La. Admin. Code tit. 43 § XVII-3315

Current through Register Vol. 50, No. 11, November 20, 2024

Section XVII-3315 - Cavern Design and Spacing Requirements

A. This Section provides general standards for design of caverns to assure that project development can be conducted in a reasonable, prudent, and a systematic manner and shall stress physical and environmental safety. The owner or operator shall continually review the design throughout the construction and operation phases taking into consideration pertinent additional detailed subsurface information and shall include provisions for protection from damage caused by hydraulic shock. If necessary, the original development and operational plans shall be modified to conform to good engineering practices.

B. Cavern Spacing Requirements

1. Property Boundary

a. Existing Solution-Mining Caverns. No part of a solution-mining cavern permitted as of the date these regulations are promulgated shall extend closer than 100 feet to the property of others without consent of the owner(s). Continued operation without this consent of an existing solution-mining cavern within 100 feet of the property of others may be allowed as follows.

i. The operator of the cavern shall make a good faith effort to provide notice in a form and manner approved by the commissioner to the adjacent property owner(s) of the location of its cavern.

ii. The commissioner shall hold a public hearing in Baton Rouge if a non-consenting adjacent owner whose property line is within 100 feet objects to the cavern's continued operation. Following the public hearing the commissioner may approve the cavern's continued operation upon a determination that the continued operation of the cavern has no adverse effects to the property rights of the adjacent property owner(s).

iii. If no objection from a non-consenting adjacent property owner is received within 30 days of the notice provided in accordance with §3315.B.1.a.i above, then the commissioner may approve the continued operation of the cavern administratively.

b. New Solution-Mining Caverns. No part of a newly permitted solution-mining cavern shall extend closer than 100 feet to the property of others without the consent of the owner(s).

2. Adjacent Structures within the Salt. As measured in any direction, the minimum separation between walls of adjacent caverns or between the walls of the cavern and any adjacent cavern or any other manmade structure within the salt stock shall not be less than 200 feet. Caverns must be operated in a manner that ensures the walls between any cavern and any other manmade structure maintain the minimum separation of 200 feet. For solution-mining caverns permitted prior to the effective date of these regulations and which are already within 200 feet of any other cavern or manmade structure within the salt stock, the commissioner of conservation may approve continued operation upon a proper showing by the owner or operator that the cavern is capable of continued safe operations.

3. Salt Periphery

a. Without exception or variance to these rules and regulations, at no time shall the minimum separation between the cavern walls at any point and the periphery of the salt stock for a newly permitted solution-mining cavern be less than 300 feet.

b. An existing solution-mining cavern with less than 300 feet of salt separation at any point between the cavern walls and the periphery of the salt stock shall provide the Office of Conservation with an enhanced monitoring plan that has provisions for ongoing monitoring of the structural stability of the cavern and salt through methods that may include, but are not limited to, increased frequency of sonar caliper surveys, vertical seismic profiles, micro-seismic monitoring, increased frequency of subsidence monitoring, mechanical integrity testing, continuous cavern pressure data monitoring, etc. A combination of enhanced monitoring methods may be proposed where appropriate. Once approved, the owner or operator shall implement the enhanced monitoring plan.

c. Without exception or variance to these rules and regulations, an existing solution-mining cavern with cavern walls 100 feet or less from the periphery of the salt stock shall be removed from service immediately and permanently. An enhanced monitoring plan in conformance with §3315.B.3.b above for long term monitoring shall be prepared and submitted to the Office of Conservation. Once approved, the owner or operator shall implement the enhanced monitoring plan.

d. For solution-mining caverns in existence as of the effective date of these regulations with less than 300 feet but more than 100 feet of salt separation at any point between the cavern walls and the periphery of the salt stock, continued or additional solution-mining may be allowed upon submittal of an enhanced monitoring plan in conformance with §3315.B.3.b above in addition to any additional maps, studies, tests, assessments, or surveys required by the commissioner to show that the cavern is capable of continued safe operations.

C. Cavern Coalescence. The Office of Conservation may permit the use of coalesced caverns for solution-mining. It shall be the duty of the applicant, owner or operator to demonstrate that operation of coalesced caverns under the proposed cavern operating conditions can be accomplished in a physically and environmentally safe manner. The intentional subsurface coalescing of adjacent caverns must be requested by the applicant, owner or operator in writing and be approved by the Office of Conservation before beginning or resumption of solution-mining operations. Approval for cavern coalescence shall only be considered upon a showing by the applicant, owner or operator that the stability and integrity of the cavern and salt stock shall not be compromised and that solution-mining operations can be conducted in a physically and environmentally safe manner. If the design of adjacent caverns should include approval for the subsurface coalescing of adjacent caverns, the minimum spacing requirement of §3315.B.2 above shall not apply to the coalesced caverns.

La. Admin. Code tit. 43, § XVII-3315

Promulgated by the Department of Natural Resources, Office of Conservation, LR 40:332 (February 2014), Amended LR 42417 (3/1/2016), Amended LR 482309 (9/1/2022).

AUTHORITY NOTE: Promulgated in accordance with R.S. 30:4 et seq.