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17h- <br /> J. E. STOVER & ASSOCIATES, INC. <br /> 2352 NORTH 7T"STREET,UNIT B <br /> GRAND JUNCTION,COLORADO 81501 <br /> PHONE:(970)245-4101,FAX:(970)242-7908 <br /> MINE ENGINEERING CIVIL ENGINEERING <br /> MINE RECLAMATION CONST. MANAGEMENT <br /> March 14, 2019 RECEIVED <br /> Janet Binns MAR 19 2019 <br /> Division of Reclamation, Mining&Safety <br /> 1313 Sherman St., Room 215 DNISION OF RECLAMATION <br /> Denver, CO 80203 MINING AND SAFETY <br /> Re: Bowie Resources, LLC, Bowie No. 1 Mine <br /> TR-64, East Roatcap Creek Culvert Removal—Reclamation Plan <br /> Adequacy Response#2 <br /> Permit C-1981-038 <br /> Dear Ms. Binns: <br /> DRMS' letter dated November 1, 2018 transmitted its adequacy review for the referenced technical <br /> revision. On behalf of Bowie Resources LLC,following are its responses to the DRMS' comment and <br /> concerns. <br /> 1. DRMS: The Division understands that Bowie Resources has reconsidered the East Roatcap <br /> Creek channel reconstruction and is no longer planning to armor the channel with riprap. <br /> However,we still require that reconstructed channels be designed, per Rule 4.05.4,which <br /> applies to both channel diversions and stream channel reconstruction. (We regret that this was <br /> not clearer in our preliminary adequacy review, but we were addressing the plan for a riprapped <br /> channel.) Please provide SEDCAD modeling results and a design drawing.Alternatively,Bowie <br /> Resources may provide another type of analysis to show that the reconstructed channel will <br /> likely remain stable during large runoff events. For example, calculations could be done with a <br /> simpler model or models than SEDCAD.The Division is available to discuss the details of a <br /> proposed alternative analysis. <br /> BRL: The approved design that was referenced in adequacy response#1 is located in Volume 8,the <br /> "Culvert Capacities"tab, Figure II-C-1. The premise of this design is to specify boulders that will mimic <br /> the upstream and downstream conditions of the natural channel bed,which are plated with boulders <br /> ranging in size from 18"to 48". For reclamation purposes, BRL wishes to restore East Roatcap Creek to <br /> its natural configuration as much as possible, and as such, proposes to intermittently place boulders in <br /> the channel bottom of the reconstructed creek bed. Using the aforementioned design,the nomograph <br /> will be used to size the boulders. Manning's equation was used to determine a velocity based on the <br /> highest peak flow that was calculated (Qloo=95.0 cfs). Next, using the nomograph mentioned above, a <br /> stone size of approximately 1.3'would be specified. To verify the stone size, and as a cross check, in <br /> Excel it was determined that rock size of 1.8'would be required. Therefore, to be conservative, a D5o size <br /> of 3.0' will be specified,which is consistent with 18"-48" cobbles/boulders that exist in the natural <br /> channel. While the entire channel length will not be plated, using boulders as energy dissipaters will <br /> help reduce erosion and help the channel to eventually achieve an equilibrium state. An example of a <br />