I talked about available reserves in the US and Europe here with numbers, and to quote from that piece:

The U.S. resource was considered to be when defined as -more than 1 ft thick for anthracite and bituminous, more than 2.5 ft thick for sub-bituminous, and at depths of less than 6,000 ft.

There are some things that you can do with thin coal seams, methane drainage, in-situ combustion etc, that might make what is now a resource into a reserve, it is circumstance driven.

Then you have to define current technology - in terms of EROI I once mined coal that was less than 2-ft thick, with a pick and shovel, but that was (cough, cough) years ago before the advent of much mechanization. There are places in the world where that technology still prevails, and is EROI efficient.

The most detailed and realistic recent survey on coal that I'm aware of was done last March by the Energy Watch Group. You can download it here.

They claim that in terms of energy content the US peaked in its coal production in 2002, and that "Global coal production to peak around 2025 at 30 percent above present production in the best case."

They also cite somewhat different values for the heating value of different grades of coal (HO: why is your number for anthracite lower than bituminous?):

Anthracite: 30 MJ/kg
Bituminous coal: 18.8–29.3 MJ/kg
Subbituminous coal: 8.3–25 MJ/kg
Lignite: 5.5–14.3 MJ/kg

Here is their summary chart:

Hi,

In metric tons, according to the EIA Annual Coal Report 2006, Table 15, at

http://www.eia.doe.gov/cneaf/coal/page/acr/acr_sum.html

the Estimated Recoverable Reserves are 239Gt.

Company reserves taken from Table 5 of the National Mining Association’s coal producer survey at

http://www.nma.org/statistics/pub_coal_survey.asp

are 55Gt.

I think it quite likely that future production will be between the company number and the government number. My vote would be 70Gt. The government reserves have repeatedly been revised downward over the last hundred years. The revisions amount to a factor of ten in all. We are due for another downward revision, because the last serious reserves survey was in 1974.

Dave

Ignorant, you have really hit upon the difficulty I ran smack into when trying to have an intelligent discussion with Wyoming's newest(appointed senator, John Barrasso who claimed Wyoming had enough coal for 500 years!. But I digress. The US EIA has info on the different reserves of coal. The link is
http://www.eia.doe.gov/fuelcoal.html. This will get you started. I have an interest in Wyoming coal because Wyoming is my home.For example Sen Barrasso said 500 years.The Wyoming state geologist Lance Cook has stated Wyoming has 38 years. The US EIA says something on the order of 270,000 million tons(I think that would be 270 billion short tons) of recoverable reserves of all types but does not break it down into the various subtypes of recoverable reserves. Looking at reserves logically requires looking at the net energy equation. After all, some reserves are more recoverable than others. Using cheap diesel to recover cheaper coal is one reserve. Using expensive diesel gives you another figure.
I have figures of US production(2006) of 1161 billion tons. The western states produced 619.4 million tons and my home state of Wyoming was 446 million tons.Coal produced 52% of US electricity making Wyoming responsible for 38% , a staggering number for one state. Our senators(Barrasso and Enzi) and single representative(Cubin) are in the pockets of the resource companies and want to dig up the whole state. They are clueless about carbon emmisions, Hg and sulphur pollution, renewable alternatives etc. All they know is that they get huge contributions from the industry.They and their ilk are obstacles to a better world. So what else is new?