HomeMy WebLinkAbout940559.tiff STATE OF COLORADO
COLORADO DEPARTMENT OF HEALTH of^Coto
Dedicated to protecting and improving the health and , r
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environment of the people of Colorado • * 0,9 i .
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4300 Cherry Creek Dr.S. Laboratory Building rain,
Denver,Colorado 80222-1530 4210 E.11th Avenue
Phone(303)692-2000 Denver,Colorado 80220-3716
(303)691-4700 Roy Romer
Governor
February 24, 1994 Patricia A.Nolan,MD,MPH
Executive Director
Mike Cervi
Northern Colorado Brine
P.O. Box 300397
Denver, Colorado 80203
RE: Liner Testing - Pond 1
Northern Colorado Brine -
Weld County
Dear Mr. Cervi:
The Hazardous Materials and Waste Management Division of the Colorado Department
of Health (the Division) is in receipt of a letter, dated February 8, 1994, from Nelson
Engineers regarding the repair work and liner testing of Pond 1 at the Northern Colorado
Brine facility located in Weld County.
The Division, upon review of the above referenced letter, has the following comments:
1. The letter indicates native soils at the site were amended with bentonite. The
bentonite was spread over the pond floor and incorporated into the soils using a
powered mechanical compactor. Typically, soil/bentonite mixtures require mixing
by means of mixing equipment such as a pugmill or cement mixer (Solid Waste
Disposal Facility Criteria-A Technical Manual, USEPA 1993). The field mixing
procedures should closely duplicate samples mixed in the laboratory which were
tested for permeability. Please provide a copy of the quality control/quality
assurance procedures which were utilized to insure appropriate soil/bentonite mixing.
2. Please provide the data which verifies failed compaction test number 11 was retested
and achieved at least 95% compaction.
3. Only one of six permeability tests for pond 1 utilized brine water as the permeant.
Pursuant to section 9.4.1 (C) of the state's solid waste regulations (6 CCR 1007-2),
permeability testing of clay liner material shall utilize a permeant of one hundredth
Normal (0.01N) calcium sulfate solution. The purpose of this permeant is to
duplicate the chemical and physical characteristics of exploration and production
brine water. The permeability tests which were not run with either brine water or
a (0.01N) calcium sulfate solution permeant shall be retested. Results shall be sent
to the Division for review and approval.
Le-f) 940559
Mike Cervi
Northern Colorado Brine
February 24, 1994
Page 2
4. In addition, section 9.4.1 (C) requires passage of at least two pore volumes of liquid
from the waste to be impounded. The information provided in the letter does not
indicate this requirement was achieved. Please provide this data. If tests were not
completed as per section 9.4.1 (C), then the samples shall be retested and results sent
to the Division for review and approval.
As requested in the Division's September 20, 1993 letter to you, data from liner testing shall
be sent to the Division and Weld County Health Department (WCHD) for review and
approval prior to transferring brine water into any tested pond at this facility. Recent
conversations with a representative of WCHD indicates Pond 1 has been refilled. In
accordance with the facilities' Design and Operations Plan, the regulatory authorities shall
approve of all liner tests prior to refilling. Please keep in mind, if the Division or WCHD
believes data is insufficient or does not meet the requirements of the regulations, it may he
necessary to empty the pond and perform additional liner testing.
These conclude the Division's comments. Please respond in writing to each issue. If you
have questions regarding this matter, please contact me at 303-692-3437.
Sincerely,
Roger Doak
Geologist
Solid Waste Section
Hazardous Materials and Waste Management Division
cc: Weld County Commissioners
T. Jiricek, Weld County Health Department
K. Schuett, Weld County Planning Department
L. Nelson, Nelson Engineers
file: SW/WLD/NOR 4
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