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FIGURE 3 TYPE II TYPE III AQUIFER AQUIFER Ground Surface 1 foot /• \ / N /• \ / N N N /• \ / / \ /—N / \ / / \ / \ / \ / N \ / \ / N / ♦ / 10 ft Grout \, 10 ft Grout Overlap _ Overlap NProduction Casing / Solid Steel Casing • irrrApproved Grout —A — \'-- WELLS WITH DRIVEN CASING Figure 3. Schematic diagram for grout placement in wells with driven steel casing. In each aquifer type, the minimum continuous grout interval must extend a minimum of 10 feet into the annulus between the driven casing and the production casing. Figure 3 could be improved by adding notation "Min 19' bgs" at the base of the solid steel casing for each example well. 10.4.4 Annular Space Requirements for All Grouted Intervals -The borehole must be constructed to provide sufficient annular space for the placement of grout. Minimum annular space requirements apply only to intervals that must be grouted to meet minimum grouting requirements. 10.4.4.1 The annulus between the casing and the borehole diameter for every wellor between two strings of casing must not be less than two and seven eighths (2-% or 2.875) inches larger than the outside diameter of the outermost casing or coupling (minimum one {-1-and seven sixteenths (1-7/16 or 1.4375) inch of annular space, as defined in Rule 5.2.1-),a 10.4.4.3 If grout is poured from the surface and the casing is not vibrated, the borehole diameter for the well must not be less than four(4) inches larger than the outside diameter of the casing (annular space of two (2) inches). 10.4.4.2 If granular bentonite grout is used in accordance with Rule 10.4.5.3 the outside diameter of the tremie pipe must not exceed the annular space between the casing and the borehole. The tremie pipe must be rigid and the inside diameter of the tremie must be a minimum of four(4)times the diameter of the pellet or chip of granular bentonite.