498

THE COLLIERY GUARDIAN.

September 15, 1916.

and underpinned the tubbing. The shaft is 15 in. out of
plumb, but it is not intended to wind coal, though rope
guides are inserted. Electric power is used at this
No. 1 shaft, but when more ground is reclaimed a suitable
steam engine will be installed. The present electric
winding engine rests on the cofferdam frame.

Sinking No. 2 Shaft.

The work of fixing the cofferdam, etc., was carried out
in a similar manner to that adopted at No. 1 shaft. The
position of this shaft is 100 ft. to the west of No. 1. The

Fig. 5.—Sections of Bottom Ring, showing
Cutting Edge.

outside diameter of tubbing is 19ft., and 16ft. Bin.
inside the tubbing, afterwards widened out to 16^-ft.
From the experience gained in sinking No. 1 shaft, it
was deemed advisable to carry -the tubbing to the rock-
head in the compound manner, that is, by building up
brickwork as the caisson sinks. The thickness of brick-
work was 14in., and this added greatly to the weight
resting on the cutting edge. ' The plates were 2|in.
thick, as compared with 2 in. in No. 1 shaft, and more
haematite was put in the metal to make it tougher. The

u" 4-

Fig. 6.—Method of
Screening Flanges.

cutting edge was kept further in advance of the pit
bottom, because, in the other shaft, all the trouble arose
when the pit bottom approached too near the cutting
edge. The debris was excavated from inside the tubes
by means of a grabber or dredger, and the shaft was
kept full of water, so that the pressure within and with-
out would be better equalised. The sinking of both
shafts was effected with a steam crane, as winding
engines could not be correctly placed till pits were down.
The debris from the sinking was used to fill up the space
between the pits and the shore.

Fig. 7.—Distortion of Shaft Section when
Plates Cracked.

Very great trouble was experienced by the caisson of
this shaft going off the vertical to a distance of 11 ft.
in 125 ft. In bringing it back to 18 in., Mr. McCulloch,
the manager, adopted a very ingenious method. At the
side to which it was intended to divert the shaft, 40
boreholes of various lengths from 10 to 90 ft. were put
down, and water, under very high pressure, was pumped
into them, the idea being to soften and liberate the mud
at that side. While this was being done, extra weight
was applied at this side, and, in time, the caisson slowly
came back, till now it is only 18 in. out of the vertical,
as stated. This greatly delayed the sinking, but owing
to the nature of the clays, it was almost impossible to

prevent the caissons tilting. The tubbing was continued
to the first coal met in the shaft, called the red coal.
The thickness of the brick wall .on which the tubbings
rest is fully 5 ft. thick all round the shaft. Ordinary
sinking was continued to the shaft bottom, a distance
of 75 fms. (No. 1 shaft is to same level). Very little
water, in fact, none, was met with in-the sinking; and
in the whole workings, as yet, practically no water is
got, and no great quantity is anticipated, owing to the
geological conditions. Wood guides are used in No. 1
shaft, owing to its. still being a little out of plumb.

The bricks used were common shaped bricks laid in
a mortar of one part sand and one part cement. In
bricking the rock portion of the shafts, sets of bricking
were put in at various intervals, as circumstances
demanded, but the usual method of leaving a ledge was
departed from, and, instead, the thickness of brickwork
at the commencement of each set was increased by about
1ft. (fig. 8). The work set quickly, and when -sink-
ing was continued the hatched portion in fig. 8 was
cut away at the start, leaving the wall well supported,
as shown.

Coal Seams.

. The section of seams is as under :—

In.

Red coal ............................... 18

Parrot coal ............................  22

Six-feet coal .......................... 68

Main coal .............................. 50

Smithy coal ............................ 34

Carsey coal ...........................12-20

The first important seam, the 6 ft., is of good quality,
but contains a band of stone. This seam may,

with some degree of accuracy,
be said to be the Lochgelly
splint of the Fife section on
the northern shores of the
Firth of Forth, owing to the
curious fossils contained in the
roof and the appearance, etc.,
of the rib of stone. The main
coal, where already worked, is
the principal seam. The coal,
splint in nature, possesses
great heating power, and is
very low in sulphur. The per-
centage of carbon is about 70.

