Agenda - Council - 10/22/1985 - Laserfiche WebLink

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Mr. Daniel A. Com(,au September 25, Page Four Preliminary interpretation of water level, water quality, and geological data developed by WMMI will be shared with MPCA. It is anticipated that a package of preliminary data will be assembled and shared with MPCA during October. WMM! is available to respond to questions about data shared with MPCA staff. Rock samples of the St. Lawrence formation consisted of fine grained sandstone interbedded with buff to green shale and dolomite. Characteristics of the rock samples in the underlying Franconia formation indicate fine to moderately grained sandstone with moderate to high concentrations of glauconite. Continued drilling in the Franconia formation produced samples of sandstone that were harder, medium-grained, somewhat less glauconitic, and with color varying from green-buff to slightly pink. The samples were collected during drilling of MW-4C, 11C, and 15C in February and March 1985. The geological interpretation was based on samples collected during drilling, the experiences of EAH and MGS personnel, and downhole geophysical logs. A correlation of downhole geophysical logs will be shared with MPCA in October as part of a package of preliminary data. A clearer understanding of the glacial till unit is being developed as the geological data are analyzed. The results of additional drilling will provide supplementary information. Pertinent figures to evaluate the significance of the glacial till unit will be a part of the package of preliminary data to be shared and discussed with MPCA staff in October. The St. Lawrence formation is believed to be present beneath the landfill site where it may act as a possible confining unit between the drift and the underlying Franconia formation, The St. Lawrence formation is believed to be absent in an area approximately 2,500 feet north of the landfill property and in an area approximately 2,000 feet east of the landfill property, as shown on Figure 5 of the Evaluation Report. The thickness of the St. Lawrence formation is being analyzed and will be submitted as part of the preliminary data package which will be provided in October. A presentation of vertical hydraulic gradient data at the landfill is given in Table 4 of the Evaluation Report. A further analysis of the preliminary data will be evaluated and discussed during the October presentation of preliminary information. Surface Water 10. Page 14. Staff gauges are used to measure water levels at surface water locations SW-1 and SW-4, as described in Table 6 of the Evaluation Report. A staff gauge is a device with measured lines and numbers that is attached