GENERAL48692

• Permit No: C1981019
• IBM Index Class Name: General Documents
• Doc Name: Proposed Decision & Findings of Compliance
• Permit Index Doc Type: General Correspondence
• Media Type: D
• Archive: No

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V. Hydrologic Balance: Surface Water - Rules 2.04.5, 2.04.7, 2.05.3(4),
2,05.6(3) and 4,05
A detailed discussion of the existing environment, including water quality
data, flow records, and water balance estimates, can be found onpages 2.04-33
through 2.04-56 in Volume I of the application. Additional water quality
data is included in Exhibit 6, Volume II.
Three existing sediment ponds control runoff from disturbed areas at the mine
site and the rail Ioadout. These ponds have been designed to meet the effluent
limitations of Rule 4.05. One proposed pond is included in the application.
A general discussion of ponds, impoundments, and diversions is found on pages
2.05-23 through 2.05-25 of Volume I. Designs and specifications are presented
in Exhibit 7 of Volume II. Diversions, ponds, and other methods Colowyo will
employ to protect the balance are discussed on pages 2.05-71 through 2.05-73
and pages 4.05-1 through 4.05-15.
In the Rpril 9, 1981 Preliminary Adequacy Letter, the Division stated that
additional chemical parameters would be required in future surface water quality
monitoring at Colowyo. The applicant proposed to measure pH, total suspended
solids, total dissolved solids, iron, manganese, and oil and grease content
of any water discharged from the permit area, and report on quality and
quantity annually as required by their NPDES permit. The applicant has
subsequently committed to sampling surface water in both Taylor and Good Spring
Creek as well, and analyzing samples for the parameters listed below:
pH Sodium (Na+)
Conductivity at 25oC Sulfate (SOg)
Total Dissolved Solids Arsenic (AS)
Total Suspended Solids Iron (Fe)
Bicarbonate (HCO3) Lead (Pb)
Calcium (Ca+2) Manganese (Mn)
Magnesium (Mg+2) Mercury (Hg)
Ammonia (NH3) Selenium (Se)
Nitrate-Ni tri te Zinc (Zn)
_3
Phosphate (P04 as P)
Certain additional information regarding the monitoring program is still required
in order to ensure that the plan will, to the extent possible, verify the
predicted effects of mining on the hydrologic balance. Field measurements
of pH, electrical conductivity, temperature and total suspended solids should
be collected monthly on Good Spring Creek. Flow measurements should also be
recorded monthly. On Taylor,Creek, flow measurements and field parameters
will not be required during winter months when the streams are iced over.
-The following stipulation is imposed: