Rule 36.21.649 - CASING CENTRALIZERS(1) Well casing to be sealed into an oversize drill hole should be equipped with centering guides to ensure the proper centering of a casing. In all events, casings shall be centered in the sealed interval. Guides should be of steel, at least 1/4 inch in thickness, evenly spaced in groups of 3 or 4 in 20 foot intervals or less. (See Figure 1.)Mont. Admin. r. 36.21.649
NEW, 1986 MAR p. 1699, Eff. 10/17/86.37-43-202(3), MCA; IMP 37-43-202(3), MCA;