Where it gets difficult is when the two properties infringe upon one another, as Jack was saying. Jack, mineral rights owners do have a "right" to access their minerals from the surface. The law states something about "reasonable" concessions, it really likes the term "reasonable", so they make it a really gray area. They cannot, for instance, tear down a house or other improved property to put up a gas rig, that infringes upon the right of the surface owner. But if you have a nice, unimproved woodlot behind the house that is not "in use", the mineral rights owner can use that land, so long as they take "reasonable" precautions to prevent disturbance to the surface landowners rights as much as possible