WORK PLANS_FILE 1 - Laserfiche WebLink

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Both of the proposed nested wells will be constructed with screen intervals spanning from approximately 18 to 28 feet and y:;3. to 48 feet bgs: These screen intervals should enable the independent &Valuation of the up E, and lower vadose zone soils, without:interference from the burieid'concru s'ab. The yen intervals will be based on field observations during the mous c , of the ,p_.neo ail ;sparge well. The proposed single-casing$V15 well will be Constructed w a , i interval r Spanning from to 2 feet tags, to evalua#e thie rerrrediation of irnpt ct d soil rr tie Vicinity of : e three former t,g i -gallon USTs (Tanks 21, 22 and.2 ). t, FIter packs f 6. tere 03 graded and washed sand will be placed around`all of the screen intervals and aplaro.X.IM rely one-toot above the tops of the screen intervais, In the nested wells,. between the tiara of ate 46. f.sand packs and the bases of the upper wells (i.6., 28 to 32 feet b s), the drill�i wtll:irts tl fbur-4uat layers of;hydrated bentonite: The ille�r will also place two-foot t layers t i rdr` rd tntonite abbve the tops pf the upper sand packs in rile nested wells, and above the sand pal k irt;the single c irrg well. Overlying the upper bentonite layer In the well nests, and brve the ltorrit layer in the ding(e-casing well, the driller Will seal the wells witty neat cement grout: T61. Cilit future underground soil vapor'extraction piping connectians,the tops of the cement seals will be apprb imately two feet below surface grade w Each of the well casings will be seeured with w tertight locking caps,and all three wells will be protected with IS- inch dfarneter. traffilc-ratecl, flus"ount street boxes. C-57; € teres c z ter will install one, ane-inch diameter air sparge test iveii to a tot81 depth of approximately 63- 4 boa, using a trUck-njounted drill rig and 8-inch diameter hblloww stem angers. 'To evaluate the sort stratigraphy wi+hi f t= e former UST source area, tt .;, air sparge wrvell bon ng will. be cr�rttinu�ausly cored :`he location of the proposed air sparge well is shown ort Figure 2. The air spam ell will be cores#rude t r�tk� �� 3-foot rr�l opor pus bubbler(kWA s arge ointT } ,from approximately60 to 63 feet bs. The actual depth of the spargepoint will ort soil apes obsery ed wring drilling. Ideally,the spargepoint should be installed within a sandy interval tb ma intize air flow into the formation, Blank PUC casing will thread into the top of the spargepoint and extend to the surface. A filter pack'of l or terey#3 graded and washed sand will be placed within the annular space around the spargepoint and two feet above the tip of the spargepoint i.e , 58 feet bgs . Overlying the filter pack,b feet of hydrated bentonite will be placed within the annular space between the borehole and tete well casing. Over the hydrated bentonite, a surface seal of heat cement grout will be installed_ To facilitate future underground air sparge piping connections, the top of the upper cement seal will be approximately two feet below surface grade. The wellhead will be secured with a watertight locking cap arra a 12-inch diameter, traffic-rated, flush-mount street box. 10