180

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THE COLLIERY GUARDIAN.

January 24, 1913.

pipe, one main being for lighting gas, and the other for
heating gas, and, by a very simple device, the gas issuing
from the ovens can be deflected into either collecting
main from each oven.

The lighting gas is usually taken off from about the
second to the sixteenth hour of carbonisation, and during
this period from 2,000 to 3,000 cubic feet per ton of coal
is obtained. This gas compares very well in quality
with that usually supplied from Continental gasworks.
There is no standard of illuminating power, calorific
value alone being considered. The average composition
of the gas is shown in the following analysis :—

Per cent.

Oxygen........................	0 6

Sat. Hydrocarbon ...............	2 0

Carbon Dioxide .................	2*4

Carbon Monoxide ...............	45

Hydrogen ..................... 520

Methane ....................... 27 4

Nitrogen....................... Ill

100’0

The calorific value of the gas is about 525 B.Th.U’s
gross and 475 B.Th.U’s net per cubic foot.

The by-products are recovered from the whole of the
gas by Koppers’ direct process, there being entirely
separate apparatus for the treatment of the lighting gas.
Five water coolers are used for condensing; the first
three or four, according to demand, are arranged to take
the heating gas and the other to take the lighting gas.
At present the whole of the gas produced is used on the
colliery, but in a short time the installation will
commence the supply of gas to the town authorities.

______________________

MINE MANAGERS' EXAMINATIONS.

We have received from Mr. W. W. Ware, the secretary
to the Board for Mining Examinations, copies of the
questions set at the examination for certificates of
competency as managers and under-managers of mines
and for certificates of qualification as surveyors of
mines, which was held by the Board on November 26
last and the two following days, at Edinburgh, Sheffield,
Wigan, Cardiff and Birmingham.

The text of the papers is given below:—

2.	What causes contribute towards elevation of tempera-
ture in the workings of mines ? Describe an apparatus by
means of which the proportion of water-vapour in the air is
ascertained, and state what effects, if any, the presence of a
larger or smaller proportion of it has upon the physical
conditions of the mine and upon the men and horses. (30)

3.	Sketch and describe a ventilating fan; show how the
air moves within and around it; give the reason why it
propels the air and produces a manometrical depression;
state where that depression is greatest, how it can be
measured, and what is meant by the efficiency of the fan ;
and show a means whereby the direction of the air-current
can be reversed on the surface if required. (40)

4.	Given an airway of uniform cross-sectional area a,
perimeter p, and length Z, and let h represent the difference
in pressure at its opposite ends required to cause a volume
of air q to pass through it in a given time v, the velocity of
the air, and c a constant representing the coefficient of
friction. By means of these symbols construct formulae to
show the relations between the resistance and (1) the
power, (2) the manometrical depression, (3) the work. (40)

6.	Show by means of sketches and describe the details of
construction of |a bonneted Clanny lamp; a means of
locking and a means of relighting without opening it; and
the course followed by the air entering, circulating in, and
leaving it. State why the flame of firedamp burning
within an unbonneted safety lamp standing in an explosive
atmosphere does not pass through the wire gauze cylinder
when the air is stagnant, and why it does so when the air is
moving with a certain velocity. (30)

7.	Sketch and describe suitable appliances for covering
the top of an upcast shaft connected with a mechanical
ventilator of such a character as to admit of the operation
of winding being carried on without interfering with the
ventilation. (30)

Subject No. 3.—Explosions in Mines, Underground Fires
and Inundations.

1.	What are the principal sources of coaldust under-
ground, and what means would you adopt—

1.	To reduce its production generally ?

2.	To render a coaldust explosion either improbable or

limited in extent ? (30)

2.	What alteration would you expect to find in the com-
position of the air in the workings of a mine as the result
(1) of an explosion, and (2) of an underground fire ? What
is the nature of the gases produced in each case, and what

(The figures in brackets against each question indicate the

maximum number of marks obtainable.)

For First-class (Managers’) Certificate.

Subject No. 1.—Winning and Working.

