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SOP-5 steel"stovepipes"are usually set over wellheads in
<br /> LABORATORY ANALYTICAL QUALITY ASSURANCE landscaped areas.
<br /> AND CONTROL
<br /> After installation,the wells are thoroughly developed to
<br /> In addition to routine instrument calibration,replicates, remove residual drilling materials from the wellbore,and to
<br /> spikes,blanks,spiked blanks,and certified reference improve well performance by removing fine material from the
<br /> materials are routinely analyzed at method-specific filter pack that may pass into the well. Well development
<br /> frequencies to monitor precision and bias. Additional techniques used may include pumping,surging,bailing,
<br /> components of the laboratory Quality Assurance/Quality swabbing,jetting,flushing,and air-lifting. All development
<br /> Control program include: water is collected either in drums or tanks for temporary
<br /> storage,and properly disposed of depending on laboratory
<br /> 1. Participation in state and federal laboratory analytical results. To minimize the potential for cross-
<br /> accreditation/certification programs; contamination between wells,all development equipment is
<br /> either steam cleaned or properly washed prior to use.
<br /> 2. Participation in both U.S.EPA Performance Evaluation Following development,the well is allowed to stand
<br /> studies(WS and WP studies)and inter-laboratory undisturbed for a minimum of 24 hours before its first
<br /> performance evaluation programs; sampling.
<br /> 3. Standard operating procedures describing routine and
<br /> periodic instrument maintenance; SOP-7
<br /> ROTARY DRILLING MONITORING WELL INSTALLATION
<br /> 4. "Out-of-Control"/Corrective Action documentation AND DEVELOPMENT
<br /> procedures;and,
<br /> Boreholes for monitoring wells may be drilled using truck-
<br /> 5. Multi-level review of raw data and client reports. mounted drill rigs capable of air-and mud-rotary drilling,and
<br /> continuous coring and/or drilling with tri-cone roller or fixed-
<br /> blade drag bits. Generally,rotary drilling is used when more
<br /> SOP-6 conventional hollow-stem auger drilling either is or becomes
<br /> HOLLOW-STEM AUGER MONITORING WELL infeasible. Various drilling fluids(mud or air),used to keep
<br /> INSTALLATION AND DEVELOPMENT the borehole from caving and to remove drill cuttings,are
<br /> chosen according to the nature of the soils and/or geologic
<br /> Boreholes for monitoring wells are drilled using a truck- formations expected to be encountered as well as the
<br /> mounted,hollow-stem auger drill rig. The borehole diameter monitoring program. Samples may be collected directly from
<br /> will be a minimum of four inches larger than the outside cores. A geologist or engineer from Apex Envirotech,Inc.,
<br /> diameter of the casing when installing well screen. The continuously logs each boring during drilling and checks
<br /> hollow-stem auger provides minimal interruption of drilling returned drill cuttings for indications of both the first
<br /> while permitting soil sampling at desired intervals. Soil recognizable occurrence of groundwater and volatile
<br /> samples are collected by either hammering(with a 140- hydrocarbons, using either a portable PID,FID,or
<br /> pound drop hammer)or hydraulically pushing a conventional explosimeter. All drilling equipment is either steam cleaned
<br /> split-barrel sampler containing pre-cleaned two inch- or washed between borings to minimize the potential for
<br /> diameter brass tubes. A geologist or engineer from Apex cross-contamination.
<br /> Envirotech,Inc.,continuously logs each borehole during
<br /> drilling and constantly checks drill cuttings for indications of Frequently,hollow-stem augers are used to drill and sample
<br /> both the first recognizable occurrence of groundwater and to either a minimum depth or auger refusal. In such cases,
<br /> volatile hydrocarbons using either a PID,FID,or an the augers may be left in place as temporary surface casing,
<br /> explosimeter. The sampler is rinsed between samples and with the center plug removed and drilling/coring carried out
<br /> either steam cleaned or washed with all other drilling through the augers. Alternatively,a shallow conductor
<br /> equipment between borings to minimize the potential for casing,or surface casing,may be set by drilling to a desired
<br /> cross-contamination. depth with a large-diameter bit,then setting the casing and
<br /> proceeding with the drilling/coring. After total drill depth(TD)
<br /> Monitoring wells are cased with threaded,factory-perforated is reached,the borehole may be logged by geophysical
<br /> and blank Schedule 40 PVC. The perforated interval means or hydraulically tested. If casing is not set to the
<br /> consists of slotted casing,generally with 0.020-inch wide by bottom of the borehole,the lower portion of the hole may be
<br /> 1.5 inch long slots,with 42 slots per foot. A PVC cap may grouted or backfilled accordingly. The borehole may be
<br /> be secured to the bottom of the casing with stainless steel drilled out(reamed)as necessary with a large-diameter bit.
<br /> screws;no solvents or cements are used. Centering devices
<br /> may be fastened to the casing to ensure even distribution of Upon reaching TO,drilling fluid is circulated to remove
<br /> filter material and grout within the borehole annulus. The cuttings. Selected casing is then run into the borehole and
<br /> well casing is thoroughly washed and/or steam cleaned,or set to the desired depth. Monitoring wells are cased with
<br /> may be purchased as pre-cleaned,prior to installation. clean,threaded,factory-perforated and blank casing. The
<br /> perforated interval consists of slotted casing,generally with
<br /> After setting the casing inside the hollow-stem auger,sand 0.020-inch-wide by 1.5 inch-long slots,with 42 slots per foot.
<br /> or gravel fitter material is poured into the annular space to fill Centering devices may be fastened to the casing the ensure
<br /> from boring bottom to generally one foot above the even distribution of filter material and grout within the
<br /> perforated interval. A one to two foot thick bentonite plug is borehole annulus. The well casing is thoroughly washed
<br /> set above this filter material to prevent grout from infiltrating and/or steam cleaned,or may be purchased as pre-cleaned,
<br /> the filter pack. Either neat cement,containing about five prior to installation. All recoverable drilling fluid and/or
<br /> percent bentonite or sand-cement grout is then tremmied cuttings are collected for temporary storage and disposed of
<br /> into the annular space from the top of the bentonite plug to properly pending analytical results.
<br /> near surface. A traffic-rated vault is installed around each
<br /> wellhead for wells located in parking lots or driveways,while
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