2012-09-21_INSPECTION - C1981019 (2)

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September 17, 2012 C- 1981 - 019 /Colowyo Coal Mine RDZ topsoil. A clinometer was used to measure the slope of part of the face; it was measured at 31 percent, which is in line with the design slope of 2.9:1 (H:V). Section 16 Fill and Streeter Fill were observed from afar, and no erosion or other problems were identified. EXPLOSIVES — Rule 4.08 Distance Prohibitions 4.08.4; Warnings 4.08.4; Control of Adverse Effects 4.08.4: A blast within FA overburden was observed in the South Taylor Pit. Safety precautions were in order including road blocks, radio communication, and sirens. After the shot, no noxious gasses were seen. FISH and WILDLIFE — Rule 4.18: A significant amount of bull elk bugling was heard near the Section 16 Pond. HYDROLOGIC BALANCE - Rule 4.05 Drainage Control 4.05.1, 4.05.2, 4.053; Siltation Structures 4.05.5, 4.05.6; Discharge Structures 4.05.7, 4.05.10; Diversions 4.05.4; Effluent Limits 4.05.2; Ground Water Monitoring 4.05.13; Surface Water Monitoring 4.05.13; Drainage — Acid and Toxic Materials 4.05.8; Impoundments 4.05.6, 4.05.9; Stream Buffer Zones 4.05.18: The following ponds were inspected: Rail Loop, Stoker Siding, Prospect, Streeter, West Taylor, East Taylor, Section 16, and Section 28. Stoker Siding, Streeter, West Taylor and East Taylor were discharging. The discharge water was clear for these ponds. No problems were identified with embankments, spillways, or other aspects of the ponds. Other observations concerning the ponds: • A delta is forming in the Rail Loop Pond. • The flume at Stoker Siding needs maintenance. • Stoker Siding Pond contains significant algae. • At the Section 16 pond, rills were observed on the embankment and should be monitored. • Prospect was being cleaned during the inspection, and West Taylor had been recently cleaned. • The flume below Section 28 Pond has some sediment that should be removed. • The flume below West Taylor is not optimum as the flow drops off at the end of the flume. The recent maintenance in Prospect Ditch was observed and appeared to be performed well (although it has not yet seen significant rainfall). The ditch was graded and erosion matting and straw booms (aka wattles) were placed in the channel. A contour ditch in the East Pit area requires maintenance. The following ditches were inspected and found to have no significant problems: upper end of the South Collection Ditch (114 +39 to approximately 102 +00), the Section 16 Fill Ditch, and the Section 16 Perimeter Ditch. The Section 16 Perimeter Ditch was deep along a 50 foot (approximately) reach, likely due to head cutting; Number of Partial Inspection this Fiscal Year: 3 Number of Complete Inspections this Fiscal Year: 1 Page 3 of 13