California Code of Regulations
Title 27 - Environmental Protection
Division 2 - Solid Waste
Subdivision 1 - Consolidated Regulations for Treatment, Storage, Processing or Disposal of Solid Waste
Chapter 7 - Special Treatment, Storage, and Disposal Units
Subchapter 1 - Mining Waste Management
Article 1 - SWRCB-Mining Waste Management Regulations (C15: Article 7)
Section 22490 - SWRCB-Mining Unit Siting and Construction Standards. (C15: Section 2572)

Universal Citation: 27 CA Code of Regs 22490

Current through Register 2024 Notice Reg. No. 38, September 20, 2024

(a) Proximity to Faults--New Mining Units:

(1) for Group A and B wastes, shall not be located on Holocene faults. Units for Group C wastes may be located on Holocene faults if displacement will not allow escape of wastes or cause irreparable damage to containment structures;

(2) shall be outside of areas of rapid geologic change. Exemptions may be allowed by the RWQCB if containment structures are designed and constructed to preclude failure.

(b) Flooding--All Mining Units shall be protected from flooding as shown on Table 1.2 of this article.

(c) Construction & Discharge Standards--General construction standards are given on Table 1.3 of this article. Procedures for determining appropriate methods for discharges of Groups A and B mining wastes are outlined in Figures 1.1 and 1.2 of this article.

(d) Registered Professionals--Containment structures shall be designed by a registered civil engineer, and construction shall be supervised and certified by a registered civil engineer or a certified engineering geologist.

(e) General Containment Structure Criteria--Dischargers shall comply with general criteria for containment structures in § 20320.

(f) Liners.

(1) FMLs--Synthetic liners (40 mil minimum thickness) can be used for waste piles where the discharger can demonstrate that the liner will function adequately during the active life of the waste pile and provided that the waste pile is closed in accordance with § 21410.

(2) Relative Permeability--Permeabilities shall be relative to the fluids, including waste or leachate, to be contained.

(3) Clay Liners--Clay liners shall be of a minimum of two feet thick and shall be installed at relative compaction of at least 90 percent.

(4) Replaceable Clay-Liners--Single clay liners may be used for Group B surface impoundments if replaced as specified in § 20330(e).

(5) Contingency Plan--If the RWQCB exempts a discharger from liner requirements for a waste pile, a contingency plan for alternative waste containment shall be developed. The plan shall be implemented if there is failure of the waste pile containment system.

(6) Dischargers shall comply with the liner criteria given in § 20330 (a & d).

(g) Leachate Collection and Removal Systems (LCRSs) for Group A and B Wastes.

(1) All LCRSs shall be of the blanket type.

(2) Dischargers shall comply with leachate collection and removal system (LCRS) requirements given in § 20340 (b - e).

(h) Precipitation and Drainage Controls.

(1) Design Storm--Diversion and drainage facilities shall be designed and constructed to accommodate the anticipated volume of precipitation and peak flows from surface runoff as follows:

(A) Group A--one 25-year, 24-hour storm;

(B) Group B--one 10-year, 24-hour storm; and

(2) Excess Runoff--Precipitation on Group A and B waste piles that is not diverted by containment structures shall be collected and managed through the LCRS. The RWQCB can make exemptions to this requirement if the collected fluid does not contain indicator parameters or waste constituents in excess of applicable water quality objectives.

(3) Precipitation/Drainage Controls--Dischargers shall comply with precipitation and drainage control requirements given in § 20365 (d & e).

(i) Incorporated Impoundment Requirements--Dischargers shall comply with special requirements for surface impoundments given in § 20375. Nevertheless, for Mining Units, dischargers shall use the precipitation conditions in ¶(h)(1).

1. New section, including Table 1.2 filed 6-18-97; operative 7-18-97 (Register 97, No. 25).

Note: Authority cited: Section 1058, Water Code. Reference: Sections 13172, 13226, and 13263, Water Code; and Section 43103, Public Resources Code.

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