December 17, 1915.

THE COLLIERY GUARDIAN.

1237

ture of 75 degs. Fahr., that in the downcast, which is of
the same depth, 52 degs. Fahr. The weight of a cubic foot
of air at 32 degs. Fahr, and mean atmospheric pressure is
0*080728 lb. How much assistance, expressed in horse-
power, does this difference in temperature render when the
quantity of air passing through the shaft amounts to 250,000
cu. ft. per minute? (30)

5.	What are the chemical composition and principal
physical properties of marsh gas, carbon dioxide, and carbon

Fig. 1.—Plan Referred to in Question 1 (Sub-
ject No. 2, First Class), and Question 2
(Subject No. 2, Second Class).

(Scale reduced.)

monoxide? Write the formula which shows the chemical
reaction which takes place when marsh gas is burnt in
oxygen. (30)

6.	State shortly from what sources firedamp is derived
in the workings of a coal mine. Apart from accidental falls
of roof and movements of the strata, to what two other
principal causes are variations in the quantity of firedamp
entering the workings due? (30)

7.	Sketch in sectional side elevation, and describe, an.
apparatus suitable for continuously recording variations in
the height of the water gauge. (30)

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

(Five question only to be answered. No. 1 is compulsory.)

1.	Compulsory Question.—You are making an inspection
of a large colliery, and you enter by the downcast shaft,
travel by the main road to the face, and by the return airway
to the upcast shaft, your object being to examine the con-
dition of the mine with regard to coal dust. Describe the
character of the dust you would generally find in the different
parts of your journey. (30)

Elevation

B

CHANNEL

FALL OF

Fig. 2.—Drawing to Accompany Question 1
(Subject No. 4).

(Scale reduced.)

2.	State the various causes of the different deposits of dust
at the places mentioned in your answer to question No. 1,
and say where the dust would probably be dangerous or
otherwise. (25)

3.	Make a sketch of the method of working a mine with
which you are acquainted, and where no precautions against
gob-fires have been necessary.—Assume that the possibility
of gob-fires has now become apparent, requiring an altera-
tion in the method of working.—Show by another sketch
what alteration you would make. (25)

4.	Upon examining the workings of a mine after an
explosion, what effects would you expect to find had been
produced : (a) if the explosion had been one of coal dust
without firedamp; (5) if one of firedamp without coal dust ?
(25)

5.	Discuss the use of rescue apparatus underground in
an atmosphere of dense smoke and high temperature after
a fire. What type of apparatus would you prefer, and what
special care should be exercised under the circumstances?
(25)

6.	What are the most likely causes of fires underground
(other than gob-fires), and what preventive measures would
you prefer to take in each case ? (25)

Subject No. 4.—Machinery.

(Five questions only to be answered. No. 1 is compulsory.)

1.	Compulsory Question.—The rising main from a pump
underground has reached nearly to the top of the shaft shown
at A in the accompanying drawing (fig. 2). The water
must be conducted to the escape channel B, but from time
to time the tank C, set higher up, must be filled by the
underground pump to provide feed water for boilers. Sketch
in your answer book the pipes and parts required to complete
the rising main and to enable the head tank to be supplied.
Note.—Do not spend time copying the sketch, but show only
the additional parts required, with leading dimensions. (38)

2.	Describe what you consider to be a good safety gate for
a large cage. Make a few sketches to illustrate the design.
It is not necessary to sketch the whole gate. (28)

3.	A shaft is 500 yds. deep and 14 ft. in diameter. There
is an inset at 250 yds. depth. A heavy permanent feeder
of water has been struck in the bottom, estimated at 500 gals,
per minute, and the water has risen to within 150 yds. of
the surface. G-iven a free choice, what pumping plant
would you instal to regain the shaft bottom and to keep
it dry ? (28)

4.	If a colliery company, already having in use an electric
power plant, were offered a “ machine for generating
electric power,” what information should be given about the
machine before lit could be decided as to whether it was
suitable or not for adding to the existing power plant ? (28)

5.	What do you understand by (a) priming in boilers;
(b) pitting and grooving of plates in boilers? What causes
these phenomena, and what can be done to prevent or over-
come them ? (28)

6.	What are the various common shapes of winding
drums? Illustrate your answer by sketches. State the
objects of the various designs and the conditions for which
each is most suitable. (28)

Subject No. 5.—Surveying, Levelling, and Drawing.
(Five questions only to be answered. Candidates for

Surveyors’ Certificate must answer Question 4.)

