HomeMy WebLinkAboutDERR-2024-007877South Facilities Groundwater OM&R Plan October 2006
Kennecott Utah Copper Corporation Page 1
SOUTH FACILITIES GROUNDWATER
OPERATION, MAINTENANCE, AND REPLACEMENT PLAN
OCTOBER 2006
1.0 INTRODUCTION
Kennecott Utah Copper Corporation (KUCC) is currently conducting groundwater
remediation at its South Facilities as selected by the U.S. Environmental Protection
Agency (EPA) and the Utah Department of Environmental Quality (UDEQ) in a Record
of Decision (ROD) dated December 13, 2000 for the Kennecott South Zone, Operable
Unit 2. In response to the ROD, KUCC submitted a Final Design for Remedial Action
(RDRA) in December 2002. EPA approved the RDRA and issued an Explanation of
Significant Differences (ESD) in June 2003. EPA and UDEQ are proposing to issue a
second ESD in December 2006 modifying certain aspects of the selected remedy.
KUCC has completed construction of facilities required to implement the selected
remedy. EPA and UDEQ are expected to certify Construction Completion for these
facilities before the end of 2006. This Operation, Maintenance, and Replacement
(OM&R) Plan addresses post-construction remedial aspects of the ROD and has been
prepared as an attachment to the Consent Decree for the South Facilities Groundwater.
This OM&R Plan supersedes the RDRA.
Groundwater contamination at the South Facilities, referred to as Zone A Plume, is
immediately downgradient of the old Bingham Reservoir and Bingham Canyon Mine
waste-rock dumps and consists of a core area with low pH and elevated metals which is
surrounded by a partially to fully neutralized zone of elevated-sulfate groundwater.
Post-construction OM&R activities include:
• Containing the plume using barrier wells and wells in the core of the plume,
• Remediating the aquifer through extraction of contaminated water and natural
attenuation,
• Management of extracted groundwater and disposal of treatment residuals,
• Mitigating, as appropriate, impacts to third parties,
• Maintaining institutional controls to prevent public exposure, and
• Monitoring and reporting progress.
Maintenance of source control measures, namely the East Side Collection System, is a
related activity that is being addressed under state permitting controls.
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Kennecott Utah Copper Corporation Page 2
2.0 OM&R PLAN CHANGES
South Facilities Groundwater OM&R activities are expected to last for several decades.
Given the length of time over which this remedy will be conducted, it is likely that
changing conditions in the aquifer, advancements in treatment technology, eventual
cessation of mining and milling operations, or other factors will, from time to time,
warrant adjustments to this OM&R Plan.
EPA and UDEQ may approve modification of this OM&R Plan. Such modification shall
not require court approval or amendment to the Consent Decree so long as the
modification does not fundamentally change or materially alter the basic components of
the remedy selected or modified in accordance with CERCLA or the NCP.
3.0 OM&R PROJECT MANAGEMENT
3.1 KUCC Project Coordinator
KUCC will designate a Project Coordinator who will have direct responsibility for day-
to-day OM&R oversight. The Project Coordinator is KUCC’s main point of contact for
communications between KUCC and the agencies.
If the designated KUCC Project Coordinator is changed, KUCC will inform EPA and
UDEQ of the identity of the successor at least 15 working days before the change is
made, unless impracticable, but in no event later than the actual day the change is made.
3.2 Supervising Contractor
In the event KUCC delegates complete OM&R oversight to a Supervising Contractor,
KUCC will notify EPA and UDEQ in writing of the name, title, and qualifications of any
contractor proposed to be the Supervising Contractor. KUCC will demonstrate that the
proposed contractor has a quality system that complies with ANSI/ASQC E4-1994,
“Specifications and Guidelines for Quality Systems for Environmental Data Collection
and Environmental Technology Programs,” (American National Standard, January 5,
1995), by submitting a copy of the proposed contractor’s Quality Management Plan
(QMP). The QMP will be prepared in accordance with “EPA Requirements for Quality
Management Plans (QA/R-2)” (EPA/240/B-01/002, March 2001) or equivalent
documentation as determined by EPA and UDEQ.
