Every owner, operator, lessor, lessee, or general contractor, engaged in the mining of bituminous coal in any county of the second class, or any president, director, general manager, superintendent, or other person in charge of or having supervision over any bituminous coal mine or mining operation in this Commonwealth, shall be and is hereby required--(a) To designate within a period of six months from the passage of this act, and to keep designated by number, each and every pillar of coal beneath the surface still remaining in place at the time this act goes into effect and all pillars thereafter created, the number of each pillar to the place in a conspicuous position with white paint or some other equally durable and visible substance; and (b) to designate or cause to be designated, by numerals of convenient and legible size, upon all maps or plans mentioned in section two of this act,¹ with the space on each map or plan designating any pillar of coal the number of such pillar.