2014-11-20_REVISION - M1977036 ‎(3)‎

• Permit No: M1977036
• IBM Index Class Name: Revision
• Doc Date: 11/20/2014
• Doc Name: Responses to the Adequacy Review.
• From: GEI
• To: DRMS
• Type & Sequence: AM2
• Email Name: PSH
• Media Type: D
• Archive: No

Groundwater infiltrating into mine areas is the source for makeup water. Water used for dust
control is taken from water stored in onsite ponds.
MM has applied for and acquired a permit through the National Pollutant Discharge Elimination
System (NPDES) Water Quality Control Division (permit number COG5000066).
1.2 Monitoring and Mitigation
Continued monthly groundwater monitoring for the purpose of this Groundwater Monitoring and
Mitigation Plan is required by the DRMS and MM is will submit the data in its annual report. In
the event adverse groundwater conditions equal to or greater than a two foot drawdown relative to
historic levels during the applicable season, the wells would be monitored on a weekly basis and/or
a schedule dictated by the DRMS to observe groundwater conditions around the site Additional
monitoring wells may be added if necessary to develop a complete understanding of the
oundwater conditions.
If adverse groundwater conditions continue in the area and are determined to be caused by the 35`"
Avenue West Pit reclamation, mitigation measures including a French Drain (or like structure) Will
be installed around the slurry wall and will be evaluated. If it is determined that a drain will be
beneficial in mitigating adverse groundwater levels, a drain may be constructed and will be utilized
as needed to restore groundwater to historic elevations. The correct sizing, location an d
positioning of the French Drain (or like structure) will be determined following an engineering
review.
One of the monitoring wells owned by MM was mined through during the mining process. This i
monitoring well was TT -MW -08 (figure G -1).The origina12014 permit amendment submitted by
the applicant stated there were 2 wells on the west and south side of the West Cell of the Greeley
35`s Avenue property. This information, gathered from the Division of Water Resources (DWR)
AQUA database, was incorrect and field inspections confirmed a total of 3 monitoring wells (the
0, TT- MW -08, was mined through) located west of the West Cell.
Exposed Water
Estimated Water for
Actual Water for
Month
Surface Area (acres)
Dust Control and
Dust Control and
Construction (gal)
Construction (gal)
February 2015
26.3
25,000
March 2015
26.3
150,000
April 2015
26.3
400,000
May 2015
26.3
700,000
-
Groundwater infiltrating into mine areas is the source for makeup water. Water used for dust
control is taken from water stored in onsite ponds.
MM has applied for and acquired a permit through the National Pollutant Discharge Elimination
System (NPDES) Water Quality Control Division (permit number COG5000066).
1.2 Monitoring and Mitigation
Continued monthly groundwater monitoring for the purpose of this Groundwater Monitoring and
Mitigation Plan is required by the DRMS and MM is will submit the data in its annual report. In
the event adverse groundwater conditions equal to or greater than a two foot drawdown relative to
historic levels during the applicable season, the wells would be monitored on a weekly basis and/or
a schedule dictated by the DRMS to observe groundwater conditions around the site Additional
monitoring wells may be added if necessary to develop a complete understanding of the
oundwater conditions.
If adverse groundwater conditions continue in the area and are determined to be caused by the 35`"
Avenue West Pit reclamation, mitigation measures including a French Drain (or like structure) Will
be installed around the slurry wall and will be evaluated. If it is determined that a drain will be
beneficial in mitigating adverse groundwater levels, a drain may be constructed and will be utilized
as needed to restore groundwater to historic elevations. The correct sizing, location an d
positioning of the French Drain (or like structure) will be determined following an engineering
review.
One of the monitoring wells owned by MM was mined through during the mining process. This i
monitoring well was TT -MW -08 (figure G -1).The origina12014 permit amendment submitted by
the applicant stated there were 2 wells on the west and south side of the West Cell of the Greeley
35`s Avenue property. This information, gathered from the Division of Water Resources (DWR)
AQUA database, was incorrect and field inspections confirmed a total of 3 monitoring wells (the
0, TT- MW -08, was mined through) located west of the West Cell.