Show BLASTING WITH LIQUID AIR denver mining american the principle involved in this kind of blasting is the fact discovered a long time ago that liquid oxygen 90 per cent pure in contact with organic matter such as powdered charcoal or with petroleum absorbed in some inert substance produces a mixture which can be readily detonated with a resultant powerful explosion there are so many practical difficulties in the way of using liquid oxygen or liquid air for this purpose that it is very doubtful it if the method has any place in mining operations except in germany where the blockade has prevented the importation of nitrates from chile the nitric acid from which is the most important component part of explosives for ordinary mining as well as military purposes in using liquid air a cartridge is manufactured containing powdered charcoal or whatever organic material is used held in place by gauze and cardboard the ends of the cartridge being closed with cork the liquid oxygen is introduced into the center of this cartridge by means of a tube passing through one of af the corks and is distributed through the organic surrounding substance through gauze ports vent holes have to be provided so that gaseous oxygen may escape electric detonators are used for the explosion the liquid oxygen has to be brought to the mine in specially devised containers and the cartridge has to be loaded at the place where it is to be used and has to be fired immediately otherwise the liquid oxygen gasifies and the cartridge becomes this method of blasting cannot be used in wet holes because the water would freeze owing to the action of the liquid air and furthermore holes of not less than two inches in diameter have to be used under conditions where no other explosives could be or were available this method might appeal to mining men but under ordinary conditions it certainly seems to be an unattractive proposition for practical work liquid oxygen is said to be one of the powerful ingredients in the hand grenades used warfare and in the bombs dropped from aeroplanes aero planes 0 |