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West Elk Mine
<br />The same Decree, along with the document entitled, "Protection of Minnesota Creek Water
<br />Supply," (Exhibit 58) included by reference in the Decree, offers mitigation in the event that
<br />monitoring reveals hydrologic changes. For example, as a last resort, MCC will maintain materials
<br />onsite to convey streamflows over cracks that might develop in stream channels. Pumps and
<br />discharge pipe will be kept onsite to lift water from the mine workings to the Dry Fork if losses are
<br />observed. If these measures are not adequate, MCC will cease diverting its senior water rights on
<br />Minnesota Creek near Paonia, thereby leaving the water in the stream to satisfy water users. MCC
<br />has extensive portfolios of water rights on both the Dry Fork and North Fork.
<br />MCC is prepared to implement and conduct its augmentation plan commitments on the "time-step"
<br />basis specified by the Colorado State Engineers Office, whether it be daily, monthly, by season or
<br />annua[iy. MCC is prepared to utilize its North Fork rights in the same manner as described in the
<br />Water Rights section of this text.
<br />MCC collects mine water inflows and operational runoff water in the mine, and pumps it directly to
<br />Lone Pine Gulch, Sylvester Gulch and/or the North Fork per NPDES dischazge requirements, to
<br />sedimentation ponds MB-1 or MB-2R for treatment, if necessary, and is discharged into the
<br />receiving streams or to temporary storage in various sumps within the mine. The changed timing of
<br />these return flows to the receiving streams is of no practical consequence, because the inflows via
<br />fault systems faz exceed the losses (or consumptive uses) to the North Fork. In addition, the mine
<br />inflows are a new, non-tributary source of contributions to the North Fork. Similazly, because
<br />losses within the mine aze roughly 5 percent of the total inflow, the annual loss will be 1 acre foot or
<br />less. It is also important to recognize that at those times when inflows (other than those from the
<br />fault systems) to the mine aze likely to be at their highest levels (during snowmelt runoff), water
<br />users in both basins should be satisfied rather than "calling" for water.
<br />Streams
<br />Baseline data for streams in and adjacent to the permit azea are being obtained as presented in
<br />Section 2.04.7 and, more specifically, on Table 5. Drainage basins and the resources monitored or
<br />proposed for monitoring are shown on Map 34.
<br />Monitoring to determine the hydrologic consequences to streams is by seasonal measurements
<br />(three times per year to correspond to the start of spring runoff, the peak spring runoff, and the fail
<br />low flow) of flow, pH, conducfivity, and temperature aze taken. Seasonal samples aze also obtained
<br />from the Sylvester Gulch and North Fork sites for analysis of TDS Fe, Mn, and TSS. Annually
<br />during the second sampling (except for the North Fork which is during the third sampling), MCC
<br />performs afull-suite laboratory analysis of water solids (TDS), total suspended solids (TSS),
<br />calcium, magnesium, sodium, SAR, hardness, bicarbonate, chloride, nitrate/nitrite, phosphate (POZ 3
<br />as P), sulfate, iron (total & dissolved), manganese (total & dissolved), aluminum (dissolved) azsenic
<br />(total recoverable), cadmium, copper, lead, mercury (total recoverable), molybdenum, selenium
<br />(total recoverable), and zinc.
<br />A seasonal, rather than quarterly or semi-annual water quality monitoring schedule was instituted
<br />. for a variety of reasons. The primary reason for selecting seasonal sampling is that, in many
<br />instances, particulazly streamflow and spring flows, these are the only periods of measurable flow.
<br />1.05-154 Revised November 2004 PR/0
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