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It is unclear to DRMS from the provided documentation if a new emergency spillway will be <br />built for Pond MN6 or if the current approved spillway design will stay in place. Upon review of <br />Appendix C, the Design Drawings for a spillway 40 feet wide is shown in Drawing #4. It is <br />unclear what spillway this desing informs and where it is located. There are no design details for <br />the Agri Drain System. The text references a series of assumptions, and the inset Figure 4-4 is <br />Appendix C, the Design Drawings for the a spillway 40 feet wide is shown in Drawing #4. It is <br />unclear what spillway this desing informs and where it is located. There are no design details for <br />the Agri Drain System. The text references a series of assumptions, and the inset Figure 4-4 is <br />illegible. It is unclear what the time frame for pumping to the Agri Drain System is. The <br />pumping schenario has implications for the sizing of the receiving pond, 6MN Pond, and pond <br />capacity in a storm event. <br />a. Does Appendix G; Foidel Creek 6MN Mine Water Storage and Stormwater Design Basis negate <br />and replace the document and exhibits (Exhibit 49EE-F1, Exhibit EX49-172), referenced in <br />adequacy questions 10 and 11? <br />b. Please provide design details and sizing for the Agri Drain. <br />c. Will pumping to the Agri Drain system be continuous? <br />d. What if any maintenance is anticipated to assure the Agri Drain functions as designed. <br />e. A gpm of 357 is suggested through the Agri Drain. Is this a historic number based on operational <br />procedures up to this point or, is this a number based on new or expected operational changes? <br />f. Is the expectation that the pump is to be turned off once the water surface elevation reaches the <br />elevation of the permanent pool? <br />g. Terminology is confusing regarding the 6MN Pond. There are references to the 6MN Pond and <br />the 6MN Pond 2. Please clarify and make terminology consistent between all documents <br />including maps and text. <br />h. DRMS was unable to locate the following information associated with the spillway in <br />Drawing #4 of the Details page <br />o Crest length <br />o Sideslope ratios for left and right slopes <br />o Spillway crest elevation <br />o Spillway location <br />Please update the Details page of the drawing packet to include the above mentioned <br />spillway details. <br />As per question 10 above, it is unclear to DRMS if a large portion of the 119.09 acre area <br />watershed will be diverted directly into the 6MN Pond utilizing the "south" and "north" diversion <br />ditchs around the proposed passive treatment system. Per the SedCAD submission, the Pond <br />curently accepts runoff from 17 acres. However, the title page suggests "the watersehd runoff'. <br />i. Please verify if 17.13 acres will continue to be routed to the pond and if 119 acres will be <br />routed around the pond. <br />j. quantify the water shed size (provide a map indicationg watershed boundaries and calling <br />out the watershed areas) <br />k. Please provideSedCAD modelling for: <br />o the North and South Ditches <br />o cascade crossection <br />1. Please provide design details for: <br />o the North and South ditches <br />o the spillway between the cells <br />