$this->bbcode_second_pass_quote('Tyler_JC', 'E')ROEI is a part of the formula for ROI (return on investment).
Currently Wyoming coal sells for $15/ton.
It has an energy content of
8700BTUs/Pound or 17.4 million BTUs per ton.
The cost per million BTU is 86 cents for Wyoming Powder River Basin Coal.
Coincidentally, the energy content of one ton of coal is the same as exactly 3 barrels of oil.
EIA Energy Kids Page (Energy Calculator)Those 3 barrels of crude oil will cost $270 at $90/barrel.
Thus, coal mining makes sense if and only if the energy return on energy invested is at LEAST 18.
$270/$15=18 EROEI.
And that assumes that there are NO other costs involved in coal mining.

Even pretending that oil is as much as half the cost of coal mining (which it clearly isn't), the EROEI of coal must be at least 36.
Otherwise coal mines would go bankrupt, no?
They couldn't afford to mine the coal because the oil input would cost too much.
I'm not sure that this is the right way to look at the issue. We're told that Saudi light crude costs only $2 or less to get out of the ground (per barrel). So market prices are not a good guide to EROEI. In order to determine the EROEI of coal, we'd need to look at all of the energy inputs and the energy outputs. Has anyone done that work, for different coal grades, concentrations and mining techniques?