The longest cave in salt is in Iran - island Queshm in Hormus - the name is "Cave of three nudes" - the first explorers were naked there first time because of large and deep salty lake in entrance. It is longer than former longest salty cave - Malham in Israel - 5685 m. The overall lenght is more than 6000 m.
The cavers from Czech Republic conected the ponor cave with main system.
The coordinates of entrance : 26 deg xx min xx,xx sec N 55 deg xx min xx,xx sec E - try Google Earth - the dark area is salt block Namakdan in which the cave is developed.
Link to map and pictures (only in Czech) but you may find more link if you look for "Cave Namakdan, Namak" in Google (there are articles in English too).