The third and final way to produce salt is to extract it from the ground in the form of brine—a saline solution that is more than 30 per cent salt, as opposed to the 3 per cent of seawater. This is called “solution mining” and in a sense it’s not so different from digging it out physically: you are still mining the same seam, only solution miners use remote hoses of pressurised water rather than drills and dynamite.
