Laserfiche WebLink
The Division has approved the use of vegetation and organic material <br />as mulch or as an amendment to topsoil to control erosion, promote <br />growth, or increase moisture retention. C4.09.1(4)). <br />The Division has approved of the location of the disposal area. <br />(4.09.1(6)). <br />The applicant has proposed an alternative method for disposal of <br />excess durable rock by gravity placement in single lifts. The <br />alternative method is certified by a qualified registered <br />professional engineer as resulting in a fill which will be stable <br />and will meet all other applicable requirements, including <br />Rules 4.09.1 and 4.09.3. The excess rock spoil consists of at least <br />80X by volume, durable non-acid and non-toxic forming rock that does <br />not slake in water and will not degrade to soil material. The fill <br />is designed to attain a minimum long-term safety factor of 1.5 and <br />an earthquake safety factor of l.l. Surface water runoff from areas <br />adjacent to and above the fill shall be diverted away into <br />stabilized channels designed to meet the requirements of 4.05.3 and <br />safely pass a 100-year, 24-hour precipitation event. Therefore, the <br />Division has approved use of the alternative method for rock <br />disposal. (4.09.4). <br />Construction of the underdrain and placement of fill was completed in <br />August 1987. At that time, inspection reports regarding construction of <br />the underdrain were conducted by Peabody Coal Company. Submittal of <br />those reports was in compliance with Stipulation No. 4 of the 1987 <br />permit. Therefore, that stipulation is no longer required on the <br />permit. Final reclamation of the fill will commence at the end of <br />mining, when the adjacent Road A2 is no longer in use. Quarterly <br />inspections of the fill will be conducted by Peabody during reclamation <br />activities and for at least one year following revegetation. <br />Additional information on the excess spoil fill is located in Tab 12 of <br />the permit application. <br />VII. Backfilling and Grading <br />Details of the backfilling and grading plan at the Seneca II Mine are <br />found in Volume 12, Tab 13 of the permit application. A backfilling and <br />grading timetable is presented on Exhibit 13-2, also in the permit <br />application. The following findings were made regarding backfilling and <br />grading practices at the mine: <br />The applicant has requested additional time for backfilling and <br />grading following coal removal in an area strip mine. A detailed <br />written analysis under 2.05.4(2)(c) has demonstrated that additional <br />time is necessary based on coal production rates. Therefore, the <br />Division approved the additional time for these areas: Auger Area E, <br />Wolf Creek and Wadge pit areas, and the non-coal waste disposal <br />site. Auger Area E will be left open for use as a portal faceup for <br />underground mining of the Cow Camp Creek reserves. If not used in <br />the underground operations the area will be reclaimed at the close <br />of surface mining activities. The Wolf Creek and Wadge pit areas <br />will not be reclaimed within 180 days of initial disturbance, but <br />will be regraded within 4 spoil ridges of the active pit. This <br />delay is necessary because of production rates and pit sequencing. <br />-30- <br />