1.	On the plan (fig. 3) the shading represents an area from
which a coal seam, dipping at a very steep angle, has
been worked out. The line AB shows the greatest distance
from the working that subsidence can be detected on the
surface. Draw a section along the line CD to the scale of
the plan, and find therefrom the angle of draw from the
vertical. (30)

2.	A circular chimney 150 ft, in height above ground level
has been thrown slightly out of the vertical by the effect
of underground workings. The taper, or batter of the
chimney is on the outside. How would you test how far
the centre line of the chimney is out of the vertical ? (25)

3.	Draw a diagonal scale of 1 in. to 10 ft. Draw and
figure it so that any distance in feet up to 50 ft. can be
taken off at one setting of the dividers. (25)

4.	A drift, or roadway, half-a-mile in length is to be
driven in a coal seam, at a depth of 100 yds., to strike a

Datum for Levels — Ordnance Datum.

Fig. 3.—Plan to Accompany
Question 1 (Subject No. 5).

(Scale reduced.)

point vertically under a given point on the surface. The
drift starts 500 yds. from the nearest shaft. In the strata
overlying the seam there 'is a thick bed of basalt, or whin,
which renders the readings of the magnetic needle unreliable.
There are two shafts, 60 ft. apart, sunk to the coal seam.
Describe generally how you would proceed to lay off the line
of the roadway, dealing fully and specially with the means
you would take to eliminate the effect of oscillation in plumb
lines. (30)

5.	Given the two sides, AB and AC, of a triangle A,
work out formulae for the angle C and the sides BC in terms
of the data given. Show clearly the several steps by which
the formulae .are obtained.

If the angle A be 35 degs. and AB and AC 10 ft. and 20 ft.
respectively, find the length of BC and the tangent of C.

Sine 35 degs. = 0-573 Tan 35 degs. = 0-700
Cos 35 degs. = 0-819 Cotan 35 degs. = 1-428

(30)

6.	What are contour lines, and what are their uses?
Describe shortly how you would lay off and put on a plan
contour lines of a piece of land at intervals of, say, 5 ft.
vertical. (25)

7.	Illustrate the common, and the collimation, or instru-
ment height method of booking levels. Which do you prefer,
and why ? (25)

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

(Five questions only to be answered. No. 1 is compulsory.)

1.	Compulsory Question.—State fully the various pro-
visions of the Coal Mines Act and Regulations concerning
travelling roads underground, for the safety of persons
passing thereon. (30)

2.	What are the conditions and restrictions as to the use
and storage of inflammable material (other than explosives)
underground, and as to the use of such material above
ground ? (25)

3.	What are the regulations concerning the construction
of stoppings, between the main intake and main return air-
ways, in the Coal Mines Act and General Regulations? (25)

4.	What are the provisions of the Coal Mines Act concern-
ing steam boilers? (25)

5.	State the provisions of the Coal Mines Act with regard
to colliery plans; state the details to be shown on the various
plans. (25)

6.	Describe the organisation of the staff at a sinking pit.

For Second-Class (Under-Managers’) Certificate of
Competency.

Subject No. 1.—Mine Working.

(Five questions only to be answered. No. 1 is compulsory.)

1.	Compulsory Question.—Lay out a district in a seam
3ft. thick, dipping 1 in 5, where coal cutters and face con-
veyors are to be used. Show the timbering and packs, with
dimensions. (60)

2.	How would you attach and detach tubs at the top of
an incline dipping 1 in 6—(a) Where haulage is done by
endless rope; (b) where haulage is done by main rope? (60)

3.	The brickwork above <a landing in an upcast where no
winding is done requires repairing for a distance of 10 yds.
Describe how you would do the work. (60)

4.	How would you proceed to clear away a heavy fall
on a level roadway? Give sketches showing how you would
keep yourself secure as the work proceeded. (60)

5.	Shots are required on a longwall machine-cut face.
Describe in detail how you would drill the holes and charge
and fire the shots. (60).

6.	To what points would you specially direct your atten-
tion in inspecting—(a) A collier’s working face; (b) the
roads leading thereto? (60)

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

(Six questions only to be answered. No. 1 is compulsory.)

