The Beypazari Trona Mine in Turkey has the characteristics of varying buried depth and thickness and proneness to pinch out, and water kicks occurs frequently while drilling at the edge of the mining area, which leads to different casing setting positions in the vertical wells of the same solution mining well set, or the mining trona layer where casing has been set is unstable and needs to be changed. In order to solve these problems, the section-milling technology was introduced and applied to expose the previously isolated trona bed and form a new mining passage. A total of 14 wells were drilled by applying this technology on the project, and all achieved satisfied results. In the paper, the section-milling process is illustrated by taking the drilling of the H066 well set as an example. Comparing with drilling a new well, it reduces greatly the construction period and saves drilling costs. Field use demonstrated that the technology is beneficial in changing the mining layer, treatment of downhole incidents, and provides many advantages such as less drilling time, less drilling cost, extension of the service life of old wells, increasing of resource recovery; therefore it has a broad application prospect.