The Journal of Explosives Engineering - January/February 2015 - 29

Other explosive substances incorporated into dynamite
increase its power over straight dynamite and it is necessary
to reduce the amount of nitroglycerin and otherwise modify
the formula so that the new compound develops the same
power in actual work as the standard dynamite. For instance,
guncotton dissolved in nitroglycerin makes a sticky, jelly-like
substance which, added to the wood meal and nitrate of
soda, makes an explosive much more powerful than one in
which nitroglycerin alone is used. Such an explosive, graded
on its actual content of nitroglycerin, would be so much more
powerful than the same grade of straight dynamite as to be
unsafe and unsatisfactory in work where the blasters were accustomed to using the standard grade.
Many explosives in the market now containing no nitroglycerin at all are equal to a 40 per cent straight nitroglycerin
dynamite, and these are graded as described on the basis of
strength developed, not on the nitroglycerin content. Other
powerful explosives widely used contain only small amounts
of nitroglycerin-from 5 to 10 per cent sometimes-which,
nevertheless, develop as much power, weight for weight,
as 50 and 60 per cent straight nitroglycerin dynamites. It is
readily seen, therefore, that a customer should not feel that
he has been injured when he finds that the dynamite he has
been buying as 40 per cent strength has actually less than
40 per cent nitroglycerin in it. While the straight nitroglycerin
dynamites are still on the market, they are the only ones that
actually contain the same percentage of nitroglycerin as the

percentage strength marked. In many ways they are distinctly
inferior, as they are too quick for a good deal of work, they
are more easily frozen and are much more sensitive to rough
handling.
RBH Note: The items in this article are examples of the wide
variety of dynamite types and strengths available to the user
in the early part of the 20th century. In addition to these, the
catalog had about a dozen permissible grades available for
the coal industry. Obviously all these types and strengths were
unnecessary for the process of breaking rock efficiently, but
they gave the explosives salesman opportunities to compete
with other manufacturers who were touting the same or similar products. When one considers the variety of sizes available
(in addition to type and strength) the explosives plants were
producing hundreds of varieties of dynamite on a regular basis. This situation continued until the early 1960's, when dynamite ran into competition from other products. Today there
is only one producer in North America, and dynamite is offered in seven varieties in very few sizes. Some of these are for
very specialized applications: for general usage there are only
about three products commonly produced.
In addition to dynamite, duPont produced a number of
grades of black powder for the mining industry, in approximately the same total number of millions of pounds as the
dynamite products.

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January/February 2015

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The Journal of Explosives Engineering

29
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The Journal of Explosives Engineering - January/February 2015

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