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A *130, 2013 C- 1992 - 080 /Carbon Junction Mine MLT <br />Reconstructed Carbon Junction Drainage <br />The team observed numerous issues with the disturbed portion of the Upper Carbon Junction <br />Channel, located upstream of the riprapped permanent diversion channel: <br />• An erosional gully, approximately six feet deep, has formed at the downstream terminus of <br />the diversion berm. <br />• Sediment generated by this erosion has created a physical barrier to the flow of the channel, <br />and would result in flow being ponded upstream of the sediment fan. <br />• The un -named tributary channel that enters the Carbon Junction drainage from the east is <br />confined behind the diversion berm, rather than being allowed to flow directly into the main <br />drainage. This would potentially contribute to continued erosion of the gully. <br />• At the location where the diversion berm was breached in the fall of 2012, the profile of the <br />channel is significantly steeper than what exists both upstream and downstream. Head - <br />cutting of the channel could potentially result from this nick point. <br />• The Lower Sump identified on the Mine Hydrology Map appears to have filled with <br />sediment, and the site is now populated by narrow -leaf cottonwoods and willows. <br />• Approved designs for this segment of the Carbon Junction Channel could not be located. <br />• The Mine Hydrology Map approved with TR -11 clearly shows that Carbon Junction was <br />diverted just downstream of the lower slope of the North Pit, and that flow was to be restored <br />to the original channel. Additionally, this map shows that the natural channel upstream of <br />the diversion was affected by the disturbance of the North Pit. <br />• The Division had identified some of these issues last year. In an August 29, 2012 letter to <br />Oakridge, the Division had requested that a Minor Revision(s) be submitted to address these <br />issues. However, due to number and complexity of items now involved, a Technical <br />Revision will be required, as set forth in the Abatement Steps below. <br />Number of Partial Inspection this Fiscal Year: 2 <br />Number of Complete Inspections this Fiscal Year: 3 Page 4 of 7 <br />