I can't recall where I first saw a reference to the size of the...

I can't recall where I first saw a reference to the size of the tailings, but the most recent public estimate of the "tailings" were included in the Empire Capital Partners Research Note (accessible from OGX's website http://www.orinocogold.com/shareholder-centre/broker-research)

"Empire places a conservative estimate on the total size of the tailings stockpile of around 30,000 tonnes... We believe the stockpile could be at least double this number (ie 60,000 tonnes) but remain conservative at this stage."