Possibly a response to this? http://www.smh.com.au/federal-polit...armichael-mega-coal-mine-20170606-gwl7h1.html
Started falling after this news. I can't say for certain this is the reason, but the timing is right. I didn't know Downer was a contractor partner to be honest. Not enough to trigger a sell off IMO, closed green today, so all steady!