Test gallery

Testing Galleries. See Galleries for Testing Permissible Explosives... 

Prussian Govt established at Neunkirchen the first testing station for investigating mining explosives, which included a testing gallery. 

As there are many factors contributing to the flammability of firedamp by the flame of expls, most countries test the expls intended fcr use in fiery mines in special testing galleries in which the actual conditions existing in mines are simulated as nearly as possible (See Vol 3 of Encycl, pp C368 to C378-L)... 

The theoretical calculation of the detonation temperature as a safety criterion was adopted only in France. In all other countries (and more recently also in France) a practical criterion has been introduced based on an experimental evaluation of the effect of explosion of a sample of the explosive on a mixture of air and methane, or on a suspension of coal-dust in air, under conditions similar to those existing in mines. For this purpose testing galleries were devised, simulating the conditions of mine galleries. 

Another testing gallery was built in Great Britain at the beginning of this century... 

In Belgium the official testing gallery was erected at Frameries under direction of Watteyne and Stassart in 1902. It was of elliptical cross section (1.85 m/1.40 m), 85 m long. 

Modern testing galleries are described later (p. 439 and Table 108). 

In addition to the experiments in testing galleries laboratory research has also been conducted, including a study of the flames produced by explosives when exploded. These flames have been studied photographically to determine their dimensions, intensity and duration. The following papers are noteworthy Siersch [8], Bichel and Mettengang [9], Wilkoszewski [10], Will [11], Taffanel and Dautriche [12]. 

When observing the flame projected from the mortar of a testing gallery Lemaire [13], Payman [14] and Audibert [15] came to the conclusion that the ignition of air-methane mixtures may also be caused by glowing particles formed on explosion and thrown out of the shothole. 

After the explosion at Courriere experiments were carried out in testing galleries on blasting explosives and on suspensions of coal-dust in air. As the coal-dust from various mines showed different inflammability, the most inflammable kind, i.e., that with a high content of volatile matter, was commonly used for testing. 

In Great Britain the first explosives which passed the test in the testing gallery at Woolwich were approved for use in mines under the name of Permitted Explosives. At Woolwich the charge of explosive in the test mortar was stemmed with dry clay, a practice that differed from that followed in other countries. 

Numerous tests were also carried out to examine other, less tangible factors which affect the accuracy and reproducibility of the results obtained in a testing gallery. The following factors were found to be of importance ... 

The shape and surface area of the testing gallery (elliptical shape and smaller surface favour easier ignition) ... 

Fig. 135. Free suspension test gallery, according to J. Taylor and Gay [4],...

Experiments in a testing gallery showed that addition of the majority of these substances increases the charge limit to such an extent that it cannot fit into the mortar. For this reason, a very strict test was carried out on the basis of the detonation of an explosive directly suspended in a methane-air mixture. Under such conditions the charge limit was diminished nearly four times as compared with that determined for a mortar. 

Explosives for use in coal mines containing methane or ignitable coal-dust must pass a test in a testing gallery. Different procedure is used in different countries. General data on galleries and methods of testing are summarized in Table 108. 

The classical method of firing explosives in a testing gallery with the charge inside the mortar does not present a true picture of the safety of explosives towards coal-dust since the explosives commonly used fail to ignite coal-dust under such conditions. The angle shot mortar (Fig. 138) is therefore sometimes used as an unofficial auxiliary test. 

A testing gallery is shown diagrammatically in Fig. 151. The wall which closes the gallery is fitted with an aperture 300-400 mm dia., to which the mortar is brought on a truck. 

The testing gallery at the Ardeer factory of Imperial Chemical Industries Ltd., which is identical with the Official Home Office Testing Gallery, is shown in Fig. 154 and the testing mortar in Fig. 155. 

Dortmund-Derne Versuchsstrecke (Testing Gallery at Dortmund-Deme). German facility used for the following official tests of permitted explosives (Wettersprengstoffe) ... 

Temperature Developed on Detonatlon(or Explosion) can be detd experimentally with a fair degree of accuracy by optical methods and can also be estimated by calcn as discussed in the following Refs l)E.Sarrau, "Theorie des Explosifs, Gauthier-Villars, Paris(1895),16—17 2)Marahall 2, (1917),453 459—60 3)Barnett( 1919),200 4) Venn in, Bur lot Lecorche( 1932), 36—50 5)Stettbacher( 1933),85 6)H.Muraour, "Poudres et Explosifs, Paris( 1947), 71—3 7)Stettbacher(1948),14 8)Stettbacher( 1952), 17 Testing Galleries. See Galleries for Testing Permissible Explosives Thermal Stability Tests. See Heat Testa... 

Woolwich Testing Gallery. See in Vol 3, C372-L under Coal Mining Explosives, Testing for Permissibility ... 

Deme mining association testing gallery see Coal mining expls 3 C371 ... 

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