Glorieux,
Nice Summary!
Yes, they are being conservative, but that would be much better than extravagant speculations. Their assumptions are now on the table for us to modify/adjust based on our own information/belief.
Just did a quick cals using my "shoe box" model with the data available to-date and the results came out to be 27 M tonnes of ore, approximately.
Now, we can play with the assumptions: With an annual production of say 50,000 tonnes/yr of the finished product (double ROTH production, but half of the 100,000 tonnes/yr production used by others) @ $1000/tonne profit the total profit would be $50M/yr (Note: this is profit).
Scale it up and down to your liking...preferably up. If the profit is expected to be $2000/tonne then total profit would be $100 M/yr, which is not too shabby!
Etc, etc...
Try this link for ROTH report
http://tradingchief.com/coverage/roth.pdf
goldhunter