This part shall not apply to surface mining activities of the Department of Transportation incident to its activities in constructing, repairing, and maintaining the public road system in Georgia. The provisions of this Code section shall also extend to any person, firm, or corporation contracting with the Department of Transportation to construct, repair, or maintain public roads, provided that such contracts contain standards for the reclamation of the affected surface mining area; provided, further, that such standards have been approved by the division.