4.0 CONTAINMENT AND EXTRACTION OF CONTAMINATED
GROUNDWATER
KUCC has constructed five wells and associated infrastructure for the purpose of
containment and extraction of Zone A contaminated groundwater. These include two
wells in the core of the Zone A plume (acid wells) and three barrier wells located along
the leading edge of the Zone A plume (Figure 4.1). KUCC is currently and will continue
to extract groundwater from the Zone A Plume until Final Clean-up levels as outlined in
the December 2006 ESD are achieved.
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Kennecott Utah Copper Corporation Page 4
4.1 Operation and Maintenance
KUCC will operate and maintain the barrier wells in order to extract groundwater at a
rate that is at least sufficient to contain the Zone A plume and meet the performance
standard of maintaining groundwater sulfate concentration in the Compliance Wells at or
below 1,500 mg/l. KUCC may pump at a greater rate than is necessary for containment
as needed to provide feed water to the RO Plant or to provide water for other uses within
the scope of KUCC water rights assigned to the barrier wells.
KUCC will operate and maintain the acid wells to extract groundwater from the plume
core at a rate sufficient to meet or exceed the minimum extraction criterion of 1,200 acre-
feet per year, calculated on a 5-year rolling average.
KUCC will set and adjust extraction rates and well-field geometry as necessary according
to monitoring and modeling results in order to contain the plume, optimize contaminant
extraction, and balance the hydraulic response of the aquifer (drawdown) with the need to
protect the ability of the aquifer to transmit plume water to the wells.
4.2 Replacement
Based on modeling results and monitoring data, KUCC has demonstrated that the present
well field geometry is adequate to meet the performance standards for containment and
remediation. However, KUCC may construct replacement, alternatively located, or
additional extraction wells or reduce the number of extraction wells as warranted to
optimize groundwater remediation and assure containment.
5.0 MANAGEMENT OF EXTRACTED GROUNDWATER
5.1 Barrier Well Water
For the duration of KUCC’s obligation under an agreement with the State of Utah and the
Jordan Valley Water Conservancy District (JVWCD) dated August 31, 2004, KUCC
plans to manage barrier well water primarily by providing it as feed water to a reverse
osmosis (RO) treatment plant. KUCC may also utilize barrier well water in its process
water system, as it has done for many years. Other management options for water
extracted from the barrier wells could include providing the water for secondary use
(irrigation), or any other lawful use and disposition of such water. KUCC will advise
EPA and UDEQ of any changes in the use and disposition of barrier extraction well
water.
5.2 Acid Well Groundwater
During operation of the Bingham Canyon Mine, KUCC will rely on operating milling
facilities for treatment of acid plume water, specifically a) the tailings pipeline, which
serves as a 17-mile treatment reactor; b) the Copperton Concentrator lime plant, which
has ability to add hydrated lime directly to the tailings line as needed, and c) the North
Tailings Impoundment, which provides a repository for non-hazardous treatment
residuals. Management of treatment residuals in the North Tailings Impoundment is
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subject to compliance with State of Utah UPDES Permit UT0000051 and Groundwater
Discharge Permit UGW350011.
5.2.1 Operation and Maintenance
Acid plume water is conveyed from the acid wells to the tailings line where it is
neutralized by 1) available alkalinity of the tailings (primarily present as calcite in the
limestone portion of the ore), and 2) residual hydrated lime added as a milling reagent.
KUCC may also add lime directly to the tailings pipeline if needed for neutralization.
Acid water pipelines and other conveyance structures will be inspected and maintained as
needed to prevent release of extracted acid water.
5.2.2 Replacement
Treatment of acid plume water is expected to continue beyond closure of the Bingham
Canyon Mine (currently anticipated between 2018 and 2030). The current KUCC plan
for post-mining management of acidic flows is based on lime treatment of acidic waters
with disposal of reaction products (i.e., gypsum sludge) in a prepared facility.
