Lessee shall furnish with each lease at the time it is filed with the officer in charge an acceptable bond not less than the following amounts:

Provided, That for leases for minerals other than oil and gas the Secretary of the Interior or his authorized representatives with the consent of the Indian landowner may authorize a bond for a lesser amount if, in his opinion, the circumstances warrant and the interests of the Indian landowners are fully protected: Provided further, That the lessee shall be allowed to file bond, Form S 1 covering all leases to which he or they are or may become parties instead of a separate bond in each case, such bond to be in the penal sum of $15,000. The right is reserved to change the amount of the bond in any particular case, or to require a new bond in the discretion of the Secretary of the Interior.