THE MAITLAND FIELD. 321 



gers and owners, of the great risk they run if they neglect to 

 take all possible precautions against outbreaks of fire through 

 spontaneous combustion in this part of the field. The fact 

 may once more be emphasised, that it is absolutely necessary, 

 in the interests of the safety of the collieries and those work- 

 ing in them, that the whole of the 'brassy tops' should either 

 be taken out of the mine to the surface when the seam con- 

 taining them is being worked, or, if any be left underground, 

 the areas where they stand should be securely walled oft' from 

 tlie rest of the workings. The former method of guarding 

 against risk from fire would be preferable to the latter. 



"I would specially here emphasise the danger of work- 

 ing the lower seam of coal in such a way as to permit the over- 

 lying strata to collapse, and so produce cracks which admit air 

 to the overlying seam containing the 'brassy tops.' In this 

 case, there is a danger of spontaneous fire breaking out in the 

 'brassy tops' of the upper seam a fire which may easily spread 

 downwards through the cracks and crevices of the broken rock 

 into the main seam. Something of this kind has already ac- 

 tually happened in the East Greta Mine (in 1903), but, thanks 

 to the energetic action taken by Mr. Azariah Thomas, the 

 manager, the portions of the lower seam, to which the fire 

 was communicated at that mine, through what was probably 

 spontaneous combustion in the upper seam, have now been all 

 safely and securely walled off. 



"A. fire due to spontaneous combustion has also occurred 

 at the Heddon Greta Mine in this end of the Greta coalfield 

 (June, 1905), and the districts affected of the mine have been 

 walled off. 



"At Stanford Mertljyr also slight heating has been ob- 

 served in refuse mine material in the neighbourhood of a fault. 

 It should be stated, however, that there is no evidence to con- 

 nect the recent fire (29th October, 1905) at Stanford Merthyr 

 Colliery with spontaneous combustion. On the other hand, 

 there is a probability that the fires, both at the Old Greta Col- 

 liery and at the Anvil Creek Colliery, were the result of spon- 

 taneous combustion." 



Mr. A. A. Atkinson, the Chief Inspector of Coal Mines, 

 draws attention to the following points : 



(1) The advisableness of laying out the workings in such 

 a way that, in the event of a fire, small districts may be sealed 

 off. instead of having to close the whole of the colliery. 



(2^ The necessity for the removal of all small coal, un- 

 necessary timber, and any other easily inflammable material, 

 from the workings. 



*Ann. Eept. Dept. Mines, N.S.W. for 1903, p. 101, and 

 1905, p. 113. 

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