My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
2016-07-13_REVISION - M1980244
DRMS
>
Day Forward
>
Revision
>
Minerals
>
M1980244
>
2016-07-13_REVISION - M1980244
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
11/20/2020 5:19:11 PM
Creation date
7/14/2016 7:18:51 AM
Metadata
Fields
Template:
DRMS Permit Index
Permit No
M1980244
IBM Index Class Name
Revision
Doc Date
7/13/2016
Doc Name
Adequacy Review
From
DRMS
To
CC&V
Type & Sequence
AM11
Email Name
TC1
WHE
ERR
AME
Media Type
D
Archive
No
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
16
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
Mr. Jack Henris <br />July 13, 2016 <br />Page 11 <br />m:\min\tc1\_teller\m-1980-244 cc-v\am-11\m-80-244-am-11maincommentr12016-07-13.docx <br />failure under the ECOSA and statements in the Hydrogeochemistry Evaluation (Vol <br />II, paragraph 3.6.6) “under high infiltration conditions, some of the infiltrating <br />precipitation water will flow along the surface of the boulder till, and emerge at the <br />northern downhill tow [sic] of the ECOSA” suggest a likelihood of a saturated <br />colluvium. Please factor this into the slope stability analyses. <br />41. Appendix 6, p. 4, Bedrock. The assumed φ (friction angle) and cohesion values are 45 <br />degrees and 5,000 psf (~35 psi), respectively. Based on a comparison of Drawing C-7, <br />District Geology (Vol. I) and the ECOSA location on Figure 2 (amended AM-11) the <br />possible bedrock underlying the ECOSA is phonolite, feldspar bearing – plagioclase <br />phonolite, and/or Cripple Creek lapilli breccia. A comparison of mean strengths in Table <br />6-1 of Appendix 5 (Vol. III) suggest the cohesion value used is conservative (i.e., less than <br />that obtained from testing), but the 45 degree friction angle is much higher than the highest <br />mean value (for RQD = 90%) in Table 6-1. The level of uncertainty for this particular <br />bedrock material suggests the use of strength parameters in the medium range (e.g., RQD = <br />50 %) and FOS from DRMS Table 1 for “Generalized, Assumed, or Single Test Strength <br />Measurements”. Please use consistent strength parameters or further justify the use of 45 <br />degrees and 5,000 psf. <br />42. Appendix 6, Paragraph 2.4, Stability Evaluation Results. The ECOSA is an engineered <br />environmental protection facility (EPF). The analyses for Sections 1 and 2 (considered <br />critical structures) need to be re-evaluated based on Comment Nos. 40 and 41 above. The <br />Section 3 (non-critical structure as slope failure would not be expected to directly have an <br />offsite impact) pseudo‐static analysis, resulted in a FOS of 1.0. This is unacceptable for <br />during operations or after reclamation. The Division will not approve an increase in the <br />height of the ECOSA if appropriate FOS’s (based on DRMS Table 1) cannot be <br />achieved. <br />43. Appendix 6, Figure 5, Section 3. Please explain why the east slope is steeper (2.5H:1V) <br />than during operations (2.9H:1V). <br />44. Appendix 7, Table 2 – Runoff Coefficients. This table indicates 100 percent runoff from <br />precipitation for areas that are actively being leached or lined, but with no ore covering the <br />liner. This is a very reasonable assumption, but it is unclear where runoff peak flows are <br />directed such that they are controlled and contained within the VLF. Please explain how <br />the runoff from the 100-year, 24-hour precipitation event is controlled and contained within <br />the VLF. <br />45. Appendix 7, PSSA Capacity and Pumping Rates. The first paragraph states “Minimum <br />operating volumes were not provided for PSSA 5 of the Arequa Gulch site or for the Squaw <br />Valley PSSA”. Why were these values not provided? <br />46. Appendix 7, PSSA Capacity and Pumping Rates. The last paragraph states “As a criterion <br />for evaluating adequacy of storage in each facility, five feet of freeboard was required to be <br />maintained in each PSSA”. Does this five feet of freeboard correspond to the maximum 80
The URL can be used to link to this page
Your browser does not support the video tag.