62-672.770. Phosphogypsum Stack Inspection and Maintenance

(1) Personnel or agents of the department may accompany inspectors on any inspection required by this rule, or inspect starter dikes or gypsum dikes at any other time which is reasonable under the circumstances involved. They may also examine any inspection reports and shall be furnished copies thereof upon request.

(2) A completed new phosphogypsum stack system, including the starter dike, shall be thoroughly inspected prior to the deposition of process water in it. The liner, spillways and water level control structures shall be certified by the design third-party engineer as meeting all specifications of the design, and the degree of compaction of the fill shall also be certified. Legible photographs, either aerial or ground, may be used to document this initial inspection, but shall not in themselves constitute certification. A complete file describing the items inspected and their condition shall be maintained by the owner, and a copy shall be furnished to the department.

(3) All stack compartments, including any noted areas containing critical conditions as listed in subsection 62-672.770(6), F.A.C., until corrected, shall be inspected daily. Stack slopes, collection ditches, and drain outlets shall be inspected weekly. Flow from drain outlets shall be checked quarterly. The total areal coverage of water on the stack shall be estimated each month and the total water inventory on top of the stack shall be estimated annually. The required inspections and estimates shall be carried out by a qualified company employee or contractor employed or retained by the owner of the phosphogypsum stack which employee or contractor has been trained in accordance with Rule 62-672.800, F.A.C. The results of the required inspections and estimates shall be recorded in a log which shall be maintained by the owner of the phosphogypsum stack and made available to representatives of the department upon request.

(4) When a critical condition listed in subsection 62-672.770(6), F.A.C., is suspected during an inspection, the inspector shall ensure that a competent technical representative of the phosphogypsum stack system owner is made aware of the condition immediately. If the existence of the critical condition is confirmed, the department shall be notified immediately. A written report of the condition and the actions proposed for its correction shall be made to the department within seven (7) days from the time existence of the critical condition is confirmed.

(5) Each phosphogypsum stack shall be inspected annually by a third-party engineer with experience in the field of construction and operation of phosphogypsum stacks at the same time that the annual inspection of the associated perimeter earthen dike occurs as required by Rule 62-672.670, F.A.C. One copy of the report pertaining to such an inspection shall be furnished to the department, and the original report shall be retained by the owner. The report shall include an updated aerial photograph and shall state the area of the top of the stack and the current height and elevation of the stack. The annual inspection report shall include recommendations and corrective measures taken. If corrective measures are not completed by the time of annual submittal, then follow up inspections shall be conducted by the third-party engineer on a quarterly basis with quarterly project reports submitted until completion of all corrective measures.

(6) Any of the following items shall be considered as indicating a critical condition which requires immediate investigation and may require emergency maintenance action:

(a) Concentrated seepage (e.g., springs or boils) on the face of a stack slope, at the toe of the slope, or beyond the toe of slope with active signs of piping at the point of seepage (e.g., a gypsum or soil cone or delta at the point of seepage).

(b) Evidence of slope instability including sloughing, bulging or heaving of the face of the stack or the toe of the slope.

(c) Lateral movement or subsidence of the slope or crest of the stack.

(d) Formation of new non-shrinkage cracks or enlargement of wide cracks in the surface of the slope or crest of the stack.

(e) Observed or suspected damage to the liner system.

(f) Drains discharging turbid water.

(g) Concentrated seepage (i.e., springs or boils) in the vicinity of a decant pipe.

(7) The following items shall be considered as indicating potential trouble areas which should be closely checked on subsequent inspections and repaired as necessary:

(a) Concentrated seepage (e.g., springs or boils) on the face of a stack or at the toe of slope without active signs of piping at the point of seepage.

(b) Previously observed localized sloughing at the toe of slope of the stack.

(c) Previously observed cracks in the surface of the slope or crest of the stack.

(d) Nonflowing drains.

(8) All logs and reports required under this section shall be retained by the owner of the phosphogypsum stack system for a period of not less than three years from the date of the last entry in a log or from the date of the report.

Specific Authority 403.4155 FS. Law Implemented 403.4155 FS. History–New 6-28-99.