UNDERGROUND WORKINGS OF A WESTERN COLLIERY. XLIII. 



the seam that is mined, except in the levels and roadways where 

 the coal is taken out to the full height of the seam. 



The tops are very friable, and if worked would produce a large 

 quantity of slack, probably 50%, which with extra labour for 

 picking out the partings and other impurities, renders them 

 unpayable at present. Taking the seam all through the coal is 

 remarkably clean; there are very few faults, and they are of an 

 unimportant character; the latter consist of sandstone dykes but 

 they seldom cause any throw in the seam ; an exceptional case 

 was one which I examined in No. 3 District, causing a downthrow 

 of one foot. (Diagram B.) 



A few 'rolls' and 'greybacks' intrude into the seam, and 

 occasionally make a good deal of dead work ; the former consist 

 sometimes of hard and sometimes of soft stone, but in every case 

 they make the coal very curly for some yards around them, the 

 latter are designated 'greybacks' from their colour. (Diagram C.) 



The experience gained in working the seam so far proves the 

 coal to be remarkably free from gas and no safety lamps are used 

 in the pit. The coal in the seam is very easily worked probably 

 due to its well defined planes of cleavage, which with a few 

 deviations, run in a northerly direction, and a miner will get more 

 coal in this colliery in one day than in many others, as the follow- 

 ing figures demonstrate, and this is typical of the whole Western 

 District. The average amount of coal raised in the State in 1899 

 per miner was 564 tons ; in the Western District 656 tons ; and 

 in the Zig Zag Mine 854 tons. The coal is mined by holing or 

 undercutting and shearing, and falls away from the tops of its 

 own weight, no blasting or explosives being necessary. 



An analysis of the coal taken from the upper part of the seam 

 is as follows : — 



Water 2 24 



Volatile hydrocarbon 

 Fixed carbon 



Ash 



Sulphur 



29-09 



5606 



11-78 



0-a3 



Total 100-00 



