(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.

     (2) To meet the mandate of subsection (1) of this section, siting of tailings facilities shall be accomplished through a two-stage process that consists of a primary alternatives screening phase, and a secondary technical site investigation phase.

     (3) The primary screening phase will consist of, but not be limited to, siting criteria based on considerations as to location as follows:

     (a) Proximity to the one hundred year floodplain, as indicated in the most recent federal emergency management agency maps;

     (b) Proximity to surface and ground water;

     (c) Topographic setting;

     (d) Identifiable adverse geologic conditions, such as landslides and active faults; and

     (e) Visibility impacts of the public generally and residents more particularly.

     (4) The department of ecology, through the primary screening process, shall reduce the available tailings facility sites to one or more feasible locations whereupon a technical site investigation phase shall be conducted by the department for the purpose of verifying the adequacy of the remaining potential sites. The technical site investigations phase shall consist of, but not be limited to, the following:

     (a) Soil characteristics;

     (b) Hydrologic characteristics;

     (c) A local and structural geology evaluation, including seismic conditions and related geotechnical investigations;

     (d) A surface water control analysis; and

     (e) A slope stability analysis.

     (5) Upon completion of the two phase evaluation process set forth in this section, the department of ecology shall issue a site selection report on the preferred location. This report shall address the above criteria as well as analyze the feasibility of reclamation and stabilization of the tailings facility. The siting report may recommend mitigation or engineering factors to address siting concerns. The report shall be developed in conjunction with the preparation of and contained in an environmental impact statement prepared pursuant to chapter 43.21C RCW. The report may be utilized by the department of ecology for the purpose of providing information related to the suitability of the site and for ruling on an application for a waste discharge permit.

     (6) The department of ecology may, at its discretion, require the applicant to provide the information required in either phase one or phase two as described in subsections (3) and (4) of this section.

[1994 c 232 § 9.]