(a) Independent and representative water samples shall be collected from each of the following:
  (1) mine area monitor wells completed in the production zone;
  (2) mine area monitor wells completed in nonproduction zones; and
  (3) baseline wells completed in the production zone within the production area.
(b) All baseline wells must be completed in the production zone within the production area. The owner or operator shall analyze all groundwater samples from the baseline wells for the following parameters. This suite of parameters shall be the basis for the aquifer restoration required under §331.107 of this title (relating to Restoration). With the exception of uranium and radium-226, any of these parameters may be removed from the list of restoration parameters if an applicant or permittee can demonstrate that a parameter or parameters is not a suitable restoration parameter. An applicant or permittee also can demonstrate that a parameter should be added to the list of restoration parameters. The executive director may require an applicant or operator to establish baseline parameters additional to the above list as appropriate, based on site-specific information. In evaluating a demonstration regarding removing or adding parameters to the list of parameters, the executive director may consider the following:
Attached Graphic
  (1) all parameters that occur in the groundwater within the production zone prior to in situ recovery;
  (2) all parameters that are in the solutions injected into the production zone;
  (3) all parameters that may be dissolved from the aquifer material of the production zone into the groundwater during in situ recovery; or
  (4) any other applicable information provided by the applicant or permittee.
(c) A minimum of five baseline wells, or one baseline well for every four acres of production area, whichever is greater, shall be completed in the production zone within the production area. All baseline wells shall be sampled in accordance with subsection (a) of this section and analyzed in accordance with subsection (d) of this section. All valid analytical measurements shall be used to determine the suite of restoration parameters required under subsection (b) of this section.
(d) All samples shall be collected, preserved, analyzed, and controlled according to accepted methods as stated in the permit and in accordance with the TCEQ Quality Assurance Project Plan (QAPP).
(e) The permittee shall propose for subsequent approval by the commission control parameters for detection of excursions in production and nonproduction wells. Control parameters shall be those constituents in the groundwater that will provide timely and reliable detection of the presence of mining solutions in production and nonproduction wells. Control parameter upper limits for production zone monitor wells shall be determined from pre-mining groundwater sample data from production zone monitor wells, and control parameter upper limits for nonproduction zone monitor wells shall be determined from pre-mining groundwater sample data from nonproduction zone monitor wells. Determination of the presence of an excursion shall be based on a statistical method proposed by the owner or operator and approved by the executive director.
(f) If a previously mined permit or production area is to be re-entered for additional in situ mining before completion of restoration under §331.107 of this title or completion of closure under §331.83 of this title (relating to Closure), baseline water quality values for determination of control parameter upper limits and aquifer restoration requirements for the area to be re-entered for mining shall be as originally required by the existing production area authorization or as modified by any amendments to the authorization pursuant to this section and §331.107 of this title.
(g) If a previously mined and restored area is to be re-entered for additional in situ uranium mining, baseline water quality values for determination of control parameter upper limits and aquifer restoration requirements for the area to be re-entered for mining shall be determined as required by subsections (a) - (d) of this section.

Source Note: The provisions of this §331.104 adopted to be effective May 13, 1986, 11 TexReg 1985; amended to be effective March 12, 2009, 34 TexReg 1638