This looks like a motor-generator unit – looks pretty beefy too – please correct us if we’re wrong! Terry Robinson tells us: ”This is the Blackstone Mirlees emergency generator unit, which is situated opposite the surface engineering building.” Terry also advises: “This is the emergency generator at Boulby mine.”
Image courtesy of Alan Franks and thanks to Terry Robinson for the updates.
This is the emergency generator at Boulby mine