20080868 Ver 2_DWR staff addendum and clarification_20171207

MEMORANDUM
TO: Tracy Davis —Director — Division of Energy, Mineral & Land Resources
THROUGH: Jon Risgaard —Section Chief — DWR — Water Quality Regional Operations Section
FROM: David May— Water Quality Regional Operations Supervisor— Washington
SUBJECT: Mining Permit Application Review Comments — Supplement;
Aurora Mine; DEMLR Permit p 07-01
DATE: December 7, 2017
The Division of Water Resources previously provided comments on the Reclamation Plan for the above
referenced facility. Additional comments below are offered as an addendum and clarification to prior
comments.
1. Department of the Army Permit No. 200110096 covers discharge of fill material into 3,927 acres
of Section 404 jurisdictional waters of the U.S. Section Q. MONITORING of the permit requires a
groundwater monitoring program to be established, as required by the State Water Quality
Certification, for groundwater in and around the mine and reclamation areas.
On September 1, 2017, the Washington Regional Office granted approval of the R-12
Groundwater Monitoring Plan. Data collected through the approved plan should identify
whether reclamation activities adversely influence groundwater quality. Should groundwater
monitoring data indicate such a need, further evaluation and/or action may be required.
2. Prior recommendations were based on information provided in the 2012 Supplemental
Sampling and Analysis Data Report prepared by Ardaman & Associates, dated May 2012. The
report attributed groundwater exceedances detected on the western perimeter of R1/R3 to
reclamation activities. Such conclusion appears to be based on limited supporting data.
Additional assessment may be required to further evaluate the position provided in the
Ardaman & Associates report.
Implementation of the R-12 Groundwater Monitoring Plan can assist with determining whether
reclamation activities influence groundwater quality. Implementation of the plan may also
assist with verifying the position provided in the Ardaman & Associates report.
Based on further project evaluation with consideration given to the R-12 Groundwater Monitoring Plan,
a mechanism currently is in place to provide continuous evaluation of influence of mine reclamation
activities on groundwater quality. As such, the Division of Water Resources amends its prior
groundwater recommendations and is supportive of a modification that addresses reclamation
timelines. For these reasons, no additional information is requested at this time. As previously stated,
further groundwater assessment may be required in the future depending upon, among other things,
data collected pursuant to the approved R-12 Groundwater Monitoring Plan.
Please contact me at david.mavCWncdenr; gov or 252-948-3939 if there are any questions or further
information is required.