THE COLLIERY GUARDIAN

AND

JOURNAL OF THE COAL AND IRON TRADES.

Vol. CX.

FRIDAY, JULY 9, 1915.

No. 2845.

The Microscopical Examination of Coal.

A general meeting of the South Staffordshire and
Warwickshire Institute of Mining Engineers was held at
the Birmingham University, Edmund - street, on
Monday, June 21, Mr. G. M. Cockin (president) in the
chair, when Mr. James Lomax gave a lecture on “ The
Formation of Coal Seams in the Light of Recent
Microscopical Investigations : Part II.”

The President, introducing the lecturer, remarked
that in December last they had the pleasure of listening
to Mr. Lomax, and seeing the wonderful slides then
exhibited. Several of the members expressed a desire
that Mr. Lomax should prepare micro-sections of some
other parts of Cannock Chase or of the Warwickshire
coal field. It was thought better that he should make,
for the purposes of comparison, a series of slides from
the same seam, showing the coal formation at the far
end of the district. The first exhibits shown in
December were slides representing samples from Earl
Shrewsbury’s Brereton Colliery Shallow coal seam
supplied by Mr. Mundle, and the slides now to be

£

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Fig. 1.—Section of Seam.

shown were from samples from the Walsall Wood
Colliery supplied by Mr. EL C. Peake. Mr. Peake was
good enough to send a complete set of samples from
Walsall Wood from the Shallow coal seam, and from
these samples slides had been prepared for the purpose
of comparison with the first set.

Mr. Lomax’s lecture was as follows :—

In bringing before you the results of a microscopical
examination of the Shallow seam, I should like again to
emphasise the fact that the microscopical examination of
coal is of great importance, quite of as much importance as
any other division of research — geological, chemical, or
mechanical—to the colliery owner or to the colliery manager.
One may go further, and say, even to the coal user. As
many of you know, it is my firm opinion that in the near
future, by systematic examination of coal seams in the way
that I have tried to do, we shall find out more about their
uses, such as the various products to be derived, and so on.
I believe that on the Continent, both in France and Ger-
many, they have made greater use of microscopical work than

has ever been made in this country. I may tell you that I
have been sending to Berlin and other places in Germany
year after year until just before the war, sections made from
their own coal. I have been sending such sections also to
France, and especially during the last four or five years I
have done a great deal with Russian coal from the coal fields
of Russia. I may say that the sections that have been sent
to Russia, France, and Germany have been nothing like the
sections that the photographs shown here have been made
from. For instance, they have only been what I term thumb-
nail sections on 3 x 1 in. slips. Sections that these photo-
graphs have been made from are blocks 6 or 7 in. in length,
and embracing the whole thickness of a seam, enabling the
full thickness to be examined microscopically, whereas in the
former case only fragmentary pieces could be examined from
various parts of a seam.

From systematic examination similar to that illustrated by
the photographs we can easily see the various kinds of
vegetable matter which enters into the composition of the
coal. We can also tell from the character of the section what
is practically the volatilibility of the coal from which the
section is made. And I say that if the work is done syste-
matically, and, at the same time, in association with the
chemist, who goes in for a thorough examination of the coal,
not to find one given thing or product, but to find the various
constituents and their uses, and work together, then we in
this country will be quite capable of getting all the good that
can be got from coal, as the German people have done for
themselves. We all know that one of the things that has
been lacking in this country is the firm application, the
scientific application of research to such branches of industry
as coal mining and its various subsidiary branches. In com-
mencing, I should like to mention that some time ago, when
looking through the Transactions of the Manchester Geo-
logical Society, I came across a paper on a section of one of
the seams in the Leicestershire coal field by Mr. W. S.
Gresley. So far as the writer knows, it is the only section
published in England dealing with a coal seam in any way
similar to what he has done with the seams already under
investigation. One of the puzzling points is the definition of
the various bands of coal; in some districts you find one
word used, and in another district another word used to
represent a similar band. There ought to be universal terms
used in speaking of the various bands, and I propose in future
to use, especially in North Staffordshire, South Staffordshire,
and Warwickshire coal, the same terms as used in Leicester-
shire. They are quite easy to remember. The first is
“ dice,” the second “ spires,” the third “ spore coal,” and
the fourth “ fossil charcoal,” or “ mother of coal.” We
shall see in the various photographs which is dice, spire,
spore, and charcoal, and it is quite easy to tell in a sample
of coal, without making a micro-section, which of the various
coals you are examining. Also that some of the bands which
are found in coal are of varying thickness from a thin
laminae to inches. They may be in one place 6 or 7 yds. in
width, in another they may run out to nothing. It is of
great use to know the various bands of coal which one finds,
because when in contact with the atmosphere they are acted
on in certain ways which may be detrimental to the working
and to the amount of various gases and heat that may be
given off.

Most of the facts given in the two lectures set forth below
are based on the examination of the Shallow seam from two
districts—the first from Brereton Colliery. Rugeley, and the
second from Walsall Wood Colliery, Walsall, a distance of
some IK miles apart. In each case the samples were got to
show the whole thickness of the seams, or, at all events,
those parts which were solid enough to be got without break-
ing up into slack. The writer found it impossible to make
a photograph of the whole series of samples joined together
as got from the seams, through, as already mentioned, its
soft and fragile nature. Therefore, as an illustration, he has
used the photograph of a pillar from the well-known Hard
Mine seam of North Staffordshire, which is a typical one
for showing the change from a soft coal to a hard coal, and
afterwards in the upper part to a soft coal again. (See
fig. 1.) It will be seen that the floor portion of the seam
consists of bright non-laminated coal, mostly soft and
fragile, composed of fine humic matter, in which may be
found fern Sporangia, portions of calamitean fruits, all
breaking up into more or less cubical pieces (dice). (See

fig. 1.) Ascending upwards in the seam, dull-looking lami-
nations begin to appear, which are sometimes composed of
leaves (cordaites), resinous bodies, layers of wood and bark
tissues, with admixture of dirt-like particles (spires), and
thin lamin® of spores, both microspores and megaspores, the
latter very sparingly at first, but gradually increasing until
the coal becomes hard and tough (hards or spore coal), com-
posed mainly of the fructiferous organs of the lycopods, the
giant club mosses of the carboniferous times. These remains
are found sometimes as whole cones containing both mega-
spores and microspores lying in the coal substance in a
natural order, showing that there has been little disturbance
of the spore bodies, with the exception of the flattening of the
more or less round bodies through the weight of the over-
lying strata since they were detached from their parent stem
or branch. With these may be found, according to the
nature of the seam, lamin® and layers of cordaitean leaves,
seeds, and other organs of plants both extinct and allied to



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*

Fig. 2.—Apparatus for Showing
Sections.





the plants of recent times, although the lycopods may have
been the dominant of that time. Or, as sometimes found in
a seam, the coal substance may be composed almost entirely
of the cordaites or other plant remains, with scarcely any
of the lycopods at all. It is more often found in a seam,
especially in the middle coal measures, that the bottom por-
tion is mainly composed, as already mentioned, of fine humic
matter, with a gradual increase of spore bodies, until the
coal is almost completely composed of them; afterwards a
total cessation of a return to the soft coal substances of a
similar character to those found in the lower portion of the
seam.

As already mentioned, sections have been made vertical and
parallel to the face or end, and at right angles to the vertical
or parallel to the bedding plane (horizontal). They are so