(1) In the processing of an application for an initial waste discharge permit for a tailings facility pursuant to the requirements of chapter 90.48 RCW, the department of ecology shall consider site-specific criteria in determining a preferred location of tailings facilities of metals mining and milling operations and incorporate the requirements of all known available and reasonable methods in order to maintain the highest possible standards to insure the purity of all waters of the state in accordance with the public policy identified by RCW 90.48.010. In implementing the siting criteria, the department shall take into account the objectives of the proponent's application relating to mining and milling operations. These objectives shall consist of, but not be limited to (a) operational feasibility, (b) compatibility with optimum tailings placement methods, (c) adequate volume capacity, (d) availability of construction materials, and (e) an optimized embankment volume.