APPCOR10147

• Permit No: C1981025
• IBM Index Class Name: Application Correspondence
• Doc Date: 12/2/1981
• Doc Name: MEMO ADEQUACY REVIEW OF MATERIALS SUBMITTED BY SNOWMASS COAL CO NORTH THOMPSON CREEK MINES FN C-
• From: MLR
• To: BOB LIDDLE
• Media Type: D
• Archive: No

Bob Liddle -S- December 2, 1981
9) The proximity of the coal processing waste pile and its associated
sediment pond to North Thompson Creek, along with the ground water communication
of the unconsolidated materials under the pile and sediment pond with the North
Thompson Creek alluvium warrants a detailed evaluation of their impacts on ground
and surface water quality. The impacts of the coal processing waste pile on
the ground and surface water quality has been inadequately addressed and
monitored. Previous studies conducted by Snowmass were deemed inadequate (see
memo of July 8, 1980). These studies were to be redone once a monitoring well
was installed and monitored upstream of the pile. These studies were never
submitted to the Division. Monitoring of water levels in monitoring wells located
around the pile and pond,and the quality of ground water in these wells were
required under the interim permit approval of the permit amendment in order to monitc~~
the effects of mining on the hydrologic balance and to determine conformance with
the applicable performance standards. Monitoring of these wells will be required
during and after mining until bond release to monitor conformance. Therefore,
the ground water monitoring section of the permit should contain a description
of monitoring of these wells.
10) R ground and surface water monitoring plan should be submitted and
ifmnediately initiated along Middle Thompson Creek. Ground water quality and
quantity monitoring along this creek should include alluvial wells downstream
of the outcrop of the Rollins sandstone, over the coal subcrop and upstream of
the area to be undermined, and within the angle of draw. Surface water stations
should be installed up and down stream of areas to be effected by mining. The
data gathered from this monitoring should serve as a baseline and as a monitor
of the effects of mining in the quality and quantity of surface and ground water
within Middle Thompson Creek. The data gathered should be used in the description
of the prevailing hydrologic balance and of the consequence of mining on water
rights and on the hydrologic balance.
II) Data on water levels and water quality from bedrock monitoring wells
were not continued after the initial aquifer testing was concluded on these wells.
This monitoring was agreed to and was included within the approved interim permit
amendment. The result of this lack of monitoring is a Lack of data needed for
the applicant to adequately assess the seasonal fluctuation of the quality and
quantity of ground water and to adequately assess the hydrologic consequences of
mining on ground water quality and quantity within the bedrock aquifers. Since
these wells monitor permeable strata above the mine which are in hydrologic
communication with the alluvial and surface waters of North Thompson Creek, data
from these wells is necessary in assessing depletion of ground water from these
bedrock aquifers, of ground water from the North Thompson Creek alluvium, and of
surface water flowing in North Thompson Creek.
The ground water monitoring section should include monitoring of the quality and
quantity of water from the bedrock wells located on the surface and within the
mine. Once a year's worth of contiguous data has been collected according to
parameters on Attachment B, Snowmass may petition the Division for a reduction
in the number of parameters analyzed, the frequency of sampling and the number
of sites sampled.