Current through Vol. 42, No. 1, September 16, 2024
(a)
Monitoring wells, direct push monitoring wells and site assessment
observation wells. Monitoring wells, direct push monitoring wells and
site assessment observation wells shall be plugged to prevent pollution of
groundwater within three (3) days after completion of use or immediately if
drilled by an unlicensed or uncertified person or if the Board determines that
the well does not meet the minimum construction standards set forth in this
Chapter. The following are minimum requirements for plugging monitoring wells
and site assessment observation wells, and the owner of such wells or other
federal or state agency may specify more stringent requirements:
(1) If no contaminated soil or contaminated
groundwater is present in the well, cement grout shall be placed in the well
through a tremie pipe and filled or pumped from the bottom of the well to an
elevation four (4) feet below the land surface. In the alternative, bentonite
pellets, granules or high solids (a minimum of twenty percent (20%) solids by
dry weight) bentonite grout shall be placed from the bottom of the well to an
elevation fourteen (14) feet below land surface and a minimum of ten (10) feet
shall be filled with cement grout to an elevation four (4) feet below land
surface, unless contaminated soil or contaminated groundwater is present in the
well. The remaining four (4) feet to land surface shall be backfilled with
compacted uncontaminated soil. If the depth of the well is fourteen (14) feet
or less, cement grout shall be placed from the bottom of well to land
surface.
(2) If contaminated soil
or contaminated groundwater is present or was previously present in the well
and the top of the screen is less than 20 feet below land surface, overdrilling
of the well is required. The casing shall be removed or drilled out and the
same size auger used to drill the borehole or larger shall be used to drill out
the casing and associated seals, annular space and filter pack. Cement grout
shall be placed from the bottom of the well to an elevation four (4) feet below
land surface effectively grouting a minimum of 95% of the original drilled
borehole depth. If the total depth of the well is in excess of twenty feet
(20') below land surface, the cement grout shall be placed by pumping from the
bottom of the hole to within four (4) feet of the land surface. If the top of
the well screen is 20 feet or more below land surface and the well meets
current minimum construction standards, then the casing need not be removed and
cement grout shall be placed in the well through a tremie pipe and filled or
pumped from the bottom upward to within four (4) feet of land surface. The
remaining four (4) feet to land surface shall be backfilled with compacted
uncontaminated soil.
(b)
Geotechnical borings except direct push geotechnical borings.
Geotechnical borings shall be plugged to prevent pollution of groundwater
within thirty (30) days after completion of drilling or immediately if drilled
by an unlicensed or uncertified person or if the Board determines that the well
does not meet the minimum construction standards set forth in this Chapter. The
following are minimum requirements for plugging geotechnical borings, and the
owner of the boring or other federal or state agency may specify more stringent
requirements:
(1) If no contaminated soil and
groundwater is encountered in the boring, uncontaminated drill cuttings,
uncontaminated surface clay, cement, and/or high solids (a minimum of twenty
percent (20%) solids by dry weight) bentonite grout, pellets, or granules shall
be placed from the bottom of the boring to an elevation fourteen (14) feet
below land surface and a minimum of ten (10) feet shall be filled with cement
grout to an elevation four (4) feet below land surface. The remaining four (4)
feet to land surface shall be backfilled with compacted uncontaminated
soil.
(2) If contaminated soil or
contaminated groundwater is encountered in the boring, or if the boring is
located at an underground storage tank site or within 300 feet of the outside
perimeter of an existing wastewater lagoon or is located on a tract of land
where a wastewater lagoon is proposed, cement grout shall be placed from the
bottom of the borehole to an elevation four (4) feet below land surface. Cement
grout shall be placed in the borehole through a tremie pipe and filled or
pumped from the bottom upward. The remaining four (4) feet to land surface
shall be backfilled with compacted uncontaminated soil.
(3) If the boring is twenty (20) feet or less
in total depth and groundwater has not been encountered, the boring shall, at a
minimum, be filled with compacted uncontaminated cuttings from the bottom of
the boring to land surface.
(c)
Direct push geotechnical
borings. Direct push geotechnical borings shall be plugged to prevent
pollution of groundwater within thirty (30) days after completion of drilling
or immediately if drilled by an unlicensed or uncertified person or if the
Board determines that the well does not meet the minimum construction standards
set forth in this Chapter as follows:
(1)
Bentonite chips shall be placed and effectively compressed within the annulus
space from the bottom of the borehole to within ten (10) feet of the land
surface.
(2) Cement grout shall be
installed through a tremie pipe in the remaining annulus space from ten (10)
feet to land surface, provided that no cement grout shall be required if the
boring is less than ten feet (10') in total depth and no groundwater and no
contaminated soil was encountered.
(d)
Cement grout requirements.
If cement grout is used, the grout shall have a mix ratio of one 94 pound sack
of cement to a maximum of six U.S. gallons of water.
(e)
Abandonment after equipment
removed. If a site assessment observation well, monitoring well or
geotechnical boring is abandoned after the drilling equipment has been removed
from the site, responsibility for proper plugging within the applicable time
period specified in this section shall lie with the owner of the land where the
well or boring is located
Revoked and reenacted at 9 Ok Reg 1679, eff 5-11-92 ;
Amended at 10 Ok Reg 3299, eff 6-25-93 ; Amended at 11 Ok Reg 2947, eff 6-13-94
; Amended at 12 Ok Reg 2703, eff 7-1-95 ; Amended at 15 Ok Reg 2440, eff
6-11-98 ; Amended at 16 Ok Reg 2686, eff 7-1-99 ; Amended at 19 Ok Reg 2498,
eff 6-27-02 ; Amended at 20 Ok Reg 2608, eff 7-11-03 ; Amended at 21 Ok Reg
2632, eff 7-1-04 ; Amended at 22 Ok Reg 1598, eff 7-1-05 ; Amended at 23 Ok Reg
3078, eff 7-27-06 ; Amended at 25 Ok Reg 1444, eff 5-27-08 ; Amended at 27 Ok
Reg 1313, eff 5-27-10 ; Amended at 30 Ok Reg 895, eff
6-13-13
