** Shares of Australia's Bougainville Copper BOC.AX fall
as much as 4.9% to A$0.58 to hit their lowest since April 17
** The copper miner says it has been served with a class
action regarding the Bougainville copper mine, which was
previously held by Rio Tinto RIO.AX
** Class action alleges mining practices at the mine
resulted in social harm and damaging environmental impacts in
the area
** BOC says it intends to defend those proceedings
** Stock has risen 79.4% this year, as of last close
(Reporting by Rishav Chatterjee in Bengaluru)
((Rishav.Chatterjee@thomsonreuters.com;))