| (a) Casing and cementing. All new Class III wells,
baseline wells, and monitor wells associated with the mining operations
shall be cased, cemented from the bottom of the casing to the surface,
and capped to prevent the migration of fluids which may cause the
pollution of underground sources of drinking water (USDWs) and maintained
in that condition throughout the life of the well. In addition, existing
wells in areas where there is the potential for contamination and
other harmful or foreign matter to enter groundwater through an open
well, shall also be cemented to the surface and capped. The casing
and cement used in the construction of each well shall be designed
for the life expectancy of the well. In determining and specifying
casing and cementing requirements, the following factors shall be
considered:
(1) depth to the injection zone;
(2) injection pressure, external pressure, internal
pressure, axial loading, etc.;
(3) hole size;
(4) size and grade of all casing strings (wall thickness,
diameter, nominal weight, length, joint specification, and construction
material);
(5) corrosiveness of injected fluids and formation
fluids;
(6) lithology of injection and confining zones; and
(7) type and grade of cement.
(b) Alterations to construction plans. Any proposed
changes or alterations to construction plans after permit issuance
shall be submitted to the executive director and written approval
obtained before incorporating such changes.
(c) Logs and tests. Appropriate logs and other tests
shall be conducted during the drilling and construction of all new
Class III wells and after an existing well has been repaired. A descriptive
report interpreting the results of those logs and tests shall be prepared
by a knowledgeable log analyst and submitted to the executive director.
The logs and tests appropriate to each type of Class III well shall
be determined based on the intended function, depth, construction,
and other characteristics of the well, availability of similar data
in the area of the drilling site, and the need for additional information
that may arise from time to time as the construction of the well progresses.
(1) During the drilling and construction of Class III
wells, appropriate deviation checks shall be conducted on holes, where
pilot holes and reaming are used, at sufficiently frequent intervals
to assure that vertical avenues for fluid migration in the form of
diverging holes are not created during drilling.
(2) Mechanical integrity, as described in §331.43
of this title (relating to Mechanical Integrity Standards), shall
be demonstrated both following construction of the well, and prior
to production or injection. For Class III uranium solution mining
wells, a pressure test shall also be conducted each time a tool that
could affect mechanical integrity is placed into the well.
(A) Except as provided by subparagraph (B) of this
paragraph, the following tests shall be used to evaluate the mechanical
integrity of the injection well:
(i) to test for significant leaks under §331.43(a)(1)
of this title, monitoring of annulus pressure, or pressure test with
liquid or gas, or radioactive tracer survey. For Class III uranium
solution mining wells only, a single point resistivity survey in conjunction
with a pressure test can be used to detect any leaks in the casing,
tubing, or packer; and
(ii) to test for significant fluid movement under §331.43(a)(2)
of this title, temperature log, noise log, radioactive tracer survey,
cement bond log, oxygen activation log. For Class III uranium solution
mining wells only, cement records that demonstrate the absence of
significant fluid movement can be used where other tests are not suitable.
For Class III wells where the cement records are used to demonstrate
the absence of significant fluid movement, the monitoring program
prescribed by §331.84 of this title (relating to Monitoring Requirements)
shall be designed to verify the absence of significant fluid movement.
(B) The executive director may allow the use of a test
to demonstrate mechanical integrity other than those listed in subparagraph
(A) of this paragraph with the written approval of the administrator
of the United States Environmental Protection Agency (EPA) or his
authorized representative. To obtain approval, the executive director
shall submit a written request to the EPA administrator, which shall
set forth the proposed test and all technical data supporting its
use. The EPA administrator shall approve the request if it will reliably
demonstrate the mechanical integrity of wells for which its use is
proposed. Any alternate method approved by the EPA administrator shall
be published in the Federal Register and may be used unless its use
is restricted at the time of approval by the EPA administrator.
(3) Additional logs and tests may be required by the
executive director when appropriate.
(d) Construction and testing supervision. All phases
of well construction and testing shall be supervised by a person who
is knowledgeable and experienced in practical drilling engineering
and who is familiar with the special conditions and requirements of
injection well construction.
(e) Injection zone characteristics - water bearing
formation. Where the injection zone is a water bearing formation,
the following information concerning the injection zone shall be determined
or calculated:
(1) fluid pressure;
(2) temperature;
(3) fracture pressure;
(4) other physical and chemical characteristics of
the injection zone;
(5) physical and chemical characteristics of the formation
fluids;
(6) compatibility of injected fluids with formation
fluids; and
(7) pre-mining groundwater quality, established in
a range table as required under §305.49(a)(10) of this title
(relating to Additional Contents of Application for an Injection Well
Permit), for a Class III injection well permit authorizing in situ mining of uranium.
(f) Injection zone characteristics - non-water bearing
formations. Where the injection formation is not a water bearing formation,
the fracture pressure shall be determined or calculated.
(g) Monitor well location. Where injection is into
a formation which contains water with less than 10,000 milligrams
per liter of total dissolved solids, monitoring wells shall be completed
into the injection zone and into any USDW above the injection zone
which could be affected by the mining operation. These wells shall
be located to detect any excursion of injection fluids, production
fluids, process by-products, or formation fluids outside the mining
area or zone. If the operation may be affected by subsidence or catastrophic
collapse, the monitoring wells shall be located so that they will
not be physically affected. Designated monitoring wells shall be installed
at least 100 feet inside any permit area boundary, unless excepted
by written authorization from the executive director.
(h) Subsidence or catastrophic collapse. Where the
injection wells penetrate a USDW in an area subject to subsidence
or catastrophic collapse an adequate number of monitor wells shall
be completed into the USDW to detect any movement of injected fluids,
process by-products or formation fluids into the USDW. The monitor
wells shall be located outside the physical influence of the subsidence
or catastrophic collapse.
(i) Monitor well criteria. In determining the number,
location, construction, and frequency of monitoring of the monitor
wells the following criteria shall be considered:
(1) the population relying on the USDW affected or
potentially affected by the injection operation;
(2) the proximity of the injection operation to points
of withdrawal of drinking water;
(3) the local geology and hydrology;
(4) the operating pressures and whether a negative
pressure gradient is being maintained;
(5) the chemistry and volume of the injected fluid,
the formation water, and the process by-products; and
(6) the injection well density.
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| Source Note: The provisions of this §331.82 adopted to be effective May 13, 1986, 11 TexReg 1984; amended to be effective April 28, 1997, 22 TexReg 3526; amended to be effective November 23, 2000, 25 TexReg 11433; amended to be effective July 12, 2001, 26 TexReg 5019; amended to be effective March 12, 2009, 34 TexReg 1638; amended to be effective December 11, 2014, 39 TexReg 9586 |
