8e27de02_lls_in_Unconsolidated_Aquifers__1
[0] Air rotary with casing advance [2] Place CMT tubing into casing with anchor plate. CMT tubing centralizers should be used to center tubing in borehole. Add alternating lifts of sand and bentonite pellets* as casing is withdrawn, either by gravity placement, tremie methods. [3] Select casing with at least a 4-inch ID. Addition of water commonly needed to prevent heaving as casing removed. [1] 
Casing prevents borehole from collapsing as CMT well is being built. Consistent-diameter borehole. Prevents redistribution of contaminants along borehole wall during drilling.
Summary of Drilling Methods & Techniques for Installing CMT wells in Unconsolidated Aquifers
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