(a) Closure Performance Standard--New and existing Mining Units shall be closed so that they no longer pose a threat to water quality. No post-closure land uses shall be permitted that might impair the integrity of containment structures.

(b) Plan--Mining Units shall be closed according to an approved closure and post-closure maintenance plan which implements this section and provides for continued compliance with the applicable standards in this article for waste containment, precipitation and drainage controls, and monitoring throughout closure and the post-closure maintenance period.

(c) Reclamation--The RWQCB shall issue WDRs which incorporate the relevant provisions of an approved mining and reclamation plan (see California Surface Mining and Reclamation Act, Public Resources Code, Section 2770, et seq.), prescribe additional conditions as necessary to prevent water quality degradation, and ensure that there will be no significant increase in the concentration of indicator parameters or waste constituents in ground or surface water, unless requirements are waived.

(d) Oversight & Monuments--Dischargers shall comply with the closure requirements given in § 20950(b & d).

(e) Inactive Units--Containment structures at inactive Mining Units shall be subject to the same standards as apply to an active Mining Unit under this article.

(f) Closure and Post-Closure Funding--The discharger shall provide for adequate funding to pay for the costs of closure and post-closure maintenance as required by this article. The discharger shall provide assurance of financial responsibility, acceptable to the RWQCB, pursuant to Chapter 6 of this title. The RWQCB shall periodically review financial assurances and shall modified them as necessary.

(g) Alternate Financial Assurance--If a lead agency acting under the authority of § 2774(a) of the Public Resources Code requires assurances of financial responsibility, these assurances can be used to fulfill all comparable requirements under ¶(f), provided that:

(h) Ending Post-Closure--The post-closure maintenance period shall end when the RWQCB determines that water quality aspects of reclamation are complete and waste no longer poses a threat to water quality.

(i) Vegetation--Vegetation for closed Mining Units shall not impair the integrity of containment features. Irrigation of vegetation shall be managed to assure that it does not cause nor increase the production of leachate.

(j) Waste Pile Closure Standards--New and existing Group A and B waste piles shall be closed in accordance with the provisions of § 21090(a - c).

(k) Surface Impoundment Closure Standards--New and existing Group A and B surface impoundments shall be closed in accordance with the provisions of paragraphs (a) and (b)(1) of § 21400. A surface impoundment can be closed in place if provided with a cover as in § 21090(a) and if the liner (or, in the case of a double liner system, the outer liner) is clay.

(l) Tailings Pond Closure Standards--New and existing Group A and B tailings ponds shall be closed in accordance with the provisions of § 21090(a - c)and § 21400(a).

(m) Erosion & Sedimentation Protection--New and existing Group C Mining Units shall be closed in a manner that will minimize erosion and the threat of water quality degradation from sedimentation.