A safety zone is hereby established beneath and adjacent to every stream, river and natural or artificial body of water in the Commonwealth that is sufficiently large to constitute a hazard to mining in the opinion and in the discretion of the department. Such safety zone shall in the case of such streams and rivers, extend horizontally two hundred feet from the high water mark of each bank. In the case of any other body of water sufficiently large to constitute a hazard to mining in the opinion and in the discretion of the department, it shall extend horizontally two hundred feet from the known perimeter. In any case, the zone shall extend downward to the limit of the workable beds.