GENERAL41890

• Permit No: C1982054
• IBM Index Class Name: General Documents
• Doc Date: 7/5/1983
• Doc Name: PROPOSED DECISION AND FINDINGS OF COMPLIANCE
• Permit Index Doc Type: FINDINGS
• Media Type: D
• Archive: No

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GENERAL DESCRIPTION OF THE EXISTING ENVIRONMENT
The proposed operation is located in southwestern Colorado, approximately
2 1/2 miles southeast of Durango (Figure 1). Elevation of the area
ranges from approximately 6500 feet to 7400 feet.
There are no documented cultural properties in the proposed permit area.
The proposed Carbon Junction Mine will be located in the upper drainage
basin of Carbon Junction Canyon. This is an intermittent tributary to
the Animas River. The total drainage basin of Carbon Junction Canyon is
0.8 square miles. This drainage has a steep gradient and, through much
of its reach, is contained within steep valley walls.
The Carbon Junction Mine permit area is located on the northern edge of
the San Juan Structural Basin in Southwestern Colorado. The sedimentary
rock strata dip 26 to 30 degrees to the southeast and strike N45oE. No
major faults exist in the permit and adjacent areas.
The rock units exposed in the permit and adjacent areas are all
Cretaceous in age. These units include the Lewis Shale, the Pictured
Cliffs Sandstone, the Fruitland Formation and the Kirtland Shale. The
Carbon Junction Mine will extract coal from the Lewis coal seam ("C"
seam), Carbonero seam ("B" seam) and the Shamrock seam ("A" seam) within
the Fruitland Formation.
Ground water within the general area of the mine occurs in the Pictured
Cliffs Sandstone, the interbedded and lenticular sandstones, and the
coals of the Fruitland Formation, the Quaternary terrace deposits, and
the alluvium of the Animas River.
Ground water movement in the rock strata is controlled by the geologic
structure and the stratigraphy. Ground water within sandstone and coal
units flows down the dip of the strata and through fracture zones.
Bedrock aquifers are recharged at their outcrops and subcrops. These
aquifers discharge at lower elevations, primarily in stream valleys.
Lenticular and interbedded sandstones support only localized ground water
flows.
There are no alluvial valley floor deposits within the permit area.
The climate of the area is relatively moderate, with a monthly low mean
temperature of 25.3oF in January and a monthly high mean temperature of
67.O~F in July. Record temperature extremes range from a high of
99oF, recorded in August, to lows of -27oF, recorded in January and
February. Annual precipitation averages 18.04 inches, with a maximum of
2.36 inches in August and a minimum of 0.98 inches in November. The
average snowfall is 65.3 inches, with the highest amount in January (21.2
inches), followed by December (14.8 inches). The average wind direction
is generally from the west, with an average speed of less than one knot.