35 Miss. Code. R. 3-05-05-102
For the purpose of this regulation, the regulations of the Internal Revenue Service shall be followed in computing the depletion allowance, except as stated above and in those cases where the Mississippi Law and the Federal Law are in conflict. The percentage depletion allowance authorized by the Federal Law may be used as a method of computing the depletion allowance for Mississippi tax purposes. However, in no instance shall the aggregate deduction for depletion exceed the cost basis of the property. Taxpayers having rights to natural resources located in this state and in other states shall confine their computation and deduction for depletion allowances to only those natural resources which produce income for Mississippi tax purposes.
35 Miss. Code. R. 3-05-05-102