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necessary. In general, excavations will be approximately two feet in width, approximately 10 to <br />20 feet in length, and up to approximately 25 to 30 feet in depth. Trench excavations will only <br />remain open long enough to obtain and record necessary data. During trenching activities, <br />trench spoils will be managed to minimize potential run off. Visqueen plastic sheeting may be <br />placed on the ground surface adjacent to the side of the trench, depending on materials <br />excavated. The upper fill/cover soils will be stockpiled separately from excavated wastes. <br />Trench excavating will continue until waste -free materials are encountered or until the greatest <br />depth of excavation is achieved with the track excavator. <br />Note that if an object or objects such as drums are encountered during trenching operations the <br />operator shall immediately cease trenching at that particular trench. If possible, a visual <br />inspection shall by made by sampling personnel to determine if hazardous materials may be <br />present within the object(s) and a decision to relocate to an adjacent location will be made to <br />continue trenching. If the object(s) are inadvertently damaged during the trenching procedure <br />and suspected hazardous materials are present then emergency response authorities will be <br />contacted. For emergency response call (911), or the Office of Emergency Services, San <br />Joaquin County, (209) 468-3969 or the Escalon Fire Department, (209) 838-7500. Also refer to <br />the Health and Safety Work Plan. <br />Each excavation will be logged on a trench log form, the location will be recorded on the site <br />map, and GPS coordinates obtained and recorded. Several photographs will be taken of each <br />trench excavation. Of these, one photograph will generally show the trench excavation and <br />several photographs will show the types of subsurface materials that were excavated. Trench <br />logging will concentrate on obtaining the vertical extents of buried wastes, visual classification of <br />the waste types, estimating the amounts of wastes relative to other subsurface materials, and <br />obtaining vertical extents of the landfill cover, if present. <br />3.1.8. Drilling and Sampling <br />Borings will be drilled if the vertical extent of wastes cannot be determined by excavating <br />trenches. Drilling will be by a bonded, C -57 -licensed, drilling contractor with the appropriate <br />current certificates, experience, and training. Borings will be drilled using hollow -stem, <br />continuous -flight auger. Soil cuttings will be placed onto Visqueen plastic sheeting. Following <br />completion of drilling, borings will be abandoned according to California governing agency <br />guidelines. The borings will be backfilled by the California -licensed drilling subcontractor with <br />cement/bentonite grout to ground surface. <br />3.1.9. Site Restoration <br />Each boring and trench excavation site will be left, as much as possible, in its original or <br />specified condition. Rains during the field exploration program would result in some trench <br />locations having relatively deep truck and equipment wheel marks in surface soils adjacent to <br />the excavated areas. Excavated areas, as well as adjacent areas that may have been rutted <br />due to truck and related equipment will be smoothed out, as much as possible, to match their <br />surrounding undisturbed ground surfaces by using the track excavator blade. All materials used <br />in association with drilling and excavating activities will be removed from the site following <br />completion of the investigation. <br />3-21 <br />