ARM 36.21.649
ARM 36.21.649. CASING CENTRALIZERS
Cite as Mont. Admin. R. 36.21.649
(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.)