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RULE §331.82Construction Requirements

(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.

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

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