International Engineering Congress (1901 : Glasgow.

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30,000 (150,000 dollars) a year. It is shipped uncut, on account
of the high duty on cut mica, to the United States, where it is used
in the manufacture of electric machinery. White mica also exists
in several places, but it \s> not at present worked.

Among the minerals of minor importance is the apatite of
the Ottawa region, where it is very abundant and was worked with
success, at one time producing an average of 25,000 tons a year;
but since the discovery of phosphate of lime in Florida and South
Carolina the mines have become unprofitable.

A deposit of galena is being worked at Lake Temiscaming, and
some other deposits of more or less importance are known but
are not at present being developed.

In the eastern townships there is an antimony mine, not now
worked, and also numerous deposits of soapstone.

In the Laurentian formation graphite, mostly in a disseminated
form, has been worked, with but little success; a few concentrating
mills have been erected, and some mineral is also shipped in the
crude form to the United States.

Felspar is abundant, but finds a limited market Sulphate of
baryta is worked to a small extent. Molybdenite is found in a
few places, but it is not developed. In Magdalen islands man-
ganese has been discovered.

Some borings have been made for gas in the Trenton formation,
showing good indications. In Gaspe prospecting for oil has been
carried on for several years, and many wells have been bored to
a great, depth. Oil of a first-class quality has been found, but so
far not yet in commercial quantity.

Granite, marble, and limestone of a good quality are found in all
the formations of the province and used for the local building
industry. Lime and bricks are manufactured at numerous places.
Large areas of peat are found in many districts, but are not yet
used. Ochre of good quality is manufactured near Three Rivers,
and many other deposits are known.

The mines on all the lands not sold previously to 1880 still
belong to the Government, which disposes of them by sales or
leases at reasonable prices.

The total value of the crude products at the mines represents
about ^500,000 (2,500,000 dollars) yearly, 5500 men being em-
ployed in this industry. Transport in the open districts is easy.
Wood fuel is abundant, and Nova Scotian coal is worth i6s. 8d.
(4 dollars) a ton. Labour is cheaper than usual in America, 45.
(i dollar) being the average wage of unskilled men. Water power


has not been much used so far for mining purposes, but it may
be used with proper transmission of power.

In conclusion, although the province of Quebec is not of the
first rank as a mining country, the few industries so far developed
are generally prosperous,* and afford good returns upon the invested

A vote of thanks was accorded to the author.


Discussion on Paper by H. W. G. HALBAUM.

This paper was read at a previous meeting of the Institution of
Mining Engineers (see Transactions, 1900, Vol. XX., p. 404).

Mr. J. T. Beard and Mr. G. Hanarte contributed in writing to
the Discussion, and the author replied.

Discussion on Paper by W. DENHAM VERSCHOYLE.

This paper was read at. a previous meeting of the Institution of
Mining Engineers (see Transactions, 1901, Vol. XXI., p. 372).
The author replied to the Discussion in writing.


Discussion on Paper by J. J. SANDEMAN.

This paper was read at a previous meeting of the Institution of
Mining Engineers (see Transactions, 1900, Vol. XX., p. 401).
Mr. John Kirsopp. jun., contributed to the Discussion in writing.


Paper by Professor G. R. THOMPSON.


IN the early history of coal mining in any district little difficulty is
experienced in the survey of the workings which, by inclines or
shallow shafts, open to the surface at many points. As the deeper
coal is worked the royalties become larger, and more accurate
underground surveys are required. These also must be accurately
connected with the surface survey. In metalliferous mines the
value of a small strip is often very great, and corresponding
accuracy is required in connection with the surface. The mining
engineer or surveyor will, in general practice, be required to make
such connections with greater or less precision according to
circumstances, and the paper examines the degree of accuracy
attainable by the various methods in use.

