Section 90(4)(i) in The Bihar (Coal Mining) Area Development Authority Act, 1986
(i)the owner of a colliery supplied at such rate not being less than Rupees [Sixteen] [Substituted for 'Four' vide Section 9 of the (Amendment) Act, 1992. [24 of 1992].] per thousand gallons subject to revision by the Government from time to time.