Laserfiche WebLink
Hydrogeological Evaluation of Sunday Mines Group <br />Geologic and Hydrologic Conditions <br />Rim Sandstone unit is currently unknown. Denison intends to continue collecting <br />groundwater quality data from the wells for a period of at least one year to further <br />define the ambient groundwater condition. <br />Marc4lApril 2009 Groundwater Investigation <br />Denison completed additional groundwater investigations in March and April, 2009. <br />The purpose of these investigations is to test the interpretive hydrogeologic <br />framework presented in Section 2.4 by collecting static water level and stratigraphic <br />information in the vicinity of the Sunday Group mines. This investigation included <br />measuring hydrogeologic information in exploration drill holes, and collecting and <br />compiling additional data regarding the locations of groundwater within the <br />underground mine workings. Data from this investigation are described in Appendix <br />A. This information is currently being analyzed but preliminary analyses suggest the <br />following: <br />¦ The interpretation of equilibration of the groundwater potentiometric surface <br />between adjacent fault blocks presented in Section 2.6 is not entirely correct, and <br />areas of groundwater compartmentalization within fault-bound blocks appear to <br />present, particularly in the area of the Sunday and Carnation mine affected areas. <br />This suggests that groundwater flow between adjacent fault-bound blocks is <br />restricted in some areas, which is consistent with the interpretation of Weir et al. <br />(1983) that faults penetrating shale units may deform plastically thereby restricting <br />groundwater flow. <br />2.4.6 Existing and Future Uses of Groundwater <br />Existing or potential future uses of groundwater within 2 miles of the Sunday Group <br />Mines are limited because the land is primarily public land administered by the <br />Bureau of Land Management and because groundwater resources are deep, generally <br />of poor to moderate quality, and yields in some formations are low (e.g. Salt Wash <br />aquifer) The only current groundwater use in the area is an industrial use to support <br />Denison Mining operations, which is permitted by a Colorado Well Permit. <br />Groundwater use in conjunction with mining activities is limited to small quantities of <br />water used for drilling and dust suppression purposes within the underground <br />mines. Currently, approximately 400 gallons per day of groundwater is pumped from <br />the base of the West Sunday Mine to several areas within the Sunday Mines Group <br />Complex (Stanley Davies, West Sunday Mine Superintendant, personal <br />communication 2008). Although the available groundwater volume is low <br />(approximately 0.3 gallons per minute), it is currently sufficient to supply needs for <br />the underground mining operations. Groundwater used in the underground mines is <br />necessary to comply with dust control limitations of the Mine Safety and Health <br />Administration. <br />Although the rate of groundwater use in the West Sunday mine is relatively modest, <br />it has lowered the water table in the vicinity of the underground workings by <br />cm 2-25 <br />T:\64986-Denison Mines\Task Order 3 - DMO Sampling and Analysis Plan\Task 3.14 - Hydrogeology Report\fnal sunday hydro reporWeATINAL Sunday Hydmgeology Report.doc