The principal methods adopted for getting a common meridian
to the two surveys are :

i. THE MAGNETIC NEEDLE METHOD. Using an ordinary 6-inch
dial, the bearing of a line can be read to about five minutes of its
true reading; hence in the underground and surface observations
we might expect an error of 8 minutes or so, or a lateral deviation
of i foot in every 480 feet traversed from the connecting point.
Such a result would suffice for small surveys, where the proportional
accuracy required was not great. If the underground and surface
surveys have each been conducted with greater accuracy than this,
and a more accurate connection by the needle is desired, this may
be done (i) by taking one direct and several indirect bearings of
surface and underground lines by. the combined use of theodolite
and dial; (2) by using a needle with vernier attached, or the
tubular modification with micrometer eye-piece, a reading of the
needle's position to 3 min., 2 min.. or even i min.. being attain-
able. The limitations to the magnetic needle method are that
the needle is subject to (a) a yearly change, which must be known
for the year and the place, and allowance made when connections
are made at different dates as in extensions; (b) a daily change,
which varies with the place and season from i to 8 minutes or so.
The curve of daily change must be known, and a correction applied
for difference of time between surface and underground observa-
tions, or the observations must be made near 8 p.m.. when the


change is very slow, and the daily mean is recorded, (c) magnetic
storms, during which readings should not be taken. Taking the
above precautions, readings accurate to i min. could be obtained,
but (d) local attraction, due to magnetic rock, may give a much
greater error than this, and until such is proved to be absent, the
method cannot be trusted.

This method makes use of one shaft only. Let us suppose the
length of the connecting line is 6 feet, and we wish to know its
direction to one minute, we have to fix the direction of this line
by fixing its two ends, and this must be done with such accuracy
that the combined error will not displace the line more than one
minute. Now in a 6-foot line a lateral error of 0.02 inch at one
end will displace it by one minute, so that each point must be
fixed to about 0.014 inch, and we must use a telescope of such
power that each point can be adjusted to within this distance
from the true direction of the line of collimation. If the shaft
be 1000 feet deep, the telescope must allow this to be done at
1000 feet The unaided eye can resolve two lines when the space
between them subtends an angle of i minute, or slightly less, and
can see them distinctly when they subtend a like angle. It can
adjust two lines to superposition to about J- minute; consequently,
to adjust the wire to within .014 inch in one observation we
require a telescope magnifying 90 diameters. An error of i minute
in the adjustment of the transit axis to the horizontal would
displace the underground line 3! inches in a shaft 1000 feet deep,
but its effect on the direction would be negligible unless the
underground line were taken off at a very high angle. Vibration
in all forms must be avoided in such a case as this, seeing that
the angle of adjustment is about 0.2 seconds.

Should a connection of equal accuracy be required through a
shaft 100 feet deep, the magnifying power of the telescope need
only be 9 diameters such a telescope as is possessed by an
ordinary 5-inch theodolite.

how accurately a line could be transferred from the surface to
the underground survey by means of plumb lines, the writer took
two tempered steel wires, 0.02 inches diameter, and suspended
them in a rectangular shaft 660 feet deep, giving a 5-foot base
line. The wires were run over pulleys with V grooves in the rims,
ari)d bearings carefully turned for true running, and shoulders on
axles to prevent side play. From each line in turn weights of
6, 13, and 19 Ibs. respectively were suspended, and the wires
allowed to vibrate with weights immersed in a pail of water, the
position of rest being determined from the average of the greatest


and least readings during each swing as observed, through tele-
scopes, on two scales placed behind the wire at right angles to
each other, one telescope being on a theodolite roughly centred in
line with the two wires, and used for extending the line under-
ground. The three plummets were used to detect and determine
any steady deflecting forces (such as air currents, spray from
dropping water, etc.). Though the experiments were regarded as
preliminary, and too few" observations were taken to eliminate
the effect of irregular impulses, yet the results from the three sets
of experiments on each wire showed the connection to be accurate
to 2 minutes of arc.

