning star in Latin (and Sirius being a bright star) and Rose after the nearby Roseberry Topping.
  4. This is a 2017 report, a factsheet released by Sirius Minerals states that the conveyor will move at a speed of 23 feet per second (7 m/s), which equates to 16 miles per hour (25 km/h)

References

  1. "Crossrail to miss December opening date". BBC News. 31 August 2018. Retrieved 1 May 2019.
  2. "26 MILES OF NEW RAIL TUNNELS CONSTRUCTED BENEATH YOUR FEET". crossrail.co.uk. Retrieved 1 May 2019.
  3. YPLA 2014, pp. 106–108.
  4. YPLA 2014, p. 106.
  5. "Potash prospects mean freight my return to Whitby". Modern Railways. Key Publishing. April 2011. p. 15. ISSN 0026-8356.
  6. Flanagan, Emily (30 September 2014). "Plans for biggest potash mine in Europe submitted". The Northern Echo. Retrieved 2 May 2019.
  7. Smale, Katherine (5 November 2018). "UK first for shaft sinking innovation at £4.2bn potash mine". New Civil Engineer. Retrieved 2 May 2019.
  8. "Woodsmith potash mine: showcasing the future of underground technology". Mining Technology | Mining News and Views Updated Daily. 25 February 2019. Retrieved 15 April 2019.
  9. Pidd, Helen (30 June 2015). "North York Moors potash mine gets £1.7bn go-ahead". The Guardian. Retrieved 13 April 2019.
  10. Bounds, Andrew (10 March 2017). "Sirius Minerals and the battle to build Britain's deepest mine". Financial Times. Retrieved 15 April 2019.
  11. "Tees Valley RIGS Group Quarterly Newsletter No. 3" (PDF). northern-england-geology.co.uk. June 2014. p. 2. Retrieved 14 April 2019.
  12. "Construction". siriusminerals.com. Retrieved 14 April 2019.
  13. Morby, Aaron (12 November 2018). "Strabag confirmed for potash mine tunnel fit-out | Construction Enquirer". www.constructionenquirer.com. Retrieved 1 May 2019.
  14. Whipple, Tom (13 April 2019). "Colossal bore gets priest's blessing to dig a giant tunnel at Yorkshire Mine". The Times (72820). p. 22. ISSN 0140-0460.
  15. Duke, Simon (22 April 2018). "I'm digging the biggest hole in Yorkshire, says Sirius Minerals boss Chris Fraser". The Sunday Times. Retrieved 2 May 2019.
  16. "Strabag to build tunnel for £3.2bn Yorkshire potash mine - News - GCR". Global Construction Review. 3 April 2018. Retrieved 2 May 2019.
  17. Copeland, Alexa (23 January 2019). "Sirius Minerals unveils impressive tunnel boring machine". The Northern Echo. Retrieved 2 May 2019.
  18. "The process | National Infrastructure Planning". infrastructure.planninginspectorate.gov.uk. Retrieved 14 April 2019.
  19. "UK approves $2.9bn mining scheme with very long tunnel for Yorkshire - News - GCR". Global Construction Review. 25 July 2016. Retrieved 14 April 2019.
  20. Ibbetson, Connor (12 November 2018). "Strabag Yorkshire mine tunnelling contract extended". New Civil Engineer. Retrieved 15 April 2019.
  21. Woodruff, Nicholas (28 June 2018). "Work begins on tunnel for Sirius Minerals fertilizer mine". World Fertilizer. Retrieved 14 April 2019.
  22. Snowden, Ros (22 June 2018). "Work starts on York Moors tunnel". The Yorkshire Post. Retrieved 15 April 2019.
  23. Atkins, Duncan (12 April 2019). "A Stella occasion as Sirius Minerals launches first machine to construct tunnel from Whitby to Teesside". The Scarborough News. Retrieved 15 April 2019.
  24. Witherow, John, ed. (28 September 2019). "Sirius seeks light at the end of the tunnel". The Times (77, 964). p. 47. ISSN 0140-0460.
  25. Moscariello, Martina (6 September 2018). "Sirius Minerals signs contracts for multi-million pound Polyhalite project". Whitby Gazette. Retrieved 15 April 2019.
  26. Morby, Aaron (4 April 2018). "Strabag wins first Yorkshire Potash mine tunnel drive | Construction Enquirer". Construction Enquirer. Retrieved 14 April 2019.
  27. Price, Kelley (26 January 2019). "Sirius Minerals' monster machine that will tunnel under Teesside". Gazette Live. Retrieved 15 April 2019.
  28. Roker, Stephanie (17 April 2019). "First boring machine launched for Sirius Minerals' tunnel from Teesside to Whitby". Global Mining Review. Retrieved 29 April 2019.
  29. "Tunnel segment factory begins operations with local labour". Sirius Minerals PLC. 9 April 2019. Retrieved 29 April 2019.
  30. "Sirius Minerals Polyhalite Mine (WoodSmith Mine)". northyorkmoors.org.uk. Retrieved 14 April 2019.
  31. YPLA 2014, pp. 30–31.
  32. EIA 2014, p. 8.
  33. Snowden, Ros (30 July 2020). "Polyhalite mine on the North Yorkshire Coast plans to increase workforce". The Yorkshire Post. Retrieved 30 July 2020.
  34. Fox, Alexa (5 October 2020). "Miles of mine tunnel transported from Teesside to the Moors". The Northern Echo. Retrieved 9 October 2020.
  35. Gosden, Emily (12 December 2020). "Anglo ploughing more into fertiliser". The Times (73, 341). p. 59. ISSN 0140-0460.
  36. "MTS Route". construction enquirer.com. Retrieved 15 April 2019.
  37. Duke, Simon (2 May 2019). "Sirius raise $425m in new share offer". The Times (72, 836). p. 44. ISSN 0140-0460.
  38. Hughes, Mike (6 March 2017). "How £2.3bn mining project will pump millions into community". Gazette Live. Retrieved 15 April 2019.
  39. Parson, Matt; Pooleman, Mark (March 2018). "We're About Delivery (presentation to the ICE)" (PDF). mom.3.org. Sirius Minerals. p. 27. Retrieved 15 April 2019.
  40. "MineralTransport System" (PDF). siriusminerals.com. p. 3. Retrieved 1 May 2019.
  41. Morby, Aaron (6 September 2018). "Cost of Yorkshire potash mine tunnel soars 70% to £1.1bn | Construction Enquirer". Construction Enquirer. Retrieved 14 April 2019.
  42. Hulme, Neil (6 September 2018). "Sirius Minerals falls 11% as North York Moors mine costs climb". Financial Times. Retrieved 15 April 2019.
  43. Benton, Dale (1 November 2018). "How Sirius Minerals will redefine the global mining industry through sustainable design excellence". Mining Global. Retrieved 2 May 2019.
  44. "Work Starts To Make Tunnel At Woodsmith Mine Near Whitby". Yorkshire Coast Radio. 4 December 2018. Retrieved 15 April 2019.
  45. "Mineral Transport System". siriusminerals.com. Retrieved 14 April 2019.
  46. EIA2014, pp. 4–5.
  47. EIA2014, pp. 12–14.
  48. EIA 2014, p. 4.

Sources

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