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INSPCCTION OF EXCCSS SPOIL PILL <br />Third Quarter 2004 Certification <br />Fill Arca No. 7 <br />Date: September 30, 2004 <br />GENERAL DESCRIPTION OR REFERENCE TO SITE PLAN: <br />The CTL Thompson report dated April 27, 2001, "Stability Analysis and Geo-technical Recommendations <br />Lorencito Surface Mine Phase 1" addresses the general requirements as also tiled in Sections 4.09.1 to <br />4.09.2 of the Colorado Mined Land Reclamation Board for Coal Mining. <br />ACTIVITY DURING INSPECTION: <br />Removal of Topsoil and Organic Matter <br />Placement of Under-drains <br />Installation of Surface Drainage System <br />Construction of Fill <br />Placement of Topsoil <br />Seeding <br />X Other None, (noted that tnain[enance had occurred durink the Quarter). <br />SEDIMENT CONTROL <br />Sediment pond construction has been completed in accordance with plans submitted to and approved by the <br />DMG and as-constructed survey/drawings certified by Registered Land Surveyor and Registered <br />Professional Engineer All surface run-off from [he fill area is directed to this sediment control facility <br />known as Pond 7. A 100-yr 24-hr storm event occurred on August 5-(, 2004. No significant erosion <br />occurred to this facility as a result of the storm and no erosional problems were noted during this inspection. <br />The pond discharged as a result of this event with some how passing through the emergency spillway. <br />SURFACE DRAINAGE <br />Armored Ditches line the east and west boundary of the fill arcs. Lateral ditches on the fill lace direct <br />runoff to these side ditches. A fourth east-west ditch was constructed at the upper most extent of the fill, <br />connecting [o both armored ditches on the east and west perimeters. Some of the large rock armouring the <br />down drains was displaced 6y the August storm event. 'I"his rock has since been redistributed returning the <br />channel profile to design configuration. No erosional problems were noted at the intersections of the lateral <br />ditches and the armored ditches. <br />SITE PREPARATION F . <br />As indicated in previous inspection reports, organic materials such as bnish and Trees were removed from <br />the proposed fill area followed by topsoil removal prior to fill placement. Design criteria did not require <br />keyway cuts for steeper valleys with minimal soil cover (fill #7). No evidence of springs or seeps was <br />observed during site preparation. <br />DRAINAGE SYSTEM (UNDERDRAINS) Drain sizes are specified by CDMG regulations for fills which <br />can be classified as Valley Fills. Fill area #7 is not a valley fill. CI'L'I'hompson a~ecommended a minimum <br />6' x 12' triangular section (area = 64 SF) for this 'size (ill. As indicated by previnus inspection reports, as <br />constructed drainages generally were more trapezoidal with a top width of 12', bottom width of 8', and <br />average height of 8' (area = 80 SF). Sandstone recovered from durable "channel" sandstone deposits <br />encountered during the mining process was used in drain construction. Mirafi 160 fabric was used in lieu of <br />Flter material. <br />