Laserfiche WebLink
7 <br />3607 County Rd. 65 <br />Rangely, CO 81648 <br />(970)675 -4300 <br />fax (970)675 -4399 <br />DESERADO MINE <br />BLUE MOUNTAIN ENERGY <br />ma son, <br />;;a <br />Mr. Jim Stark D � V M tien9 and oaf e�`1 <br />Division of Reclamation, Mining and Safety <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />July 18, 2012 <br />RE: Minor Revision #152 — B -Seam Dewatering and Treatment System — As- Builts. <br />Response to Adequacy Review. <br />Dear Jim: <br />Enclosed is our response to the Adequacy Review Letter concerning MR -152. Each item <br />is addressed per our response below. <br />1. Appropriate corrections were made to Map 157 (enclosed). <br />2. On Map 157 appropriate additions of contour markers were added to the Last <br />Chance Pond. The intent of the emergency spillway is to not allow discharge until the <br />primary spillway (H- Flume) has reached 0.9 feet. A detail for the emergency spillway was <br />added as requested. <br />3. On Map 157 details were added for Pond #4 as a `typical' design. The other <br />dewatering ponds are similar enough that specific details are not of little value and are not <br />warranted. <br />4. The requested refinement was added to Map 157. <br />5. The SedCAD model was adjusted to use a spillway crest length of 17 feet for <br />Dewatering Pond #4. The bottom width was reduced to 5 feet. Both changes result in a <br />modeled increase in the pond depth upon design flows from a 25 -year event. The model <br />demonstrates that this structure can adequately pass the design events. Revised SedCAD <br />model runs are enclosed. <br />It also should be pointed out that the Dewatering Pond structures utilize a single /combined <br />spillway design. The emergency spillway routine within SedCAD most accurately models <br />this design. These ponds are internal to the overall system and are designed to see <br />