Laserfiche WebLink
Name of Addressee <br />Page 3 <br />Date <br />Division Response: Proposed Map 22-D was revised to reflect information associated with Pond <br />D. <br />This item has been adequately addressed. <br />6. Division Initial Comment (3/11/2015): The cover letter for TR -98 states that the points on the <br />hillside are being graded to generate material for final reclamation at gob pile #2 and provides a <br />final slope angle for the three borrow areas. The Division was unable to identify a discussion in <br />the proposed text or figures which would provide information concerning compliance with Rules <br />4.14.1 and 4.14.2. Rule 4.14.2(1) states that the final graded slopes shall approximate pre - <br />mining slopes or any lesser slopes approved by the Division based on consideration of soil, <br />climate, or other characteristics of the surrounding area. In order for the Division to make a <br />determination that the proposed post -mining final graded slopes are approximate in general to <br />the pre -mining topography, please provide information discussing the grading plans associated <br />with Borrow Area 1, 2, and 3 to incorporate into the proposed text of the PAP. Please also <br />submit a figure or an addition to a figure that identifies the post -mining topography and cross <br />sections of the post mining topography of the borrow areas. <br />BRL Response: Slopes in the vicinity of borrow areas 1-2 vary from 1.2H:1 V to 4.5H:1 V. The <br />proposed final slope angles are 2H:1V. The natural angle of repose for most native materials in <br />the area of the gob pile #2 is 1.5H:1 V. Please see a discussion about the borrow areas on Page 8. <br />New Figure 5 has been created detailing the locations of borrow areas 1-2 and showing cross <br />sections for each borrow area. <br />Division Response: A discussion including information associated with the grading plans of <br />Borrow Areas 1 and 2 have been included on proposed page 8. In addition, Figure 5 has been <br />submitted identifying the locations, and cross sections of Borrow Area 1 and 2. These items have <br />been reviewed per Rules 4.14.1 and 4.14.2. <br />This item has been adequately addressed. <br />Division Initial Comment (3/11/2015): In a report dated July 29, 2013, submitted with TR -81, <br />BRL's geotechnical consultant analyzed the stability of a proposed expansion of Gob Pile #2. <br />Results for Sections A -A' and F -F' were presented, showing that the minimum static Factor of <br />Safety (FoS) of 1.5 could be achieved. With TR -98, a somewhat different configuration for the <br />pile is being proposed, and although the peak elevation will not change, the thickness of <br />material proposed for placement along the axis of the original valley is increasing (as shown on <br />revised Section E -E' of Volume IX Figure 1). Material parameters utilized in 2013's TR -81 analysis <br />differ slightly from those used in later analyses (for TR -84, MR -171, and TR -94) which were <br />conducted by a different geotechnical consultant. Please analyze the stability of the proposed <br />configuration depicted on Section A -A' of Volume IX Figure 1, to determine whether a minimum <br />