"only 60,000 dry metric tons of copper ore and 900,000 dry metric tons of iron ores would be needed to exceed $100,000,000.00 in gross revenues" http://biz.yahoo.com/iw/080201/0356012.html
JMO but the $100,000,000 estimate was an understatement based on the surface observation.
"The surface of the mineral deposits contains many visual magnetite and hematite outcrops that are easily distinguished in the pictures. A magnet is shown attached to many of the outcrops verifying that the minerals are iron magnetite, gray in color or grayish/red in color where the iron minerals are mixed Magnetite/Hematite. http://biz.yahoo.com/iw/080109/0346478.html
I'm figuring CWRM came up with the modest expectations of $100,000,000 estimate from the surface observations and the EXCEED $100 Million from the belief that there is much more iron and copper below the surface that's why they are having this done to get a better idea of the exceeding estimate that they may be able to give.