ML19270G065
| ML19270G065 | |
| Person / Time | |
|---|---|
| Issue date: | 03/06/1979 |
| From: | Scarano R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Wolff T PHILLIPS URANIUM CORP. |
| References | |
| REF-PROJ-M-20 NUDOCS 7906010335 | |
| Download: ML19270G065 (4) | |
Text
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Project M-20 Dr. Ted Wolff, Director Radiation Protection Section Environmental Improvement Division P. 0. Box 968, Crown Bldg.
Santa Fe, New Mexico 87503
Dear Dr. Wolff:
Attached are the NRC questions on the Phillips Uranium Corporation's Nose Rock Mill submittal. Please forward these questions to the appropriate corporate authority for response.
Upon receipt of Phillips' response, we will schedule the completion of the NRC review.
If you have any questions concerning this submittal, please contact Steve Manger.
Sincerely,
,W i A Ross A. Scarano, Section Leader Uranium Mill Licensing Section Fuel Processing & Fabrication Branch Division of Fuel Cycle and Material Safety
Enclosure:
As stated 2237 201 7906010 3 3 f
ENCLOSURE QUESTIONS FOR PHILLIPS URANIUM CORPORATION ON THEIR NOSE ROCK PROJECT 1.
The bedrock underlying the tailings impoundment was depicted in Attachment III as having permeabilities ranging from essentially impermeable (<.1 ft/yr) to 13 ft/yr:
a.
discuss the areal extent of those areas having a permeability greater than 10-7 cm/sec; b.
discuss the availability of a suitable natural liner material, having a permeability of < 10-7 cm/sec, and applied in three foot layers.
2.
The S. E. corner of section 12 Tl8N R12W has yielded water from subsurface depths of less than 50 feet.
Provide information concerning:
a.
the source of this water; b.
its extent; c.
the flow quantity and gradient; d.
potential of this shallow water for human consumption and/or livestock watering use; and e.
the source of the ponded water located in the NW corner of section 18, T18N RllW.
3.
The Environmental Report (PII-6-7) states that three seepage monitoring wells will be installed downdip of the site around the periphery of the tailings dam.
Sheet M-316 of attachment VI indicates that monitoring wells are to be placed along the crest of the final stage of the dam.
Elaborate on and document the rationale for the selection of your proposed monitoring program.
4.
The sand disposal area is to be enclosed by a system of dikes and ditches, and seepage is to be pumped from the ditch to the slimes pond at a rate of 70 gpm (113 acre /ft/ year):
a.
provide water balance diagrams and calculations showing water inputs to and losses from the sands area, and relate these figures to the remainder of the system; 2237 202
ENCLOSURE b.
discuss more thoroughly the design and construction of the sands disposal area (i.e., permeabilities, surface preparation, cut offs,etc.).
5.
Page 5-5 of Attachment VI states that borrow material consists essentially of the alluvial soils in section 12, T18N R12W...
yet page 5-3 of the same attachment presents embankment settlement figurd based on a 47-foot thickness cf compressible alluvium.
a.
Please clarify your proposal in this regard; b.
If stripping is not planned, how will the presence or absence of excessive weathering, faulting, or other conditions which may affect seepage through the upper Menefee formation be demonstrated?
c.
Delineate barrow areas and preser,t a detailed cross section of the final embankment at the point of maximum dam height.
6.
Page 5-5 of Attachment VI discusses the permeability of borrow material :
a.
Provide the results of the permeability tests on which the 0.2 ft/ year permeability of the core material is based; b.
Is the embankment " filter" to be graded so as to prevent piping of the core?
7.
Present the calculations on which the 5 foot freeboard allowance is based.
8.
In the reclamation plan:
a.
propose a cover scheme that will attain an attenuation of radon to twice background in both the sand and slimes areas, and provide the data and calculations that were used to demonstrate that level of attenuation; b.
discuss the time period required for the slimes area to dry sufficiently to support heavy equipment, and provide data and calculations that demonstrate the capacity of six inches of solidified slimes to support the weight of heavy equipment and ten or more feet of overburden; 2237 203
ENCLOSURE c.
provide a description of the chemical characteristics of the tailings liquids which is to be evaporated (e.g. pH);
d.
in the event the toe drain system becomes plugged, what are the potential impacts of the water contained in the reclaimed tailings on the stability of the embankment; e.
discuss the potential for disruption of the cover of the slimes area due to settlement as the moisture from the reclaimed tailings is lost;
' f.
proposed a final reclamation program which is designed to meet the performance ojbective of eliminating the need for an on-going monitoring and maintenance program (include grading, topsoiling, revegetation and/or rip rapping, etc.).
2237 204