KUCC will continue to investigate alternative treatment technologies, particularly ones
that have the potential to decrease both lime consumption and sludge volumes. The plan
for post-mining water management and disposal of treatment residuals will be updated
formally as part of the 5-Year Reviews during Remedial Action. At least three years
prior to closure, KUCC will prepare a preliminary engineering design for all aspects of
post-closure acid plume water treatment. Prior to mine closure a replacement treatment
system and repository for treatment residuals will be designed and constructed.
6.0 MITIGATION OF IMPACTS TO THIRD-PARTIES
KUCC will maintain a program to evaluate and address concerns by third-party water
rights holders related to Zone A groundwater quality or extractions. If a complaint is
received, either directly by KUCC or indirectly through a regulatory agency, KUCC will
gather and evaluate water quality and quantity data and water right seniority information
related to the issue. KUCC may also refer the matter for an independent review by a
consultant. The results of this evaluation will be reviewed and discussed with the third
party, EPA, UDEQ, and the Utah Division of Water Rights (State Engineer). If a third-
party impact is attributable to KUCC’s remedial program, KUCC or the independent
consultant will recommend potential mitigation with the water right holder and regulatory
agencies. If acceptable to the water right owner, the mitigation will be implemented.
This process is designed to address concerns of third-party water right holder regarding
potential interference with pre-existing water rights utilizing criteria consistent with Utah
law. Nothing in the process is intended to create, modify, expand, limit, or restrict the
legal rights or remedies of either the water right owner or Kennecott.
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7.0 MAINTENANCE OF INSTITUTIONAL CONTROLS
KUCC has initiated institutional controls to prevent public exposure to contaminated
groundwater. First, a drilling restriction on certain lands (Figure 7.1) owned by KUCC
will be utilized to restrict the drilling of any well that would extract, or is capable of
extracting, water. This restriction will be consistent with the Utah Environmental
Institutional Control Act, which provides UDEQ with authority to enforce the restriction.
Second, the Utah Division of Water Rights Salt Lake Valley Groundwater Management
Plan provides for critical review of any application to change point-of-diversion or drill a
replacement well in the contaminated area defined in the Management Plan so as not to
interfere with the remediation process.
KUCC will assist with maintenance of these institutional controls by actively monitoring
applications filed with the Division of Water Rights in the contaminated area and
working proactively with the Division of Water Rights and the UDEQ as appropriate, to
control the drilling of wells that would interfere with the remedy.
8.0 MONITORING AND REPORTING
KUCC will conduct water quality monitoring at a network of compliance wells to
demonstrate compliance with the performance standard for containment of the Zone A
plume and at the remedial extraction wells to measure progress towards achieving final
clean-up levels. KUCC may also conduct supplemental monitoring at its discretion. A
monitoring plan is included as Appendix A. Monitoring will continue until final clean-up
levels are achieved.
KUCC will prepare and submit annual reports on OM&R monitoring, remedial activities,
and remedial progress. All groundwater monitoring information collected as part of the
remedial effort will be included in the annual report. Annual reporting (in a format to be
specified by the agencies) will be prepared on a calendar-year basis, and an annual report
will be submitted to EPA and UDEQ by April 15 of the following year. The annual
report will include a summary of monitoring results and other compliance activities for
the source control measures.
Separate from the report described above, KUCC will prepare and submit to EPA and
UDEQ by April 15 of each year an annual summary of activities related to 1) third-party
inquiries and KUCC’s responses, and 2) maintenance of institutional controls.
KUCC will make timely notifications or submit ad hoc reports as needed to inform EPA
and UDEQ of significant changes in either operating strategy or groundwater conditions.
To support completion of Five-Year Reviews by the agencies, KUCC will provide timely
response to reasonable requests from EPA or UDEQ for information relevant to Zone A
plume remedial activities.
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8.1 Determination of Achievement of Final Clean-Up Levels
Final clean-up levels to be achieved as a result of the Zone A plume remedial activities
are specified in the December 2006 ESD. At a future date when KUCC believes that
final-clean up levels have been achieved or could soon be achieved, KUCC will propose
to EPA and UDEQ appropriate statistical, analytical, and/or other methodology for
determination of achievement of the final clean-up levels.
