16 



Dr. T. L. Llewellyn. 



[Dec. 19, 



Table VII. — Age and Duration of Underground Work. 



Average age at onset 40 years. 



„ period of underground life before onset 26'96 years. 



„ interval between onset and failure 1T14 months. 



Occupation. 



In this table figures are given as to the percentages of cases and of men 

 employed in various ways in a steam-coal colliery. The latter data are taken 

 from two Welsh steam-coal collieries employing over 2,500 men. 



Table VIII. 



Occupation. 



No. 

 of cases. 



Per cent. 



Per cent, of workmen in 

 steam-coal pit. 





337 



84 -25 



60 





29 



7-25 



8-7 





24 



6 



14 -6 





3 



0-75 



2 



Contractors and hard ground men ... 



2 



0-5 



7-5 





3 



0-75 



1-8 



Under officials (firemen) 



1 



0-25 



1 -9 





1 



0-5 











3 -5 various 



It will be seen that the men who work at the coal face are the class chiefly 

 affected, but that no class of worker is exempt. It is interesting to note that 

 the first two classes contain 91*5 per cent, of the cases. These men are the 

 most skilled workers, and have to use their eyes more than the others. 



The collier places each blow of his mandril accurately, or loses so much 

 work. I have tested colliers by making a mark, the size of a half crown, 

 on the coal with chalk. Every collier struck the mark accurately with 

 the pick when I asked him to do so. The timbermen have to adjust 

 accurately the pieces of timber used to support the roof, and the work is 

 of a very skilled nature. 



A few words on the manner in which the collier obtains his coal are 

 necessary. There are, roughly speaking, three ways — 



(1) By holing. 



(2) By taking advantage of the cleavage lines of the coal. 



(3) By the use of mechanical coal cutters. 



(1) Holing has been briefly described above. In thin seams, or when the 

 coal is undercut beyond 3 feet, the collier has to assume a reclining 

 position. In thicker seams the collier often kneels at his work, and then 

 his vision is directed downwards. 



