2009-03-02_PERMIT FILE - C1980004A ‎(9)‎

• Permit No: C1980004A
• IBM Index Class Name: Permit File
• Doc Date: 3/2/2009
• Section_Exhibit Name: Appendix N Probable Hydrologic Consequences
• Media Type: D
• Archive: Yes

• PROBABLE HYDROLOGIC CONSEQUENCES
EAST SALT CREEK-SURFACE WATER
The Division of Wildlife (DOW) has requested additional information (as part of
TR-16 adequacy response #3, item #52) specific to the impact of adding mine water
and leachate to the surface waters of East Salt Creek. In particular, if the heavy metals
in the mine water and leachate will be detrimental to wildlife utilizing the waters. The
DOW suggested evaluating East Salt Creek monitoring points above and below
McClane Canyon mine and suggested analyzing the waters for,heavy metal
concentrations.
Data has been gathered quarterly for the surface waters of East Salt Creek as
part of the Annual Hydrologic Report required by the DRMS, over the last several years.
The monitoring points that are applicable to the DOW's request are SW-1 which is
above McClane creek and SW-8 which is above Munger Creek. The data evaluated for
SW-1 and SW-8 is an average of the values recorded during the irrigation season for a
five year period during Quarters 2 and 3 and the summary is shown in Table N-9.
Laboratory data for mine water discharge has been collected over a two year
time period at the request of the Colorado Department of Public Health and
Environment (CDPHE). The mine water samples, shown in Table N-8, will be used to
compare to the surface waters of East Salt Creek. For the purposes of projecting the
effect of mine discharge on East Salt Creek, it will be assumed the maximum mine flow
rate is 100 gpm or 0.22 cfs, as explained on page 2.
Data for the leachate will be those parameters sampled from the McClane
Canyon Coal Mine waste pile in 2001 and are shown in Table 2.1-6. In order to
account for the leachate from the Sediment Pond into the groundwater, and thus into
East Salt Creek, steady-state seepage at full-pool was assumed. Using a hydraulic
conductivity of 1(10-4) ft/sec, GeoSlope 2007 calculated the flow to be 0.08 gpm, as
shown in Appendix S. In addition, leachate from the gob pile, at 1.5 gpm will be added
to the sediment pond leachate for a total of 1.58 gpm (0.004 cfs) and from here forward
be referred to as `leachate'. Discharge from the sediment pond into East Salt Creek will
be a manually controlled event, via a 6" plastic pipe, and historically has been a very
rare occurrence. In the last three years, the sediment pond has only discharged three
times and therefore not considered a contributor, even minor, to the overall quality of
East Salt Creek and will not be included in this analysis.
The metals that were evaluated for comparison between East Salt Creek and the
mine water discharge and leachate are arsenic, copper, manganese, lead and selenium
and are highlighted yellow in Table N-8. These metals were chosen for analysis
because the CDPHE required them to be evaluated, and they are part of the quarterly
monitoring program required by the DBMS. In addition, the DOW listed iron, selenium,
and arsenic as potentially damaging metals to the wildlife utilizing East Salt Creek
• surface waters.
Appendix N - TR-16 - 11 - 10/08