21.
When the mineral has to be raised from two or more seams or two levels by the same mine the arrangement has to be made in intermediate seam called . . . . . . . .

26.
No working of gallery in gassy mine which has approached within . . . . . . . .m of known dyke, shall be extended to a distance of . . . . . . . .m from the nearest ventilation connections unless the air is coursed upto a point within . . . . . . . .m from the face.