In-situ method and apparatus for sparging gas bubbles

A gas sparging unit for use in introducing finely divided gas bubbles into a lixiviant used for in-situ mining of minerals, said device comprising:

• a hollow casing having a first chamber formed therein into which liquid lixiviant is supplied and a second chamber isolated from said first chamber;
• a plurality of porous tubes formed of sintered powdered metal and having micropores with a diameter between the range of 2-1000 microns, said tubes extending into said second chamber with said tubes having one end in fluid communication with said first chamber;
• means for introducing a pressurized gas about the portion of said tubes in said second chamber to enable the gas to penetrate into said tubes so that the gas can be wiped from the interior of the tubes by the lixiviant flowing through the tubes to form a lixiviant containing finely divided bubbles;
• said casing having an outlet end with said first chamber being isolated from said outlet end and with downstream end of said tube being positioned so that lixiviant containing gas bubbles can pass through said outlet end;
• and,
• means for removing gas bubbles trapped upstream of said outlet, said means comprising a conduit for providing communication between the interior of said casing adjacent the outlet end and the exterior of said casing.