235 
splinters of wood ; if broken off at a right angle to its natural 
formation, or on the end, you obtain large cubical blocks of 
the same. It is just the same with Coal ; unless so worked, 
we cannot obtain that maximum quantity of large Coal so 
much to be desired, for instead of 30 to 50 per cent, of slack 
in bankwork, I have known it reduced in one instance, where 
the Coal is riddled in the pit, to under 6 per cent, for the 
average of one year's workings in Longwall got endway. 
This increased yield of round Coal will far more than com- 
pensate for any slight extra cost incurred in getting, which 
the following figures, calculated from the seam referred to, 
and strictly correct, will show to be very slight indeed. 
To avoid going over unnecessary commercial ground, I 
have only calculated the items of cost up to such a stage in 
the getting of the Coal, as when the charges become the same 
under both systems. The following figures, therefore, repre- 
sent not the actual profit obtained, but only the difference in 
favour of one system over the other. In working this seam 
in Banks and Pillars, I find that 60.88 per cent, of large 
Coal, and 39.12 per cent, of slack, was obtained, which cost 
in getting 2s. Id. per ton ; this, taken at the respective sale 
prices of 7s. and 3s. 6d. per ton, realised £28 2s. 9d. ; or an 
average of 5s. 7.5Sd. per ton. 
"Working the same seam by Longwall, I found that 81.75 
per cent, of large Coal, and 18.25 per cent, of slack, was 
obtained, which cost in getting 2s. M. per ton ; this, at the 
above sale prices, deducting the slight difference in cost of 
getting, amounts to £30 18s. 7d. per hundred tons; or an 
average of 6s. 2.23f/. per ton. Now, assuming an average 
weekly production of 3,000 tons of Coal (which a modern 
well-arranged Colliery, where the discipline is good, ought 
to attain without any difficulty), we have a difference in 
favour of Longwall of 6.7 Od. per ton, which is equal to £83 15s. 
per week, or a saving of £4,355 on one year's production. 
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