Coal Sample Mill 2 To 6. Distributions and extraction of rare earth elements from coal and coal by -products.Elliot roth 1,2, megan macala 1,2, ronghong lin 1, tracy bank 1,2, robert thompson 1,2, bret howard 1, yee soong 1, and evan granite 1.1 u.S.Dept.Of energy, national energy tech nology laboratory, 626 cochrans mill rd., pittsburgh, pa 15236, usa.2 aecom, national energy technology ...