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Prince Albert Mine 110(d) Permit Application Exhibit U - EPP <br />Structural erosion control features such as riprap, silt fence, and straw -bale or excelsior velocity -check <br />barriers will be implemented as needed to minimize erosion. The growth medium stockpile(s) will be <br />seeded with the specified BLM seed mix at an appropriate interval to reduce erosion and loss of material. <br />Direct precipitation surface drainage that accumulates within the affected area will be diverted into one of <br />four proposed detention ponds. One pond (Ore Pad Sump) is located directly down gradient of the ore <br />stockpile and is described under Section U (6.a.1) "Ore Stockpile ". The other three ponds (labeled North, <br />Central, and South Detention Pond on Appendix A, Attachment U.8.2, Exhibit U -1 "Overall Plan ") are <br />sedimentation ponds at three locations down gradient of potentially disturbed areas that are not ore <br />storage and handling areas. The sedimentation ponds are designed to contain the 10 -year, 24 -hour event <br />and will safely pass the 100 -year, 24 -hour event. The North Detention Pond, with a capacity of 4,624 <br />cubic feet, is located northeast and down gradient of the Primary Waste Pile and will collect runoff from <br />the Primary Waste Pile. The Central Detention Pond, with a capacity of 5,837 cubic feet, is located <br />northeast and down gradient of the mine portal and ore handling areas and will collect runoff that is <br />diverted around the ore storage and handling area and from the disturbed areas between the Primary and <br />Secondary Waste Piles. The South Detention Pond, with a capacity of 7,980 cubic feet, will collect run- <br />off from the Secondary Waste Pile and future maintenance / office location southwest of the Secondary <br />Waste Pile. These ponds will remain intact throughout the life of the active mine, and the initial period of <br />site reclamation, until adequate vegetation has been established over the newly disturbed areas. <br />U (8.b) Surface Water Containment and Diversion Structure Construction Schedule <br />The containment and diversion structures for surface water management at the Prince Albert Mine site <br />will be constructed under a series of operational milestones that include prohibitions against beginning the <br />next phase of operations until the construction schedule goals have been met for the current operational <br />phase. This type of schedule was developed instead of a strict timeline in order to allow for the necessary <br />flexibility required by a small mining operation and avoid a stringent timeline -based construction <br />schedule that must be met regardless of adverse weather or logistics problems. The construction schedule <br />is included as Attachment U.8.3 "Prince Albert Mine Surface Water Controls Construction Schedule." <br />U (8.c) Surface Water Containment and Diversion Structure Construction QA/QC <br />All surface water containment and diversion structures will be built to the specifications detailed in the <br />Appendix A, Attachment U.8.2, Exhibit U -1 through Exhibit U -5 construction drawings. The work will <br />be inspected in the field by a qualified person at each critical phase during the construction process. <br />Critical phases of construction are listed in Section U (8.d.1). The construction shall be certified as built <br />to design specifications by a professional engineer (preferably the engineer performing the certification of <br />the construction plans will also certify the field construction work). Any field modifications to the <br />Rimrock Exploration & Development Page 29 of 39 <br />