HYDRO29683

• Permit No: C1981033
• IBM Index Class Name: Hydrology
• Doc Date: 1/20/1998
• Doc Name: COMPARISON OF WEST ELK MINE FAULT DISCHARGE WATER WITH DISCHARGE WATER FROM THE EDWARDS MINE PORTAL
• Permit Index Doc Type: OTHER SURFACE WATER
• Media Type: D
• Archive: No

Mayo and Asaodafer, lC
~ groundwater inflows into WEM. This investigation is now complete and the final report will
' be released in early February 1998.
Thermal groundwater issuing from the 14 SEHG fault was pumped to the NE Tailgate sump
1 where it acquired considerable total suspended solids. From the NE Tailgate sump a portion
of the thermal groundwater was discharged to the surface; however, a large volume of this
discharge water was pumped to the NW Panels sealed sump for underground storage and
J settling of suspended particulate matter. In Mazch 1997 groundwater from the 14 SEHG and
BEM faults filled the NW Panels sealed sump to the elevation of the ventilation seals near
the Lone Pine Gulch fan portal (Figure 1). Pumping [o the NW Panels sealed sump was
discontinued at that time. Dischazge from BEM fault has now ceased; however, water is now
flowing from a northeast extension of this fault in the 14 SE Tailgate.
Solute and Isotopic Composition of Mine Waters
1 Mean solute compositions of various mine waters are listed in Table l . These waters include
samples from eight fault-related sources in WEM (Figure 2), one sample from the 7 NWLP
seal near the Lone Pine Gulch fan, one sample from the Edwards portal spring (Figure 1), and
one sample from a Rollins Sandstone monitoring well, LP-1 (Figure 2). Table 1 lists
chemical analyses in both mg L"' and meq L-' reporting units. Stable and unstable isotopic
compositions of various mine waters are listed in Table 2.
Tables 1 and 2 contain four different groups of waters:
l 1. WEM in-mine fault groundwater,
J 2. WEM NW Panels sealed sump at the Lone Pine seal,
3. Edwards portal spring water,
1 4. Well water from the Rollins Sandstone at LP-1.
Each of these waters has a distinct solute composition as illustrated by the shape of their Stiff
diagrams (Figure 3) and their plotting locations on the Piper (1944) plot (Figure 4). Except
for LP-1 groundwater, the key differences between these waters are summarized below. LP-
1 is included in the tables because it is a high SO water from the Rollins Sandstone from a
location near the Bear Mine. It is not discussed in detail because complete laboratory
analysis of the composition is not available.
WEM Fault Groundwater
Although 14 SEHG fault waters may be statistically distinguished from other fault waters on
1 the basis of Na' and SO;-contents, all in-mine fault waters have similar solute compositions
J in that they are Nay-HCO; type waters and have small concentrations of other solutes. Solute
differences between 14 SEHG and other fault waters are due to hydrodynamic partitioning in
l the Rollins Sandstone. The S'-H and 5180 contents of these waters, discussed below, also
J demonstrate hydrodynamic partitioning. The two fault waters of interest to this investigation
are the 14 SEHG and B East Mains (BEM). These waters have mean Na' contents of ~ 50
edwspr.doc 2 20 January 1998