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INTRODUCTION <br />The original (proposed) location for Pond 005 was submitted to CNLRD on November 9, 1990 <br />as part of Permit Revision No. 1. Subsequently, in a memo dated May 23, 1991 from Bruce <br />Stover to Larry Routten, a number of concerns were raised raga rdin9 land stability in the <br />north mining block. These Concerns prompted CNLRD to issue approval of PR #1 with certain <br />stipulations. In brief, Stipulation No. 17 required Peabody to revise its design, <br />complete land form mapping, and include plans for geotechnical monitoring. Please see <br />Proposed Decision end Findings of Compliance for the Seneca 11-Y Mine, Permit C-82-057, <br />Permit Revision No. 1, September 4, 1991 for complete discussion regarding the <br />stipulation. <br />That stipulation prompted Peabody to contract the services of John Ivey of Amuedo and <br />Ivey, Inc. to map and investigate the landforms near the proposed facilities, and Dick <br />Suedkamp of Ground Engineering Consultants, Inc. to investigate the gcotechnical stability <br />of the area end assist in the embankment design. These reports can be found in <br />Attachments 13-3A end 13-38. Peabody conducted the hydrology and sedimerttology portions <br />of the pond design. This information can be found in Attachment 13-3. As a result of <br />~. these investigations, the final location for Pond 005 is shown on Exhibit 13-2 and <br />described as located in the NY1/45Y1/4 of Section 10, Township 5 North, Range 88 Yest in a <br />tributary to Dry Creek (referred to in some sections of the report as Pond 005 Gulch). <br />Sediment Pond ODS was designed and constructed in accordance with the criteria set forth <br />in 4.05.6. The primary function of the pond is to control sediment from the mine <br />disturbance area. Surface runoff not requiring treatment is diverted around the pond. <br />According to the definition of a sedimentation pond (1.04(115)), this structure does not <br />meet either the State Engineer's requirements or those set forth by MSNA. <br />The embankment for Pond 005 was designed in accordance with 4.05.6(11). Due to the <br />saturated condition of the foundation at least part of the year, the embankment was <br />constructed with a horizontal drainage system. A toe drain was installed that will <br />collect the water end discharge it below the toe of the embankment. This system is <br />designed to act as controlled seepage through the embankment. <br />Although a temporary impoundment, the pond and embankment was constructed to the <br />prescribed standards for a permanent impoundment structure. The primary purpose of the <br />13.3-1 Revised 08/11/92 <br />