California Code of Regulations
Title 14 - Natural Resources
Division 2 - Department of Conservation
Chapter 8 - Mining and Geology
Subchapter 1 - State Mining and Geology Board
Article 9 - Reclamation Standards
Section 3704 - Performance Standards for Backfilling, Regrading, Slope Stability, and Recontouring

(a) Where backfilling is proposed for urban uses (e.g., roads, building sites, or other improvements sensitive to settlement), the fill material shall be compacted in accordance with the Uniform Building Code, published by the International Conference of Building Officials and as adopted by the lead agency, the local grading ordinance, or other methods approved by the lead agency as appropriate for the approved end use.

(b) Where backfilling is required for resource conservation purposes (e.g., agriculture, fish and wildlife habitat, and wildland conservation), fill material shall be backfilled to the standards required for the resource conservation use involved.

(c) Piles or dumps of mining waste shall be stockpiled in such a manner as to facilitate phased reclamation. They shall be segregated from topsoil and topsoil substitutes or growth media salvaged for use in reclamation.

(d) Final reclaimed fill slopes, including permanent piles or dumps of mine waste rock and overburden, shall not exceed 2:1 (horizontal:vertical), except when site-specific geologic and engineering analysis demonstrate that the proposed final slope will have a minimum slope stability factor of safety that is suitable for the proposed end use, and when the proposed final slope can be successfully revegetated.

(e) At closure, all fill slopes, including permanent piles or dumps of mine waste and overburden, shall conform with the surrounding topography and/or approved end use.

(f) Cut slopes, including final highwalls and quarry faces, shall have a minimum slope stability factor of safety that is suitable for the proposed end use and conform with the surrounding topography and/or approved end use.

(g) Permanent placement of piles or dumps of mining waste and overburden shall not occur within wetlands unless mitigation acceptable to the regulatory agencies with jurisdiction over wetlands, which may include the lead agency, has been proposed to offset wetland impacts and/or losses.