1992-12-16_GENERAL DOCUMENTS - C1980007

• Permit No: C1980007
• IBM Index Class Name: General Documents
• Doc Date: 12/16/1992
• Doc Name: Proposed Decision & Findings of Compliance for RN2
• Permit Index Doc Type: Findings
• Media Type: D
• Archive: No

Hydrologic Balance - Rules 2.04.5, 2.04.7, 2.05.3(4) , 2.05.6(3) and 4.05
Ground water information can be found in Section 2.04.7 of the permit
application. Additional information can be found on Map 34 for locations of
the ground water monitoring stations and Map 35, which is a composite Barren
member well water level and spring elevation map.
A description of ground water occurrence and mining impacts on ground water
within the permit and adjacent areas can be found in the "Probable Hydrologic
Consequences of Mining" section of this document and the "Cumulative
Hydrologic Impact Study" document for this mine area.
The ground water systems relevant to mining activities in the region are the
alluvial deposits associated with streams and the Mesaverde Formation. Ground
water use in the general area around the West Elk Mine is confined to shallow
wells in the alluvium and Rollins Sandstone of the North Fork of the Gunnison
River and its tributaries .
The West Elk Mine ' s experience in mining the F seam indicates that ground
water inflows are associated with fractures near the subcrop and are
seasonal . Evidence suggests that ground water movement is controlled largely
by fracture patterns and topography.
There are seven categories of potential aquifers that occur in the Somerset
Coal Field. These are: 1 ) the alluvial and terrace deposits associated with
the North Fork of the Gunnison River; 2) the localized, shallow alluvium along
creeks tributary to the North Fork; 3) the discontinuous, lenticular and
laminar sandstones of the Mesaverde Formation; 4) the Rollins Sandstone;
5) the coal seams; 6) shallow colluvial surficial deposits ; and 7) fracture
zones in bedrock.
The most continuous sandstone aquifers of any significance in the region are
the Rollins Sandstone and the massive sandstone separating the upper and lower
Coal members of the Mesaverde Formation. However, the latter massive
sandstone produces very little water, as evidenced by the dryness of the Bear
Mine and the lack of springs associated with this unit. The Mesaverde
Formation tends to be dry, or the rock units are of such a low permeability,
they yield insufficient water for sustained use or mine discharge. The
sandstones are lenticular and discontinuous and are usually highly cemented.
A description of the surface water system can be found in Section 2.04.7 of
the permit application. Supporting information is contained in Map 34, which
illustrates the drainages associated with the WEM coal lease area, Map 37,
which delineates the location of all known springs on the coal lease area, and
Map 36, which shows the reservoirs and irrigation ditches associated with the
Minnesota Creek Basin.
A description of the surface water occurrence and mining impacts on adjacent
areas can be found in the "Probable Hydrologic Consequences of Mining" section
of this document, and the "Cumulative Hydrologic Impact Study" document for
this mine area.
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