Current through Bulletin 2024-18, September 15, 2024
Drill holes shall be properly plugged as soon as practical
and shall not be left unplugged for more than 30 days without approval of the
Division. The procedures outlined below are required for the surface and
subsurface plugging of drill holes. The Division may approve an alternate plan,
if the operator can prove to the satisfaction of the Division that another
method will provide adequate protection to the groundwater resources and long
term stability of the land. Dry holes and nonartesian holes which do not
produce significant amounts of water may be temporarily plugged with a surface
cap to permit the operator to re-enter the hole for the duration of the
operations.
1. Surface plugging of
drill holes shall be accomplished by:
1.11.
Setting a nonmetallic permaplug at a minimum of five (5) feet below the
surface, or returning the cuttings to the hole and tamping the returned
cuttings to within five (5) feet of ground level. The hole above the permaplug
or tamped cuttings will be filled with a cement plug. If cemented casing is to
be left in place, a concrete surface plug is not required provided that a
permanent cap is secured on top of the casing.
1.12. If the area is tilled farmland, a five
(5) foot cement plug must be placed above a permaplug or tamped cuttings so
that the top of the cement plug is a minimum of three (3) feet below the ground
surface. The hole above the cement plug is to be filled with soil. If cemented
casing is to be left in place, a concrete surface plug is not required provided
that a permanent cap is secured on top of the casing. The top of the casing and
cap must be a minimum of three (3) feet below the ground
surface.
2. Drill holes
that encounter water, oil, gas or other potential migratory substances and are
2-1/2 inches or greater in surface diameter shall be plugged in the subsurface
to prevent the migration of fluid from one strata to another. If water is
encountered, plugging shall be accomplished as outlined below:
2.11. If artesian flow (i.e., water flowing
to the surface from the hole) is encountered during or upon cessation of
drilling, a cement plug shall be placed to prevent water from flowing between
geologic formations and at the surface. The cement mix should consist of API
Class A or H cement with additives as needed. It should weigh at least 13.5
lbs./gal., and be placed under the supervision of a person qualified in proper
drill hole cementing of artesian flow. Artesian bore holes must be plugged in
the described manner, prior to removal of the drilling equipment from the well
site. If the surface owner of the land affected desires to convert an artesian
drill hole to a water well, he must notify the Division in writing that he
accepts responsibility for the ultimate plugging of the drill hole.
2.12. Holes that encounter significant
amounts of nonartesian water shall be plugged by:
2.12.111. Placing a 50 foot cement plug
immediately above and below the aquifer(s); or
2.12.112. Filling from the bottom up (through
the drill stem) with a high grade bentonite/water slurry mixture. The slurry
shall have a Marsh funnel viscosity of at least 50 seconds per quart prior to
the adding of any cuttings.
