Laserfiche WebLink
March 22, 2010 <br />1.0 Introduction <br />2 <br />In compliance with Rule 4.09.1 (11) of the Regulations of the Colorado Mined Land Reclamation Board <br />for Coal Mining, a quarterly inspection and report on the construction and associated activities of the <br />Horse Gulch Fill (HGF) at Trapper Mine in Craig, Colorado has been completed. The quarterly inspection <br />was conducted on March 17, 2010, by Seth A. Puls, a licensed professional engineer in the State of <br />Colorado. <br />Construction activity related to the fill has been consistent with the approved design. Details of this <br />design can be found in Agapito Associates, Inc.'s (AAI) Horse Gulch Fill Stability Analysis, dated May 29, <br />2009. <br />No appearances of instability, structural weakness, or other hazardous conditions were observed. <br />2.0 Critical Construction Periods <br />2.1 Removal of All Organic Material and Topsoil <br />Topsoil and organic material removal activities were not conducted during the first quarter of 2010. <br />2.2 Placement of Underdrainage Systems <br />Construction of the underdrainage system was completed in the first quarter of 2010. Construction <br />activities were limited to addition of rock fill to the main underdrain, in accordance with the approved <br />design and Section 4.09.2(2), and placement of filtration fabric. Mirafi 140N was used to cover the <br />completed sections of the main drain to prevent infiltration of fines into the drainage structure through <br />Station M-40. From Station M-40 to the termination of the underdrain at Station M-47, Mirafi 140NC <br />was used. Additional sediment control was accomplished through the use of roads and ditches along <br />either side of the channel. <br />The rock core was completed in the main drain from Station M-36 through its termination at Station M- <br />47. The total rock depth was checked to confirm construction to designed dimensions (see Photographs <br />1 - 10). This section was then covered with Mirafi 140N and Mirafi 140NC filtration fabrics (see <br />Photograph 11). Gravity separation of materials in the dump face provides additional filtration material <br />over the underdrain (see Photograph 12).