Abstract: A well for the solution mining of salt from an underground salt formation, comprising a borehole (12) extending from the earth's surface downwards into the formation, a casing (10) that is cemented in said borehole down to the upper level of said formation and separate conduct means provided within said casing and extending through the borehole downwardly beyond said casing, respectively for introducing leaching water into the salt formation and for withdrawing pregnant leach liquor from said formation, which conduct means have adjustable effective lengths, said conduct means each comprising a tubing string (13, 14), the two strings extending parallel through said casing and at least one of said strings carrying a tailpipe (18, 19) of smaller diameter, which tailpipe is axially telescopic in said string, can extend downwardly beyond said string and carries a liner assembly (20, 21, 22, 23) at its upper part that can engage the inner wall of said string at any desired location above the bottom end of the strin