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r.4 3 31 March'2004 r'• s '- 1 �d.� a r z �� 1 .Y.r r w_'{•• t •Nr` .T -S - - eti Z ( F` AGE-NC Prod ect No 06 1156 Page 6 of 8 • F �-"+ f - -- - F ♦ �...Y�i G. ,"L u _ p4 M1 f J _ 4 k 4 3 IN SITU GROUND WATER SAMPLING PROCEDURES ' k g Far.collection-of depth discrete ground water .s samples;_the 46i probe bonrlgs wild be advance to 3 the top of the ground water table as:identified by collection of a satufftted soil sample;, n.O ground �1 k ' i hn` .device.wiltb%b:-advanced.two: ft watern>.e .has beencountered, a Geoprobepush driven Ovater s a,np g. to.three feet Into ,the'water bearing zone Dep#h-discrete ground water sail pies will be collected -; •-using a beoprol'ie water:sampting assembly fitted wIt11 a pre.cleaned ane-Inch drameter;_0 01 'inch 'slotted temporary well'scre'en Eac`h?rground water sample will_be e)itfa6t6c ys,lowering a fi= polyethylene bailer through the hollow center of the push rods,into the screen section Samples for ,; _� �A ' r BTEX;TPH and fuel:ox .genate.arial ses;wlll be collected into laborato su lied 40 hil-VOA - g, ._- yg, Y i.- M s vials containing 0y.5-ml:df hydrochloric acid as,sanlple preservative The labeled sample,containers will be placed in.a chilled container;under ice-and transported-underchairi of custodyto a DHSS 4 certified:laboratory - - u b T . 44 MONITORING.WELL INSTALLATION-PROCEDURES . - R`�l - ..-,t - Y''. _ '"sem `_' '4 _-- 'c • _. rk.�a i - ` 'K �` - . ��: .Proposed rrionitoring.well borings will be=completed using hollow,stem auger drilling Techniques ;fir - i" Relatively undisturbed soil samples-will be collected at five-foot intervals-an each of the borings w ,- using'-a California modified split-'spoon-sampler-fitted�wlth 4.2_ nch diarrieter,J'6=inch Long lirass s r sleeves Soil sample handling well be!consistent with the procedures'presen e In.Section 4 2 - .. '. 1 Fallowing compI' tion of drlllih' the�boring,.a 2 inch diameter Schedule 40 PUC 0.010 irich'slotted ` =well screen and casing will be installed.A.rriaxlmum 20=.foot=ectlon ofwellscreen will he nstalled,` t in each well, extending approximately'l 2.to;:15 feet below and five to eight feet above the top'of the 4 f �rt _ ground.water table,the design_rnay vary based on-the boring logs and definition ofhydrologlc units The well casing;filter pack and sealing materials will be placed into the borehole thraugki the Interior l: ' w of the hollow stem augers After installing:=the�well casing,,filter pack material consisting'of.1 ' .4 . washed#2112 Lonestar sand will be..added from the Bottom`of the-borehUe to approxiinately'two feet above,the screened'interval Followmg`placement of the'filter pack, the well-will be.=surged to -`' 3 y .assist In settling t-he,filter,pack: Additional sand will be`added`if-, ng occurs ` -A nominaltwo-foot thickbe-nto-ni e seal will be placed above the filter pack to minimize the potential `of grout.penetration'into the screened section of'the well yThe bentonite^seal .will be-formed by ` = .pouring bentonite chips into the annular space between the auger.and tlie.:we113casing and A owing,_: -_ a ,<z ' them to sett eon the:f iter pack Bentonite;chlps_wiil behydrated using five gallons of_water The ;f :._ •, . r bentonite chips will be.allowed to hydrate fora minimum oi.one half hour prior to grouting . r"'""' F'�'.r5 r ` _ ,s'x ) _ # �^ f, k . The anhul-ar space above the-bentonite.seal:will lie filled to within one foot of the ground surface with-a cement grout:=The grout-mixture will"consist of Type UII portland neat cement and not,xnore _ than-,6 gallons of=water-per 94 pound-sack;of cement The grout will be placed bypumping through Advanced GeoEov�ronmental;Inc g - y w - ...f,