REP00024 ‎(2)‎

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INTRODUCTION
Wyoming Fuel Company's (WFC) Canadian Strip Mine is located in Jackson County, Colorado (TBN,
R78W). The mine was projected to utilize a phased open pit mining technique with two general areas of
production. Pit #1 lies in Section 2 MN, R78W) and has been mined out with reclamation activities
completed in 1987. The proposed Pit #2 lies in Section 10 (TBN, R78W) with no development occurring.
1 WFC discontinued all mining operations at the mine site in mid 1982 because of coal marketing difficulties.
To comply with Stipulation I of the permit issued by CMLRB, an annual report of water resources
' monitoring must be submitted. The intent of this report is to comply with this requirement by presenting
the data collected to date for groundwater investigations. The following sections contain the materials,
methods and results of the groundwater and NPDES monitoring program in the Pit #1 area during the 1989
water year.
GROUNDWATER
' The Canadian Strip Mine lies in the northeast corner of North Park, a large basin underlain by thick
sequence of sediments. These sediments fill the large synclinal depression between the surrounding
mountain ranges. Within this synclinal depression lie numerous smaller structural features. One such
' feature is the McCallum anticline with the mine site being located on its southern terminus. At this
location, the anticline is breached such that the older rocks of the Pierre Formation arc exposed in the
center of the younger strata of the Coalmont Formation. As a result, this area acts as a groundwater
recharge zone for the Coalmont Formation. However, being at a high topographic elevation with no
' perennial streams, the recharge potential is limited to snow melt and major precipitation events.
Fifteen groundwater monitoring wells were installed within the vicinity of the Canadian Strip Mine
' (Exhibit C-2) all of which are completed in the Coalmont Formation. Four wells were initially installed for
monitoring the Pit #1 area. Wells 1 and 1C are completed below the Sudduth Coal Scam, Well IA is
completed in the seam and Well 1B is above the seam. The rationale for locating the wells where they are
was to monitor the down dip and down gradient effects on the groundwater system before, during and after
' mining.
In addition to those four wells, ten wells were installed in the proposed Pit #2 area. Wells 4A, 5A and
' 6A are completed in the underburden below the coal; Wells 4B, 5B and 6B are completed in the coal; Wells
4C, 5C and 6C are completed in the overburden immediately overlying the coal; and Wcll 2 is located in
unconsolidated surface material adjacent to Weir #1. All of these wells (except Well 2) were reclaimed in
' September, 1989.
Well 7 was installed in late 1980. It is located in the reclaimed area of Pit #1 to monitor groundwater
beneath the backfill. Additional information and lithology logs for each well have been provided in the
' permit document.
Water levels in each of the wells have been monitored monthly during 1981 and 1982 and annually from
' 1984 through 1989. Water levels were measured with a Soiltest, Inc. Model DR-762A electric line to the
nearest hundredth of a foot from the top of the well casing. Water samples were collected with a hand
bailer. Prior to sample collection, a minimum of three columns of water were evacuated to obtain a
' representative sample. All samples were filtered with glass fiber filters, preserved and stored in bottles, and
analyzed at Core Laboratories utilizing the methodologies as specified in Appendix 2. Those parameters
which were analyzed are listed in Table 1.
' The physical characteristics of each well are listed in Table 2. Water levels in each of the wells
(Appendix 1, Figure 1) have exhibited a relative increase in water level over the monitoring period. These
water levels may be affected by the artesian head which exists because of the down dip locations of the
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