Laserfiche WebLink
<br /> <br />Tab 16 and 17 <br />53, A response for Items 1 and 8 listed in the Division's <br />59. June 7, 1995 letter is included here per PWCC's <br />conversation with the Division (Larry Routten) on June <br />14, 1995. Certain issues related to the PHB and PHC <br />for the life-of-mine operations in the Sage Creek basin <br />(Items 2 through 7 and forthcoming CDMG comments) will <br />be resolved at a later date. <br />Item 1: Attachment 16-3 of Tab 16 has been revised to <br />address AVF's in hydrologic communication with the <br />Yoast Mine. Discussions related to Hubberson Gulch was <br />deleted. <br />Item 8: Attached 17-5 of Tab 17 has been revised to <br />include units (eg. tons/day) for the numbers contained <br />in the equations listed. In addition, the attachment <br />was revised to include more explanations regarding how <br />the input values for each of the equations were <br />derived. Finally, the attachment was revised to <br />introduce and explain both the chemical load (L) and <br />resultant TDS (DSC) equations. <br />Tab 20 <br />70. The original question the Division had was to provide <br />additional information supporting our design for the <br />reclaimed drainage calculations. The SCC channel was <br />to carry 3.51 cfs, while the Division's model estimated <br />the flow to be 20.15 cfs. In the follow-up letter <br />dated April 27, 1995, the response was CDMG had not <br />received the supporting information for the postmine <br />drainage channel. This input information and the <br />resulting SEDCAD+ output calculations are now included <br />in Attachment 20-1. The following table shows the <br />comparison between the SCC and the Division model for <br />the reclaimed postmining drainage channel. <br /> SCC CDMG* <br />Watershed Acres 94.76 98.00 <br />Curve Number 70 70 <br />Time of Concentration (hrs) 0.402 0.363 <br />Runoff Volume (ac-ft) 3.59 3.34 <br />Peak Discharge 21.23 20.15 <br />Storm (100 yr, 24-hr) (ins) 2.5 2.4 <br />*The SEDCAD+ run was included with the January 20, 1995 <br />letter. <br />The watershed size is included in Table 20-3 on Page 11 <br />of Tab 20. The curve number of 70 can be found on Page <br />8 of Tab 13 in Table 13-1, under the category of <br />6 <br /> <br />