Underground.

The principal bottom is in
No. 2 shaft, though a simi-
larly constructed bottom is
made in No. 1 shaft. The
length of the bottom is 80 ft.,
40 ft. arched, and 40 ft. with
side walls and cross girders.
The side walls for the arch and
girders are 2| ft. thick, and the
arch is 1| ft. thick. Very little X
roof pressure is expected. From
each bottom parallel stone
cross mines are being driven,
that from No. 1 shaft having
passed through the smithy
coal. Hard drills, driven by
compressed air, are used in the
stone work.

Surface Plant.	Fig. 8 —Thickened

Very little surface plant is Brickwork.
erected as yet, as more ground
will have to be reclaimed by means of the debris
got in working. The I-girder pulley frame and engine
of the working shaft are erected and in use. The electric
supply is obtained from the town mains. Sidings are
to be constructed in connection with the North British

Railway system, which, in turn, runs to the Bo’ness
Docks. At present the Bo’ness Docks are closed to
traffic, but when they are again opened, and the pit is
fully going, an output of about 3,600 tons per week is
expected.

Coal Trimmers’ Grievances.—The Trades Union Congress
on Saturday unanimously passed a resolution in favour of the
compulsory provision of means of escape and ventilation for
coal trimmers engaged in holds. The resolution also asked
for the passing of the Checkweighing Bill.—Mr. Houghton
(Glasgow Dockers) maintained that the Bill was the only
way to settle the matter of paying the men correctly, as the
employer would be fined <£100 if he did not put up the
proper weight.—Mr. Fisher (Bristol) stated that a national
conference of trimmers would be held immediately.

Mining Examinations. — An examination for first- and
second-class certificates of competency as manager and under-
manager of mines will be held on November 21 at Edinburgh,
Newcastle-upon-Tyne, Sheffield, Wigan, Cardiff, and Bir-
mingham. An examination for certificates of qualification
as surveyor of mines will be held at the same places on
November 22. Candidates must, on or before October 7,
send their names and state the district in which they are
employed to the Secretary to the Board for Mining Examina-
tions, Home Office, Whitehall, London, from whom all
particulars can be obtained.

Swedish Coal Imports.—According to the official returns
just issued, Sweden imported from Germany during June
501,152 tons of coal, against 536,095 tons in May last, valued
respectively at 25-73 million and 26*37 million kroner. For
the year ending on July 1, the total Swedish coal imports from
Germany were 4,404,263 tons, valued at 187-97 million kroner.
The imports consisted of 2,204,182 tons of coal, 828,563 tons
of briquettes, and 1,312,870 tons of coke. From Great Britain
the Swedish imports were from January 1 to July 1 this year,
808,799 tons of coal, and the total Swedish imports for the
first half of this year 3,398,549 tons. During the same period
last year the imports were 2,242,905 tons, in comparison with
2,134,508 tons for the same time in 1914. This year some
American coal had also been imported.

THE ABSORPTION OF OXYGEN
BY COAL*

By J. Ivon Graham, B.A., B.Sc.

Part X.—Formation of Water in the Oxidation of Coal.

In Part IV.f of this series of papers, figures were
given showing the ratio :

Quantity of oxygen absorbed

Quantity of carbon dioxide produced

at temperatures varying from 30 to 160 degs. Cent. It
was there shown that for any definite temperature this
■ratio gradually diminished in value as the time of expo-
sure to air increased, being more nearly constant after
several days. With rise of temperature also this ratio
diminished in value.

The following figures can be calculated from the
results given in Part IV. :—

Quantity of Oxygen in Carbon Dioxide Produced as a
Percentage of the Oxygen Absorbed.

30 degs. 50 degs. 70 degs. 100 degs.
Cent. Cent. Cent. Cent.

