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Y • <br /> BORE HOLE DESTRUCTION CALCS. <br /> BORE HOLE <br /> 55 feet deep, with 10"diameter, 8"casing <br /> Volume of this bore hole is approximately 1.125 cubic yards <br /> EXCAVATION FOR WELL HEAD PER PHS/EHD WELL STANDARDS <br /> 3 feet deep, three feet wide, three feet long <br /> Volume of this excavation is approximately I cubic vard <br /> Total minimum volume oferout reauirks approximately 2 cubic yards <br /> VOLUME OF NEAT CEMENT PLACE IN HOLE WITHOUT PRESSURE GROUT <br /> 8 yards total placed in bore hole. This volume(6 extra yards) is equivalent to an additional bore hole with <br /> a 10"diameter, 300 feet deep. <br /> QUESTIONS <br /> Should we sign off? <br /> Is this unapproved procedure equivalent to the conditions of the permit issued? <br /> Does the remaining potential contamination pose a risk to the lower part of the well which is not <br /> destroyed? <br /> DISCUSION WITH UNIT II AND IV MANAGERS(6-22-98) <br /> Grout not placed per permit conditions set by CVRWQCB,the comparative quality of actual effectiveness <br /> yet to be determined. Lower section(44' bgs)well casing petroleum hydrocarbon contamination may be a <br /> critical issue as it relates to vertical transport(conduit to lower aquifer). CVRWQCB has issued a letter to <br /> the RP (Tesoro, 3-12-98) directing them to clear the destroyed upper 55' and lower section to completely <br /> discover the total depth of this well and destroy it under pressurized conditions. On July 18, 1998 <br /> PHS/EHD staff met with Emcon to discuss the situation and PHS/EHD requested that they submit a report <br /> which details the site activities for the February 6, 1998 well destruction. This report is to be reviewed by <br /> CVRWQCB and PHS/EHD. It is likely that verification of the contamination and grouting process will be <br /> required followed by deeper interval destruction. <br /> Tesoro Well Destruction Notes <br /> 6-22-98 VI/ <br />