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Name of Addressee <br />Page 2 <br />Date <br />Based on the approval of Minor Revision No. 177 associated with, C- 1996 -083, the disturbance <br />area boundary has been revised to reflect the current on- the - ground conditions. The proposed <br />Map 18 does not reflect the current disturbance area boundary as approved under MR -177. <br />Please revise the proposed Map 18 to reflect the proposed disturbance boundary to include <br />what is approved. <br />5. Proposed Map 22 -D provides cross sections for the Embankment Spillway of Pond C and the <br />Emergency Spillway for Pond C. No spillway cross sections were included as a part of the <br />proposed Map 22 -D Pond D designs. Please submit design cross sections of the Pond D <br />spillways or revise Map 22 -D to include the information of the Pond D Spillways. <br />6. The cover letter for TR -98 states that the points on the hillside are being graded to generate <br />material for final reclamation at gob pile #2 and provides a final slope angle for the three borrow <br />areas. The Division was unable to identify a discussion in the proposed text or figures which <br />would provide information concerning compliance with Rules 4.14.1 and 4.14.2. Rule 4.14.2(1) <br />states that the final graded slopes shall approximate pre- mining slopes or any lesser slopes <br />approved by the Division based on consideration of soil, climate, or other characteristics of the <br />surrounding area. In order for the Division to make a determination that the proposed post - <br />mining final graded slopes are approximate in general to the pre- mining topography, please <br />provide information discussing the grading plans associated with Borrow Area 1, 2, and 3 to <br />incorporate into the proposed text of the PAP. Please also submit a figure or an addition to a <br />figure that identifies the post- mining topography and cross sections of the post mining <br />topography of the borrow areas. <br />In a report dated July 29, 2013, submitted with TR -81, BRL's geotechnical consultant analyzed <br />the stability of a proposed expansion of Gob Pile #2. Results for Sections A -A' and F -F' were <br />presented, showing that the minimum static Factor of Safety (FoS) of 1.5 could be achieved. <br />With TR -98, a somewhat different configuration for the pile is being proposed, and although the <br />peak elevation will not change, the thickness of material proposed for placement along the axis <br />of the original valley is increasing (as shown on revised Section E -E' of Volume IX Figure 1). <br />Material parameters utilized in 2013's TR -81 analysis differ slightly from those used in later <br />analyses (for TR -84, MR -171, and TR -94) which were conducted by a different geotechnical <br />consultant. Please analyze the stability of the proposed configuration depicted on Section A- <br />A' of Volume IX Figure 1, to determine whether a minimum static safety factor of 1.5 can be <br />achieved, in accordance with 4.10.4(2). If material properties used in this new analysis <br />differ from those assumed in the recent revisions listed above, please provide a justification <br />for the change, such as the coal mine waste's being blended with coverfill material to reduce <br />the moisture content. <br />8. During the Division's 2014 review of TR -89, the question was raised whether a stability analysis <br />for ditch side slopes / borrow areas was needed, where cut slopes of 1.5h:1v were proposed. <br />