In that process, higher-grade ore is crushed to sand-size or finer particles and the copper minerals are physically separated by flotation.
(higher-grade ore; is crushed; to sand-size or finer particles and the copper minerals; L:In that process) (higher-grade ore; are physically separated; by flotation)
higher-grade ore higher-grade ore
is crushed are physically separated
to sand-size or finer particles and the copper minerals L:In that process
by flotation