FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

r �... The surface mulch was cleared to about -1 ' and a surface sample taken. This well is located near the pulled tank location and within about 3 or 4 feet of the former gasoline pump location, just "down-gradient" with respect to both the regional gradient and the local gradient established herein. The well was bored to -23 . ' Cores were taken at -6 ' and at -111 . The water table was located at about -11 ' by the driller. The soils are described as follows : Surface to one foot, organic silts (planting mulch) ; from -1 ' to -81 , silty sands, fine to medium-grained, tan to brown in color; from -S ' to -101 , clayey sands (clay balls) ; from -10' to -151 , coarse sand and pebbles, tan colored; from -15 ' to -231 , silty sand, fine to medium-grained, well graded, tan color. The casing and perforations were designed to place about 11 ' of perforations in the water table and one foot above in the vadose zone . When the casing. was inserted into the hole, it would not stay on bottom and then stuck several feet above bottom with the perforations at wrong elevations . After about one hours work, the casing was retrieved and the hole was cleaned out with the auger to bottom. The casing string was placed in the borehole once again and would not go below -21 1/2 ' . As in the other two wells, the annulus was gravel packed to about 1 ' above the perforations and the well was swabbed for about 30 minutes . Gravel was added to bring the level up above the perfs . , bentonite pellets were placed on top of the gravel as a seal and the well was then cemented to the surface with grout containing cement and 3% bentonite. The casing string from bottom up is as follows : Slip-on bottom seal , perforated casing from -21 1/2 ' to -91 , gravel packed from bottom to - B ' , blank casing from -9 ' to surface, with bentonite from -- 8 ' to -6 ' and cement grout from -6 ' to surface . The well was capped at the surface with a locking vault and well cap as described previously. Details are shown on Figure 4. All three wells were then bailed by the driller until about 5 casing volumes of water had been removed from each. The bailer was washed and rinsed with house tap water between each well operation. Soil Sample Collecting Samples were collected in 3" brass sleeves, supplied by the test laboratory, FGL of Stockton. A cooler containing blue ice and sterile, three inch brass sample holders, caps and Teflon end covers was picked up at the FGL laboratory prior to going to the well site . Two, 3" samples were collected at each interval sampled, when conditions permitted. Blank 6" brass tubes were used as spacers in the split spoon 6