PIT TIMBER

Evening Star, Issue 22272, 25 February 1936, Page 2

PIT TIMBER

QUESTION OF PRESERVATION Although timber to the value of about £6,000,000 is used every year in the mines of the United Kingdom, it is estimated that less than 2 per cent, receives any preservative treatment (says a writer in the ‘ Colliery Guardian’). Where conditions are favourable, such as in humid shallow pits, decay is exceedingly rapid, and the timber has only a very short life if pot treated with preservative. In such pits the timber maintenance costs are high, and it is here that the value of preserved timber is most pronounced. The cost of the actual timber used in replacements may be relatively small, the labour costs and delays resulting from falls being the factors that make for high maintenance costs. It may not be generally realised that fungal decay is accompanied by considerable reduction in strength, even in the early stages when it may not be apparent, and the failure of timbers may often'be due to incipient decay rather than to lack of - initial strength. Thus, apart from its economic value, preservative treatment may have a considerable influence on the safety of the underground roads. It is, of course, realised that timber used at the coal face has in any case a short mechanical life, -and that the value of treated material is confined to the timbering of roadways and airways, and it is with such timber that this report is mainly concerned. It was decided that the experiments should take the, form of service tests on props treated with a few watersoluble preservatives in. a, cheap, and practical manner. With these objects in view, arrangements were made for tests to be carried out at two pits. The pits' chosen for the tests were the Langton pit of Pinxton Collieries Ltd., Pinxton, near Nottingham, and the Wbolmet pit of the Niddrie and Benbar Coal Co., Portobello, near Edinburgh. At Langton the timber was placed in the Waterloo workings, at about 800 ft, from the surface. At Woolmet it was placed in Salters seam, at approximately the same depth from the surface. Fungus growth flourished in both pits.