ARCHIVED REPORTS XR0006437 - Laserfiche WebLink

Home Browse Search

1 . Working to Restore Nature Ir Water Sampling With a H dro unch A CME 55 or similar drill rig equipped with 8-inch-outside-diameter by 4-1/4-inch-inside- diameter hollow-stem augers was used to drill borings to approximately 3 feet into first encountered groundwater. After the auger was terminated in groundwater, a Hydropunch sampling device was driven into groundwater and the auger was pulled up to the top of groundwater. Groundwater samples were then collected from the Hydropunch sampling device The water samples were handled and transported to a State-certified laboratory am ling of Drill Cuttings Soil samples were collected from the stockpiled drill cuttings by driving a hand-operated percussion sampler fitted with a clean brass sleeve into the stockpiled soil The sleeve was removed from the sampler and promptly sealed with aluminum foil, plastic caps, and Teflon tape. The sample was then labeled and placed in iced storage Chain of Custody Records were initiated by the geologist and accompanied the samples to the analytical laboratory Disposal of the drill cuttings at an appropriate disposal facility is the responsibility of the client Vapor Extraction Well Construction Vapor extraction wells were constructed using clean 4-inch-inner-diameter, thread-pointed, Schedule 40 polyvinyl chloride (PVC) casing The screened portion of the vapor extraction well consists of 5- and 10-foot sections of factory-perforated casing with 0 1-inch slots Unperforated casing was set from the top of the screen to several inches below surface grade The annular space of each well was packed with pea gravel from the bottom of the screen portion to approximately 1 foot above the top of the screen A plug of hydrated bentonite pellets (approximately 2 feet thick) was placed above the sand to prevent cement from entering the sand pack The remaining annulus was backfilled to the ground surface with a mixture of water, cement, and bentonite The construction details of the individual wells are shown on the Logs of Borings The wellheads are secured in cast-aluminum utility boxes with PVC aprons The boxes have watertight seals and are set in concrete approximately flush with the surrounding ground surface to reduce surface-water infiltration A special wrench is required to open the box This design discourages vandalism and reduces the possibility of accidental disturbance to the well Each wellhead is also fitted with a locking well cap to further protect against unauthorized disturbance of the well, until the well is plumbed to a remediation system • 1215bnn/123020 01