Laserfiche WebLink
Presented at the 9th Natsonal Outdoor Action Conference,Las Vegas. !Nevada., V-c 1995 <br /> ' introduction <br /> ' In recent years, the environmental industry has witnessed explosive growth in the development <br /> and use of innovative technologies for site charactenz ation The need for new tools for site <br /> characterization became apparent in the mid 1980's Up until then, environmental professionals <br /> Irelied on technology borrowed from other industries, in particular the geotechnical and water <br /> well drilling industries When the costs of conventional investigations and long-term <br /> ' groundwater monitoring were totaled, it became clear that the environmental industry needed <br /> better ways to characterize contaminated sites more quickly and more thoroughly <br /> ' The environmental industry responded, and new technologies for site characterization were <br /> developed Soil gas sampling using small-diameter probes (e g., Geoprobel-type sampling) and <br /> on-site chenucal analysis of soil gas samples with mobile labs helped to quickly define the nature <br /> ' and extent of adsorbed and dissolved contanunants The Hydropuncho and BA1I21 Enviroprobe, <br /> driven probes used to collect groundwater samples, quickly became popular tools for plume <br /> delineation Cone penetrometer testing (CPT),utilized extensively in the geotechnical industry, <br /> 1 became a valuable tool to quickly define the stratigraphy of unconsolidated sediments during <br /> environmental investigations The late 1980's and early 1990's witnessed the mamage of CPT <br /> for Iithologic control, and BAT or Hydropunch systems for collecting groundwater samples <br /> Most recently, these new methods are being referred to collectively as "Direct-Push" (DP) <br /> technologies, since they are typically pushed or driven into the ground <br /> While these new DP methods are welcome additions to a field geologist's "site characterization � <br /> tool kit", none have been very successful at quickly collecting continuous soil cores, a vital <br /> component of any subsurface investigation Continuous soil coring is often the only wiay to <br /> Iidentify thin permeable layers (e g , sand partings), artificial fill, zones of discolored soil, free <br /> product, and secondary pedologic features (e g ,root holes and desiccation cracks) These <br /> elusive features commonly control the moNement of contaminants in the subsurface, and the <br /> effectiveness of in situ remediation technologies such as soil vapor extraction(SVE) and air <br /> sparging <br /> ' In 1990, Precision Sampling, Inc , of San Rafael, California, miniaturized components of large, <br /> comb entional drilling ngs (i e., drive casing and wireline core barrels), and developed a way to <br /> ' quickly advance the small-diameter sampling tools into unconsolidated sediments without <br /> rotating the dnll string Precision's Enviro-Core system (patent pending),cases the borehole as <br /> it is deepened, and allows rapid collection of continuous soil cores, soil gas samples, and <br /> ' groundwater samples Like other DP systems,no drill cuttings are generated, saving the cost of <br /> disposing of the contaminated drill cuttumgs <br /> The Enviro-Core system is advanced using small,portable, vibratory rigs, although the system <br /> could be adapted for use by CPT ngs and conventional drilling rigs The Enviro-Core system is <br /> currently capable of sampling to depths of 50 feet with nearly 100% sample recovery and can <br /> ' collect up to 150 feet of continuous soil cores per day <br /> 2 <br />