ML20033A206
| ML20033A206 | |
| Person / Time | |
|---|---|
| Issue date: | 10/19/1981 |
| From: | Fleming T NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Scarano R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-22 NUDOCS 8111240910 | |
| Download: ML20033A206 (5) | |
Text
.........
tv M - 2. 2.
v n
v w.V.
O 18 PDs Distribution; WMUR s/f WMUR w/f muR r/f WMUR:TEF m r/f 3001.6 TFleming WM-22 DMartin BFisher MEMORANDUM FOR: Ross A. Scarano, Chief JL nehan Uranium Recovery Licensing Branch Division of Waste Management
"[* "* ""11 REBrowning FROM:
Thomas E. Fleming, Project Manager f"$r[U" New Facilities Section Uranium Recovery Licensing Branch
SUBJECT:
TRIP REPORT Place and Date Cotter Uranium Mill Colorado - Department of Health Canon City, Colorado Denver, Colorado September 9,1981 September 10, 1981 Purpose 1.
To inspect the existing groundwater contamination problem and to investigate what remedial action that has and/or will take place to resolve this problem.
2.
To observe the tailings moving operation.
Attendees - Cotter Uranium Mill Site Jack Rothfleisch - Cotter Jim Cain - Cotter
-dQ, k~ (c3.
John Reese - Whaler Associates Roy Williams - NRC/ Williams Robinette and Associates, Inc.
Jim Obsinsky - NRC/ University of Idaho p
Bill Staub - NRC/0RNL p
Tom Fleming - NRC
@ 4 b
9 Attendees - Meeting with Colorado Department of Health b
Jake Jacobi - Colorado Department of Health Dick Gamewell - Colorado Department of Health Chuck Mattson - Colorado Department of Health k N j-Dennis Brown - Colorado Department of Health Roy Williams - NRC/ Williams Robinette and Associates, Inc.
Tom Fleming - NRC 8111240910 811019 PDR WASTE WM-22 PDR
- DATEf
+\\y NRd FORM 318 i10'80) NRCM O240 OFFICIAL RECORD COPY
' uscm '***329 *
-w- -
e
-e r
g.
i-I.
Summah Report -
Mer Urani Mill Sitet 9h The following is a trip report by Roy E. Williams and myself on a site visit to the Cotter Corporation uranium mill near Canon City, Colorado during the second week of September,1981.
Items discussed with Cotter include transfer of mill tailings produced by the previously operatedjalkaline ieac' mill from their original tailings ponds into the lined secondary h
impoundment, alterations in the pump-back system since November,1980, efforts to detemine background water qualities, efforts to delineate contaminated ground water by resistivity, improvements on water quality data analysis and diversion of surface water out of the Sand Creek drainage basin.
Water Quality Sampling Program Under the direction of the Colorado Department of Health, the company has altered considerably its water quality sampling and water quality reporting program since November of 1980.
Considerable effort has been expended toward the-objective of standardizing field collection procedures and sample preparation. Mechanisms for pumping wells prior to sampling have been implemented in many cases so that at least one casing volume of fluid can now' be removed from each wcll prior to sample collection.
Standardized filtration and acidification procedures have been implemented. The company is in the r.
process of organizing water quality data in a format which facilitates data storage on a computer.
This move eventually should facilitate easy access to individual data points as well as make convenient the presentation of time dependent _ data in graphic form.
In combination these changes should help alleviate some of the variability in data referred to in Roy E. Williams' report of November 6,1980.
However, some time will be required for the Cotter Corporation computer analyst to introduce all of the historic data into core storage. One individual has been put in charge of the water quality data collection and analysis program.
This individual is Mr. Jim Cain, Cotter's Radiation Safety Officer. This move should improve greatly the reliability and validity of the data collection and analysis program over that of earlier ye ars. A significant reduction in the time delay between time of sample collection and time of a.nalysis: should 'be one of: the; principal-results of this new management practice. The company also is in the process of estab-lishing a radiological analysis laboratory of its own.
New Deep Well The Cotter Corporation has completed the drillings of a 1, 054-foot deep well into the old Wolf Park Mine workings.
This well was drilled approx-imately 200 feet north of the old Wolf Park Mine shaft. Considerable difficulty.was experienced during the drilling because of locations and elevations that had changed during the period since available maps were constructed and because of geologic conditions encountered near the bottom of the hole.
OFFICE k sumwr)
DATEf NRC FORM 318 do 80lNRCM O240 OFFICIAL RECORD COPY
- 'w329 e24
+
1
%CT 1 3 M M 4
s
.O b
e 9
U V
f,.
L,)
Nevertheless, the hole was completed in one of the openings of the abandoned drif ts.
Initial water qua'ity data from the well revealed basic conditions.
The initially alkaline environment at the bottom of the hole was probably the result of the influence of the dHiling mud and/or grout. More recent data indicate acid conditions in the abandoned drift.
The existence of acidic conditions in the drift suggests that pyrite in the old workings may be reacting with oxygenated water that has moved down the old Wolf Park Mine shaft and seepage from tailings pond #1. However, this water should have been alkaline since tailings pond #1 received water from an alkaline leach mill.
Apparently the supply of pyrite in the drift is sufficient to dominate the reaction of the acidic water in the drift with the alkaline water that has moved down the Wolf Park Mine shaft. These two environments in combination will make difficult the interpretation of the chemistry of the water in the Wolf Park drifts and complicate the interpretation of the existence of a deep flow path at the site.
Pump-back System The pump-back syst.em at the Cotter site has been a tered considerable since 3
Roy E. William's report of November,1980.
The central objective of the alterations has been to collect seepage from individual sources and direct it to a central pumping facility via which the collected seepage now enters the new lined primary tailings pond.
