Sheathed expls

Sixteen permissible expls, 7 of which were in cartridges of 2 sizes, I%x8 inches and 1 x8 inches. Nine different sheaths were tested at low loading densities in one application and with confinement and fireday stemming in another. Results indicate that sheathed expls do not introduce important hazards from prod of CO and in some cases amt is reduced by their use. Undesirable amts of N oxides may be produced by too great a wt ratio of sheath to expl Ref E.J. Murphy, USBurMines Reprs Invest 4220, 57pp(1948) CA 42, 4348(1948)... 

Under the term Vzryvchatyiye veshchestva v predokhraniteTnoy obolochke (Explosive substances in protective envelope), sheathed expls have been used in Russia. There are two types of sheaths inert sheath which consists of Na bicarbonate with or without Na chloride and active sheath which consists of Na bicarbonate with ca 10% NG incorporated. The active sheath has the advantage of being pulverized completely on expln of enclosed cartridge, thus filling the mine atmosphere uniformly with non combustible dust (Ref 6, p 514)... 

Under the term cartuchos con corteza de seguridad (cartridges with safety crust) are known Spanish sheathed expls. They consist of a cartridge of permissible expl,... 

EqS Equivalent Sheathed (Explosive). An expl as safe as a sheathed expl of the same type... 

Tests for " sheathed and for EqS (equivalent sheathed) expls, as required by regulations of 1953 are listed in Ref 40, pp38-9 ... 

It should be noted that a sheathed expl is safe against firedamp and/or coal dust as long as the sheath is not damaged (as could happen if the sheathed cartridge is driven into the borehole which is too tight). 

Abbreviations and notes EqS - Equivalent in safety to sheathed expls NG - Nitroglycerine NGc such as woodmeal, wheat flour, oat husk meal or plant fibers Other ingredients, such as AW (Acid Barytes, Resin or AS No 2( ) d - density of unsheathed cartridges Strength as % of BG (Blasting cartridge suspended in 9% methane/air... 

Hall et al, Ibid 15 (1912) (Investigation of expls used in coal mines) 8)Marshall 1 (1917), 44-47 2 (1917), 582-606 (Permitted expls) 8a)Colver (1918), 247 681 (Nauck-hoff s expls) 9)Barnett (1919), 117-42 (Safety coal mine expls) 10)E.Lemaire, AnnMines-Belg 23, 649(1922) (Sheathed expls) 10a)C. 

MiningEngrs (London), 109, 358 (1949-50) W. Shepherd H.Grimshaw Ibid 109, 889 (1949 -50) (Recent Brit expls equivalent in safety to sheathed expls) 31)J-Taylor A.H. Phillips, USP 2513531 (1950) CA 44,... 

Uhikol which are equivalent in safety to sheathed expls) 33a)Jimenez, Explosivos... 

Denespex One of che Brit permitted NG gelatin expls belonging to the class of EqS [Equivalent (in Safety) to Sheathed] expls. Its compn is not given in Ref Ref Taylor Gay (1958), 100... 

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