9.0 SOURCE CONTROLS
KUCC has constructed source control measures that include a series of cut-off walls,
french drains, pipelines, and canals to capture and convey meteoric leach water from the
waste rock dumps. Maintenance and monitoring of source controls is addressed in
KUCC’s Utah Ground Water Discharge Permit UGW350006 for the Bingham Canyon
Mine and Water Collection System.
The source control measures will be operated pursuant to the state Ground Water
Discharge Permit conditions. Any non-conformance with the permit will be addressed
solely as specified in the permit and state groundwater protection permitting rules. As
part of the five-year review process, EPA and UDEQ will evaluate the effectiveness of
the groundwater protection permit in assuring maintenance of source controls
10.0 RECORDS RETENTION
Until 10 years after KUCC receives a notification from EPA of Certification of
Completion of the Work pursuant to the terms of the Consent Decree, KUCC will
maintain the following records and types of records:
1. The final version of the Remedial Investigation/Feasibility Study and appendices
dated March 16, 1998.
2. The final version of the Final Design for Remedial Action at South Facilities
Groundwater dated December 2002.
3. All final versions of subsequent design documents related to replacement of
extraction or treatment systems necessary to implement the post-construction
requirements
4. EPA’s Record of Decision dated December 13, 2000 for Kennecott South Zone,
Operable Unit 2.
5. EPA’s Explanation of Significant Differences, Kennecott South Zone Operable
Unit 2, signed by EPA on June 23, 2003.
6. Any subsequent Record of Decision amendments or Explanation of Significant
Differences documents.
7. The Remedial Action Consent Decree.
8. Any subsequent Consent Decree modifications or amendments.
9. This OM&R Plan and any subsequent revisions or replacements.
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10. All final versions of annual OM&R reports, which will include all relevant
groundwater monitoring data.
11. All subsequent agency approvals of plans, modifications, reports, etc.
12. Annual groundwater extraction records for KUCC wells and any available
extraction records for neighboring wells that are needed for calibration of
groundwater models.
13. Well drilling and construction records.
14. Key geologic data and evaluations including geologic maps, geologic cross
sections, geophysical survey results, geologic and geophysical well logs.
15. Any other scientific or technical data or studies relating to geology,
hydrogeology, or water treatment that may be deemed to have enduring relevance
to the project and are so designated by the KUCC Project Coordinator.
Until the completion of each five-year review, KUCC will maintain all reports submitted
during the five-year review period pursuant to compliance with the state permits
referenced in this OM&R plan.
For purposes of this section, records, reports, or documents (records) can include either
electronic or written/paper documents; however, the requirement to retain such records
does not apply to both forms, but to either form at the discretion of KUCC.
11.0 REFERENCES
Kennecott Utah Copper Corporation, 2002, Final Design for Remedial Action at South
Facilities, Groundwater, December.
Kennecott Utah Copper Corporation, 2005a, Groundwater Characterization and
Monitoring Plan, Revision 7, February.
Kennecott Utah Copper Corporation, 2005b, Standard Operating Procedures for Water
Sampling, Revision 5, March.
Kennecott Utah Copper Corporation, 2005c, Quality Assurance Project Plan for the
Groundwater Characterization and Monitoring Plan, Revision 6, March.
United States Environmental Protection Agency, 2000, Record of Decision for Kennecott
South Zone, Operable Unit 2, Southwest Jordan River Valley Ground Water Plumes,
December 13, 2000.
United States Environmental Protection Agency, 2003, Explanation of Significant
Differences, Kennecott (South Zone) OU2, June 23, 2003.
United States Environmental Protection Agency, 2006, Explanation of Significant
Differences, Kennecott (South Zone) OU2, December.
South Facilities Groundwater OM&R Plan October 2006
Kennecott Utah Copper Corporation
APPENDIX A
MONITORING PLAN
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Kennecott Utah Copper Corporation Page 1
SOUTH FACILITIES GROUNDWATER
MONITORING PLAN
VERSION PREPARED APPROVED EFFECTIVE
1.0 October 2006 October 2006 October 1, 2006
1.0 PURPOSE
This plan describes the monitoring that KUCC will conduct as part of the South
Facilities Groundwater Operation, Maintenance, and Replacement Plan (OM&R
Plan). This monitoring plan is based on and replaces in whole the monitoring
plan presented in the Final Design for Remedial Action at South Facilities
Groundwater (RDRA) dated December 2002.
