US Patent 7896443 Ore extraction using combined blast and thermal fragmentation

A process for extracting ore from a vein (10) comprises drilling spaced-apart boreholes (16) directly in the vein (10). The boreholes (16) are enlarged using thermal fragmentation generally up to the boundaries between the vein and surrounding waste. A blasthole (18) is then drilled in the vein between the thermally enlarged boreholes (17) for placement of explosive. The explosive is fired to break the ore between the enlarged boreholes (17). The enlarged boreholes (17) act as weakening regions to direct the blasting effect and minimize dilution.