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J. J. Dudash -4- April 25, 2007 <br />shaft construction, please comment on the possibility of TR-47 activities, including <br />temporary road closures or flyrock hazards, interfering with Oxbow Mining operations. <br />BRL: In the area where the vent shaft will be constructed and installed, Oxbow <br />Mining does not have any surface activities or facilities that will be impacted. As <br />mentioned in adequacy item number 8, workers will be stationed above and <br />below the blast site on Hubbard Creek road to temporarily stop traffic during <br />blasting, so if for some reason Oxbow is on Hubbard Creek Road, they may <br />temporarily be inconvenienced by having to wait for the blasting to occur. <br />Rule 4.03 -Roads <br />12. DRMS: The Division's review of the haul road is not finished yet. When it is done, <br />the Division will send any comments or questions to BRL. <br />BRL: Comment noted. <br />Rule 4.05.3 -Diversions and Conveyance of Overland Flow <br />13. DRMS: On page Exh-8-213, the right sideslope ratio is listed as being 0.5:1 for ditch <br />HC-D1 Steep. It appears that this should be 1.5:1. Please revise if this is the case. <br />BRL: See updated page Exh-8-213 showing the right sideslope ratio as 1.5:1. <br />14. DRMS: In the vent shaft pact plan view on Map 39, the upland diversion <br />subwatershed area is listed as being 12.9 acres in size. However, on Sedcad pages <br />Exh-8-212 and Exh-8-218, the acreage used for the subwatershed is 12.0 acres. Please <br />revise. <br />BRL: The correct acreage is 12.9 and has been corrected on pages Exh-8-212, <br />Exh-8-218. <br />Rule 4.05.6 -Sedimentation Ponds and Rule 4.05.9 -Impoundments <br />15. DRMS: In the Elevation-Capacity-Discharge Table on page Exh-8-217, the peak <br />stage is shown as being at an ek~vation of 6398 feet. This makes it appear that the 10 <br />yr-24 hour event peak stage is right at the emergency spillway elevation. In the Detailed <br />Discharge Table on the same page, the full flow depth is listed as being at an elevation <br />of 6398.25 feet. As written, this makes it appear that the 10 yr-24 hour event would flow <br />out of the emergency spillway, which is prohibited in Rule 4.05.9(2)(b). In reality <br />however, as shown on page Exh-8-2 19, the actual peak stage of the 10 yr-24 hour <br />event plus sediment storage amounts to 0.118 acre feet or 5140 cubic feet, which <br />corresponds to a pond elevation of about 6397.2 feet, which is below the emergency <br />spillway elevation. Please explain these apparent discrepancies and revise for the sake <br />of clarification. <br />BRL: DRMS is correct, the peak stage is at elevation 6398 feet, this is the <br />elevation of the emergency spillway and can be seen on Map 39 on Section A-A <br />