GENERAL47858

• Permit No: C1981008
• IBM Index Class Name: General Documents
• Doc Date: 5/25/1988
• Doc Name: PROPOSED DECISION & FINDINGS OF COMPLIANCE FOR RN1
• Permit Index Doc Type: FINDINGS
• Media Type: D
• Archive: No

observed blas~;ing operations casting rocks onto the roads and requests for
additional information from Ms. Nyland-Naff went unanswered. Based on the
information on file, the Division believes this allegation has been adequately
addressed.
Besides these two letters, the Division had some adequacy concerns as
addressed in a January 14, 1988 letter. Peabody responded to these concerns
on February 18, 1988, March 10, 1988, and April 6, 1988. These response
letters adequately addressed the Division's concerns.
Description of the Environment
The Nucla Mine permit area encompasses 426.6 acres. The topography is gently
sloping with a few small ridges and swales. Most of the land surrounding the
permit area is agricultural and is used primarily for irrigated and
non-irrigated farmland which produces alfalfa and pasture grasses.
Agricultural practices have been abandoned within the permit area.
The mine is located within the southeast portion of the Colorado Plateau. The
region is characterized by broad, fairly smooth surfaced plateaus and mesas
with gently dipping slopes dissected by steep canyons. Surface elevations at
the mine range from a high of 5,767 feet (MSL) in the northwest part of the
permit area to a low of slightly less than 5,672 feet in the southeast part of
the permit area along Tuttle Draw (see Exhibit 7-1 of the permit application
and the attached Index Map Figure 1). Total topographic relief for the permit
area is about 9:5 feet.
Surficial geolo~ly in the area consists largely of consolidated sedimentary
rock of Cretaceous age Dakota Sandstone. A veneer of Quaternary
colluvial/alluvial material is present in the drainages becoming more
significant along the major streams in the area (Figure 2).
The upper two seams of coal within the Dakota Sandstone member are mined at
the site. In a~.cending order these are the Number 2 or Lower Dakota seam and
the Number 1 or Upper Dakota seam.
Due to the nature of the Dakota Sandstone in the permit area, discontinuous
aquifers are present in the overburden, coal, and underburden. These areally
limited aquifers are generally characterized by poor quality water.
Surface water draining from the Nucla Mine enters Tuttle Draw, a tributary of
the San Miguel River. The San Miguel is located in west-central Colorado and
is tributary to 'the Dolores River. Streamflow in the San Miguel is a result
of snowmelt runoi'f from the Uncompahgre Mountains to the east and summer
thunderstorms within the watershed, Low elevation tributaries such as Tuttle
Draw contribute relatively small amounts of streamflow due to low
precipitation. F~eak flows occur in late Mdy to June and are related to
snowmelt. The 1o•west flow on record for the San Miguel above the mine at
Naturita, Colorado occurred during August of 1977 when streamflow completely
ceased.
Most of the baseflow in Tuttle Draw is the result of irrigation return flow.
The source of this irrigation water is the San Miguel River. The historic use
of Tuttle Draw has been identified as irrigation return flow for downstream
agricultural use. Water quality in the San Miguel tends to exhibit increased
total dissolved solids concentrations in late summer due to this use and lack
of available dilut;ion water during this low flow period.
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