<br />' William J. Carter March IZ, 1998
<br />Re: Response to Susan Burgmaier's comments on the 1996 Annual Hydrologic Report
<br />Since the mine water discharge from Outfall 011 enters the North Fork of the Gunnison River
<br />between NF-1 and NF-2, the upstream and downstream monitoring sites, it stands to reason that
<br />' NF-2 will have higher total dissolved solids than NF-1 due to the effluent of Outfall 011. Again,
<br />results of the "Aquatic Impairment Study of the Sanborn Creek Mine Discharge, Somerset,
<br />Colorado" by John C. Emerick, Nevis E. Cook, and Susan M. Hoffineister, January 30, 1995, do
<br />' not indicate a significant impact.
<br />For 1996, the average total suspended solids for Ou[fall 011 was 3 mg/l, with a maximum of 7
<br />mg/l.. There has not been an exceedence of [he total suspended solids limitations of Colorado
<br />Wastewater Discharge Permit System, Permit Number CO-0000132 for the Daily Maximum of 70
<br />' mg/1 or the 30-Day Average of 35 mg/1 since the C-Seam sump was established in April 1994. For
<br />1993, the average total suspended solids for Outfall 011 was 21 mg/l, with a maximum of 100 mg/I.
<br />In 1993, when samples were required weekly, 10 samples had total suspended solids between 35
<br />' mg/I and 70 mg/I, and 2 samples were over the Daily Maximum of 70mg/1.
<br />Because of the improvement to water quality, the Colorado Department of Public Health and
<br />Environment reduced the frequency of sampling for Outfall Ol l from weekly to monthly, effective
<br />in the fourth quarter of 1995. Although we are only required to analyze the samples for total
<br />dissolved solids quarterly, and total dissolved solids is no longer listed as having a discharge
<br />' limitation, under the existing Colorado Wastewater Discharge Permit System, Permit Number CO-
<br />0000132, December 1, 1996, we continue to routinely analyze for total dissolved solids from the
<br />t monthly samples.
<br />Comment 5.
<br />' "Outfall 011 showed a marked increase in flow for the period of February 5-12, 1996. The
<br />excursion from average is no[ discussed in the report test. Has OCM determined a cause for this
<br />increase?"
<br />' Response 5.
<br />The Sanborn Creek Mine uses one of two pumps for the mine water discharge, Outfall Ol 1. On, or
<br />' about February 5, 1996 the water being pumped out of the mine was switched from one pump to
<br />the other pump. On February 5, 1996, one meter was read as 36,337,000 gallons, and the other
<br />meter was read as 99,379,800 gallons. On February 12, 1996, the first meter was read as
<br />' 36,337,000 gallons, and the other meter was read as 99,927,000 gallons, indicating the switch over
<br />in the pumps.
<br />' The data presented in Table 1, Ol 1 Meter Readings for 1996, suggests the meter may have read
<br />97,379,800 gallons on February 5, instead of 99,379,800 gallons. This could have been an error in
<br />' the meter reading, or a error in writing down the reading. The meters are read at the start of the
<br />week, during Sunday night graveyard shin, by the Fire Boss as part of his weekly inspection of the
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