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8 COAL AND TIMBER February, 1905
and 5 in the Province of Namur, having
13 presses and employing about 90 working
men. The quantity of coal used for
manufacturing briquettes in the Province
of Hainaut was about 1,450.000 tons, and
this produced about 1,570,000 tons of briquettes
valued at 30,615,000 francs, or
about 19.50 francs per ton.
Compared with 1900 and 1901 the production
has increased, though the price has
decreased about 4.33 francs per ton from
that of the year 1900.
Production.
Tons.
Ter Ton.
1897 1,140,330 12.50 Francs
1898 1,279,180 13.40
1899 1,250,290 16.21
1900 1,200.150 23.83
1901 1,240,000 19.31
1902 1,570,000 19.50
Countries Where the Belgium Briquettes
Have Been Exported.
Tons Tons
1901. 1902.
Argentine Republic 4,350 4,670
Chili 2,782 2,980
China 5,900 6,700
Congo ,Kree State) 9,420 11,800
Egypt 2,150 3,200
England 6,475 7,320
France 469,500 498,900
Germany 43,200 46,260
Grand Duche de Luxemburg 24,100 23,800
Greece 1,120 1,350
Holland 9,180 11,200
Italy 12,190 14,520
Japan 6,300 7,100
Portugal 3,450 3.890
Russia 3,650 4,220
Spain 34,200 36,890
Switzerland 13,697 11.127
Tunis 2,100 1,920
Turkey 4,820 5,390
United States 81,460 82,320
Total 740,049 788,647
These coal briquettes are used by Manufacturers,
Railroads and Steamship Companies.
Report on the Production of Briquettes in
France in 1902.
There were in France in 1902, 27 factories
making briquettes and bullets; the principal
ones being in the Northern section and
Pas do Calais. These 27 factories have produced
together in 1900 about 780,600 tons;
in 1901, about 910,900 tons; and 1902, about
1,200,600 tons. This compared with the
year 1900 shows an increase of about
130,300 tons for 1901, and 420,000 tons
for 1902. The railroad companies of the
East manufacture for their own personal
use about 200,000 tons per year.
Report on the Production of Briquettes in
Germany in 1902.
The making of briquettes in Germany is
under the control of a trust, which includes
about 35 firms or companies. This
trust manufactured in 1900 about 1,600,000
tons of briquettes. In addition to this
trust there are several other small independent
works, which together manufactured
in 1900, 98,000 tons; in 1901, 125,000
tons, and in 1902, 146,200 tons.
Production.
Tons.
Per Ton.
1897 1,020,400 10.10 Marks
1898 1,170,200 10.32
1899 1,320,900 10.60 "
1900 1,600,000 12.55 "
1901 1,690,000 13.40 '•
1902 1.782,000 13.85 "
Total, 8,583,550
These briquettes are used by Manufacturers,
Railroads and the Navy, and are exported
to the Gel man Colonies.
ELECTRICITY AS APPLIED
TO MINING
By Harry C. Hubbell, Newark, N. J.
NOTE—Paper read before the Central Mining Institute
of Western Pennsylvania at the Winter Meeting. Mr.
Hubbell was ill and unable to be present, so the paper
was read by Mr. Joseph Simpson, one of the vice-presidents
of the Institute.
Gentlemen:—I sec that I am down on
this program for a paper on electricity as
applied to mining. This is rather a broad
subject, and as 1 have made no particular
study as to the question of mine haulage,
whether mule, pneumatic, or electric, I
guess 1 will have to side step this and talk
aboMit something that 1 am familiar with,
that is, mine illumination, and mine signalling.
Electric mine signalling in gaseous
mines can be done with perfect safety, if
the following method is used:
Construction should be rubber covered
wires, and porcelain knobs; signal button
should be of the "break circuit," instead
of the "make" circuit variety; about four
cells of ordinary blue stone gravity battery
should be placed in circuit connected with
a high wound relay. Now the current from
four cells of blue stone gravity battery,
operated through a relay of such high resistance
will produce hardly a perceptible
spark, if circuit wires should be broken.
In the engine house or pumping station,
or wherever the place to be signalled is,
an auxiliary set of three or four cells of
some good type of salamoniac battery
can be placed in circuit with repeating side
of relay, and electric bell; this brings no
high power onto the wires running
through mine, and any break in wires will
immediately be noticed by the ringing of
the be!l. To say any more on this subject,
would be mere play on words, as this
is, in my opinion, the only practical way
to accomplish mine signalling, whether
mines are gaseous or not, as the relay will
operate a very feeble current, and it will
not be necessary to maintain a large bank
of liattcries to operate over long distances.
In regard to the circuit breaking signalling
buttons I would suggest that they be
placed in tin or sheet iron boxes, and
wires coming down into same should be in
small iron pipe. I will state right here that
wherever electric signalling is done by the
ordinary methods that a dangerous spark
can readily be made from the same, as I
have demonstrated time and time again, in
the laboratory. This is due to the inductance
of the circuit caused by the electromagnet
of the bell, which would not be the
case with a relay wound to 150 ohms, where
not more than six cells of blue stone battery
were used. The spark from a high
power magneto, such as used in telephone
work, is very feeble; but that from a low
power magneto is quite strong, and can
ignite; for instance, magneto blasting machine.
I do not know as though I ought to say
anything against the lighting of bottom,
stable, etc., by the use of the ordinary 110
volt electric light. Perhaps when conductors
are run through iron conducts and
lamp bulbs are placed out of reach of everybody,
and switches operating in oil are used,
it can be considered as practically safe.
One hundred and ten volts is really the
safe and economic voltage to be used on
mine circuits. If insulation is poor at any
particular point, leakage lost will be considerable,
increasing with rise in voltage.
Should this be too high, a dangerous arc
is liable to follow and consequent ignition;
therefore, conducting lines must be placed
as far apart as practical, insulation must be
moisture proof, and every precaution taken
to prevent short-circuiting. In mines where
the soldering of joints would be accompanied
by danger and the wires are simply
twisted together, and taped, the action of
the copper on the rubber of this tape is
injurious and soon rots it. The best plan
is to cover the joint with two. or three
turns of ordinary tin-foil and tape over this
in the usual manner. The tin protects the
lubber from the copper and thus greatly
lengthens the life of the tape. This is
the reason that all copper wire is tinned
before the rubber insulation is put on.
One might as well strike a match as to
open an ordinary knife switch, and the
flash from a short circuit on conducting
wires would ignite wood, or set coal afire,
not to mention mine gas.
Some one well known to you told me
that he knew of one instance where the
electric lighting wires actually set coal
on fi: _ e; but this I suppose you all
know just as well as I do. The incandescent
electric light must appeal practically
to every one; no smoke, no heat and no
odor. The question of smoke is in itself
an important factor in mine ventilation, to
say nothing of the vitiating of the air by
flame light, due to its great demand for
oxygen and the formation of carbonic acid
gas.
I am the inventor of a portable electric
miner's lamp, which cannot explode gas.
Even if the terminals are short circuited
there is no possible way of causing an
igniting spark from same, and yet this little
lamp will maintain a three candle power
electric bulb for 12 hours, and give as
much light as half a dozen oil safety
lamps. I do not want to infringe upon
the rides of this association by using this
paper as an advertising medium, but I
am simply stating facts. The same current
that it would take to maintain one
32 cand'e power ordinary incandescent
lamp for eight hours, would suffice to
charge nine of these miner's lamps, which
would burn 12 hours.
I have frequently been asked how to prevent
the accumulation of moisture upon
telephone boxes, and other electrical apparatus
in mines. This is quite easily ac-