ARCHIVED REPORTS_XR0007370 CASE 2

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I ria ��►� SSS -� the primary section of the 2002 work area Six of the borings were drilled down to forty feet below surface grade (bsg) The last two borings were drilled down to one hundred L b forty feet to intersect the groundwater table Drilling commenced on June 9 and was completed on June 14, 2004 All borings were advanced using a Becker® style, twin-walled percussion, pneumatic drill rig All soil cuttings were constantly monitored and logged by the USC system of soil � .a classification as the borings advanced The boring logs, describing the lithologies Iencountered, are presented as Figures 4 through 10 The original field logs are included in Appendix B The full depths of the shallow borings (BH-10 through BH-15) were backfilled to the surface with a neat cemcnt/bentonite grout All grout was tremmied in after the t� sections of drilling pipe were extracted The two deep borings (BH-16 & BH-17) were completed as groundwater-monitoring wells MW-07 and MW-08 for the site The new wells are constructed of four-inch interior diameter, flush couple, schedule-40 PVC casing with twenty feet of 0 02-inch slot screens and a screw cap at the base The lower Iportion of the annular space between the casing and the boring wall was packed with r Lapis Luster#3 sand to a level two feet above the top of the screened interval Directly above the sand pack, a three-foot layer of bentonite pellets was placed, densely packed Iand hydrated, to provide a firm seal to the well screen All depths and thickness of the sand pack and bentonite seals were verified by sounding with a weighted tape The remaining annular space was backfilled with a neat cement grout tremmied up to the . ground surface I The surface completions of the two new wells extend approximately three feet above surface grade and are enclosed in a i 0-inch diameter steel monument pipe with a lockable lid Each monument is surrounded by a 3-foot by 3-foot square concrete pad and I steel bollard posts to identify the wells and protect them from damage A state licensed surveyor has been contacted to survey the top-of-casing elevations of the new wellheads The results of that survey will be submitted to EHD in an upcoming quarterly sampling Ireport SOIL SAMPLING • Soil samples were collected for chemical analysis at five-foot intervals in the I upper forty feet of each soil boring In the two borings that were extended beyond that level, additional sampling intervals were selected based on observing lithologic color, or composition changes of the bore cuttings or whenever a marked increase in organic vapor concentration was detected by the use of a Foxboro organic vapor analyzer (OVA) Model 88 Soil samples were collected into a laboratory supplied, precleaned, 8-oz jar All jars were filled and leveled off even with the rim to minimize air space before the cap was firmly installed Each sample jar was labeled, and then immediately placed into a cool ice chest for subsequent laboratory analysis at the Severn Trent Laboratory (STL) facility in I I2