1.	Describe the different irregularities which occur in the
continuity of coalseams and say how these have been
caused. (35)

2.	Describe fully how you would prove an unexplored
coalfield of 5,000 acres by means of boreholes. Say how
many boreholes you would put down and what records you
would keep. Give an example of an imaginary proving of
the above coalfield, and work out calculations therefrom as
to amount and direction of dip. (40)

3.	Describe, with sketches, the general surface arrange-
ments you would require for the sinking of a shaft 18 ft. in
diameter, finished, through several fiery seams of coal to a
depth of 600 yards, the strata being very lightly watered.
Give the principal dimensions. Give a list of signals you
would adopt, and say what special precautions you would
take when shotfiring. (45)

4.	A seam of coal 4 ft. 6 in. thick, with 7 in. of fireclay at
the bottom, and a strong shale roof, in a royalty
4,000 yards long, north to south, by 1,000 yards wide, has
to be worked from a pair of shafts sunk near the centre,
the full dip being 1 in 10 to the south. Show by sketches
how you would lay out and work this area, coal being
wound at both shafts. Show the main roads, and say how
much coal you would expect to get from each when fully
developed. (55)

5.	In working, on the longwall system, a seam of coal of
the following section—

Ft. in.

Top coal ................. 2 2
Soft fireclay ............. 1 6
Bottom coal ............. 2 0

the roof being shale and the depth of the seam 400 yards,
show clearly, with sketches, how you would timber the
faces and gate or branch roads, which are 16 yards
apart. Give distances apart of the props or other roof ;
supports. (40)

6.	What are the chief differences between the nitro-
glycerine and the nitrate of ammonia classes of explosives ?
Give examples of one of each with their respective approxi-
mate compositions and physical properties. What special
precautions have to be taken with each class ? Which do
you prefer ? Give reasons. (35)

Subject No. 2.—Theory and Practice of Ventilation.

1. State the specific gravity and the principal properties
of the various gases that occur in mines under normal
conditions. Describe how you would proceed to test for	____________________________________________________________

firedamp with a safety lamp, and give the height of the
firedamp “cap ” which corresponds to the presence of 2, 3,
and 4 per cent, respectively of that gas in the air. (30) .

tests would you make before permitting men to enter the
workings ? (25)

3.	In working a seam of coal known to be liable to spon-
taneous combustion, show by sketch how you would lay out
the workings so as to limit the area that would be affected
by a fire, and state what preparation you would make in
order to deal with an outbreak promptly ? (25)

4.	With what type of rescue apparatus are you familiar P
Describe and sketch same. (25)

5.	How many rescue men would you require, and how
would you organise them for repairing a stopping 100
yards distant from fresh air, only two men being able to
actually work at the stopping at one time, and no material
having to be carried to them ? The completion of the
work to occupy six hours. (25)

Subject No. 4.—Machinery.

1.	Describe one example of one, but not both, of the
following types of plant:—(a) Coal-cutting machine; (b)
face conveyor. State carefully the conditions as regards
nature of coal, roof and floor, and thickness of seam (or
mine), dip and other factors that make the plant you
describe suitable for use. (30)

2.	In connection with electricity, what is meant by the
term “earthing”? What kinds or parts of apparatus or
plant is it desirable to “ earth,” and why ? (30)

3.	On your rounds underground you find the mechanical
haulage at a standstill and that a crack has appeared in the
rim of the cast iron spur wheel as shown in the sketch
attached.* Make a hand sketch of a good cover plate or
patch suitable for sending to the workshop, giving enough
particulars for the fitter to make the plate with bolt holes,
for bolting to the outside of the wheel rim to enable a
re-start to be made with the least possible delay. Specify
the bolts wanted, and what material the plate should be
made of. (30)

4.	What are the differences between the action of a three-
throw ram pump and a centrifugal pump in raising water ?
State the good and bad features of each type considered as
pumps for use in collieries. (30)

5.	In the above indicator diagram* (which you must
repeat freehand at the head of your question) mark the
expansion line, the point of cut-off, the point of release and
the atmospheric line. The boiler pressure is 100 lb. What
is the drop in pressure between boiler and engine cylinder
measured on the scale given ? The engine exhausts to
atmosphere. Can you detect any defect in the engine from
the diagram ? If so, what ? (30)

Subject No. 5.—Surveying, Levelling and Drawing, f

1. The levels taken on the floor of an undulating roadway
from A to B are as follow :—

* Not shown here.

f This paper was that set also for the surveyors*
certificate.

