The Secretary shall prepare or cause to be prepared an economic assessment that shall address, among other things:

(a) Whether there are assurances in the minerals agreement that operations shall be conducted with appropriate diligence;

(b) Whether the production royalties or other form of return on mineral resources is adequate; and

(c) Whether the minerals agreement is likely to provide the Indian mineral owner with a return on the production comparable to what the owner might otherwise obtain through competitive bidding, when such a comparison can reasonably be made.