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INSPECTION OP EXCESS SPOIL DILL <br />Third Quarter 2004 Certification <br />Fill Area No. 8 <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 Gco-technical Reconmicndatiuns <br />Lorencito Surface Mine Phase 1" addresses the general requirements as also cited in Sections 4A9.1 lu <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 ofUnder-drains <br />Installation of Surface Drainage System <br />Construction of Fill <br />_Placement of Topsoil <br />-Seeding <br />X Other Maintenance <br />SEDIMENT CONTROL <br />Sediment pond construction has been completed in accordance with plmu 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 the fill area is directed to this sediment control ftcility also <br />known as Pond 8. A 100-yr 24-hr stone event occurred on August 5-6, 2004. "fhe pond discharged as a <br />result of this event with significant flow passing through the emergency spillway and over the embankment. <br />Both annoyed down-drains incurred significant erosion with the flow under-cutting the armoring and <br />eroding the sub-base. 1'he operator was in the process of reestablishing the drainage system at the time of <br />inspection. The channels had been repaired and rock was being placed as armoring in the west drain. Work <br />on the east drfatn had been completed. <br />SITE PREPARATION <br />As indicated by previous inspection reports, organic materials such as brush 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 #S). No evidence of springs or seeps was <br />observed during site preparation. <br />DRAINAGE SYSTEM (UNDERDRAINS) <br />Drain sizes are speci5ed by CDMO regulations for fills which can be classified as Valley Fills. Fill area !78 <br />is a valley fill. CTL Thompson recommended a minimum 6' x 12' triangular section(area = 64 SF) for this <br />size fill. Under-drain system was extended down slope to allow establishing the designed slope criteria for <br />the final slope (assuming no resumption of mining). 'fhe typical dimensions of the extended driinagc <br />generally were more trapezoidal with a top width of 10', bottom width of 14', and average height of R' (area <br />> 96 SF). Sandstone recovered from durable "Cliannel" sandstone deposits encountered during the mining <br />process were used in drain construction. Mirafi 160 fabric was used in lieu of filter material. <br />