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<br />10. Response: Not applicable, concerns the P and J'seams.' ' <br />2.05.3(3)(c)(i) Road Drainage <br />Response: Paragraphs 1, 2, and 3 all deal with Northern 270. 2 and No. 3 <br />developments. As such we have not addressed them in this response. <br />4. A 54-inch CSP culvert is proposed at the location where the disposal road <br />• .crosses a discharge drainage way from the sediment pond. This culvert must be <br />sized for the 25-year, 24-hour discharge since the end area is greater than 35 <br />square feet. However, no calculations have been provided to assure the culvert <br />design is adequate. Please provide this information. <br />Response: A 54 inch diameter culvert has 15.9 sq. feet, which is less than the <br />35 sq. feet cited in the above question. Additionally, in the submittal <br />correspondence of October 14, 1980 on the refuse facility, it shows that a 30 <br />inch culvert was installed instead of the 54 which was projected in the June <br />1980 Mine Plan Application. This was approved by the State and OSM and calculations <br />for the 30 inch culvert appear in Section 2 of the Oct. 14, 1980 submittal on the <br />refuse area. <br />2.05.3(4) Ponds, Impoundments and Diversions <br />Northern No. 1 (FF-Seam) Mine <br />1. At the termination of mining how does the applicant propose to maintain the <br />sediment control structures? Specifically, since the ponds are dewatered manually <br />who will be available to open the gate valves on ponds after a story event? <br />Would it be possible to leave the valves partially open to allow for dewa[ering <br />and still achieve the required detention time? <br />Resoonse: The land upon which the FF mine is located is owned by a private land <br />owner in fee. Discussions, to date, with [hat land owner, while not having been <br />formalized, have revolved around the idea of a surface owner maintaining the <br />improvements which iorthern leaves upon his land. We would expect to make such <br />