Laserfiche WebLink
adsorption ratio. The six lithologic units identified for the New Horizon 2 study area are very <br />• similar to previous lithologic units formulated for Mine Areas 2 and 3. As discussed in the <br />Mixing and Mitigation of Marginally Suitable to Unsuitable Material section and Section <br />2.05.4(2)(d), Topsoil (Redistribution), only pH and acid-base potential will impact overall spoil <br />suitability. In most instances, avoidance and normal overburden mixing will effectively dilute <br />and mitigate potentially inimical zones as documented in Attachment 2.04.6-3 (previously <br />Peabody Appendix 6-5). <br />The major or significant concern within the New Horizon 2 study area is the active and potential <br />acidity associated with lithologic Units 2 and 4. Sodium concentrations (SAR) are unsuitable in <br />the southwestern portion of the study area, however, these areas will not be disturbed by <br />mining. Approximately 83 percent of the overburden and interburden strata, predominantly <br />consisting of Units 1 and 3, is classified as suitable and would be potentially available as a top <br />dressing medium. <br />Additional Exploration Drilling <br />• As approved via a technical revision in September, 1992, twelve exploratory holes were drilled <br />in order to better define the crop/subcrop boundary. The holes averaged 50 feet in depth, and <br />were 5-1 /8" in diameter. See Map 2.04.6-6 for the hole locations and access. <br />During 1993, Western Fuels-Colorado, drilled 35 coal exploration holes,(fourteen of which were <br />core drilled) in lands adjacent to the New Horizon 2 mine area. This new data as well as the <br />existing data provide the geologic information for mine planning for this permit revision. Details <br />of the Peabody drill holes are included in Attachment 2.04.6-1. Data and current status on the <br />post-Peabody holes is contained in Attachment 2.05.3(3)-10. All drill holes from the Peabody <br />time period to the present are shown on Map 2.04.6-7. <br />L J <br />REVISED August 2006 2.04.6-44 <br />