Patent ID: 7478771

Claim:
A method of providing crushed rock, comprising the steps of: A. passing rocks through an early-stage rock crusher; B. passing crushed rocks from the early-stage rock crusher to a sizing device; C. recrushing, in a later-stage rock crusher unit, rocks from step B that fail to pass completely through the sizing device; D. constraining the recrushed rocks to gravitate downwardly toward an exit of the later-state rock crusher unit in the form of a column of recrushed rocks; E. providing first and second air ports on opposite sides of the recrushed rock column wherein the first air port communicates with ambient air; and F. generating suction at a location downstream of the second air port which communicates with the second air port, to cause ambient air to be sucked transversely through the recrushed rock column from the first air port to the second air port to extract fines from the recrushed rock column prior to the recrushed rocks exiting the later-stage crusher unit.