JB

I don't think it was Rickford who stated that.  It was the author MCGEE from the Globe.  I expect nobody knows the true value of the chromite in the ring except to add up all the known deposits from all the companies.  (help of more knowledgable poster?) 

He refers to his previous article where he states.....

https://www.theglobeandmail.com/business/article-the-road-to-nowhere-why-everything-youve-heard-about-the-ring-of/

The road to nowhere: Claims Ontario’s Ring of Fire is worth $60-billion are nonsense

Around the time Cliffs was giving up, the Ring of Fire got an unexpected boost from an unlikely source: James Franklin, a respected geologist. The former chief scientist for the Geological Survey of Canada (GSC) mused that the Ring of Fire could contain $60-billion worth of minerals. He mentioned the figure in a talk at the 2013 Prospectors & Developers Association of Canada (PDAC) convention, a popular international mining conference held every year in Toronto.

Mr. Franklin said he came up with this astronomical number by looking at all the public companies that had published resource estimates of their Ring of Fire discoveries. He simply added up the total projections for minerals in the ground from these reports, and calculated the value if the metals were sold at market prices.

But Mr. Franklin also readily admits the figure contained no analysis of costs or potential return, and no insight on whether any project should be developed.

"There might well be $60-billion worth of metal sitting in the ground, but it might cost you $80-billion to get it out,” he said.

Even the most promotional of mining companies wouldn’t dare print such a figure in a regulatory document, because it would be misleading to investors.

“If any company did the same kind of thing, they would have gotten slapped down by regulators," said Mr. Srivastava.

In the mining industry, geologists categorize deposits based on how sure they are that the metals found underground can be mined economically. “Proven and probable” is the highest bar, meaning metal that can be mined for a profit.

The vast majority of mines around the world are built off of a proven and probable resource. One notch below proven and probable is “measured and indicated,” a far less certain category in which economics have not been proved. “Inferred” is the lowest tier, essentially an educated guess.

No one “sober” would build a mine off an inferred resource, said Mr. Srivastava.

Mr. Franklin says about 70 per cent of his Ring of Fire estimate came from the inferred category, with the rest coming from measured and indicated. Now, he has second thoughts about including any of the inferred in his calculation.

“I [did something] that you’re not supposed to,” he said.

Despite its shaky foundation, that $60-billion figure had a big impact on the public imagination. The number has been cited in scores of news articles and other media (including The Globe and Mail), rarely explaining how it was calculated or attributing its source.