THE FARM HOLDING. 1 1 1 



Methods of Using Explosives. 



The application of explosives to the various methods of clearing, from 

 shattering for burning to the blowing right out of stumps and trees, varies so 

 widely — what with the different root systems, variety of timber, soil conditions, 

 &c. — as to make it next to impossible to give a conci.se description in writing 

 of just where to place the charges, and just how much explosive to use. A 

 certain variety of tree may " tap " very badly in one district, and may make 

 no tap-roots at all in another; or the soil may be strongly resistant, with a 

 good stiff solid subsoil for shooting off, and everything in favour of good 

 results in one place, or it may be sandy and friable, and offering but little 

 resistance in another. Such cases need to be tackled rather differently, so 

 that the beginner, after he has mastered the handling and preparing of the 

 charges, &c, and' has thereby gained confidence, has "to study many pointn 

 if he is to succeed in keeping down the cost of his clearing, never using the 

 axe if gelignite will do the job quicker and better, or vice versa, and never 

 using two plugs if one will be enough. 



On most areas the stump question looms large, and in describing the 

 method of handling the stump, the handling of the tree is also described, in 

 general principles, since one is the same as the other, except that the trunk 

 and branches have been removed. 



It may be taken almost as an axiom that charges should never be placed 

 by means of auger or bulb bar holes in sandy ground or under hollow stumps, 

 that is, stumps with, say, a hollow of a foot or more in diameter. In such 

 cases the charges should be placed by means of the chisel bar close under the 

 hip roots and where the stump is held the strongest, so that the gelignite 

 is resting right up against the timber in a bunch. This ensures the maximum 

 of shattering. The amount of the charge depends wholly on the mass of 

 timber to be shattered; it is next to impossible to lay down hard-and-fast 

 rules as to the amount of charge to be used where such wide variations are 

 the rule rather than the exception. 



If a battery is being used, all the charges will be fired at the one time and 

 together, but very good results can be obtained by placing one charge and 

 firing it with ordinary fuse ; then preparing another charge hole, the position 

 of which will be dictated to a large extent by the results of the shattering of 

 the first charge, in conjunction, of course, with the next heavy hip root. 

 The work can be continued thus right round the stump, until it is shattered 

 satisfactorily for burning. This is where the grub-hole application of charges 

 is ahead of the auger or bulb-bar application, since a charge put in with the 

 latter would so loosen up the whole soil area of the stump as to make it 

 quite impossible to place another auger or bulb-bar charge under it. 



In handling strongly-rooted solid stumps of, say, up to 3 or 4 feet diameter, 

 the auger or bulb-bar can be employed with advantage for a one-charge and 

 ordinary fuse job, but it is advisable to put this hole down quite 4 feet and 

 well under the centre of the stump. The reason for putting this hole down 

 so deep is that the explosive force of the charge travels at a definite and 

 regular angle towards the point of least resistance, which naturally is the 

 surface soil ; consequently the deeper the charge is placed, the wider will be 

 the range of the explosive force, and the greater will be the total area of root- 

 system affected. A point in manipulation which might with advantage be 



