Minor mineral lease rights cannot be altered by State law once the central field is occupied by Parliament.

Parliament's declaration under the Mines and Minerals (Regulation and Development) Act, 1957 was treated as occupying the field for minor minerals, leaving no room for State legislation to alter existing lease terms. The Bihar amendment to section 10(2) of the Bihar Land Reforms Act, 1950 was therefore beyond legislative competence and invalid. The amended rule applying revised rent, royalty and surface rent to leases already in force was also ineffective, because vested rights under pre-existing leases could not be displaced by subordinate legislation without authority from competent legislation. The text concludes that the enhanced demands could not be enforced against existing leaseholders.

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Issues: (i) Whether the Bihar Legislature had competence to amend section 10(2) of the Bihar Land Reforms Act, 1950 so as to substitute the terms of existing minor mineral leases in the face of the Mines and Minerals (Regulation and Development) Act, 1957; (ii) whether rule 20(2) of the Bihar Minor Mineral Concession Rules, 1964 could validly apply the revised rent, royalty and surface rent to leases already subsisting before the rules came into force.

Issue (i): Whether the Bihar Legislature had competence to amend section 10(2) of the Bihar Land Reforms Act, 1950 so as to substitute the terms of existing minor mineral leases in the face of the Mines and Minerals (Regulation and Development) Act, 1957.

Analysis: The declaration in section 2 of the Mines and Minerals (Regulation and Development) Act, 1957, read with section 15, showed that Parliament had taken control of the regulation of mines and development of minerals to the extent provided in that Act. In respect of minor minerals, section 14 excluded the operation of sections 4 to 13 and section 15 specifically entrusted rule-making for their regulation to the State Government. The Court held that this legislative scheme occupied the field relating to minor minerals and left no room for State legislation altering the terms of existing leases. An amendment by the State Legislature, even if framed through a land reform statute, could not validly trench upon that field.

Conclusion: The Bihar amendment to section 10(2) was beyond legislative competence and invalid.

Issue (ii): Whether rule 20(2) of the Bihar Minor Mineral Concession Rules, 1964 could validly apply the revised rent, royalty and surface rent to leases already subsisting before the rules came into force.

Analysis: The rule, as amended, sought to extend the new terms to leases already in existence. The Court held that vested rights under existing leases could not be taken away by rule-making power alone unless authorised by competent legislation. Section 15 of the 1957 Act permitted regulation of future grants and connected matters, but it did not itself authorise modification of pre-existing leases of minor minerals. Since the State amendment supplying the supposed legislative basis was itself invalid, rule 20(2) could not stand independently.

Conclusion: Rule 20(2) was ineffective insofar as it applied to pre-existing leases.

Final Conclusion: The impugned State amendment and the retrospective application of the rule were struck down, and the appellants obtained protection against enforcement of the enhanced demands.

Ratio Decidendi: When Parliament, by a declaration and operative provisions, occupies the field of regulation of minor minerals, the State Legislature cannot alter existing lease terms in that field, and vested contractual rights cannot be displaced by subordinate legislation without authority from a competent legislature.

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