N.D. Cent. Code § 47-01-06

A thing is deemed to be incidental or appurtenant to land when it by right is used with the land for its benefit, as in the case of a way or watercourse, or of a passage for light, air, or heat from or across the land of another. Sluice boxes, flumes, hose, pipes, railway tracks, cars, blacksmith shops, mills, and all other machinery or tools used in working or developing a mine are deemed affixed to the mine.