it is easily seen that, if two shafts are available, and a direct sight
can be had between, this method can become very accurate; and
if a direct sight cannot be got, the accuracy of the connection depends
on the accuracy of the survey between the two plumb lines alone.
In this case the line of survey should be as nearly as possible
in the direction of the connecting line, and the distance between
the two shafts should be considerable. The probable error of
determining the traverse angles consists of three parts: (i) Read-
ing the angle, (2) bisecting the signal, (3) centreing the instrument
at the station. In a 5-inch theodolite the first may be about 20
seconds, the second about 2 to 3 seconds, while the third depends
on the length of sight available, and the care in centreing. The
probable error in position of the last point of a traverse of twelve
lines is discussed in the paper and illustrated by a figure; by
traversing back and completing the polygon, the actual accumulated
error can be determined, and this distributed over the polygon
reduces the probable error, which in any case is only the same as
would come in the underground survey itself. When the under-
ground survey is circuitous and the shafts comparatively near, the
lateral error in the traverse may become so great that the method
fails for accurate connection.

5. SURVEY DOWN INCLINES. As in 4, the error made in carrying
an angle forward by traverse applies, but the error of sighting
increases proportionately to the secant of the angle of inclination,
as also the error due to centreing; and the probable error of each
angle increases to such an extent that with high inclinations
accuracy of direction cannot be maintained through many lines.
Points, however, fixed by surveys down two distant inclines, may
be treated in the same way as plumbed points in 4.

A vote of thanks was accorded to the author.


Paper by H. D. HOSKOLD.


THE writer devoted much attention to the improvement of survey-
ing instruments prior to 1863, but the " Miners' Transit Theodolite"
then introduced, and which he had in use prior to that date,
although efficient for most surveying purposes, did not meet all
the conditions proposed. Between that date and 1870 he con-
ceived the idea that a portable transit theodolite might be con-
structed, with a hollow or perforated vertical axis, rendering it
efficient for the object of sighting down a, perpendicular shaft
through the centre of the instrument, with a view to connecting
underground and surface surveys with facility and great precision,
the instrument also being adapted for general surveying.

The contrary case of producing a surface line through a per-
pendicular pit and in the same direction below 7 ground often occurs
where shafts are sunk to produce railway or sewer tunnels in a
given direction, and for these operations a proper instrument is
absolutely necessary.

An instrument was designed before 1870, but it was not until
after 1893 that a design was placed in the hands of Messrs. John
Davis & Son, Derby, who have constructed an instrument. It
supplies admirably a deficiency long felt in surveying, because it
is a perfect substitute for the portable astronomical transit instru-
ment which was formerly employed exclusively for the object of
connecting underground and surface surveys by the late Mr.
Beanlands, Mr. Richardson (Severn Tunnel), and Mr. E. H. Liveing.

The great objection to the use of transit theodolites with long
and powerful telescopes is the great height of the standards or Y's
supporting the telescope, rendering such instruments top heavy,
clumsy, and easily affected by vibration ; but in sighting down the
deepest shafts considerable power of telescope is needed in order
to bisect two illuminated marks placed at the bottom of the shaft.

The telescope of this instrument is made much longer than is
usual in order to supply the power needed. At the same time,
the standards or Y's are made shorter than is usual, rendering the


instrument more compact and not easily affected by vibration; in
fact the half of the telescope is longer than the height of the
Y's or standards, so that apparently the telescope would not
transite. This difficulty is avoided by constructing the telescope
tube in one piece, and causing it to slide in a sleeve or long socket
forming part of the horizontal axis. This movement is brought
into action by turning the? head of a large milled screw attached
to a pinion and rack formed in the sleeve, so that the object glass
can be made to point perpendicularly and right through the
vertical axis down a shaft, and it can also be arranged so that a
sight in the vertical or zenith may easily be taken through a long
and powerful diagonal eye-piece.

