The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1913-04-24
THE VARIOUS KINDS OF EXPLOSIVES EXPLAINED
BY GOVERNMENT AUTHORITIES. THEIR USE
WEATHER AND UNDERGROUND CONDITIONS WHICH AFFECT Elk.
PLosVEs-How MOST EFFECTIVE RESULTS MAY BE OBJ
TANEp-cARE IN HANDLING

any of the other commercial classes of
explosives tested, and for this veason
they should be used for producing the
shattering effects or for blasting very
tough or hard materials whenever the
conditions permit. If the straight"
nitroglycerine dynamites are found to
be too violent for certain classes of
work, the low freezing dynamites or
the ammonia dynamitcS, which haze
lower rates of defamation and hence
less descriptive effect. are recommend
ed. The low freezing dynamites have
| the advantage of not freezing until en-
posed to II temperature of 35 degrees
f. or less, but, like all nitroglycerne
explosives. after they become frozen
they must be thawed before use in or
der to insure the most effective re-
suits. As the ammonium nitrate used
in ammonia dynamite Is deliquescent,
this ella sig of explosives absorbs mois-
ture more readily than other dyna-
mites. therefore it is emphasized that
care should be observed when storing
this class of explosives IN wet or damp
places The gelatin dynamites have
been used to large extent in wet
blasting, such as in the removal of OBJ
stacles To navigation and In deep
workings, and. as a general rule, they
are best suited for these purposes,
Poisonous Gases.
The products of combustion of eX-
plosves used in closed work is said to
be of vast Importance because in such
work large quantities of explosives are
generally used and they may produce
dangerous quantities Of poisonous
gases. on explosion. The gelatin dy-
Mantle on defamation produce the
smallest percentage of poisonous gases
but it is pointed out that this class OF
explosive Is far from being satisfactory
in this respect. The bureau had spe-
cial gelatin dynamite made which, on
detonation, produced no poisonous
gases, and it is believed that this H.
lustration of the possibility OF produc,-
ing gelatin dynamite that Will not
evolve poisonous gases on detonatlon
will result in it's being commercially
manufactured.
This special gelatin dynamite was
tested at the Pittsburgh testing station
of the bureau, in limestone mine at
West winfield Pa, and in zinc mine
at Franklin Furnace, N. j., the detail
ed results of which are reported in
bulletin As.
The bulletin points out dangers aris-
ing from the burning of high eXplo-
sives by showing the great increase II
the percentage of poisonous gases
levolved.
Various Tests.
The authors describe the method OF
blasting at Lock No |, Monongaheli
river. as an example of submarine op-
orations, giving the difficulties encoun-
tered. showing the causes of mistires
and the methods used for overcoming
these difficulties. The tests incidep
thereto showed that variation IN the
cross sectional area Of the bridge OF ar
electric detonator was an importan
factor in it's failure to explode when u
series with other electric detonators.
The bulletin closes with table
showing the relative potential energy
disruptive effect which bears cloS'
relation to the persuasive or shatter'
4 ing force of explosives, and propulsl''
effect which corresponds to the push
ing or heaving force of nine explosives
of different classes and grades.
Copies of this bulletin may be OBJ
tanned by applying to the director
bureau of mines, Washington, d. e.
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AIT EArlDClN RIGLT