2020-10-22_PERMIT FILE - C1981012A ‎(4)‎

• Permit No: C1981012A
• IBM Index Class Name: Permit File
• Doc Date: 10/22/2020
• Section_Exhibit Name: Section 2.05 Operation and Reclamation Plan
• Media Type: D
• Archive: Yes

concentrations of trace elements are far below both the reliability of
the computation method and the ability to detect the changes.
Surface runoff from the refuse pile is expected to be in the range
of 7.6 to 12.7 acre -ft in the year of maximum surface area. Runoff will
be routed through a sediment pond that will result in concentrations of
suspended and settleable solids in compliance with effluent limitations.
Concentrations of iron and manganese in the discharge are estimated at
0.3 mg/l and 0.03 mg/1, respectively. These values are well below the
corresponding limitations of 3.5 and 2.0 mg/1 for average daily
conditions. The concentration of dissolved solids in the sediment pond
discharge is estimated at about 1000 mg/l. It is estimated that this
will increase the average in -stream TDS concentration in the range of 0.3
to 0.5 mg/1 at the Madrid gaging station. The increase will be on the
order of 1 mg/1 immediately downstream from the New Elk Mine.
Subsurface seepage through the refuse pile is expected to occur
as the result of abnormally wet years, only. Average precipitation
conditions should result in no leachate production. The maximum annual
volume of seepage resulting from an abnormally wet year is estimated at
3.6 acre -ft and is expected to contain about 4200 mg/l dissolved solids.
Such a discharge would increase the average in -stream TDS by 0.5 mg/1 at
Madrid and by about 1 mg/l at the New Elk Mine. Calculated changes in
the in -stream concentrations of all trace elements are far below the
level at which change can be measured. The calculations on which these
statements are based were made for conditions substantially worse than
expected to occur on the average.
In summary, the construction of the refuse pile will have no
effect on the quantity of water yielded by the watershed. Under
reasonable worst case conditions, the combined effect on in -stream water
quality (Purgatoire River) will be to increase the average TDS
concentration in the vicinity of the mine by about 2 mg/1. Changes in
the in -stream concentrations of trace elements will be well below the
level at which such changes can be measured. Concentrations of iron and
manganese should be on the order of 20 percent or less of applicable
effluent limitations.
RN -6 2.05-95 (Repaginated 10/21/16)