Breccia Zones -Often major ore carriers in the porphyry system. Have very high grades(2-5% Cu) and can occur both in the porphyry or the country rock. May be formed by hydrothermal activity, gravitational collapse or later explosive volcanismBreccia Zones - Often major ore carriers in the porphyry system. Have very high grades (2-5% Cu) and can occur both in the porphyry or the country rock. May be formed by hydrothermal activity, gravitational collapse or later explosive volcanism