"Section 246.    Definition of the terms "gross output" — Disposition of royalties and ad valorem taxes. — The term "gross output" shall be interpreted as the actual market value of minerals or mineral products, or of bullion from each mine or mineral lands operated as a separate entity without any deduction for mining, milling, refining, transporting, handling, marketing, or any other expenses: Provided, however, That if the minerals or mineral products are sold or consigned abroad by the lessee or owner of the mine under C.I.F. terms, the actual cost of ocean freight and insurance shall be deducted. The output of any group of contiguous mining claims shall not be subdivided. Ten per centum of the royalties and ad valorem taxes herein provided shall accrue to the municipality and ten per centum to the province where the mines are situated, and eighty per centum to the National Treasury."