2019-06-28_REVISION - M1977004 (9)

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Homestake Mining Company May 10,2019 Regular(112d)Operation Reclamation Permit Application Package 1983). Additional survey monitoring points were added in subsequent years to cover more of the mine site area and replace monitoring points that became obsolete due to regrading and other factors. Annual data compilation and review of this data has been performed by various consulting parties since the initial installations (BGC, 2019b). 3.4.2.4. Photo Stations The photo station monitoring program was initiated to document any change to the system of tension cracks and scarps that define the eastern limit of slope movement of the North Pit's East Wall for the purpose of detecting any eastward propagation of the surface deformation (EAI, 2014). The monitoring program operated on a near-annual basis from May 2000 to 2013. Photographs were collected in 2000, 2003, 2004, 2006, 2007, 2008, 2009, 2011, 2012, and 2013. Change detection analysis is performed by comparing those baseline photographs against other photographs taken from the same location on subsequent site visits. Photographs for each station, for each year, are compiled and compared in the Engineering Analytics, Inc. (EAI) Tension Crack Monitoring and Photo Station Documentation at the Pitch Reclamation Project report (EIA, 2014). 3.4.3. Current Slope Movement Conditions The current state of slope conditions is assessed based on results and observations made over the course of the slope movement monitoring program (Section 3.3.3)which includes inclinometer readings, survey monuments, visual assessments of tension cracks and scarps, and over 35 years of slope movement observations. 3.4.3.1. Surficial Mapping of Landslide Features The map of tension cracks and scarps (Drawing 02)along the eastern margin of the North Pit and South Pit provides a basis for monitoring any change in the surficial extent or rate of slope failure. Original mapping was completed by Golder (as noted by AAI, 1999) and later updated by AAI (1999) and SRK (2007). AAI (1999) notes possible minor movement across a tension crack, but a location or scale of movement is not provided. SRK (2007) reports no visual changes to the geometry or character of the tension cracks, and no new tension cracks when they updated the map. In August 2018, BGC performed a reconnaissance-level field-based visual inspection to assess the extent of surface deformation caused by slope failure along the eastern margins of the North and South pit slopes (BGC, 2019c). The findings from the inspection were: 1)the existing map of tension cracks and scarps appears to delineate the extent for most surface deformation caused by slope movement (excluding creep), but 2) some tension cracks and scarps were mapped outside the extent mapped by Golder (1995) as cited by Agapito (1999), AAI (1999) and SRK (2007) (Figure 3-16). These finding suggests that the scarps either formed since SRK (2007) updated the map, that these scarps were missed during the previous reconnaissance trips and site inspections by AAI (2000a) and SRK (2007), or 3)that the scarps are included in the map but are inaccurately portrayed. Depending on which is true, the implications could include a scenario EXHIBIT E-RULE 6.4 5(AMENDED RECLAMATION PLAN) Page 45 HOMESTAKE MINING COMPANY