"If someone thinks they can guess BHP to within a dollar or two,...

"If someone thinks they can guess BHP to within a dollar or two, what they are really saying is that they can predict growth rates to fractions of percentage points. That's akin to madness in my mind. What sayeth you?"

I agree.
I'm actually a big fan of Benjamin Graham's
One of intrinsic formula I know is the two stage discounted cash flow model, but I never use it.
Too many assumptions that could go wrong.
The interesting thing about Graham was that he only based his valuations on stuff that you could actually know.
He therefore based his valuations on assets and extreme discounting
He rarely used a growth multiple and he only used it if he could be sure that the company had a franchise

Here is one

Earnings Power Value = adjusted earnings/ Weighted average cost of capital

Minus debt

It is used if a company has no competitive advantage.

eg BHP
debt = $5
WACC = 11%

$2.58/.11 = $23.45
minus debt = $5

$18.45

thing is I think BHP may have a franchise and growth characteristics
when a company gets a mining lease it more or less gives it monopolistic characteristics

someone mentioned earnings dropping to $2
Using the BG formula you'd get you $13.18

Bookvalue is $12.14

when a company makes a profit and bookvalue = EPV, then that is about a low it goes

so the lowest price would be probably be in the $12-$13

This would tally well with the long term growth on charts