62-528.405. Evaluation of Geologic and Hydrologic Environment for Class I and III Wells

(1) General.

(a) Class I Wells. An applicant for an injection well shall demonstrate that the hydrogeologic environment is suitable for waste injection as provided in paragraph 62-528.440(2)(c), F.A.C., and without modifying the ambient water quality of other aquifers overlying the injection zone. In the Class I well construction permit application, the applicant shall address the proposed testing and sampling procedures for adequately defining the depth at which total dissolved solids exceed 10,000 mg/L in formation waters. An assessment of the lateral position at which total dissolved solids exceed 10,000 mg/L in the injection zone waters shall also be provided. The Department shall, when necessary to protect underground sources of drinking water, request that the applicant provide, in addition to site-specific and area of review information, regional information that will allow prediction of the regional impact of the proposed injection well.

(b) Class III Wells.

1. The Department shall evaluate each proposed mining operation for potential effects of the mining activity on the underground sources of drinking water. The Department shall, at a minimum, consider the effects of depressurization of the aquifer on the water quality of any underground source of drinking water. An applicant for a Class III injection well project shall demonstrate that the hydrogeologic environment is suitable for injection for extraction of minerals or energy without endangering the underground sources of drinking water.

2. No Class III mining activity shall be allowed in an underground source of drinking water, or shall result in a violation of ground water standards. If the proposed mining activity is in an underground source of drinking water, an aquifer exemption pursuant to subsection 62-528.300(3), F.A.C., shall be obtained prior to the well being placed into operation.

(2) Confining Zone.

(a) Class I Wells.

At least one confining zone above the injection zone is required. The applicant shall demonstrate that the confining zone(s) has sufficient areal extent, thickness, lithologic and hydraulic characteristics to prevent fluid migration into underground sources of drinking water.

(b) Class III Wells.

If an underground source of drinking water exists above or below the proposed mining zone, a confining zone is required between the mining zone and the underground source of drinking water. The confining zone must be of such thickness, areal extent, and permeability to constrain the effects of the mining to the mining zone, and the integrity of the confining zone must be maintained for the life of the project.

(c) Testing of Confining Zone for Class I and III Wells.

The proposed methodology for testing the confining zone shall be submitted to the Department as part of the permit application. The applicant shall provide sufficient data such as geophysical logs, lithologic cores, physical core analysis, borehole video television surveys, water samples, and drill stem tests (or aquifer tests) to adequately demonstrate the confining characteristics of the bed. A monitoring system is required, which shall include one or more on-site monitor well(s), designed to confirm the long-term effectiveness of the confining zone. The following geophysical logs shall be considered for use in determining if adequate confinement is present:

1. Resistivity log;

2. Natural gamma-ray;

3. Fluid conductance log;

4. Caliper log;

5. Static and pumping temperature log;

6. Static and pumping spinner flowmeter;

7. Acoustic velocity; and

8. Porosity log.

(3) Injection Zone for Class I Wells.

(a) The applicant shall demonstrate that the proposed injection zone has sufficient extent, thickness, lithologic and hydraulic characteristics to adequately receive waste.

(b) The proposed methodology for testing the injection zone shall be submitted as part of the permit application to the Department. The purpose of testing the injection zone is to demonstrate the zone’s capacity for receiving injected fluid. The applicant shall demonstrate the suitability of a proposed zone by determining the hydraulic characteristics, lithology, thickness, extent, and compatibility of injection and formation fluids. Testing of the injection zone shall include a pumping injection test at a flow rate of not less than the maximum design capacity of the well, and of such duration that can demonstrate the trend of the injection pressure on the long-term operating conditions. If an adequate water supply for the injection test does not exist, and the data collected during drilling provide assurance of the presence of confining bed(s), the applicant shall, after demonstrating mechanical integrity pursuant to subparagraphs 62-528.300(6)(b)2. and (c), F.A.C., be allowed to use secondarily treated domestic wastewater effluent after disinfection or desalination concentrate for testing only with specific prior written authorization from the Department as described in subsection 62-528.100(2), F.A.C. Methods to be considered for testing the injection zone include:

1. Water samples;

2. Withdrawal tests;

3. Video television survey;

4. Lithologic cores;

5. Drill cuttings.

6. Geophysical surveys such as:

a. Resistivity survey;

b. Natural gamma-ray;

c. Fluid conductance survey;

d. Caliper survey;

e. Static and pumping temperature survey;

f. Static and pumping spinner flowmeter;

g. Acoustic velocity; and

h. Porosity survey.

Specific Authority 373.309, 403.061, 403.087 FS. Law Implemented 373.308, 403.021, 403.061, 403.062, 403.087, 403.721 FS. History–New 4-1-82, Amended 8-30-82, 5-8-85, Formerly 17-28.21, 17-28.210, 62-28.210, Amended 8-10-95, 6-24-97.