(A) Mines and Minerals (Development and Regulation) Act (67 of 1957) , S.15— Meghalaya Mineral Cess Act (7 of 1988) , S.7— Meghalaya Mineral Cess Rules (1989) , R.5, R.11(2), R.11(4)— Mining lease - Demand notice for payment of arrear cess - Lessee failed to submit monthly return - Lessee well aware of their liability to pay cess - Mere non adherence to procedural formality, would not vitiate demand notice. (Para 24 25) (B) Constitution of India , Art.226— Meghalaya Mineral Cess Act (7 of 1988) , S.7— Writ petition - Constitutionality of Meghalaya Mineral Cess Act, 1988 is under challenge - Petitioner seeking refund of current cess already paid during pendency of petition - Held, challenge to vires of enactment cannot cease or suspend operation or implementation of such enactment unless same is set aside. (Para 30) .....