1993-06-08_GENERAL DOCUMENTS - C1981041

• Permit No: C1981041
• IBM Index Class Name: General Documents
• Doc Date: 6/8/1993
• Doc Name: Proposed Decision & Findings of Compliance For RN2
• Permit Index Doc Type: FINDINGS
• Media Type: D
• Archive: No

of Health (CDOH) addressing the feasibility of diminishing salt
contribution to the Colorado River. This report was prepared
as required by the mines ' NPDES permit and has been reviewed by
the Colorado Department of Health at this time. CDOH has
determined that no action be required of Powderhorn Coal
Company to reduce salt contributions to the river and has
exempted the Roadside and Cameo Mines from specific numeric
limitations or construction of new treatment facilities .
Quarterly total dissolved soldis monitoring is still required .
Mine discharge from the Roadside and Cameo Mines were estimated
to increase soluble salts in the river by 0. 1 percent and
dissolved iron by 0.2 percent (November 4, 1982 DMG Findings
Document) . These predictions have proven to be accurate to
date.
In its 1982 Findings , the Division also predicted that water
quality effects would be "minimal and will not significantly
decrease water quality in the Colorado River . " Surface and
ground water monitoring will determine if the effects are
minimal , as expected .
Water monitoring conducted by Powderhorn since 1982 has not
identified any unanticipated effects on river water quality.
Portions of the water monitoring plan were suspended when the
mine was placed in temporary cessation from 1987 to 1989. As
of this renewal of the permit, mine water discharges from the
three approved NPDES points for mine water discharge will be
analyzed annually for the list of parameters in Table 2 .05. 68
of the permit .
2. Surface water runoff from disturbed areas on the mine site
passes through sediment ponds , with the exception of the 21
small areas discussed in Section II . A. of this document.
Discharges from these ponds have historically met effluent
limits in the mines ' NPDES permit except for discharges related
to severe storm events . Effects on water quality due to
disturbed—area runoff have been and should continue to be
insignificant.
Ground Water
Ground Water Quality
Four hydrologic units have been identified as aquifers that may be
effected by the mining operation . These are: Colorado River
alluvium, strata overlying the Cameo coal seams , Cameo coal seams ,
and the Rollins sandstone unit. Each of these will be addressed
below as to the mines ' probable impact on the aquifer .
Colorado River Alluvium
The Colorado River alluvium consists of silty sand intermixed with
gravel along the canyon and mine facility site . The alluvium varies
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