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3.1 OBTAINING SAMPLES 3.1.1 Soil Samples Soil samples shall be obtained by coring. Coring shall be accomplished by driving or pushing a nominal 2-foot long, Geoprobe Large Bore Soil Sampler. The sampler shall be fitted with either Teflon or brass liners for collection of soil cores. In general, the cores will be retained 1 for visual inspection and possible subsequent chemical or physical testing. The field geologist J or engineer will carefully record on a field log (Figure B-1) information pertaining to the coring, such as rate of penetration, hydraulic ram pressure or drive-hammer blow count, coring smoothness, core recovery, and intervals of core loss. The cores will be stored and labeled to show project number, boring number, orientation, and cored interval denoted either by depth or sequential number numbering system. 3.1.2 Groundwater Samples Groundwater samples shall be obtained by driving a Geoprobe Screen Point Sampler into the formation to be sampled. When desired sampling depth is reached, the sampler will be pulled up about 2 feet, disengaging the expendable drive point and leaving an open borehole. The perforated stainless steel sleeve, equipped with a stainless steel mesh screen insert, will be pushed out into the open borehole, allowing water to enter the sampler. A groundwater sample will then be collected using either a peristaltic pump attached to 318-inch polyethylene sample tubing, or a bottom check-valve assembly attached to the end of the tubing. Tubing will be discarded after sample has been collected. 3.2 LOGGING OF EXPLORATORY BORINGS 1 The observations of the field geologist or engineer shall be recorded on a soil boring log as JI shown on Figure B-1. The probe rig operator and the field geologist/engineer will discuss significant changes in material penetrated by the probe, changes in drilling conditions, hydraulic pressure, and probe penetration rate. The field geologist or engineer will be present during advancement of soil borings and will observe and record such changes by time and depth. Core samples shall be examined in the field. A lithologic description shall be recorded on the log including soil or rock type, grain size, texture, hardness, degree of induration, calcareous 1 content, presence of fossils and.other materials (gypsum, hydrocarbons), color, relative moisture L! content, estimated Unified Soil Classification System (USCS) soil type, and other pertinent information. J The original logs shall be sent or delivered to the B&R office in Fresno for review by the registered geologist or engineer and the project manager and for storage in the project files. Copies of the boring logs will be retained in the project field notebook. B - 2 D:19&1171PR0T000L.WPN