PERMFILE41947

• Permit No: C1980007A
• IBM Index Class Name: Permit File
• Doc Date: 4/8/2005
• Section_Exhibit Name: 2.05 Operation and Reclamation Part 2
• Media Type: D
• Archive: Yes

West Elk Mine
(~ With the findings and observations provided above as background information, the permit
document now toms to site-specific evaluation of probable hydrologic consequences (PHCs), based
on data from the current permit area, which includes the Box Canyon permit revision area.
PHCs are projected based on past experience, expected rates of water use and water discharge,
location and extent of mining (and subsidence) relative to basin geology and hydrology, and
hydrogeologic conditions of the mined interval and its overburden.
The probable surface and groundwater hydrologic consequences presented herein assume
implementation of the West Elk mining plan as shown on Map 51 and Map 52. This mining plan is
subject to refinement during detailed mine plan preparations by MCC. However, for purposes of
discussing anticipated hydrologic consequences, these plans (Map 51 and Map 52) reasonably
represent what will occur.
The discussion in the following sections specifically refer to events that occun•ed during 1996 and
1997 because they represent a divergence from the typical mine inflows the West Elk Mine
experienced in the past. MCC will provide the status of the past and any future large inflows,
including details regarding quality and quantity and how the water was managed in subsequent
Annual Hydrology Reports.
WWE's September 18, 1995 memorandum to CDMG entitled: "Basis for WWE's estimate of 15 to
20 acre-feet of Average Annual Hydrologic Impacts Due to Proposed Mining in Apache Rocks
+. Permit Revision Area" (Exhibit 19D), estimated that, using conservative assumptions, the
maximum average annual "loss" to the mine workings of waters from springs, streams,
groundwater and stock ponds in the Apache Rocks pemut revision area would be 15 to 20 acre-feet.
In the Apache Rocks permit revision application (PR06), W WE coricluded that: "This water will be
collected underground, pumped to the surface, treated and released into the North Fork or Dry Fork.
There is little practical consequence associated with losses of this magnitude." This was WWE's
projection prior to the fault inflows at the mine in 1996 and eazly 1997. The fault inflows represent
a major new source that was not accounted for in the September~l8, 1995 WWE memorandum.
The analysis in that memorandum remains valid; however, the analysis must be broadened to
include the fault inflows. The text that follows explicitly describes haw fault inflows change the
hydrologic balance at the West Elk Mine, and presents the associated hydrologic consequences. For
each of the key PHC elements (surface water quanfity, surface water quality, groundwater quantity
and groundwater quality), key findings are presented.
The PHCs anticipated within the current permit and Box Canyon pernut revision areas are
presented as follows:
1. Surface Water Quantity Effects.
2. Surface Water Quality Effects.
3. Groundwater Quantity Effects.
4. Groundwater Quality Effects.
~i
1.05-148
November 2004 PRI /