ML20141C968
| ML20141C968 | |
| Person / Time | |
|---|---|
| Issue date: | 05/15/1997 |
| From: | Jagannath B NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Mackin P SOUTHWEST RESEARCH INSTITUTE |
| References | |
| CON-NRC-02-96-004, CON-NRC-2-96-4, REF-WM-67 NUDOCS 9705190284 | |
| Download: ML20141C968 (2) | |
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May M, 1997 Mr. Patrick Mackin.
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' Assistant Director for Systems Engineering and Integration CNWRA/ San Antonio Office.
Southwest Research Institute 6220 Culebra Road. Bldg 189 l
San Antonio, TX 78238-5166 L
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SUBJECT:
COMMENTS ON DRAFT REPORT ON SEISMIC STABILITY EVALUATION OF SLOPES DESIGN FOR SELECTED TITLE II SITES: TASK 16
Reference:
Technical Evaluation of Slope Design for the Tailings Retention Systems at the'Ouivira-Mining Company Ambrosia Lake Site, NM, Draft report: Milestone 8265-016-725: April 30, 1997
Dear Mr. Mackin:
Attached are review comments on the above referenced draft report presenting the evaluation of seismic stability of Quivira-Ambrosia Lake, Title II site.
This is the first in a series of such evaluation reports under task 16 of i
contract NRC-02-96-004.
These comments should be considered in all the reports under this task.
I have discussed these comments with Asad Chowdhury and Simon Hsiung of your staff.
Please contact me at (301) 415-6653, if you have any questions regarding this matter.
Sincerely, (Original signed by)
Dr. Banad N. Jagannath l
NRC Technical Project Manager Uranium Recovery Branch
. Division of Waste Management Office of Nuclear Material Safety and Safeguards
Enclosure:
As stated
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Review Comments on Stability Eva]uation of Slopes i
l-Document Reviewed:
Technical Evaluation of Slope Design for the Tailings Retention System a Quivira Mining Company Ambrosia Lake Site. NM, Draft Report This is the fist of a series of slope stability evaluations to be performed u
=under Task 16 of Contract-No. NRC- 02-96-004.
The Center-submitted a draft l
-report and requested staff comments on it. The Center intends to use the l
final version of this as an example to be followed for other slope stability evaluations ur. der this task.
Following are staff comments.
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- 1. The report should present the cross section.used in the analyses and the critical. failure surface with the lowest factor of. safety.
The strength and physical properties used in the analyses ~should be presented in tabular form.
.2.' Comments'on the cross section modeled in the draft report.
e Do not extend the model in the X and Y axis direction too far beyond the 3
I actual zone of interest.
Otherwise, the slope becomes a insignificant part of the overall cross section modeled.
e Delete the slopes indicated by lines 1 and 2 in the current model. Start the cross section from line 3 onwards. The Stable / Slope-stability codes can analyze a slope rising in the right direction efficiently. - Slope rising in the left direction can not be analyzed.
You have to model a flipped or' mirror image of such a cross section to get a right-raising slope.-
- Keep the cross section simple and as close to reality as possible.
e In'the cross section madeled there is an error. There should be line joining the point of intersection of lines 10 and 11 with the point of
.. intersection of lines 12 and 13.
e The failure surfaces are very shallow and almost tangential to the face
.of the slope. This can be expected for slopes in granular material. 'In the code you can control the zone of failure or surfaces-to be investigated by (1) appropriate execute commands and (2)' introducing intermediate lines in the cross section with similar properties on both sides of the line and controlling the zone of investigation by such lines.
By this technique.
the lowest factor of safety for failure through zones of lower strength can be investigated.
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