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David Wang, P.E. <br /> Page 3 <br /> August 17, 1989 <br /> - Sampling Results <br /> - Complete System Site Specific Engineering and <br /> Construction Requirements <br /> - System Evaluation Report <br /> Section 3 . 2 . 2 . 4 LIQUID LEVEL CONTROL FOR SUBMERSIBLE WELL PUMPS: <br /> o The Department cautions against installing a liquid level <br /> control system that may allow your submersible well pumps to <br /> run dry. The pumps could be severely damaged by excessively <br /> heated bearings or cavitation. We recommend that the liquid <br /> level control system be modified to eliminate this <br /> possibility. <br /> Sections 3 . 2 . 2 . 9 , 3 .4 . 4 . 11, and 3 . 4 . 5. 6 SAND PACK INSTALLATION: <br /> o The Department recommends that a sieve analysis be <br /> performed on the formation opposite the screened interval. <br /> The sieve analysis will aid in selecting the sand pack and <br /> screen slot size. Such analysis will allow the well to <br /> remain relatively sand free and increase efficiency. <br /> o We further recommend that the sand pack be placed more <br /> than two feet above the screened interval for the extraction <br /> and injection wells. The additional height will protect the <br /> screened interval against the sloughing of grout and <br /> formation material during operation. <br /> Section 3 . 4 . 5 MONITORING SYSTEM: <br /> o The Department recommends that centralizers be installed. <br /> Centralizers aid in keeping the casing and well screens <br /> centered in the borehole during the placement of the sand <br /> pack, bentonite seal, and grout. Our guidance recommends <br /> that the centralizers be placed at the top and bottom of the <br /> well screen and every forty feet on the blank casing. <br /> Sections 3 . 2 . 2 . 11, 3 .4 . 4 . 13 , and 3 . 4 . 5. 8 GROUTING PROCEDURES: <br /> o The Department is concerned that the grout mixture <br /> outlined in the statement of work may be too thick for <br /> pumping. The mixture may have to be thinned with additional <br /> water. Without precise control of the water, too much may <br /> be added, weakening the structural integrity of the grout. <br /> We therefore recommend that the grout mixture outlined in <br /> the attachment to this memorandum be substituted. <br /> o The Department further cautions against the use of <br /> beneficiated bentonite in the grout mixture. Its' use will <br /> lead to erroneous results in mixture calculations. <br />