Bise.	Fall.		Dista	nee.
Ft. dec.	Ft. dec.		Ft.	Ft.
3-50 ...	— 		.. From	A to	50
2'75 ...	—		50 „	100
175 ...	— ....		100 „	150
—	... 100 ....		150 „	200
—	... 250 ....		200 „	250
—	... 0‘50 		• •	99	250 „	300
150 ...	—		300 „	350
3-25 ...	—		350 „	400
325 ...	—		400 „	450
—	... 200 ....		450 „	500 (B)

Plot a section of the roadway to a scale of 1 in. to 50 ft. for
horizontals and 1 in. to 10 ft. for verticals. Give the average

gradient from A to B, and mark the depth of cutting, or the
height of banking, or filling up at each 50 ft. necessary to
make the roadway of uniform gradient from A to B. The
roadway being originally 6 ft. high, give also the cutting
necessary from the roof, if any, to maintain that minimum
height. Calculate the cubic contents in cubic yards of the
cutting from roof and from floor to form a roadway 6 ft. in
width. (35)

2. An old plan of a coal working is put into your hands,
and you are required to survey and lay down on the same
plan new workings in the same seam in another part of the

field. How would you proceed so as to make sure that your

survey would be correctly laid down in relation to the

surface lines and old workings, assuming these to be

correctly shown on the old plan ? (30)

3. Plot the following bearings to a scale of 1 in. to 100

links, give the bearing and length of the line connecting
A and B, and calculate the area in square yards of the closed

figure from A:—

N. 21 degs. W..............
..............

N. 28 degs. E..............

.............

.............

N. 60 degs. E...............

N. 32 degs. E..............

N. 67 degs. E...............

S. 15 degs. E...............

S. 40 degs. W..............

120 links from A.

100 „

117 „

105 „

150 „

200 „

75 „

to B. (35)

4. Make a protractor 6| in. in diameter, dividing it into

quadrants. Divide one quadrant into 10 degs. divisions,

and one of these divisions into 1 deg. divisions. Show

clearly your method of graduation. (20)

5. Plot sections along the lines A B and C D from the
annexed contour plan*, and calculate the average gradient
from A to E. Scale for horizontals : 1 in. equals 100 ft.;
ditto verticals, 1 in. equals 10 ft. (20)

Subject No. 6.—General Management and Mining
Legislation.

1.	State the conditions as to thickness, inclination and
number of seams; their depth from the surface; presence
of water and gas; of any mine with which you are
acquainted and describe how you would organise the official
staff underground. (40)

2.	What arrangements would you adopt under the Explo-
sives Order of May 1912 for storing and distributing
explosives and for the safe keeping of unused explosives
after the day's work were done ? (25)

3.	What are the provisions of sections 64 and 65 of the
Mines Act relating to inspections before commencing work
and during shifts ? How are these carried out in practice
at any colliery with which you may be acquainted ? (25)

4.	What are the subjects of examination for firemen's,
examiners' or deputies' certificates ; and what are the
reasons for subjecting them to these tests ? (20)

5.	Quote the Electrical Bule 12 (b) relating to the
protection and support of cables. How would you suggest
that this rule could best be complied with ? (20)

For Second-class (Under-managers’) Certificate.

Subject No. 1.—Mine Working.

1.	Describe, with sketches, the method of working coal
you are best acquainted with. Show the working face and
gate or branch roads, and give position of the props, bars,
and other roof supports. Under what circumstances would
you use for the support of the working face, (a) ordinary
props, (6) tapered timber props, (c) steel props ? (60)

2.	In longwall working is it generally desirable that the
line of face should be straight? If so, why ? Under what
circumstances is this undesirable? What effect has the
cleavage of the roof and seam on the working of a
seam ? (60)

3.	Sketch and describe a suitable hand-drilling machine—
(a) for shots in coal, (b) for shots in shale, (c) for shots in
strong sandstone rock. Give details, with principal
dimensions. (60)

4.	What points have to be kept in view in making your
permanent main roads for haulage and ventilation under-
ground, and afterwards in maintaining them ? (60)

5.	How would you proceed to clean up a large fall of roof
in a main dip road dipping 1 in 6? Show by sketches
how you would timber or otherwise secure the place, and
state what special precautions you would take in order to
ensure the safety of the workmen engaged. (60)

Subject No. 2.— Ventilation.

1.	Under what circumstances, and from what causes, does
natural ventilation occur in a mine in which there is no
artificial source of heat? What changes in the conditions
would have the effect of stopping or reversing the direction
of the air current ? (50)

2.	What is the object of “ splitting ” the air ? To what
general result is it conducive, and how is it effected ? (50)

* Not shown here.