Rank code numbers:-
Just to expand on the previous comments:- in the NCB classification
system (there are others which are superficially similar)- coals were
allocated a three digit number.  The first two digits denoted the
volatile matter in the coal, based on a dry, mineral matter free
basis,the lower the numbers, the lower the volatile content, hence the
higher the 'quality' of the coal. But the third digit referred to the
caking property of the coal, based on a Gray-King type test.  This is
essentially a fusing and free swelling index, where the values range
from A- no coking properties to G- where the coal is well fused but
retains its volume. If it swells beyond its volume it is said to have
superior coking properties and is further tested. Thus anthracites may
be 100, 101 or 102.  A low volatile steam coal is 200. A dry steam coal
is 201 (subdivided into a and b), coking steam coal is 202, 203 or 204.
A medium volatile coal is 300, a prime coking coal is 301 (subdivided
into a and b), medium volatile medium-caking coal is 302 and a medium
volatile weakly caking coal is 303, etc. Note that these are the only
numbers available for anthracites, steam coals and medium volatile
coals, for example there isn't a 105 or a 208. Crucially, to complicate
matters the third digit does not indicate the same  caking
characteristics throughout the rank code series, i.e. the "1" in a 201
is not the same as a "1" in a 301 and the actual Coal Board
Classification system needs to be consulted.  Hence the highest caking
properties are found in the 401 and 402 coals, as stated previously.

-----Original Message-----
From: Pat McIntosh-Spinnler [mailto:[log in to unmask]]
Sent: 10 September 2004 10:28
To: [log in to unmask]
Subject: Re: Caking


Peter Claughton wrote:

> If your correspondent refers to Great Britain: National Coal Board,
>The Coalfields of Great Britain: variation in the rank of coal,
>(London, 1960) and determines the ranking of the coal in the Kingswood
>area, he should get some idea. Best coking coal is in the old NCB
>ranking 301a and 301b whereas the 'caking' coal is in the rankings 400
>to 800 with its ability to cake diminishing towards 800. Coals with the

>ability to cake, ie. ring coals, were in demand for smithing purposes
>throughout the medieval and early modern periods and such coals were
>shipped, even overland, to sites well away from the coalfields.


Hello everyone. I'm a new member, in here looking for accurate
background for a historical novel. I'm a geologist/palaeontologist by
training (so I do have some concept of 'accurate' here) but despite
living in the west of Scotland have no real feel for the way coal varies
from one locality to another. (Brachiopods yes, coal no.)

In view of the above, can anyone tell me how much a named coal seam
would vary over the extent of its outcrop/area of working? And how much
coals would vary from one cyclothem to the next? My guesses would be (a)
not enormously and (b) very widely but I'd rather the expert view!

The information in this email is confidential and is intended solely for
the addressee. Access to this email by anyone else is unauthorised.

If you are not the intended recipient, any disclosure, copying,
distribution or any action taken or omitted to be taken in reliance on
it, except for the purpose of delivery to the addressee, is prohibited
and may be unlawful. Kindly notify the sender and delete the message and
any attachment from your computer.