2013-03-06_REVISION - M1994117

• Permit No: M1994117
• IBM Index Class Name: REVISION
• Doc Date: 3/6/2013
• Doc Name: TR-09 ADEQUACY REVIEW
• From: DRMS
• To: OPERATOR
• Type & Sequence: TR9
• Email Name: MAC
• Email Name: TAK
• Media Type: D
• Archive: No

Parameter
Agricultural
Water Standard
Aluminum, mg/1
5
Arsenic, mg/1
0.1
Cadmium, mg/1
0.01
Chromium, mg/1
0.1
Cobalt, mg/1
0.05
Copper, mg/1
0.2
Fluoride, mg /1
2
Iron, mg/1
5
Lead, mg/1
0.1
Lithium, mg/1
2.5
Manganese, mg/1
0.2
Mercury, mg/1
0.01
Nickel, mg/1
0.2
Selenium, mg/1
0.02
Vanadium, mg/1
0.1
Zinc, mg/1
2
pH
6.5 -8.5
Mark Steen
Page 12
March 6, 2013
are being sampled on a quarterly basis. The Operator has stated that MW -3 and MW -4
should not be sampled as they are not down - gradient of the tailings impoundment. The
bedrock in the Gold Hill District is highly fractured and faulted; therefore, groundwater does
not flow as it would in a typical alluvial aquifer. The Division believes that all four wells are
down - gradient from the tailings impoundment and have the potential to capture impacts from
the mill facility. Therefore, the Division will require the Operator to continue sampling all
four of the wells below the tailings impoundment.
Upon reviewing the permit file for the Gold Hill Mill, the Division has determined that a
compliance point was never established. Rule 3.1.7(6) states that one or more points of
compliance shall be established to evaluate protection afforded groundwater quality or to
comply with groundwater standards. Therefore, one or more of the monitoring wells must be
selected as compliance points for the water monitoring associated with the Gold Hill Mill.
Please respond.
The Division could not find any record of baseline data to which the water quality data was
being compared. Absent any baseline data, the Division will require that the water quality
data be compared to the Colorado Agricultural Water Standards, which have been applied to
the Cash and Who Do Mines since 2007. The Division has reviewed the past water quality
monitoring data for Gold Hill Mill and has determined the following parameters no longer
need to be sampled: Beryllium, Boron, Nitrate, Nitrite and Sulfate. The Division has found
that the past water quality monitoring data is inconsistent in terms of parameters sampled and
there are many quarters of data which were never submitted. Without additional justification
from the Operator, the Division will require that the following parameters (in addition to pH,
temp., conductivity, and TDS) continue to be sampled: