Current through Register Vol. 49, No. 13, September 23, 2024
Subpart
1.
Casing, protective casing, and capping.
The inner casing of a monitoring well, and when installed,
the protective outer casing as specified in subpart 2, item B, with bentonite
grout in the annular space, must be covered with a cap or cover according to
part 4725.2250, subpart 17. The protective outer casing may be covered with an
overlapping cap or cover without a compression gasket.
A. Either the inner casing or the protective
outer casing must be closed with a watertight, locked cap or a
wrench-tightened, threaded metal cap.
B. The top of the well must be constructed to
prevent entry of flood waters according to part 4725.4350, subpart 2.
C. A monitoring well cased with plastic must
be protected with an outer steel protective casing as specified in subpart 2,
item B.
Subp. 2.
Protection.
A monitoring well must be protected by:
A. surrounding the casing with a concrete
pyramid or cone that has horizontal dimensions of at least 24 inches by 24
inches at the established ground surface, that rises 12 inches above the
established ground surface at the casing, and has a base with a mass of at
least three cubic feet below the established ground surface;
B. installing a steel outer casing meeting
the material standards of part 4725.2350 that is at least 3.0 inches in
diameter greater than the inner casing, that extends at least two feet above
and four feet below the established ground surface, and that has bentonite
grout, neat-cement grout, or cement-sand grout in the annular space between the
casings from the bottom of the outer casing to the established ground surface;
or
C. placing three posts at least
four inches square or four inches in diameter around the well at equal
distances from each other and two feet from the casing. The posts must extend
two feet above and four feet below the established ground surface or to a depth
of two feet if each post is set in concrete to a depth of two feet. The posts
must be made of reinforced concrete, decay-resistant wood, or ASTM Schedule 40
steel pipe capped with an overlapping, threaded, welded steel or iron cap, or
be filled with cement.
Statutory Authority: MS s
103I.101;
103I.111;
103I.205;
103I.221;
103I.301;
103I.401;
103I.451;
103I.501;
103I.525;
103I.531;
103I.535;
103I.541;
103I.621;
144.05;
144.12;
144.383;
157.04; 157.08; 157.09; 157.13
