2016-06-02_HYDROLOGY - M1977342

• Permit No: M1977342
• IBM Index Class Name: Hydrology
• Doc Date: 6/2/2016
• Doc Name: Annual Watering Report - Groundwater Management Plan
• From: Climax Molybdenum
• To: DRMS
• Email Name: PSH
• Media Type: D
• Archive: No

CMC—Henderson Operations
DRMS 2015 Annual Water Monitoring Report
May 2016
Introduction
The GWMP establishes a plan for groundwater monitoring at the Henderson Mine and Mill for
the protection of groundwater quality pursuant to Rule 3.1.7(5) of the Mineral Rules and
Regulations of the Colorado Mined Land Reclamation Board for Hard Rock, Metal, and
Designated Mining Operations and the Colorado Water Quality Control Commission (WQCC)
standards. Henderson has prepared this report in accordance with the requirements of Section 7.1
of the GWMP to summarize results of 2015 water monitoring activities.
1.0 Discussion of Annual Water Monitoring Data
This section provides a summary of the annual water monitoring data collected in 2015 in
accordance with the GWMP for each permit-identified POC well and non-POC long-term
surface water monitoring location at the Henderson Mine and Mill. Monitoring is conducted
three times per year as stipulated in the GWMP as follows:
• During the April through June spring run-off period;
• During the summer months of July and August; and
• During the September through December low-flow period.
To provide a better data set for trending purposes, the graphs generally include historical data
from triannual DRMS monitoring and 5-Quarter Baseline monitoring. Data can be seen in trend
evaluation graphs as well as in the data tables. Note that for the purpose of trending the
analytical data, results reported below the laboratory detection limit are shown as a value of zero.
All monitoring locations are depicted in Figures 1 and 2.
Outliers are identified, as needed, using either the Dixon's or Rosner's statistical method
depending on the available number of data points. Although data from prior reporting years is
presented herein for trending and discussion purposes, outlier and NPL assessments/discussions
are limited to current reporting year data.
2.1 Henderson Mine
Henderson Mine monitoring locations include POC well MNGW-1 and surface water locations
BG-20, CC-10 and CC-30. Graphical trends for MNGW-1, BG-20, CC-10 and CC-30 are
presented as Trend Evaluations 1-16 of this report.
2.1.1 Point of Compliance Sampling Location: MNGW-1
MNGW-1 is a shallow alluvial well located downgradient of the Henderson Mine operations. No
iwerein 2 1 Following the installation of
apparent trends, deviations orexceedances observed 0 5.
pp
two new monitoring wells, the focus of further evaluation has shifted to influence by a
diversionary channel (No Name Gulch/NNG-50), as well as other potential contributing factors.
As discussed with DRMS at Henderson's first routine inspection (April 215t), Henderson would
like to continue with a source evaluation to determine any contributing factors, such as No Name
Gulch, or potential from nearby development rock from early mining activities. Freeport-
McMoRan has also identified internal geochemical specialists (Life Cycle Analysis Team,
Tucson, AZ) who will begin an evaluation of this area, in concert with past evaluations from
AJAX and CCA, to identify the most likely contributors to low pH readings witnessed at the
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