GENERAL35449

• Permit No: C1984063
• IBM Index Class Name: General Documents
• Doc Date: 12/14/1984
• Doc Name: PROPOSED DECISION AND FINDINGS OF COMPLIANCE
• Permit Index Doc Type: FINDINGS
• Media Type: D
• Archive: No

_P2_
1. Eastside Coal Co., Inc.--Eastside Mine, CMLRD File No. C-84-063
2. Storm King Mines--Coal Ridge No. 1 Underground Mine, CMLRD File
No. C-84-065
These two mining operations are underground operations. The life-of-mine
areas of these mines are plotted on figure 3. In addition, the area of
surface disturbance, the area to be undermined during the permit term, and the
area to be undermined during the life-of-mine are tabulated in Table 2.
The Coal Ridge No. 1 Mine and the Eastside Mine are both located along the
Grand Hogback Monocline. The Grand Hogback trends east-southeast in the area
with rock strata dipping to the south-southwest at an average of 500. The
general direction of ground water movement is down dip. The life-of-mine
boundaries of the Eastside and Coal Ridge No 1 Mines are 7 miles apart along
strike. The coal seams to be mined are located within the lower section of
the Mesa Verde Group in the upper portion of the Iles Formation (E-seam) and
the lower portion of the Williams Fork Formation (Wheeler seam). The
stratigraphy of the area is shown in Figure 2. These two seams are separated
by 200 feet of interbedded shales, sandstones, siltstones, and coal. The
five-year operation plan of the Eastside Mine calls far mining of the E-seam.
The Coal Ridge No. 1 life-of-mine plan calls for mining of the Wheeler seam.
The potential of the Mesa Verde to produce ground water within the area of
these mines is greatly limited by the extreme dip of the rock strata. An oil
and gas well drilled five miles southwest of the Eastside Mine encountered the
Wheeler coal at a depth of 7300 feet. Another well drilled approximately 6
miles southwest of the Coal Ridge No. 1 Mine encountered the Wheeler seam at
approximately 9000 feet in depth (Tremain, 1983).
As previously stated in Section VIII (the PHC of the Eastside Mine), there is
little potential for cross-communication between strata within the Mesa Verde
Group due to the interbedded impermeable shales located throughout the
section, Also, in the vicinity of the mines, the Mesa Verde Group is
underlain and overlain by impermeable thick shale members of the Mancos and
Wasatch Formations respectively. Therefore, the ability of ground water to
migrate upward or downward through the section is extremely limited. For
these reasons, the bedrock ground water impacts of each mine are localized to
the immediate vicinity of the mine. It is assumed that ground water will not
migrate along the strike. However, cumulative impacts to the hydrologic
balance due to localized degradation or diminutiion of bedrock ground water
could affect the nature of surface water and alluvial aquifers of the region.
The Eastside anc
River Basin. Tt
River, with the
approximately 5t
Harvey Gap, a
consequences of
section. This
Coal Ridge No. 1 Mines are both located within the Colorado
e Coal Ridge No. 1 Mine is directly adjacent to the Colorado
surface facilities located on alluvial /colluvial fan terraces
feet above the Colorado River. Eastside Mine is located on
tributary to the Colorado River. The probable hydrologic
mining on Harvey Gap have been detailed in the previous
CHIS addresses the potential of the hydrologic impacts
predicted for the two
mines to cumulatively affect the Colorado surface water
system and the related ground water of the alluvium.