“As much of it as possible will be underground and what is above ground will look like farm buildings,” Murray said. “It won’t look like a traditional mine.”
The mine shafts will not be visible from the ground. Instead, miners will walk 300m down an inclined path to the top of a 1,600m lift shaft down to the polyhalite shelf.
The raw material will travel up another shaft before being crushed, mixed with salt water and pumped for 45km along a pipe to a processing plant in Teesside, Middlesborough.
“We’re using a lot of subsurface buildings,” Murray said. “It won’t see daylight until it arrives at Teesside.”
At peak production in 2020, the mine is expected to produce more than 20 million tonnes of potash a year. From the port most the potash will be exported to China, India and Brazil and other countries with large amounts of intensive farming.
Murray said the mine could also supply all of Britain’s potash demand several times over. The UK currently imports potash from Germany and Canada.
Before work on the mine can begin, Sirius needs to win approval from the park authority, which is to hold a 16-week public consultation.
The Campaign for National Parks said it was “very concerned about the negative environmental impacts of locating such a significant development in a national park.”
A spokesman said the law prevented Sirius from building the mine inside the national park if alternative sites were available, adding that Sirius had “not provided an adequate explanation” as to why it could not locate the mine outside the park.
Murray said it was “quite hard to find an isolated location that isn’t in the protected part of the moorland.”