My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
PERMFILE46135
DRMS
>
Back File Migration
>
Permit File
>
500000
>
PERMFILE46135
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
8/24/2016 10:48:23 PM
Creation date
11/20/2007 12:38:07 PM
Metadata
Fields
Template:
DRMS Permit Index
Permit No
C1981020A
IBM Index Class Name
Permit File
Doc Date
5/13/2002
Section_Exhibit Name
2.0 MINE PLAN
Media Type
D
Archive
Yes
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
32
PDF
Print
Pages to print
Enter page numbers and/or page ranges separated by commas. For example, 1,3,5-12.
After downloading, print the document using a PDF reader (e.g. Adobe Reader).
View images
View plain text
i° ~,Q-~3 <br />Nb~~~~t <br />t'~" A report will be provided to the division by the inspecting engineer within two weeks of the <br />• completed inspections. A copy of this report will be kept at the mine site. To direct natural runoff <br />and/or collect surface runoff and control sediment from the waste rock disposal area, diversion <br />ditches and a sedimentation pond are provided. Diversion of surface water from upgrade areas and <br />improvements of overall site drainage are incorporated in the design. An NPDES permit will be <br />obtained for this sediment pond prior to commencing construction. <br />Diversion Channels <br />The total drainage area associated with the proposed site is approximately 18 acres. The area <br />was further divided into two separate watersheds draining into diversion channels designed to carry <br />peak flows generated from the 10-year precipitation event. These drainage areas are indicated on <br />Figure 2.2-6. Drainage of the eastern portion of the area (12 acres) has been diverted to Flow <br />beneath the existing haul road and joins a natural drainage channel. The flow from the western area <br />(6 acres) is diverted westerly and eventually joins a natural channel. <br />Construction of the diversion channels upgrade from the actual fill area may involve rock <br />excavation. Section C-C on Figure 2.2-7 shows the requirements for the diversion channels in this <br />situation. Calculations and assumptions are provided in Appendix M. <br />Interceptor Channels <br />Interceptor channels are designed to carry flows from direct precipitation in the disposal site <br />• (disturbed) area. All surface runoff from this area is directed to a sedimentation pond as shown on <br />Figure 2.2-6. All channels are to be riprapped in order to minimize erosion. <br />Sedimentation Pond <br />The sedimentation pond is designed to collect the sediment eroded Y'rom the disposal area. <br />Erosion potential will be limited to direct precipitation over the site. The estimated annual erosion <br />rate, based on the Universal Soil Loss Equation, is on the order of 900 cubic feet per year. The <br />design three-year total sediment would reach 2,700 cubic feet. This volume is based on unprotected <br />slopes and is conservative. <br />This 10-year 24-hour storm event for the site is 1.5 inches and will generate approximately 3,960 <br />cubic feet of runoff. The pond has been designed to contain 2-ten year events, 7,920 cubic feet. <br />This volume is sufficient to totally contain a 50-year 24-hour storm (7,700 cubic feet). When <br />sediment stored reaches 60% of the maximum storage, the sediment will be removed and disposed <br />appropriately. Calculations are shown in Appendix M (vii). <br />Site Preparation <br />Prior to disposal of material at the site the area will be cleared of all vegetative or organic <br />material and large boulders. Suitable topsoil will be removed, and stockpiled as outlined in Section <br />2.4, and the area grubbed of objectionable material below the surface. <br />• ~~ <br />~` <br />M~ Page 2.2 - 12 10-13-00 <br />/0~3~0 / <br />
The URL can be used to link to this page
Your browser does not support the video tag.