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<br />COLORADO YAM PA COAL COMPANY <br />CERTIFICATION INSPECTION FOR DRAINAGES <br />DATE OF INSPECTION July 29, 1988 <br />INSPECTION ACTIVITIES <br />o Rechecked grade for Drainages 31-1 and 31-2 <br />o Checked grade and channel dimensions for Drainage 41 <br />FINDINGS <br />o Dra_ ij 31-1 had been regraded to a uniform rade. Spot <br />checks along the 640' channel length indicate a maximum <br />gradient of 15.6%. This is considered acceptable, being <br />within +0.5% of the design gradient of 15.3%. <br />o Drainage 31-2 had been regraded to a uniform grade. Spot <br />checks along the 310' channel length indicate a maximum <br />gradient of 21.0%. This is considered acceptable, being <br />within -2.0% of the design gradient of 21.6% (A flatter <br />gradient of up to 2.0% is acceptable). <br />o A check of the upper 200' of the channel indicated a maximum ~~I <br />gradient of 22.0%. This is considered acceptable, being. <br />within -2% of the design gradient of 23.7%. Measured top and <br />bottom channel widths were 12.7' and 26' respectively. Bottom <br />channel width was noted as being acceptable, however, top <br />width needed to be increased. <br />CORRECTIVE MEASURES NOTED <br />o Pull sideslope on Drainage 41 back to increase <br />r- <br />design. <br />~- <br />