WORK PLANS - Laserfiche WebLink

Home Browse Search

' I I DRILLING AND SAMPLING METHODS AND PROCEDURES To obtain discrete groundwater samples from the two water zones three methods of drilling/probing were found to be acceptable. All three methods use the "hydropunch" method for obtaining water samaples; 1. Conventional hollow stem auger drilling method using a three inch ID X three foot long California Split Spoon sampler to core and direct push water sampler, ie "Hydropunch" to obtain water samples; 2. Sonic drilling direct push vibrate drilling method using similar direct push water sampling device and 3. Cone Penetrometer testing/sampling using direct push method.and hydropunch water sampling procedure to obtain discrete water samples. Hydropunch water sampling method The boring or direct push probe hole is advanced to within three feet of the interval for water sampling. The drilling assembly is removed and the hydropunch is attached to drill rod that will push the hydropunch to the desired depth to be sampled. The h o h pp p yr punc is connected to the drive point. Once the sample depth has been achieved, the drive rods (1.75 inch diameter hollow rods) are retracted,exposing the filter screen and allowing for groundwater infiltration. A small diameter bailer is then used to collect groundwater samples through the hollow rod. Hollow Stem Auger-Hydropunch Estimated Cost: V&W Drilling $8,955.00,three working days. Using a truck mounted drilling rig, eight inch hollow stem augers will be used to advance the boring to thirty feet below the surface. Once this depth is achieved, continuous cores will be obtained to verify groundwater interface and high transmissivity formations. Once groundwater has been penetrated a hydropunch sample will be obtained from three feet below the augered depth. Continuous coring will then.proceed to the base of the A zone and another hydropunch sample will be obtained. The continuous coring will proceed into the B zone and a third hydropunch sample will be obtained. The Hydropunch sample intervals are anticipated to be at the 50 foot depth(zone of highest concentration, top of A Zone), the 85 foot depth (bottom of A Zone) and between the 115 and 140 foot depth (B zone). To obtain the hydropunch water sample, the core sampler is ' removed. Any groundwater that entered through the augers would be removed by bailing and the "GeoProbe" would then be pushed three feet past the cored interval to obtain the water sample. The augers and the push probe seal off the formation fluids from above to insure sample integrity for the interval being sampled. Once the water sample is obtained. The boring is continuously cored to the next test interval and the above procedure is again performed. I 4 R-603 extent WP 2-2001 I