The annular space between the drilled hole and the outermost casing shall be sealed to the depths specified in Section 6-8.1008 of this article as follows:
(a) Using neat cement, cement grout, or concrete with an aggregate size not to exceed three-eighths (3/8") inch; or
(b) Using puddled clay mixed with clean materials supplied for preparing clay-base mixtures; or
(c) Using bentonide when drying conditions are not present. When a drilling method does not provide a two (2") inch annulus, the drive shoe annulus shall be maintained full of bentonide slurry during the advancement of the casing through the depth of the required seal. The surface seal shall be maintained through the completion of the well.
(d) Such sealing materials shall be placed in one continuous operation with the displacement from the bottom to the top of the interval to be sealed.
(e) Any well deeper than 1,000 feet and which penetrates two (2) or more distinct aquifers shall have a minimum fifty (50') foot annular seal placed in the confining materials between each two (2) aquifers. The installation of such seals will be based on the interpretation of the well log by the Enforcement Officer and the well driller or owner. (§ 1, Ord. 765, eff. October 7, 1976, as amended by § 16, Ord. 811, eff. July 27, 1978; as amended by § 3, Ord. 1470, eff. July 14, 2016)