Milling Practices Ore is direct tipped into a gyratory crusher and crushed to minus 209mm and fed to stockpiles for the blending of
grade into the mills. Secondary and tertiary crushing reduces the mill feed to minus 12mm. Mill feed is a blend of
breccia and porphyry ore into two primary mills with the overflow to a regrind mill and then into the leach tanks,
followed by a conventional counter current carbon in leach circuit. Underflow from the cyclones feeds back into
the primary mills for additional grind. An unusual feature of the Mt Leyshon milling circuit is a desire to produce
scatts. The scatt by product is the polished base rock of the Mt Leyshon Breccia clast and contains little grade.
These scatts are produced because of the additional time and energy required to produce a proportionally small
quantity of gold. The residence of these scatts in the mills decreases the mill feed rate. Scatts account for twenty
percent of the mill feed and are screened from the discharge of the primary mills.