This greatly improved pump-back system essentially eliminates the potential for the recycling of seepage referred to in the Williams' report of November,1980.
In essence, all of the suggestions made in the aforementioned report have been implemented.
Diversion of Surface Runoff Around the Sand Creek Drainage
~
~
The Cotter Corporti' n is considerii19 six alt'ernat'ive dEversion systems o
to minimize the rate of inflow of surface water into the Sand Creek drainage.
Surface runoff moving down the Sand Creek basin is either collected in the Soil Conservation Reservior or it recharges the shallow ground water fiow system upgradient from the reservoir.
In either case it merges with the existing old mill tailings pond seepage and increases the volume that must be removed ultimately by the pump-back system.
The elemination of this additional volume of water would reduce the pump-back system's work load and is therefor a proposal which, if feasible, should be considered.
Resistivity Surveys The feasibility of utilizing resistivity surveys for the purpose of deline-ating ground water with high total dissolved solids content was discussed among the Cotter Corporation, the Colorado Department of Health and Roy E. Williams in November 1980.
Since that time, the Cotter Corporation has experimented with the use of resistivity surveys as a mechanism for achieving such delineation.
The processing of data has not yet been completed, but the company reports that the results appear to be encouraging.
- However, OF FICE k sum m )
^4 OFFICIAL RECORD COPY
" 3 " -3?
- uncronu3eoo.eoinacu0:40
ET 191981 ipis possible that such a large nump of data points will pe requiredIi' Y
b for effectiveness that the method wi not be ec6domically f6Esible.
the method does prove to be feasible, the company is considering using the results of the resistivity surveys as a guide to the location of aaditional recovery wells in order to speed up the withdrawalof contaminated ground water.
Tracer Studies Tracer studies are being evaluated as a mechanism for identifying specific sources of seepage that contribute to the ground water contamination problem.
This action is being taker, via a purchase order with hydrologists from the University of Arizona.
Current efforts consist of the identification of a stable tracer that will be unique to the system. Bromide is being considered at the present time.
This effort is being conducted as authorized by the Colorado Department of Health.
Transfer of Old Tailings The Colorado Department of Health has consistently been a strong proponent of the expeditious transfer of the tailings from the old mill into the new lined secondary impoundment area.
This transfer currently is being implemented.
Most of the problems anticipated prior to the initiation of the transfer have not materialized.
This is primarily a consequence of the fact that the tailings constitute a much freer draining porous medium than was predicted. Water encountered during the excavation process by mechanical equipmen; is drained to one or more centrci sumps and pumped into the new primary lined impoundment. The mechanical excavation equip-ment is able to operate continually as the tailings drain into the So called " quick" conditions have not been encountered.
collection sumps.
The mechanical equipment employed consists of a variety of sizes of dozers, scrapers, backhoes and trur' Scrapers are used to remove the dryer portions of the tailings and backhr used to construct ditches and load trucks.
Roughly speaking, the backhoes cperate in the center of the old tailings Tailings are pushed pile and the scrapers operate around the periphery.
toward the periphery of the tailings pile by D-8 dozers with U-Shape blades, where they are collected by scrapers and transported to the new secondary Trucks also haul tailings directly to the new secondary impoundment.
Small dozers push tailings impoundment after being loaded by backhoes.
toward a large track mounted backhoe that is used to load the trucks.
Dust does not appear to constitute a problem during the transfer process.
The moisture content of the tailings is sufficiently high to preclude eclian erosion of the soda ash rich tailings. Suppression of soda ash rich dust on haul roads is accomplished by watering trucks.
Also plowing of the tailings oile with a dozer-ripper perpendicular to the major wind direction promotes disposition by reducing wind contact and promotes tailings The transfer operation appears to by increasing total surface exposure area.
be proceeding efficiently and the contractor is approximately two months ahead of schedule.
The transferred tailings are being emplaced in the secondary impoundment under what appear to be conditions of optimal or near optimal compaction.
The transferred tailings are being emplaced in layers by the scrapers and The dozer is used to spread the tailings that are trans-by a D-8 dozer.
i Compaction of the layers spread by the dozer is being forrod hv truck.
CFF1Ctf sumum) om>
NRC FORM 318 60 BCi NRCM O210 OFFICIAL RECORD COPY
~ " ' * -32"2' CCT 191981 nr=
v
,O q
e y'_'
6 der these conditions we% predict Jch eved by the weight of th D-8 cat.
that the volume of the secondary impoundment utilized for transferred tailings emplacement will be less than anticipated.
In sumary, the tailings transf:r operation is proceeding much more efficiently and expeditiously than many experts' predicted.
The transfer of the tailings apparently has not yet proceeded to the point where the rate of seepage production at collection points has been reduced.
We anticipate that as the transfer continues, the rate of " low of seepage i
will begin to be reduced.
This reduction could possibly begin to occur l
within the next two or three months.
l Summary Report - Colorado Department of Health On Thrusday, September 10, 1981, Roy Williams and myself met with the -
Colorado Department of Health concerning our site visit to the Cotter i
Corporation uranium mill.
Items included in the above site visit report which were discussed with the Colorado Department of Health include j
improvements on water quality data analysis, carrent pump-back system, background water quality, improvements on water quality data analysis, diversion of surface water, and the tailings transfer operation. These items were presented to the Colorado Department of Health as presented above.
1 waal 81%nNN i
i i
Thomas E. Fleming New Facilities Section i
Uranium Recovery Licensing Branch Division of Waste Manatement cc:
Jake Jacobi - Colorado Department of Health Dr. Roy Williams i
l 1
i
~
A l
i om">
>~A
..T.QT(.?....g?......
... w.a : m.
w
"+ m a 9.. t......wd81...
NRCFORM 318 410/801 NRCM O240 OFF!CIAL RECORD COPY "8 * "*