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Homestake Mining Company May 10,2019 <br /> Regular(112d)Operation Reclamation Permit Application Package <br /> The current permit area totals 2912.0 acres (HMC, 1984). However, the permit area currently <br /> calculated totals 2908.0 acres. This does not represent a reduction in permit area that HMC is <br /> responsible for, rather it reflects a difference in measuring the permit area that cannot be <br /> reconciled from the original 1977 data. Therefore, HMC has added a 4.0 acre Permit Boundary <br /> adjustment line item to the permit area to reconcile the difference. <br /> 2.4.2. Water Management and Treatment <br /> Between 1995 and 2015, water management related activities at the site have focused on <br /> flow/water level and water quality measurements at surface water monitoring points, seeps and <br /> springs, and piezometers for evaluating the evolution of groundwater and surface water conditions <br /> over time. Starting in 2015, evaluation of BMPs for achieving uranium load reduction were initiated <br /> with pilot testing of source zone and passive water treatments systems Activities in 2015 and <br /> 2016 included relatively small-scale pilot test phosphate injections into the underground mine <br /> workings and the IRD. Phosphate injection pilot testing was upscaled in 2017 with the construction <br /> of field-implementation scale reagent dosing and recirculation systems. In parallel, pilot testing of <br /> ETCs using solid-phase reactive media for passive treatment of surface water and shallow <br /> groundwater was also initiated. Water management BMP development work conducted from 2015 <br /> to the end of 2018 are discussed below. <br /> 2015 water treatment activities included the following: <br /> • Installation of wells P-11 and P-12 in the underground mine workings for water extraction, <br /> reagent injection, and performance monitoring of phosphate injection pilot tests. <br /> • Small-scale "push-pull' phosphate injection pilot test conducted at underground mine <br /> workings wells P-4 and P-11. <br /> 2016 water treatment activities included the following: <br /> • Larger scale phosphate injection pilot tests conducted in the underground mine workings <br /> with development of well pairs P-4/P-11 and P-5/P-12. <br /> • Installation of wells RD-01, RD-02, RD-03, and RD-04 at the foot of the IRD for reagent <br /> injection and performance monitoring. <br /> • Phosphate injection pilot test conducted on the IRD, including injection into RD-01 with <br /> extraction from RD-02 and RD-03. <br /> • Drum-scale field pilot tests of solid-phase ETC reactive media, including zerovalent iron, <br /> fish bone apatite, and on-site peat soil. <br /> • Construction of an iron reagent-based "treatment residuals management' system for <br /> treatment of residual phosphate in surface water as required. <br /> 2017 water treatment activities included the following: <br /> • Expansion of phosphate reagent injection infrastructure on the IRD and underground mine <br /> workings, included: <br /> o Construction and operation of two phosphate dosing/mixing structures, housed in <br /> Conex boxes (one at the underground mine workings and one on the IRD). <br /> EXHIBIT E-RULE 6.4.5(AMENDED RECLAMATION PLAN) Page 11 <br /> HOMESTAKE MINING COMPANY <br />