3(1)(b) which is very material and it runs as follows : "3(1) The provisions of this Act, except those contained in sections 7, 8, 9, 44, 45 and 46, shall not apply to (b) any mine engaged in the extraction of kankar, murrum, laterite, boulder, gravel, shingle, ordinary sand (excluding moulding sand, glass sand and other mineral sands), ordinary clay (excluding kaolin, china clay, white clay or fire clay), building stone, road metal earth, fullers earth and lime stone : Provided that (i) the workings do not extend below superjacent ground; or (ii) where it is an open cast working (a) the depth of the excavation measured from its highest to its lowest point nowhere exceeds six metres; (b) the number of persons employed on any one day does not exceed fifty; and (c) explosives are not used in connection with the excavation.