At 4th hour ... 2-9	...	3-0	... 3-8	... 4-0

At 120th hour . 6-2	...	7-7	... 12-5	... 20-0

Thus, even at 100degs. Cent., after 120 hours of oxida-
tion, the quantity of oxygen in the carbon dioxide pro-
duced is only 20 per cent, of the oxygen absorbed.

It seemed desirable, therefore, that the quantity of
water, if any, produced during oxidation at temperatures
below 100 degs. Cent, should also be measured, and
since quite a considerable proportion of water is formed
compared with the amount of oxygen absorbed, an
apparatus was fitted up by means of which a known
quantity of oxygen would be delivered to the vessel con-
taining the powdered coal (BOgrms.), and the products
of oxidation drawn through a series of weighed U tubes
containing calcium chloride.

From the preliminary experiments it was found impos-
sible to obtain the coal absolutely dry, there being a
small increase in weight of about 0-005 for a period of
24 hours heating at 110 degs. Gent., or a further loss,of
0*0015 per cent, of moisture from the coal per 24 hours.
A blank experiment demonstrated -that the small con-
tinued increase in weight observed when coal is present
is due to further loss of water by th© latter. This small
gradual loss of water is probably due to the breaking down
of parts of the coal substance containing hydrogen and
oxygen, with the formation of -water, a reaction which
becomes more pronounced the higher the temperature to
which the coal is heated.

Th© gases, nitrogen, and oxygen used in the experi-
ments were thoroughly dried and purified. The drying
of the coal dust before and after oxidation by heating in
vacuo at 110 degs. Cent, and washing out with dry
nitrogen was continued in each case until there was only
the aforementioned small increase in weight, which was
constant for every 24 hours heating in vacuo.

In the case of one sample, oxidation was carried out in
three stages, the temperature of the coal being kept con-
stant to within, a few degrees of 50 degs. Cent, and the
quantity of oxygen absorbed and the amount of water
produced measured in each case. Before 'adding the
first lot of oxygen, the coal tube was left in the oven for
a couple of hours or so as to ensure that the coal dust had
acquired the temperature of the oven. The tubes were
exhausted, and then oxygen was admitted, until the
pressure reached about a fifth of an atmosphere, the
quantity of oxygen added being noted.

The- oxidation was continued for about 5| hours, freshly
■measured quantities of oxygen being added as fast as that
in the coal tube was absorbed, and the oxygen pressure
kept below 200 mm. of mercury, in order to make the
results comparable with the oxidation of coal dust in a
normal air current. After about 5| hours’ oxidation, the
pressure in the coal tube and connections was ascertained
by the gauge reading and the apparatus exhausted.
Nitrogen was admitted and the apparatus again
exhausted, and the temperature of the oven raised to
110 degs. Cent. The heating of the coal in vacuo at
110 degs. .Cent, with periodic w-ashings out with nitrogen
was continued until there was only the small increase in
weight of the U tube constant for every 24 hours ’ heating
in vacuo. The total increase in weight of the calcium-
chloride tubes after oxidation was thus made up of the
amount of water produced as a result of oxidation,
■together with the small amount given off as a result of
the slow decomposition of the coal substances containing
hydrogen and oxygen. The amount of water produced
after the absorption of a further quantity of oxygen
(about 100 cu. cm.) was then determined in the same
way (second stage), and then by further oxidation the
amount produced after an additional 108*5 cu. cm. of
oxygen had been absorbed (third stage). These three
stages, compared with the oxidation of Barnsley hards
in air, are equivalent to: (1) 5| hours’ oxidation; (2)
further 45 hours’ oxidation; and (3) further 100 hours’
oxidation.

The temperature of the oven was then raised to and
maintained at 90degs. Cent., and further oxidation
carried out. After about 120 cu. cm. had been absorbed
at tliis temperature, the amount of water produced was
ascertained, as in the previous experiments. The
results of these experiments are recorded in the table
uiven below. Other determinations were carried out in
much the same manner with a second sample of coal

* From a paper read before the Institution of Mining
Engineers, Glasgow meeting.

f Colliery Guardian, September 11, 1914, p. 566.