Transactions of the American Society of Civil Engineers, vol. LXX, Dec. 1910 | Page 7

OTIS SMITH, "Director."
In the meantime, many of the explosives submitted, which heretofore
had been on the market as safety explosives, were found to be unsafe
for use in gaseous or dusty mines, and the manufacturers were
permitted to withdraw them. Their weaknesses being known, as a result
of these tests, the manufacturers were enabled to produce similar, but
safer, explosives. Consequently, applications for further tests continued
to pour in, as they still do, and on October 1st, 1909, a second list of
permissible explosives was issued, as follows:
"EXPLOSIVES CIRCULAR NO. 2. "DEPARTMENT OF THE
INTERIOR. "United States Geological Survey. "October 1, 1909.
"LIST OF PERMISSIBLE EXPLOSIVES. "Tested prior to October 1,
1909.
"The following list of permissible explosives tested by the United
States Geological Survey at Pittsburg, Pa., is hereby published for the
benefit of operators, mine owners, mine inspectors, miners, and others
interested.
"The conditions and test requirements described in Explosives Circular
No. 1, issued under date of May 15, 1909, have been followed in all
subsequent tests.
"Subject to the provisions named below, a permissible explosive is
defined as an explosive which is in such condition that the chemical
and physical tests do not show any unfavorable results; which has
passed gas and dust gallery tests Nos. 1 and 3, as described in circular
No. 1; and of which, in test No. 4, 1½ pounds (680 grams) has been
fired into the mixture there described without causing ignition.
"Permissible explosives tested prior to October 1, 1909.

"[Those reported in Explosives Circular No. 1 are marked *.]
------------------------------+------------------------------------- Brand. |
Manufacturer.
------------------------------+------------------------------------- *Ætna coal
powder A | Ætna Powder Co., Chicago, Ill. Ætna coal powder AA | Do.
*Ætna coal powder B | Do. Ætna coal powder C | Do. Bituminite No. 1
| Jefferson Powder Co., Birmingham, | Ala. Black Diamond No. 3 |
Illinois Powder Manufacturing Co., | St. Louis, Mo. Black Diamond No.
4 | Do. *Carbonite No. 1 | E. I. Du Pont de Nemours Powder Co., |
Wilmington, Del. *Carbonite No. 2 | Do. *Carbonite No. 3 | Do.
*Carbonite No. 1-L. F. | Do. *Carbonite No. 2-L. F. | Do. *Coalite No.
1 | Potts Powder Co., New York City. *Coalite No. 2-D. | Do. *Coal
special No. 1 | Keystone Powder Co., Emporium, Pa. *Coal special No.
2 | Do. *Collier dynamite No. 2. | Sinnamahoning Powder
Manufacturing | Co., Emporium, Pa. *Collier dynamite No. 4. | Do.
*Collier dynamite No. 5. | Do. Giant A low-flame dynamite. | Giant
Powder Co. (Con.), Giant, Cal. Giant B low-flame dynamite. | Do.
Giant C low-flame dynamite. | Do. *Masurite M. L. F. | Masurite
Explosives Co., Sharon, Pa. *Meteor dynamite. | E. I. Du Pont de
Nemours Powder Co., | Wilmington, Del. Mine-ite A. | Burton Powder
Co., Pittsburg, Pa. Mine-ite B. | Do. *Monobel. | E. I. Du Pont de
Nemours Powder Co., | Wilmington, Del. Tunnelite No. 5. | G. R.
McAbee Powder and Oil Co., | Pittsburg, Pa. Tunnelite No. 6. | Do.
Tunnelite No. 7. | Do. Tunnelite No. 8. | Do.
------------------------------+-------------------------------------
"Provided:
"1. That the explosive is in all respects similar to sample submitted by
the manufacturer for test.
"2. That No. 6 detonators, preferably No. 6 electric detonators (double
strength), are used of not less strength than 1 gram charge, consisting
by weight of 90 parts of mercury fulminate and 10 parts of potassium
chlorate (or its equivalent), except for the explosive 'Masurite M. L. F.,'
for which the detonator shall be of not less strength than 1½ grams
charge.

"3. That the explosive, if frozen, shall be thoroughly thawed in a safe
and suitable manner before use.
"4. That the amount used in practice does not exceed 1½ pounds (680
grams), properly tamped.
"The above partial list includes all the permissible explosives that have
passed these tests prior to October 1, 1909. The announcement of the
passing of like tests by other explosives will be made public
immediately after the completion of the tests.
"With a view to the wise use of these explosives it may be well in this
connection to point out again certain differences between the
permissible explosives as a class and the black powders now so
generally used in coal mining, as follows:
"(a) With equal quantities of each, the flame of the black powder is
more than three times as long and has a duration three thousand to
more than four thousand times that of one of the permissible explosives;
the rate of explosion also is slower.
"(b) The permissible explosives are one and one-fourth to one and
three-fourths times as strong and are said, if properly used, to do twice
the work of black powder in bringing down coal; hence only half the
quantity need be used.
"(c) With