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designs are provided in Appendix 13 -12.3 of the PAP. Postmine channels are designed to safely convey
<br />the peak discharge from the 10 -year, 24 -hour storm event in accordance with Rule 4.05.3.
<br />In the North Pit area, a section of Postmine Drainage Channel PM -10, and the entirety of PM -11, PM-
<br />21, PM -21B, PM -9, and PM -13 were included in SL -2. PM -9 and PM -13 drain east to Sediment Pond
<br />11 adjacent to Grassy Creek, while the other channels with the exception of PM -11 drain into Annand
<br />Draw (PM -11 is actually a short segment of Annand Draw drainage that was impacted by road
<br />construction and erosion, and subsequently reconstructed). The drainage segments noted in the North
<br />Pit area, with the exception of PM -11, had been evaluated as a part of the SL -1 bond release, but were
<br />excluded from the Division's SL -1 approval due to erosional stability concerns.
<br />A large number of permanent channels were constructed within the Neck Pit and South Pit areas. The
<br />channels were included in the SL -2 application, and have been evaluated by the Division for erosional
<br />stability and compliance with approved designs, as a part of the SL -2 review.
<br />Neck Pit area drainages PM -22, PM -16, and PM -20 drain into Annand Draw, as do PM -8 and PM -15,
<br />which drain the northern portion of the South Pit Area. All of these drainages were included in the
<br />SL -2 application. Sediment Pond 010 is located on Annand Draw, downstream of all pit area
<br />disturbance in the watershed.
<br />The largest watershed in the South Mine Area drains into Pond 012, which discharges to Grassy
<br />Creek. Designated channels in the watershed include PM 1 -1, 1 -2, 1 -3, 6 -1, PM -2, 18, 19, PM -7, 7A,
<br />6 -2, 6 -2A, 5 -1, and 54A. All of these channels drain into Pond 012A, constructed upstream of Pond
<br />012 to provide additional sediment control in the watershed. All of the drainages listed, with the
<br />exception of PM -6 -2, were included in the SL -2 release request. PM -6 -2 extends from the confluence
<br />of PM -6 -1 and PM -7 down to Pond 012A, and channel construction has not yet been completed along
<br />the drainage. The lower -most portion of the watershed, including PM -6 -3 and adjacent slopes down
<br />to Pond 012, was not included in the SL -2 application, due to a slide area on the slope northeast of
<br />Pond 12. Slide remediation and final reclamation in the Pond 012 vicinity was delayed to allow for
<br />completion of hydrologic and geotechnical investigations and remediation plan development. The
<br />remediation plan was submitted to the Division in February 2010 and is under review.
<br />Two smaller watersheds are located in the southwestern portion of the South Pit area. The southern
<br />of the two drains to Pond 14 and includes PM -3 -1, PM -3 -1A, PM -3 -2, PM -3 -2A, and PM -14. The
<br />final watershed drains to Pond 13, and includes PM -4, PM -4 -1, PM -3 -2,
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