2007-03-16_REPORT - C1981010 (7)

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1.0 INTRODUCTION This report presents the ground -water and surface -water monitoring results for Trapper Mine for 2006. Significant mine activities during 2006 include continued expansion of the Ashmore (A), Flintlock (F), Gatling (G) and Z pits. Mining was completed in 2002 in the Derringer (D) pit. Dewatering was conducted in the A, F and G pit areas in 2006. Well dewatering was used in 2006 in the G pit area Ground -water monitoring of the aquifers associated with Trapper Mine started in 1974. The ground -water flow regime has been divided into the major sandstones and coal/adjacent sandstone aquifers. This division of the aquifer systems was selected at clay and shale units, which have the potential to retard vertical movement. A pull -out index presents the schematic of the aquifer units at Trapper on one side and the basic well data table on the other. It is suggested moving this index sheet to the section of the report being reviewed. Aquifer properties are presented in Table 2 -1 of the 1990 Annual Hydrologic Report. The Twenty Mile Sandstone is the first major sandstone below the mined coal seam at Trapper Mine. The U coal seam and adjacent sandstones is a minor aquifer between the mined coal seams and the Twenty Mile Sandstone. The Q and R coal seams and sandstone between these two coal seams have been labeled the QR aquifer. This is one of the major aquifers of interest because C, D, E, F, G and Z pits have mined the Q and/or R coal seams, currently the F and Z pits mine the Q seam. The K, L, and M coal seams and the sandstones, which are stratigraphically in this interval, are called the KLM aquifer. The F pit mines the I, L, M and Q seams while the G pit mines the H, I and K seams and the Z pit mines the I, L, M and Q seams. The KLM aquifer is above the QR aquifer, but below the HI aquifer. The H and I coal seams and sandstone between Trapper Mining Company 1 -1 2006 Annual Report