Schemes comparation of layered and continuous solution mining in bedded salt formations by horizontal interconnected wells

Salt deposits in China predominantly originate from lake deposits, characterized by thin salt beds interspersed with numerous interlayers, collectively termed bedded salt formations. Historically, the solution mining practices have adopted the layered solution mining approach, inspired by coal mining techniques. However, this approach fails to account for the unique challenges of salt solution mining. Practical implementation is inefficient, costs escalate post-construction, and cavern geometry is constrained by salt beds thickness. Additionally, resource loss in abandoned beds and stability risks in adjacent mining zones remain unresolved. This study investigates mining scheme selection for low-grade salt deposits in Huai’an Salt Basin, introducing a continuous solution mining method that traverses multiple interlayers. Through comprehensive analysis of plastic deformation in caverns and surrounding rock, volume shrinkage rates, and economic costs comparing continuous and layered solution mining approaches, the results demonstrate that: (1) In the layered solution mining with horizontal interconnected wells scheme, plastic deformation zones propagate unevenly, posing interlayer connectivity risks. Concurrently, roof subsidence and floor heave destabilize the structure; (2) the continuous solution mining with horizontal interconnected wells scheme reduces plastic deformation zones to 3.4% of cavern volume, with volumetric shrinkage below 17%, markedly improving stability; (3) Economically, the continuous solution mining scheme generates caverns 2.43 times larger than the layered solution mining, slashing unit volume costs to 41.1% while enhancing resource recovery and long-term viability. The continuous method demonstrates distinct economic advantages and achieves higher resource utilization efficiency in solution mining compared to layered mining. Furthermore, its superior cavern stability presents strong potential for large-scale implementation.