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Prince Albert Mine 110(d) Permit Application Exhibit U - EPP <br />U (8) Surface Water <br />There are no perennial or intermittent streams on the Prince Albert site. Two ephemeral drainages exist, <br />one on the east side of the affected area and one on the west side of the affected area. These drainages <br />flow only during storm events and possibly during the peak snow melt. The mine portal location and <br />affected area boundary were sited between these drainages so that runoff from storm events and snow <br />melt could be routed around the disturbed area and site facilities with minimal impact to surface water <br />resources (see Figure U.8.1 "Existing Drainage Map "). Ephemeral flow direction is to the east and <br />northeast, down the steep slopes below the mine permit area and to the San Miguel River approximately <br />one mile away. <br />Surface water bodies within 2 miles of the proposed mine site are stock watering ponds located over one <br />mile away, and the San Miguel and Dolores Rivers (see Exhibit A, Figure A.1 "General Location Map "). <br />Water quality sample results for the five quarters of record are attached as Exhibit U, Appendix A, <br />Attachment U.8.4 (Water Quality Sampling San Miguel / Dolores River Confluence 2009 — 2010"). <br />The planned permit area was surveyed (Pierce, 2010) and no springs or seeps were found within the <br />planned permit boundary or within 2 miles of the proposed mine site. <br />U (8.a) Surface Water Containment and Diversion Structures <br />Operations at the Prince Albert Mine site should have very little effect on surface water resources. On -site <br />storm -water control structures and best management practices for any site runoff that may be impacted by <br />mine operations are designed to prevent contaminants from entering the local ephemeral drainages in <br />concentrations that exceed the Water Quality Standards for the local San Miguel River segment (see <br />Table U.8.1 "San Miguel River Segment 5 Water Quality Standards "). These control structures and best <br />management practices are detailed in the Exhibit U, Attachment U.8.2 engineering drawings labeled <br />Exhibit U -1 through U -5 and in the Stormwater Management Plan included as Exhibit U, Attachment <br />U.8.1 "Prince Albert Mine Stormwater Management Plan (SWMP)." <br />The disturbed areas of the mine site are bounded on both the southeast and northwest sides of the affected <br />area by existing natural drainages. Surface drainage from undisturbed areas up slope from the areas that <br />may be disturbed during mining operations will be diverted into these drainages and around the disturbed <br />areas using constructed ditches, berms, water bars and swales. These diversions will eliminate most, if <br />not all, of the direct run -on of surface water from undisturbed areas into the areas disturbed by mining <br />activity and significantly reduce the potential for surface water contact with toxic materials. Surface <br />drainage from disturbed areas around the ore storage and handling location and current storage and <br />maintenance area will be diverted around these areas and into sedimentation ponds. Direct precipitation <br />runoff in the ore storage and handling area and current storage and maintenance area will be diverted to a <br />sump location (see Section U (6.a.1) "Ore Stockpile "). All diversion structures are designed for a 100 - <br />year, 24 -hour storm event. Ditches, swales and berms will have a maximum side slope of 2H:1 V. <br />Rimrock Exploration & Development Page 28 of 39 <br />