2014-02-07_REVISION - M1979094HR ‎(5)‎

• Permit No: M1979094HR
• IBM Index Class Name: REVISION
• Doc Date: 2/7/2014
• Doc Name: Revised DDP
• From: Whetstone Associates
• To: DRMS
• Type & Sequence: AM1
• Email Name: TC1
• Email Name: DMC
• Media Type: D
• Archive: No

JD -7 Mine - Drainage Design Plan
5.1 Runoff Results — Peak Flow and Total Volume ................................... ............................... 48
5.2 Peak Flow Regression Analysis ........................................................... ............................... 52
5.3 Diversion Structure Capacity ............................................................... ............................... 53
5.4 Diversion Structure Stability ................................................................ ............................... 54
5.4.1 Stability Analysis — Pit Diversion West .................................. ............................... 55
5.4.2 Stability Analysis — Pit Diversion East ................................... ............................... 55
5.4.3 Stability Analysis — OPWRD .................................................. ............................... 55
5.5 Retention Structure Capacity 56
5.6 Culvert Capacity ................................................................................... ............................... 60
6.
STORMWATER ROUTING (PLANNED CONDITION) ..................................... ...............................
61
6.1 Sub -Basin Delineation — Planned ......................................................... ...............................
62
6.2 Stormwater Routing on the Expanded and Reclaimed JD -7 Mine Site ...............................
65
6.3 Reach Definition — Planned .................................................................. ...............................
67
6.3.1 Pit Diversion West - Planned .................................................. ...............................
67
6.3.2 Pit Diversion East - Planned .................................................... ...............................
67
6.3.3 Open Pit Waste Rock Pile Diversion - Planned ...................... ...............................
70
6.3.4 North Diversion - Planned ....................................................... ...............................
70
6.4 Storage Structures (Planned) ................................................................ ...............................
70
6.4.1 Planned Stormwater Catchment Northwest (SCN) ................. ...............................
70
6.4.2 Upstream Storage Ponds ( USPs) ............................................. ...............................
72
6.5 Model Implementation of Stormwater Routing ................................... ...............................
73
7.
PEAK FLOW MODEL RESULTS (PLANNED CONDITION) ............................ ...............................
76
7.1 Runoff Results — Peak Flow and Total Volume ................................... ...............................
76
7.2 Diversion Structure Capacity ............................................................... ...............................
81
7.3 Diversion Structure Stability ................................................................ ...............................
84
7.4 Retention Structure Capacity
86
8.
ADDITIONAL STORMWATER BMPS ................................................................ ...............................
89
9.
REFERENCES ........................................................................................................ ...............................
91
LIST OF TABLES
Table 1. Major Sub -Basin Areas at the JD -7 Mine ......................................................... ............................... 1
Table2. Terms and Abbreviations .................................................................................. ............................... 4
Table 3. Design Storm Parameters .................................................................................. ............................... 6
Table 4. Regression Equations for Southwestern Colorado .......................................... ............................... 11
Table 5. Generalized Least Squares Regression Equations for Estimating Regional Flood - Frequency
Relations for Western Colorado ................................................................... ............................... 12
Table 6. Manning's "n" Values Used in Cowan's Method for Channel Roughness ..... ............................... 13
Table 7. Soils Types in Vicinity of the JD -7 Mine ........................................................ ............................... 17
Table 8. Runoff Curve Numbers for Arid and Semi -Arid Rangelands ......................... ............................... 18
4149A.140207 Whetstone Associates