ML20246G379

Advises That Review of Durango Disposal Cell Cover Design Will Be Completed as Soon as Feasible.Placement of Cover Before Tailings Dewatered Would Very Likely Result in Differential Settlement of Tailings Under Cover

ML20246G379
Person / Time
Issue date:	02/27/1989
From:	Hawkins E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:	Maynard O ENERGY, DEPT. OF
References
REF-WM-48 NUDOCS 8903170382
Download: ML20246G379 (2)

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'datok UNITED STATES y

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NUCLEAR REGULATORY COMMISSION l

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REGION IV

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URANIUM RECOVERY FIELD OFFICE DENVER L

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FEB 271989 URF0:SRG Docket No. WM-48 i

l Oni Maynard, Chairperson Durango Mill Tailings Task Force q

P.O. Box 1484 Durango, Colorado 81302

Dear Ms. Maynard:

We are in receipt of your February 7,1989 ietter encouraging expedit'ious l

review and approval of the cover design for the Durango disposal cell.

We can assure you that we will complete our review of the Durango disposal cell cover design as soon as is feasible, considering the obligations that this office has to licensed uranium recovery facilities and other Uranium Mill Tailings-Remedial-Action (UMTRA) Projects. Although our init'ial review of_the cover.

design did not identify any major problems, we currently have significant concerns about the placement of the cover in light of the " construction". water -

that has been recently identified to be saturating.the tailings cell.

Our

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l concerns regard the source of the water,-proposed dewatering schemes, i

potential for differential settlement and ground-water characterization and monitoring.

These are discussed in the enclosed January 31, 1989 letter to the-Department of Energy (D0E).

To elaborate somewhat, placement of the-cover before the tailings are dewatered would very likely result in differential settlement of the tailings underneath the cover.

This settlement would cause cracking of the cover, resulting in additional time and work to repair the damage.

Since this is a carefully engineered cover, repair is considerably more difficult.

This would-further delay completion of the project, which does not appear to be 'a very effective or prudent way to proceed.

In addition, placing the cover over_ saturated' tailings will further exacerbate the ground-water contamination problem.'

In j

their submittal of the cover design, DOE indicated that they.are now experiencing ground-water contamination at the site.

In regard to your concern that not covering the tailings'may result in furthe'r water infiltration and blowing tailings, we agree.

These concerns can be addressed by placing an interim cover as soon as practicable-over the tailings i

until the saturated tailings and final. cover design issues are resolved.

In light of_these issues, it appears unlikely that'they can be resolved and the j

tailings dewatered, if necessary, before Apri1~ 1.

However, we are awaiting DOE's response to our January 31, 1989 letter.

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8903170382 890:227

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I PDR WASTE WM-48 PDC

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FEB 27 l989 i

We met with representatives of the Colorado Department of Health (CDH) on.

February 15, 1989, to discuss their concerns that the re-initiation of.

I construction at the Durango site not be delayed.

In general, the CDH agrees with us that the concerns raised need to be addressed by DOE prior to placement of the final cover.

We will be coordinating our review, to the extent-practicable, with the CDH on the Durango site.

If you have any questions, you may call this office at (303) 236-2805.

Sincerely, d

1 tdward F.

awklas

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Branch Chief i

Uranium Recovery Field Office l

Region IV

Enclosure:

As stated cc: Mark Matthews, DOE Elizabeth Demler, DOE Edward Bischoff, CDH i

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' pa atooq UNITED STATES g

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NUCLEAR REGULATORY COMMISSION 4

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REGloN IV URANIUM RECOVERY FIELD OFFICE e,,,,,8 box 2532s DENVER, COLORADO 8022s JAN 31 1989 I

URF0:SRG Docket No. WM-48 040WM48910E

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Mark L. Matthews, Acting Project Manager l

Uranium Mill Tailings Project Office

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U.S. Department of Energy Albuquerque Operations Office i

P.O. Box 5400 Albuquerque, New Mexico 87115

Dear Mr. Matthews:

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l We are in receipt of your December 23, 1938 transmittal of the Durango final l

' cover design and ground-water comoliance strategy.

In your letter, you are j

asking for, concurrence on the cover design.

We have identified several areas I

i that will need to be addressed prior to our concurrence of the final cover design, primarily as a result of the occurrence of the " construction" water in the relocated tailings.

These are discussed below.

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Source of Water Please provide discussion as to the source of water.

Discuss whether or not the water could be from another source other than construction (i.e., spring, surface water runoff, snowmelt, etc.) activities.

The discussion should include some type of water' balance calculations as well as procedures to prevent future infiltration of the relocated tailings.

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Proposed Dewatering Scheme Tailings should be dewatered prior to placement of the cover.

This will limit unnecessary contamination of the ground water under the disposal cell.

Your submittal appears to indicate that ground-water contamination is already taking place. ' Accordingly, please provide your proposed dewatering and ground-water cleanup plans for our review and approval.

Settlement l

Please provide a discussion of whether or not the saturation and/or subsequent dewatering the tailings will cause differential settlement.

Placement of the cover should not be initiated until differential settlement, if any, is complete.

OFFIClAl. DOCKET COPY e4fD+WIMF

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.JAN 31 1989 1

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l Ground-Water Characterization l

I Please keep us informed on current ground-water monitoring information at Durango. We need to be aware of the constituents you are monitoring at the j

depository and the processing sites so we can determine-if characterization is adequate.

This will be necessary for us to be able to determine compliance with the EPA standards. _ Furthermore, you should be proposing background water i

quality as well as point of compliance well locations.

We also consider this a l

part of adequate site characterization and should be addressed now. Otherwise, when the time'comes to determine compliance, there may be major information i

gaps that might preclude us from concurring.

You should propose background l

water quality (with supporting data), point of' compliance well locations and constituents to be monitored as soon as possible.

i These items were discussed in the January 23, 1989 meeting between DOE,'NRC.and Colorado Department of fiealth.

If you have further questions, please contact Scott Grace of my staff at (303) 236-2805.

Sincerely, Edward F. flawkins, Chief l

Licensing Branch 1 Uranium Recovery Field Office Region IV cc:

Elizabeth Damler, 00E Steve Itamp, DOE h

Mark Jackson, 00E/ TAC 1

Russell Edge, 00E/ TAC l

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CONCURRENCE:

DATE:

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