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 1
TABLE OF CONTENTS
1. INTRODUCTION ................................................................... ...............................
1.1
Purpose ................................................................................................... ...............................
1
1.2
Overview - Runoff Areas and Routing ................................................... ...............................
1
1.3
List of Abbreviations .............................................................................. ............................... 3
2. DESIGN
CRITERIA & METHODOLOGY ............................................................. ............................... 6
2.1
Design Storms ........................................................................................ ............................... 6
2.2
Runoff Estimates .................................................................................... ............................... 6
2.2.1 Volume ....................................................................................... ..............................6
34
2.2.2 Peak Discharge .......................................................................... ............................... 7
35
2.2.3 Computational Methods ............................................................ ............................... 9
4.4.3 Open Pit Waste Rock Pile Diversion ...................................... ...............................
2.2.3.1 Spreadsheet Simulation ................................................ ............................... 9
2.2.3.2 NRCS WinTR- 55 .......................................................... ..............................9
36
2.2.3.3 Regression Analysis ................................................... ...............................
10
37
2.2.3.4 HydroCAD ................................................................. ...............................
12
2.3
Structure Design ................................................................................... ...............................
12
37
2.3.1 Channel Capacity .................................................................... ...............................
12
37
2.3.2 Channel Stability ..................................................................... ...............................
13
39
2.3.3 Culverts ................................................................................... ...............................
15
42
2.3.4 Retention Ponds and Spillways ............................................... ...............................
15
43
2.3.5 Riprap / Granular Bedding / Gravel Mulch ............................. ...............................
15
3. HYDROLOGIC CHARACTERISTICS OF SITE SOILS ...................................... ............................... 17
4. STORMWATER ROUTING (CURRENT CONDITION) ..................................... ...............................
22
4.1
Sub - Basins Contributing Stormwater to Diversion Structures and Valley Floor ................
22
4.2
Sub - Basins and Stormwater Routing on the JD -7 Mine Site ............... ...............................
25
4.3
Sub - Basins Receiving Stormwater Downstream of the JD -7 Mine Site .............................
31
4.4
Reach Definition ................................................................................... ...............................
31
4.4.1 Pit Diversion Ditch — West ...................................................... ...............................
34
4.4.2 Pit Diversion Ditch — East ....................................................... ...............................
35
4.4.3 Open Pit Waste Rock Pile Diversion ...................................... ...............................
35
4.4.4 Stormwater Collection Ditches for the Underground - Waste -Rock Pile ................
36
4.5
Storage Structures ................................................................................. ...............................
37
4.5.1 Pit Pool Retention Pond .......................................................... ...............................
37
4.5.2 Retention Ponds 001B -A North and 001B -A South ................ ...............................
37
4.5.2.1 Current Design ........................................................... ...............................
37
4.5.2.2 Retention Pond Expansion ......................................... ...............................
39
4.5.3 Upstream Storage Ponds ( USPs) ............................................. ...............................
42
4.6
Model Implementation of Stormwater Routing ................................... ...............................
43
4.7
Transmission Losses, Channel Infiltration ........................................... ...............................
47
5. MODEL RESULTS (CURRENT CONDITION) .................................................... ............................... 48
4149A.140207 Whetstone Associates