Abstract: A precious metal leaching method includes providing a slurried feed, comprising (i) in the solid phase, a refractory sulfide-containing material, the material comprising at least about 0.05 oz/tonne of a precious metal, at least about 0.75 wt. % sulfides, optionally at least about 0.1 wt. % feldspar (i.e., muscovite), and at least 0.3 wt. % preg-robbing carbonaceous material; and oxidizing the sulfide-containing material at more than about 240° C. and super-atmospheric pressure to oxidize at least most of the carbonaceous material and optionally convert at least most of the sulfide sulfur to sulfate sulfur and form an oxidized precious metal-containing material, wherein at least one of the following is performed during oxidizing: maintaining a pH of at least about pH 1.5; maintaining at least about 98.5% of the feldspar (i.e., muscovite) in the solid phase; maintaining a dissolved cupric ion concentration of at least about 0.