The purpose of monitoring at South Facilities Groundwater is to:
1) demonstrate compliance with the performance standard for containment of
the Zone A plume,
2) measure progress toward achieving final clean-up levels, and
3) gather supplemental monitoring data which benefits KUCC in managing
and optimizing its groundwater remediation and treatment program.
It is expected that this monitoring plan will be revised on a regular basis in
response to changes observed in the plume over time.
2.0 METHODS
KUCC’s Groundwater Characterization and Monitoring Plan (GCMP), as
updated, and associated Standard Operating Procedures (SOPs), as updated,
will be followed for all water quality sampling and water level measurements.
The GCMP has been approved by the Utah Division of Water Quality and is
updated on an annual basis. Procedures for documentation and sample
handling, equipment maintenance and decontamination, quality control sampling,
field measurements, and groundwater sampling are detailed in the SOPs. All
water quality analyses will be conducted by Kennecott Environmental Laboratory
or another state-certified environmental laboratory.
3.0 REQUIRED MONITORING
The monitoring described in this section fulfills the monitoring needs specified in
the December 2006 ESD to demonstrate compliance with performance
standards and monitor progress of remediation. Performance of this monitoring
is subject to enforcement under the Consent Decree.
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3.1 Locations
Required monitoring consists of sampling at a network of Compliance Wells on
the perimeter of the Zone A plume and at the remedial Extraction Wells within the
plume. These wells are listed in Table 3.1 and shown on Figure 3.1.
Table 3.1 Required Monitoring Locations
Well Type
COG1178A Compliance
WJG1169A Compliance
WJG1154A Compliance
W189 Compliance
P192B Compliance
P194B Compliance
EPG1165A Compliance
BSG1135A Compliance
HMG1123A Compliance
HMG1126A Compliance
ECG1146 Extraction
BSG1201 Extraction
B2G1193 Extraction
BFG1200 Extraction
LTG1147 Extraction
3.2 Sample Frequency and Timing
The sampling frequency and timing for Compliance Wells is dependant on sulfate
concentration as shown in Table 3.2.
Table 3.2 Compliance Well Sampling Frequency and Timing
Sulfate (mg/l) Frequency Timing*
<1,000 Annually 3rd Quarter
1,000-1,250 Semi-annually 1st and 3rd Quarters
>1,250 Quarterly Each Quarter
*Reference to quarters here and subsequently are based on calendar-year quarters
When sulfate concentrations decrease from a higher sulfate range to a lower
sulfate range, required sampling frequency will decrease after two consecutive
periods with sulfate concentrations in the lower range.
Extraction wells will be sampled semi-annually in 1st and 3rd quarters.
3.3 Parameters
The parameters to be monitored at the Compliance Wells and Extraction Wells
are those listed in the December 2006 ESD for which a final clean-up level is
specified. These parameters are listed in Table 3.3.
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Table 3.3 Compliance and Extraction Well Monitoring Parameters*
pH
Arsenic (D)
Barium (D)
Cadmium (D)
Copper (D)
Fluoride
Lead (D)
Selenium (D)
Nickel (D)
Sulfate
*(D) means dissolved
3.4 Reporting
All monitoring data for Compliance and Extraction Wells will be reported annually
as described in the OM&R Plan.
If any water sample from a Compliance Well exceeds the 1,500 mg/l sulfate
criterion, KUCC will notify in writing EPA/DEQ of probable out-of-compliance
status within 10 working days of receiving official laboratory analytical results.
(Informal verbal notification will be provided as soon as practical after KUCC
becomes aware of the results.) KUCC will have the opportunity to re-sample the
well within 5 working days of making written notification to EPA/DEQ.
