The £167m tunnel which will transport polyhalite from a mine near Sneatonthorpe will be comparable in size to the Channel Tunnel.
Plans to construct a pipeline from the Doves Nest Farm site to a processing plant at Teesside have been abandoned in favour of a six-metre tunnel which will run the 37km distance at a depth of 350m.
York Potash spokesperson Gareth Edmunds said: “It addresses the concerns about the pipeline put forward during public consultation. We have always said we would try and reduce the impact where we sensibly can, so we feel good about being able to change and we feel it’s a positive impact on the project.”
Sirius says the tunnel will reduce surface buildings and environmental impact by 70 per cent and allow the mine a greater capacity.
“It’s going to cost more in the long run,” said Mr Edmunds. “But we think it’s worth it.”
Mr Edmunds said the idea of a tunnel was discussed when initial plans for the mine were made but it was thought that a pipeline would have a lower cost and impact.
Following consultation it was decided that the extra infrastructure required to make a pipeline work meant it was no longer the viable option. It would have required a trench 45m wide to be dug along the length of the route and issues arose when attempting to cross rivers or skirt around sites of specific scientific interest. “The impact goes up and the cost goes up with it,” said Mr Edmunds.
The 6m wide tunnel will have a conveyor belt and a roadway running alongside it which will allow access to maintenance vehicles.
It will have three access points running along the length of it, and Mr Edmunds said this makes it effectively five mining tunnels, of a length regularly seen in underground mining operations.
However in total, the mine will measure up to the Channel tunnel, which is split into three 7.8m sections which run for 38km underneath the English Channel.
The tunnel would see over 1 million cubic metres of bedrock brought to the surface - the waste material could almost fill the inside of Wembley Stadium.
But the mining company says there would be a degree of compression which would reduce the impact, and suggested that if spread across an area of around 20 hectares at each access point, the ground level would only be raised by about a metre.