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To reduce the potential for cross contamination, augers, sampling equipment and all associated downhole equipment were decontaminated prior to each use Auger flights were decontaminated by steam cleaning while the split spoon sampler, brass liners and associated tools were washed in a solution of Alconox detergent and potable water, followed by a double rinse with potable water and a final rinse with deionized water. All decontamination rinsate was contained in labeled 55-gallon drums for temporary storage onsite Soil cuttings from the born were laced in 55-gallon drums (appropriate for the temporary g g P g storage and transport of hazardous materials) and left onsite. Headspace screening results were used to aid in the disposition of these cuttings As there was no evidence of petroleum compounds in the soil based on field screenings, drill cuttings from MW-4 will be re-used onsite as fill material. Well Construction Upon completion of drilling and sampling activities, the boring was converted to a monitoring well Four-inch-diameter, Schedule 40 PVC casing and screen was used to construct NfW-4 The well screen was 20 feet long and contained 0 020-inch machine-cut slots A threaded PVC end cap was affixed to the bottom of the screen sections to prevent formation material from entering the well casing through the bottom Fifty feet of blank casing was ,joined to the 20 feet of slotted casing and the top of the screen was placed at approximately three feet above the water table as encountered during drilling The well casing and screen were suspended during placement of the sand pack material, bentonite seal and cement/bentonite grout Well construction details are listed in Table A-1 The sandP ack consisted of Lonestar #1C sand and was placed through the 8-inch augers by alternately filling the augers with 2 to 3 feet of sand and withdrawing approximately one foot of auger This process continued until the height of the sand pack was approximately 2.5 feet above the top of the well screen After placement of the sand was completed, a 4-inch surge block was used to swab the well in order to settle the sand pack Additional sand was added to maintain the appropriate sand pack height of 2 5 feet above the top of the well screen A water level probe was then used to assess whether water was present on top of the sand pack Water was not present at this depth during the well construction, therefore a 2-foot thick bentonite pellet-seal was placed on top of the sand pack and hydrated with potable water obtained from the site 1 Cement/bentonite grout was then placed in the remainder of the annular space via a tremie pipe The grout mixture consisted of approximately two pounds of powdered bentonite, added to ' approximately 10 gallons of water (obtained from the ng) per 94 pounds (one sack) of cement. The bentonite was added to the water and circulated with a mechanical mixer to hydrate the bentonite After the bentonite was hydrated (approximately five minutes), the cement was added and thoroughly mixed ' MXC\RWS\SJCMAD WP A - 4 [W1402