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additional information and engineering reports. As for the web and barrier pillar <br />designs, Exhibit 21, Item I Second Letter, Page 2 of the permit states "The <br />highwall mining configurations (web widths, barrier pillar criteria, extraction <br />ratios, etc.) were designed by Agapito Associates, Inc. (AAI) in their report, <br />"Geotechnical Design and Operational Considerations for Hgghwall Mining, West <br />Pit South, F12 and E2 Seams": <br />3. In the first paragraph of the Agapito report it is stated that "...no critical <br />structures overlie the planned mining. We further understand that a power line <br />on the ridge overlying the highwall mining panels will be relocated, so no <br />protective measures are required. " A review of Map 22A- Existing Structures <br />South Area, however reveals that there is a 345 kV power line that will be <br />undermined by the proposed highwall mining. The Agapito report states there <br />will need to be "protective measures" to ensure that there is no impact to the <br />power line. Since the power line is located above the proposed highwall mining, <br />please provide the Division with a narrative of the protective measures to be <br />employed to ensure there is no impact to the power line. These protective <br />measure needs to be more than a general statement that the proper measure will be <br />taken to ensure that there is no impact to the power line, please describe the <br />specific protective measures that will be undertaken. A change to the text in the <br />South Taylor portion of the permit as well as an engineering report or similar <br />study will be necessary. <br />Response: The 345kV line in question is located in the northwest area, which is <br />not being mined at this time. Colowyo will address this when and if this area is <br />mined. <br />4. The Agapito report states that they recommend Colowyo use the design curves i.'or <br />web pillar design, barrier pillar design and recovery presented in Figures 23a <br />through 23c, which are attached to their 13 April 2007 report, due to the highwall <br />mining's proximity to drill holes WP-05-08. This statement and these figures are <br />important as the design of web and barrier pillars (based on pillar width and <br />depth) is critically important to the zero subsidence plan. The Division would like <br />to see a reference to these Figures in the text as it related to the zero subsidence <br />plan for highwall mining in the South Taylor Pit. <br />Response: References to the Agapito report are located in Exhibit 21, Item 1 <br />Second Letter, Page 2 of Colowyo's permit. <br />Colowyo has provided a letter from Shannon and Wilson, Inc. (Shannon), dated <br />21 November 2008, that states, "...the highwall mining will not significantly <br />affect the spoil foundation conditions and should not reduce the global stability of <br />the spoil fill." This general statement was based on their review of the Agapito <br />reports for highwall mining and the design criteria for web and barrier pillars. <br />The information that Shannon reviewed was also exclusively for the E-Seam <br />highwall mining evaluated in the Agapito study. As with question 1 above, if