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Reference to the Reports of Her Majesty's Inspectors of 
Coal Mines, show very conclusively the relative safety of 
these two systems of getting Coal, which, taking the average 
nature of the Coal seams in various districts, will be a strictly 
just and reasonable comparison. 
The number of accidents from falls of roof and Coal in the 
Yorkshire Coal Field, amounted in 1869 to 59 per cent, of 
the accidents from all causes. This refers to a district where 
*^Longwall" is the exception, and some form of bankwork the 
usual method employed. 
Mr. George Fowler, in a recent paper read before the 
Institute of Civil Engineers, has very ably analysed this im- 
portant inquiry. He finds that, " Out of a gross tonnage of 
198,636,043 tons obtained by pillar work in 1866, 1867, 
and 1868, the casualities by falls were 814, or 231,739 tons 
of Coal for each life lost. Of a gross tonnage of 22,899,000 
"tons extracted by the longwall plan, the casualities were 
" 75, or 1 life for every 305,320 tons. If the latter ratio 
"existed in pillar work, the casualities would have been 
"reduced from 814 to 614, or a saving of 200 Hves.'' This 
happy feature in longwall is produced by the absence of 
those small and weak pillars of Coal which we find in all 
pillar or bankwork ; on the other hand, Longwall attains its 
smaller percentage of accidents from the fact that the roads 
are built well and there only being a limited area of roof 
exposed to the workman ; the worn out and bad roof being 
allowed to bend itself and settle upon the old goaf, and, as I 
previously explained, utilised to help in getting the Coal. As 
the miner advances, there is always a new roof to protect him 
which has never done any duty before. Then, again, there 
is another arrangement very general in Longwall mines, 
which, the writer thinks, greatly helps to bring about these 
results, viz., that the building of the packwalls, and the 
timbering and supporting of the roof, in Longwall mines, are 