An exchangeable micrometer eye-piece, measuring angles to one
second of arc, is fitted to the instrument, and is admirably adapted
to find distances by the sub-tense mode without direct measure-
ment with a chain. The instrument has also two spirit levels to
its upper part i.e., one is attached to the vernier arms of the
vertical circle, and the other, a very long and sensitive one, is
attached to the opposite side of the telescope.

In addition, therefore, to the instrument being a transit theo-
dolite, the spirit level renders it equal to the finest spirit level for
levelling operations. It is supplied with a lantern and axis level,
and also a long trough magnetic compass, with short and long
diagonal eye-pieces. It is made in composite aluminium metal,
and is comparatively light.

To connect an underground survey with the surface, the travers-
ing stand of the new transit theodolite is fixed upon a platform
over the centre line of a down cast shaft, and by moving the
instrument laterally by hand, and a fine adjusting screw, the tele-
scope is brought into the same vertical plane as two illuminated
marks or electric lamps placed in the bottom of a shaft, and in
line with the heading leading from it. When the illuminated
objects appear in the field of the telescope, the slow motion screw
of the traversing stand is moved, causing the vertical spider line
in the telescope to bisect the illuminated objects. The telescope
is then raised to the horizontal, and the underground line set out
upon the surface, and in the same direction.

Mr. G. D. Ridley, Mr. J. A. Longden, Mr. James Stirling. Mr.
T. Lindsay Galloway, Professor Henry Louis, Mr. J. Barton. Mr.
C. C. Leach, and the Chairman took part in the Discussion. Mr.
G. R. Thompson contributed in writing.

The author replied to the Discussion in writing.

A vote of thanks was accorded to the author.






IN the first part of this paper the writer dealt with the principles
of alternating currents of electricity, and explained in what way they
differed from continuous currents. In the present paper he pro-
poses to show how alternating currents may be used in mining work,
and the advantages of their use.

The advantages and the method of application may be divided
into two sections, viz. :

1. The distribution of energy over a large area.

2. The use of alternating current apparatus underground.

The tendency at the present time is, for economical reasons, to
produce power at a convenient centre, and distribute it over the
area to be served. Power, like so many other things, can be
produced more economically in large quantities. At the present
time, where a number of collieries are owned by one company,
with perhaps an ironworks dependent upon the collieries for its
supply of coal and coke, it is usual to have a battery of steam
boilers at each colliery, sometimes more than one at each colliery,
and often at different parts of the ironworks. The boilers are
worked at pressures varying from 30 Ibs. per square inch to 80 Ibs.,
with, in a few cases, 100 Ibs. and 150 Ibs. Higher pressures than
these cannot in many cases be used, because it is not practicable
to use compound engines, and because there is so much condensa-
tion of steam during the time the engines are standing, and this
condensation increases with the pressure. If the whole of the
power can be generated at one centre for the whole of the works
interested, pressures of 150 Ibs. to 250 Ibs. per square inch can
be economically used, by means of triple and quadruple expansion
engines, and considerable economies in coal consumption realised.
It will be remembered that, in raising steam, it is the operation of
converting the water at 212 deg. F. to steam at the same tempera-
ture that consumes the major portion of the heat, while the higher


