Unless otherwise authorized by the Commissioner of Indian Affairs, the minimum rates for minerals other than oil and gas shall be as follows:

(a) For substances other than gold, silver, copper, lead, zinc, tungsten, coal, asphaltum and allied substances, oil, and gas, the lessee shall pay quarterly or as otherwise provided in the lease, a royalty of not less than 10 percent of the value, at the nearest shipping point, of all ores, metals, or minerals marketed.

(b) For gold and silver the lessee shall pay quarterly or as otherwise provided in the lease, a royalty of not less than 10 percent to be computed on the value of bullion as shown by mint returns after deducting forwarding charges to the point of sale; and for copper, lead, zinc, and tungsten, a royalty of not less than 10 percent to be computed on the value of ores and concentrates as shown by reduction returns after deducting freight charges to the point of sale. Duplicate returns shall be filed by the lessee with the Area Director within 10 days after the ending of the quarter or other period specified in the lease within which such returns are made: Provided, however, That the lessee shall pay a royalty of not less than 10 percent of the value of the ore or concentrates sold at the mine unless otherwise provided in the lease.

(c) For coal the lessee shall pay quarterly or as otherwise provided in the lease, a royalty of not less than 10 cents per ton of 2,000 pounds of mine run, or coal as taken from the mine, including what is commonly called “slack.”

(d) For asphaltum and allied substances the lessee shall pay quarterly or as otherwise provided in the lease, a royalty of not less than 10 cents per ton of 2,000 pounds on crude material or not less than 60 cents per ton on refined substances.