94 COALFIELDS AND COLLIERIES OF AUSTRALIA. 



Rippite. 



Parts by weight, 

 not more than, not less than. 



Nitro-glycerine 62.5 .. .. 59.5 



Nitro-cotton 4.5 . . .. 3.5 



Nitrate of potassium 



Oxalate of ammonium 11 



Castor oil 1.5 . . . . 0.5 



Wood meal (dried at lOOdeg. C.) 5.5 .. .. 3.5 



Moisture 1 . . 



Excellite. 



Parts by weight, 

 not more than, not less than. 



Nitre-glycerine 9 . . . . 7 



Nitrate of ammonium 84 . . 80 



Collodion cotton 1.5 .. ... 0.5 



Di-nitron toloul 3.5 .. .. 2.5 



Wood meal (dried at lOOdeg. C.) 4.5 . . . . 3.5 



Castor oil 1.5 .. . . 0.5 



Moisture 2.0 .. . . 



The chief requirement of a safety explosive is that it shall 

 not produce a flame, which might ignite any fire-damp or fine 

 coal dust present. Of the above, monobel and saxonite find 

 most use in New South Wales collieries ; monobel being em- 

 ployed for breaking down coal, as it has a slow rending action 

 favourable for producing lump coal, while saxonite is used 

 for blasting rock, as it shatters hard rock better. In wet 

 places saxonite is sometimes used instead of monobel for coal, 

 as the nitro-glycerine in its composition makes it less liable 

 to be hurt by moisture, but anyhow the monobel cartridges 

 are dipped in a special wax to preserve the explosive from the 

 action of moisture. Monobel is light yellow in colour, and IP 

 made into cartridges of various sizes, packed in cardboard 

 packets, containing 51b., and ten of these packages are placed 

 in a wooden box. Its strength is reckoned to be at least 

 2 times that of blasting powder, which means that for the 

 same amount of work, less explosive and smaller holes are 

 necessary. This explosive is not ignited by a spark, it does 

 not require thawing in cold weather, and it does not give 

 headaches like those compounds containing large quantities 

 of nitro-glycerine. It is exploded by a sextuple, or No. 6 

 detonator. In a fiery mine, monobel is exploded by means of 