1.	Compulsory Question.—Illustrate by means of sketches
in plan and side elevation, one method of closing the top of
an upcast shaft in such a manner that winding can be carried
on in it with a minimum loss of air when the cages reach,
and are standing at, the surface. (50)

2.	Indicate by means of the usual symbols how you would
ventilate the workings of the mine shown on the accompany-
ing plan (see fig. 1) with six separate splits of air. (50)

3.	To what purposes are the barometer, thermometer, hygro-
meter, and anemometer, respectively, applied in connection
with coal mines? Give a short description of each instru-
ment (50)

4.	State the chemical composition and properties of air,
firedamp, and carbonic acid gas. What means would you
adopt to detect the presence, or absence,, of the two latter in
the air of a mine? (50)

5.	Describe in detail how you would proceed to measure the
quantity of air passing through an airway. Suppose its
width to be 7 ft. at the roof and 9 ft. at the floor, its height
6ft., and the volume of air passing through it 15,000 cu. ft.
per minute; what would be the velocity of the air? (50)

6.	Show by means of sketches, in plan and side elevation
(the latter viewed from a point in the intake airway), the
construction of an air crossing over an intake airway, partly
in brickwork, and partly in iron and timber. (50)

7.	Leaving out of account the cost of compressed air or
electric current for actuating small auxiliary fans under-
ground, what saving would you effect by the use of fans of
this kind in a mine that was being opened and developed by
means of narrow headings driven in the solid coal? Show by
means of a sketch, and describe how you would apply these
fans. (50)

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

(Five questions only to be answered.)

1.	What are your views about the prevention of the
accumulation of coal dust underground, and the practic-
ability of removing at? (20)

2.	As means of rendering coal dust harmless, under what
circumstances would you adopt stone dust, or water, or
both? In each case how would you apply it? (20)

3.	Sketch and describe a type of rescue apparatus with
which you are familiar, and state particularly what risks
and dangers are to be guarded against in its use. (20)

4.	What are the most likely causes of fires underground
(other than gob-fires), and what preventive measures would
you take in each case? (20)

5.	As under-manager, you are in the distant workings of
the pit with your men when you see smoke coming in with
the air. You suspect a fire at the pit top. What would
you do ? (20)

6.	What are the causes of spontaneous combustion or gob
fires underground? How are they first detected, and what
changes are observed as the heating progresses to actual
fire? (20).

Subject No. 4.—Machinery.

(Five questions only to be answered.)

1.	Sketch and describe what you consider to be a good
safety gate for the top and bottom of a shaft respectively. (20)

2.	Describe a Lancashire boiler, dealing with its shape and
method of construction and its method of working. Name a
common size, and also state the ordinary working pressures of
such boilers. (20)

3.	What is meant by “ earthing an electric coal-cutting
machine ”? Why is it necessary to earth such a machine?
How is the earthing done? (20)

4.	Describe a self-righting tippler for trams (hutches or
tubs) designed to cause as little breakage of coal as possible.

(20)

5.	In the case of direct-acting pumps :—(a) What is meant
by the term duplex? (5) What is the difference between
plungers and pistons (or buckets) for the water end, and why
are both types used? (20)

6.	Discuss the question of wheels, axles, bearings, and
guards (or keeps) for colliery trams (hutches or tubs), and
describe the best type and arrangement of these parts that
you know. Illustrate your answer by sketches with the
chief dimensions shown. (20)

Subject No. 5.—Arithmetic and Surveying.

(Five questions only to be answered, at least two of them
being from the part headed “ Surveying.”)

Arithmetic.

1.	How many square chains, square yards, and square
feet are there in a statute acre? How many cubic feet are
there in an acre one inch thick, and what is the weight of
an acre of coal one inch thick if the specific gravity be
1-280? (20)

2.	If the number of men employed in producing 850 tons
of coal per shift be reduced by reorganisation by 50, what
is the reduction of wages cost per ten if the wage of the 50
men be 8s. 6|d. each per shift; and what is the percentage
reduction of wages cost if it were 5s. 3d. per ton before
reorganisation ? (20)

3.	A mine pump lifts 450 gals, per minute while running.
After the pump has been standing three hours it runs 10
hours to reduce the water in the sump or standage to the
same level as at the beginning of the three hours’ steppage.
What is the feeder, or growth of water per minute? (20)

4.	What is the average effective horse-power expended by
a winding engine (in raising four tens a depth of 625 yds. in
50 seconds? (20)