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A. Backfilling 1. The Contractor shall measure the depth of the bore hole in the presence of the Engineer before backfilling. 2. Remove any organic materials from the drain rock backfill. 3. The Contractor shall maintain the well pipe vertical 4. Place backfill materials in a controlled manner to avoid bridging or overfilling the boring, or damaging the well pipe. 5. Bentonite plugs shall be hydrated in the borehole with five gallons of water. Wait one hour before adding neat cement on top of the bentonite plug. 6. The Contractor shall tremie neat cement in the borehole. 7. Soil backfill in the well bore hole shall be firmly compacted in maximum of two-foot lifts. Compaction in the borehole shall be from above with weighted plastic pipes or equivalent method. B. Uncompleted Wells 1. If a well bore hole is not drilled by the end of the day and is to be left open, the Contractor shall securely cover opening of the bore hole for safety and to prevent landfill gas escaping into the atmosphere. A 8'x4'x Y2" inch thick sheet of plywood with weights may be placed over the borehole or the drilling auger may be left in the borehole with its top covered. The Contractor shall also cordon off the area with safety cones. 2. The Contractor shall be responsible to enforce Cal OSHA Health and Safety requirements and secure the construction area. C. Construction Well Logs The Contractor shall provide a well construction log of each well to Engineer at the end of the project. The well log shall be a sketch identifying the following information: • Logger's name, Company's name, date and time. • Name of EHD inspectors on site. Construction Specifications San Joaquin County Dual LFG Extraction Wells Public Works Department Harney Lane Sanitary Landfill Page 8 of 13 Solid Waste Division Revised 11-18-09