the pressure to which the steam is raised, the more work a given
quantity will do. But when all the power is generated at one centre,
the question of distribution comes in. In many cases the collieries
lie at great distances apart, an outside distance of 20 miles not
being excessive. If the power is to be distributed by etectric
currents, it is absolutely necessary to use high pressures on the
transmission lines, while it is equally necessary to be able to use
low pressures, 100 volts to 500 volts, in the lamps and motors. If
1,000 horse power has to be transmitted 20 miles, it will be practi-
cally impossible to lay down enough copper to transmit it at 100
volts; the pressure would be all lost; and it may be taken that
economy in transmission varies approximately as the square of
the pressure employed. At 1,000 volts the economy is 100
times that at 100 volts, and at 10,000 volts it is 10,000
times that at 100 volts, and this applies to losses in
transmission, and to the size of the cables. In America they
are using pressures up to 60,000 volts, and there can hardly be any
doubt that for such distributions as sketched above, pressures of
10,000 volts and upwards will have to be used. Now, for pressures
above 2,000 volts, it has not been possible, so far, to construct
machines generating continuous currents that will work satisfactorily.
The insulation problems involved in a revolving apparatus with high
pressures have been so far insuperable. With alternating currents,
on the other hand, no such trouble exists. The stationary or static
transformer consisting of a magnified induction coil, a mass of
laminated iron plates, with two coils of copper wire embedded in
them, or coiled round them, allows of all sorts of transformations,
up and down, from low to high pressures, and vice versa, without
any trouble. Hence alternating currents can be generated at any
convenient pressure, transformed up to the pressure required for
the line transmission, and transformed down again to any required
pressure, at the points of consumption ; and in addition, alternating
currents may be transformed into continuous currents, where it is
moie convenient to use these. The advantages of using alternating-
current apparatus for machine driving in mines are, the complete
absence of a revolving commutator, with the attendant breakage of
circuit and sparking in the electric motor, and the lower pressure
employed in the revolving portion of the apparatus. The induction
motor, the apparatus that would be most suitable for use in collieries,
is actually a transformer in itself, in that it receives currents at any
pressure in its stationary coils, where insulation can be accomplished
with comparative ease, and transforms them into low pressure
currents in the armature, or revolving portion of the apparatus,
at the same time producing motion of revolution, only low pressure
currents appearing in the revolving portion. The revolving portion



of the apparatus also presents no breaks in its coils, except in case
of accident, and there is no break of any kind in the circuit of
which the revolving portion is a part, except for the purpose of
securing a large starting torque, while this, again, is not absolutely
necessary where the machine can be started off the load, and
switched on to it afterwards. These advantages are very consider-
able for underground work.

Mr. J. L. Walters and Mr. G. A. Mitchell took part in the Dis-
cussion, and the author replied.

A vote of thanks was accorded to the author.

On the motion of Mr. G. A. Mitchell, seconded by Mr. J. T.
Forgie, a vote of thanks was accorded to the Chairman, Mr. James
S. Dixon, and he replied briefly.

On the motion of Mr. J. C. Cadman, seconded by Mr. W. N.
Atkinson, a vote of thanks was accorded to the University Court.

The proceedings then terminated, and the business of the Section
was brought to a close.



Section YI I. Municipal.*


Mr. E. GEORGE MAWBEY, Chairman, in the Chair.




IN opening the meetings of the Section the Chairman gave a brief
address, in the course of which he said that, as representatives
of the branch of engineering practice which is, perhaps, more
closely identified than any other with the health of the people of
the United Kingdom and the Colonies, it was fitting that municipal
engineers should take a duly prominent part in the International
Engineering Congress at what was possibly the greatest exhibition
ever held away from London in the British Isles. It would have
been difficult, if not impossible, to have selected a more suitable
site for a great exhibition and particularly for a congress of civil
and sanitary engineers than the city of Glasgow; which is the
commercial capital of Scotland, the Manchester or Liverpool of
the North, a seat of profound learning, and a veritable hive of
industry. Indeed, comprehensive as the scope and character of
the exhibition was, he considered it doubtful whether it could
convey more vividly and strikingly an adequate idea of the indomi-
table energy, pluck, skill, and enterprise of the British race than
was conveyed by the great manufacturing works of Glasgow itself,
and the world-famed shipbuilding establishments and other gigantic
centres of production on the Clyde. A mere enumeration of the
vast and varied industries so successfully carried on in the city and

* The full Proceedings of Section VII. are published by The Incorporated
Association of Municipal and County Engineers, n Victoria Street, West-
minster, London, S.W., price 6s. 6d., post free.


its environs would occupy much more time than could be devoted
to a brief address. He referred to one typical instance of the

Online LibraryInternational Engineering Congress (1901 : GlasgowReport of the proceedings and abstracts of the papers read → online text (page 22 of 37)