3.5 Replacement
KUCC will make diligent and reasonable effort to retain designated Compliance
Wells; however, it is recognized that development pressures and other factors
may require abandonment of some Compliance Wells. Prior to abandonment of
any Compliance Well, KUCC will recommend to and seek approval from
EPA/DEQ for a replacement well, which may be a reasonably adjacent existing
well or a new well within reasonable proximity of the well to be abandoned.
4.0 SUPPLEMENTAL MONITORING
The purpose of the supplemental monitoring described below is to benefit KUCC
in managing and optimizing its groundwater remediation program. Performance
of this monitoring is not subject to enforcement under the Consent Decree.
Supplemental monitoring data may also be used to demonstrate, at an
appropriate future date, achievement of the final clean-up levels.
4.1 Water Quality and Water Level Monitoring
Within and adjacent to the Zone A plume are over 300 monitoring wells, in
addition to the Extraction and Compliance wells listed above. KUCC may select
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and conduct water quality and/or water level monitoring on any number of these
wells each year. Water quality samples will be analyzed for those parameters
that KUCC believes useful to managing the remedial program.
4.2 Ground Surface Elevation Monitoring
KUCC monitors ground surface elevation at selected locations on a regular basis
to detect land surface elevation changes that may be caused from groundwater
extraction. Current surface elevation monitoring points are listed in Table 4.4.
KUCC may add or remove sites from this list as necessary.
Table 4.4 Locations for Ground Surface Elevation Monitoring
Well Site ID
K105
ECG1116
ECG1124
BSG1180
BFG1156
WJG1170
BSG1137
1973 West
¼ Section 13/14
¼ Section 15/22
4.3 Tailings Monitoring
KUCC monitors the solid and aqueous chemistry in the tailings system to assure
that acid plume waters and other mining-affected waters which are managed in
the tailings line do not adversely impact the process water system or the long-
term acid-generating potential of the tailings.
4.3.1 Locations
Monitoring of the solid and aqueous phases of the tailings slurry and discharged
water to the tailings slurry is conducted by sampling at two locations in the
tailings system. Composite samples for solid and aqueous phase monitoring are
collected once a month over a 24-hour period 1) at the GMT (general mill tailings;
BCP1483) entering the Tailings Thickeners Distribution Box and 2) at the NSB
(North Splitter Box; MCP2536). The GMT sample is collected from the
automated sample cutters that sample Copperton Concentrator tailings. The
GMT sampler automatically samples the waste stream every 20 to 30 minutes.
The NSB composite sample is collected using a peristaltic sampling pump on the
tailings line approximately 200 feet upstream of the NSB. The pump is
programmed to sample every 20 minutes.
The aqueous pH of tailings is monitored continuously at the North Splitter Box.
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4.3.2 Parameters
Solid tailings samples are analyzed for neutralization potential (NP) following
standard methods. Aqueous samples are analyzed for the parameters listed in
Table 4.7.
Table 4.7 Process and Tailings System Aqueous Monitoring Parameters
pH
Alkalinity/Acidity
Aluminum (D)
Cadmium (D)
Copper (D)
Iron (D)
Manganese (D)
Zinc (D)
4.3.3 Management Criteria
KUCC utilizes the following management criteria in management of acidic waters
in the tailings system:
1. The neutralization potential (NP) value of samples collected from the
tailings North Splitter Box should be either greater than or equal to the NP
of Copperton Mill Tailings for the month or at least 5 t CaCO3 eq/kt. The
monthly NP values will be determined based upon a 24-hour composite
sample and using a six-month rolling average. In making comparisons,
the uncertainty in both GMT and NSB will be taken to be 10% of the
average value, and a significant difference must lie outside the joint
uncertainty.
2. Aqueous alkalinity should be greater than or equal to 10 mg CaCO3 eq/L
at least 90% of the time. Aqueous alkalinity will be evaluated as a rolling
six-month average.
3. The aqueous pH at the North Splitter Box should be greater than or equal
to 6.7 during at least 90% of the time over a calendar year.
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5.0 REGISTER OF CHANGES
Version Date Changes
1 Oct. 2006 Initial release