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10 <br /> <br />10 <br />Trapper Mine PR8 Preliminary Adequacy Review <br />Prepared by: R. Reilley July 2017 <br />DRMS received the following Pond Designs as per rule 4.05.6(4) with the PR8 application: <br />o Deacon Drainage, 25 year, 24 hour event a design for two proposed sediment ponds <br />o Deacon Pond 1, Embankment and Spillway Configuration and Stage Storage Curve <br />o Deacon Pond 2, Embankment and Spillway Configuration and Stage Storage Curve <br />o Deal 2, Pond Design 25 year, 24 hour event <br />o Deal 2, Pond Embankment and Spillway Configuration and Stage Storage Curve <br />o Jeffway Pond 1, 25 year, 24 hour event; a design for one of two proposed sediment ponds <br />o Jeffway Pond 1, Embankment and Spillway Configuration and Stage Storage Curve <br />o Jeffway Pond 2, 25 year, 24 hour event; a design for one of two proposed sediment ponds <br />o Jeffway Pond 2, Embankment and Spillway Configuration and Stage Storage Curve <br /> <br />July 2017 DRMS <br />DRMS notes that pond designs contain the 25 year 24 hour event and comprise a single open <br />channel spillway. Also, that two curve numbers were employed, one for disturbed and another for a <br />different classification of land use. It is unclear form the information and mapping provided where <br />in the watershed the two different land uses should be delineated and thus where these sub <br />watersheds should be delineated. It is also unclear where various structures (currently Null) would <br />be located. DRMS infers that some of this information would become more clearly defined once a <br />mine plan is put forward and would review additional pond design details at that time. From the <br />Map submitted (Map 51), it is not clear which pond is pond 1 and which is pond 2 for both Deacon <br />and Jeffway ponds. Spillways and ponds appear to be adequately designed, however DRMS would <br />appreciate additional subwatershed details to fully assess the designs submitted. DRMS notes the <br />missing information on Table 4.8-7, that work is underway to provide the missing design <br />information and that the information will be presented in a forthcoming revision. This aspect of the <br />Rules is adequately addressed in the permit with the exception of: <br /> <br />14. There is no indication that these designs were prepared by, or under the direction of a <br />registered professional engineer as per Rule 2.05.3(4)(a)(i) A. <br />15. Please describe the operation and maintenance requirements for each proposed structure; <br />as per Rule 2.05.3(4)(a)(ii) C, or indicate where this is information resides in the permit. <br />16. Please advise DRMS if any stream channel diversions, beside the Deal Channel are planned <br />for this expansion area. <br />17. Please advise DRMS if these ponds should be considered permanent impoundments. <br />18. As per Rule 4.05.9 9(d), if these ponds are expected to be permanent, please demonstrate <br />that no diminution of water quality or quantity to water right holders will ensue. <br />19. Without a mine plan DRMS finds it problematic to adequately assess the models provided <br />for the additional sediment ponds. Please provide subwatershed delineations for expected <br />disturbed and undisturbed areas. <br />20. Modelling for the Deal channel lacks a freeboard value. This value is required as per Rule <br />4.05.3(7)(b) <br />21. Modeling for Deacon Ponds does not differentiate between pond 1 and pond 2. <br /> <br />Rule 2.05.3(5) Topsoil <br /> This aspect of the Rules is adequately addressed. <br /> <br />Rule 2.05.4 Reclamation Plan