20. CERTAIN OTHER PROVISIONS OF LAW NOT BARRED. – Subject to the provisions contained in Sec. 15, the provisions of this Act and the rules made there under shall be in addition to, and not in derogation of, the provisions of the Factories Act, 1948 (63 of 1948), the Plantations Labour Act, 1951 (69 of 1951) and the Mines Act, 1952 (35 of 1952).