2013-11-07_PERMIT FILE - M2013070

• Permit No: M2013070
• IBM Index Class Name: PERMIT FILE
• Doc Date: 11/7/2013
• Doc Name: New Application
• From: Liberty Mining, LLC
• To: DRMS
• Email Name: GRM
• Email Name: THM
• Media Type: D
• Archive: No

Liberty Mining, LLC
DRMS 110 -d Permit Application
October 2013
Operational Site Analysis
The analysis of the operational site began with delineating the offsite basins contributing
drainage flow toward the site and the basins within the site. The offsite flows will be intercepted
by two detention ponds located on the west side of the operations site at the foot of the hillside
above the site. The objective will be to prevent off site flows from coming onto the site.
Drainage flows generated on site will be directed to retention ponds located on the site. See
Exhibit U2 — Site Grading, for basin delineation.
As with the roadway analysis, the site drainage basins were determined, the areas contributing
to each basin were delineated, and the parameters of each identified basin were then
determined. The parameters determined included the area of the basin, the flow length of each
basin, and the average slope of the basin from the top to the bottom. These parameters were in
addition to the described parameters of soil types, rainfall data, vegetation cover, etc. See
Exhibit U2- Drainage Basin Delineation, for basin configurations.
Using the Rational Method of analysis for determine runoff rates, a peak runoff, based on the
100 year, 24 hour rainfall event, was calculated. The analytical parameters and the results of
the calculations are presented in Table U(10 -3) -Peak Runoff Resulting from 100- Year /24 -Hour
Rainfall Event.
Table U (10 -3)
Peak Runoff Resulting from
100- Year /24 -Hour Rainfall Event
For Operational Site
Drainage
Basin No.
Basin Area,
Acres
Length of Flow
Path, Feet
Average Slope of
Basin, %
Time of
Concentration, Min
100- Year /24 -Hour
Runoff Q, CFS
1
0.234
100
9.00
9.40
0.20
2
0.276
240
3.30
11.30
0.30
3
0.320
240
6.24
11.30
0.30
4
0.190
150
13.33
8.00
0.20
(Note - Because Drainage Basin #4 is the portals to the mine and all flows from the basin flow
toward the mine entrance, it was assumed that the drainage water would be pumped to the
closest pond, Pond #3 for disposal. Basin #4 flows are therefore added to the Basin #2 flows to
become the total flows into Pond #3.)
Sizing the detention and /or retention ponds to contain the drainage water from the operations
site and the intercepted offsite drainage water employed the use of the Simplified Peak Flow
Method of analysis to determine the volume of runoff generated by the design stone, i.e. the
100- year /24 -hour event. The analytical parameters and the results of the calculations are
presented in Table U (10-4) -Peak Runoff Volume Resulting from 100- Year /24 -Hour Rainfall
Event,
Liberty Mining, LLC Moab, Utah SMA Ref. 5821697 Page 63