(6)The plans maintained under clauses (a) and (b) of sub-regulation (1) shall also show the settled boundary of the mine, or where the boundary is in dispute, the boundaries claimed by the owner of the mine and by the owner of the mine adjacent to the disputed boundary:Provided that where it is not possible to show the complete boundary of leasehold on the same plan, an additional key plan on any other suitable scale showing such boundaries and the outline of the workings shall also be maintained.
