GENERAL35006

• Permit No: C1991078
• IBM Index Class Name: General Documents
• Doc Date: 3/13/2007
• Doc Name: Proposed Decision & Findings of Compliance for RN3
• Permit Index Doc Type: Findings
• Media Type: D
• Archive: No

3. Surface and Ground Water Monitoring was temporarily halted in July, 1999
until two years prior to the submission of a Phase III bond release request.
4. Probable Hydrologic Consequences
a. Ground Water
The permit area for the Hamilton Mine consists of 757 acres and is located
approximately 2 miles southeast of the town of Naturita in Montrose County. The
permit area overlies part of the Nucla-Naturita Coal Field. The azea is characterized
topographically by dissected mesas sloping to the north towazd the San Miguel
River. The region is underlain by sedimentary rocks of Jurassic and Cretaceous age
which dip gently to the north. The entire permit area is underlain by the Lower
Cretaceous Dakota Sandstone, which consists of interbedded conglomeratic
sandstones, dark-gray cazbonaceous shale, and numerous coal seams. Five coal
seams are present in the Dakota Sandstone in the permit area, three of which are of
minable thickness.
Underlying the Dakota Sandstone is the Lower Cretaceous Burro Canyon
Formation, which is approximately 150 feet thick. It consists generally of two beds
of conglomeratic sandstone, each 10 to 40 feet thick, separated by a shale sequence.
The lower sandstone of the Burro Canyon Formation contains the only significant
ground water accumulations in the permit azea. This aquifer lies 90 to 100 feet
stratigraphically below the lowest coal seam to be mined. The applicant has
monitored wells BW-1, BW-2, and BW-3 to establish pre-mining water levels and
quality. Yield from these-wells vary from zero to three gpm. No other ground water
development has taken place in the vicinity of the permit area.
Five springs or seeps have also been located in and azound the permit azea at the
contact of the Burro Canyon and the underlying Morrison Formation. The dischazge
of these springs is generally so slight as to be immeasurable, and most have been dry
since the second quarter of 1989. Specific conductivity of the water varies from
approximately 1100 to 1700 umhos/sec.
Potential impacts to ground water from the operation include:
- Lowering of water levels in the Burro Canyon aquifer;
-Contamination of the Burro Canyon aquifer,
- Lowering of water levels in alluvial aquifers of Bramiers Draw and
Section 33 Creek;
-Contamination of the same alluvial aquifers.
As described above, relatively continuous sandstones in the lower Burro Canyon
Formation yield small amounts of water to wells and aze the source of several small
springs and seeps in and azound the permit azea. Along with the rest of the
13