BOH Agenda 022620 - Laserfiche WebLink

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1. Casing shall be grouted to a minimum depth of 20 feet below the natural land surface. 2. In addition to the grouting by this Rule,the casing shall be grouted as necessary to seal off all aquifers or zones that contain contaminated or other non-potable water so that contamination of overlying and underlying aquifers or zones shall not occur. 3. Bentonite slurry grout may be used in that portion of the borehole that is at least three feet below land surface.That portion of the borehole from land surface to at least three feet below land surface shall be filled with a concrete or cement-type grout or bentonite chips or pellets that are hydrated in place. 4. Grout shall be placed around the casing by one of the following methods: a) Pressure. Grout shall be pumped or forced under pressure through the bottom of the casing until it fills the annular space around the casing and overflows at the surface; b) Pumping. Grout shall be pumped into place through a hose or pipe extended to the bottom of the annular space which can be raised as the grout is applied. The grout hose or pipe shall remain submerged in grout during the entire application; or c) Other. Grout may be emplaced in the annular space by gravity flow way to ensure complete filling of the space. Gravity flow shall not be used if water or any visible obstruction is present in the annular space within the applicable minimum grout depth specified in this Rule at the time of grouting,with the exception that bentonite chips or pellets may be used if water is present and if designed for that purpose. d)The annular space of the top twenty(20)feet for wells grouted with bentonite chips or pellets must be no less than ten (10)inches in diameter for a six(6) inch casing. 5. If a Rule of this Section requires grouting of the casing to a depth greater than 20 feet below land surface,the pumping or pressure method shall be used to grout that portion of the borehole deeper than 20 feet below land surface,with the exception of bentonite chips and pellets. 6. If an outer casing is installed, it shall be grouted by either the pumping or pressure method. 7.The well shall be grouted within seven days after the casing is set. When grout is Comment[VH59]:OCHD REQUEST FOR emplaced b gravity, the entire drilling process must be completed prior to rout QUICKER GROUTING TO PROTECT EXPOSED WELL p Y g Y g p p p g BORING emplacement. When emplaced by the pump or pressure methods,the grouting COmment[VH60]:BECAUSE THE ALLOWABLE process may be initiated at any time after the casing is set, Including during the GROUT SECTION WAS RE-WRITTEN LIKE THE STATE, drilling process. IT REMOVED A VERY"OC"WAY OF FINISHING GROUT.THE FORMER WAY WAS NOT FOUND TO PRODUCE BETTER WELLS BUT IT DID ENSURE THAT 8. It is the responsibility of the well contractor to verify that the grout does not settle. THE GROUT WAS TOPPED OFF IF IT SETTLED. THIS REQUIAny settling greater than five(5)feet below the natural land surface shall require re- CONTRACTOR TwouLDALNYSLOW THE WELL CONTRACTOR TO FILL IN ANY SETTLING,BUT IF THE SETTLING IS TOO GREAT,OCHD WILL INSPECT. 25