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i 1 • • <br />' During the drilling of each of these boreholes, the borehole was geologically logged from drill <br />cuttings returned. A summary geologic log for wells M-12 and M-13 are shown in Figures 2 <br />' and 3, respectively. <br />Using air as the sole drilling fluid allowed the field hydrogeologist to evaluate when the Cirst <br />water was encountered in each borehole. Since well M-9 was completed in the first water- <br />bearing interval, wells M-12 and M-13 were similarly completed. The apparent dip of the Santa <br />' Fe beds was evaluated from cuts made into the Santa Fe Formation south of wells M-12. Using <br />this information, and the depth to water identified in each borehole, the new monitoring wells <br />' M-12 and M-13 are completed similarly to well M-9, and are monitoring the uppermost water <br />in the Santa Fe Formation in this area. <br />' Once the boreholes had been drilled to total depth, 4-inch inside diameter (I.D.) Flush-tlueaded <br />' PVC casing and screen was emplaced in the hole and the annular space between the casing and <br />the borehole wall was backfilled with select gravel pack to a level above the uppermost screen. <br />' A bentonite pellet seal was then emplaced above the gravel pack and the remainder of the <br />anmilar space was filled with a grout slurry. A steel protective cover and locking cap was then <br />' emplaced at the surface and a concrete pad, sloping away from the well, was emplaced around <br />the protective steel cover. The construction details for wells M-12 and M-13 are presented in <br />Figures 2 and 3, respectively. <br />' Between each borehole all drilling equipment that had been emplaced in the borehole, or had <br />come in contact with water produced from the borehole, was decontaminated according to the <br />quality assurance/quality control (QA/QC) protocols outlined in the QA/QC document submitted <br />as Technical Revision-06 (Halepaska and Associates, Inc., April 1992). <br />' Once the grout had set in each of the monitoring wells, the wells were developed by surging <br />with a surge block, following by bailing and pumping. Each well was developed for a period <br />' of time such that the discharge from the well had cleared and was essentially free of suspended <br />material. <br />' -3- <br />1 <br />