2020-10-22_PERMIT FILE - C1981012A (4)

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45 plan. A report will be provided to the Division by the inspecting engineer within two weeks of the completed inspections. A copy of the report will be kept at the mine site. As shown on Map 24 — Refuse Area, an access road has been constructed along the west side of the RDA. The refuse area will be serviced by this access road. In 2011, TR -66 modified this road to a haul road. Figure 6, RDA Final Configuration, shows the refuse fill area. The refuse disposal area will be constructed as shown by the conceptual plan and cross sections illustrated in Figure 7, Conceptual Fill Configuration, Figure 8, Generalized Cross Sections, and Figure 9, Benched Keyway Cut. Out slopes will be 2H: IV, benches will drain to riprap side ditches along the contact between the refuse and the undisturbed areas. Benches and roads will be sloped so that drainage will be routed to toe areas before draining laterally to the riprap side ditches. All runoff within the basin whether disturbed or undisturbed will enter pond 008 via side collection ditches. Pond 008 has been sized to accommodate this runoff. Although this is an ephemeral drainage with no springs or seeps, an underdrain made up of durable rock will be maintained along the existing drainage for the length of the fill. Temporary diversion ditches will be installed above the rock under drain to divert runoff away from drains and minimize clogging. The drains will consist of durable rock placed to minimum dimensions of 16 feet wide and eight feet high. The rock will consist primarily of 1 to 3 foot boulders with occasional smaller or larger pieces (see Exhibit 30, Supplemental Stability Investigation RDA). In addition, to the temporary diversion system, and as outlined in section 4.09.2, a filter fabric will also be used to keep the under drain free of debris and refuse. The fabric will be placed on top of the rock under drain in advance of the refuse placement (see Figure 8). Typically, the operator will use a fabric that is inert to biological degradation, naturally encountered chemicals, alkalides and acids, and has the following characteristics: Weight 6.05-oz./sq. yard Thickness 7.5 mil Apparent opening size 100+ (US Std sieve) Flow rate 100 gpm/sq. ft. A benched keyway cut will be constructed as shown on Figure 9, Benched Keyway Cut, in the toe area to stabilize the toe and allow for sub drainage. The refuse disposal area final configuration is shown on Figure 6, RDA Final Configuration and Figure 11, Cross Section A -A' Final Configuration. The overall average slope is about 3AH: 1V as a result of benches crossing the out slope of the fill. A slope stability analysis was completed based on assumed fill parameters. When representative refuse material is available for testing, Section 2.05 RN -6 10/17/2016