ML19327A431
| ML19327A431 | |
| Person / Time | |
|---|---|
| Issue date: | 07/11/1980 |
| From: | Linehan J NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Kirner N WASHINGTON, STATE OF |
| References | |
| REF-WM-33 NUDOCS 8008060192 | |
| Download: ML19327A431 (2) | |
Text
I db v Krcy UNITED STATES
, 'o NUCLEAR REGULATORY COMMisslON j
4 y' g WASHINGTON, D. C. 20555 e,.... /
4 JUL 111980 i
Department of Social and Health Services ATTN: Nancy P. Kirner j
Radioactive Materials Licensing P. O. Box 1788 Olympia, Washington 98504 Gentlemen:
Enclosed you will find requests for additional inforTnation based upon our review of Dawn Mining Company's proposed new tailings disposal facility as described in various submittals.
To enable us to meet the September 1 completion date for our environmental assessment previously agreed to, we ask that you request a response from Dawn by August 1,1980. To further expedite our review, Dawn should be requested to transmit a copy of their response directly to us.
If you have any questions concerning this transmittal, please contact P..Garcia of my staff at 301/427-4109.
Sincerely, M
l John J. Linehan, Section Leader l
Operating Facilities Section Uranium Recovery Licensing Branch Division of Waste Management cc:
J. Thompson, Dawn P. E. Lapat, Newmont Mining Corp.
Enclosure:
As stated
[
l 48008060Mg
6' REQUEST FOR INFORMATION l
DAWN MINING COMPANY 0
U 1.
The geometry of the proposed pit is such that considerable stress will be placed on the liner near the toes of the slopes.
Provide an evaluation to show that the 30 mil reinforced hypalon liner will have adequate tensile strength to resist the stresses or, alternatively, increase the thickness of the liner to be placed near the toes.
2.
It is stated on page 4 of the report entitled "Geotechnical Design j
Data'l that the eastern half of the proposed tailings disposal area is underlain by basalt, while the remainder of the disposal area i
is underlain by a " stiff" clay.
In combination with the fact that i
the saturated weight of tailings placed in the pit will be greater l
than the weight of the material excavated in constructing the pit, the foundation conditions indicate a potential for differential settlement. Therefore, provide an analysis to show the amount of l
differential settlement which could.be expected to occur, as well as an evaluation of the potential for disruption of the liner due i
to this settlement. Included in the analysis should be data on the l
compressibility of the clays underlying the site.
3.
It is stated on page 13 of the "Geotechnical Design Data" report that the proposed disposal facility will be filled to its maximum pool level with water and then gradually filled with tailings.
Clarify the operatir.g procedure to be employed and perform a water balance study to show that the operating procedures will not result in a short-term liquid disposal problem.
4.
Provide clarification on the function of the five foot high perimeter dikes to be constructed around the proposed disposal facility.
Will they provide freeboard only, or will they serve as containment for the operating pool.
If they will provide containment for the operating pool, seepage control, as well as erosion protection measures should be utilized.
If this is the case, provide information on the seepage control and erosion protection methods to be employed.
5.
Provide an analysis to show that sufficient flood storage capacity exists above the maximum operating pool level to store the direct precipitation and runoff resulting from the design floods specified in NRC Regulatory Guide 3.11, " Design, Construction, and Inspection of Embankment Systems for Uranium Mills."
6.
Provide a detailed description of liner installation procedures as well' as a description of the quality assurance program to be employed to ensure that the liner is installed properly.
s