212 GEOLOGY AS AN ECONOMIC SCIENCE 



Coal 



When we consider the economic history of the 

 British Isles, we cannot fail to recognise that our 

 great commercial prosperity in the past, more 

 especially since the seventeenth century, has been 

 due in no small measure to our mineral-wealth, 

 more particularly to our vast stores of coal and 

 iron. But in addition to these essentials, our 

 Islands furnish us with large quantities of other 

 useful metallic and non-metallic substances which 

 have enabled us to build up and carry on a variety 

 of industries. 



Although geology as a science owes much to 

 mining operations, it is a correct knowledge of 

 geological principles that guides the miner in his 

 costly undertakings, and it is ignorance or disregard 

 of these principles that so often renders his efforts 

 fruitless. Not only is a complete knowledge of the 

 geological structure of a mining-district a necessary 

 premise for the location of mineral-masses, but only 

 by the utilisation of such knowledge can any 

 deposit be exploited to the greatest advantage with 

 the minimum of waste. In the past the working 

 of a thick seam, a seam yielding the maximum 

 amount of coal at a minimum cost, has often been 

 carried on over large areas, as in Staffordshire and 

 North Wales, with absolute disregard of valuable 

 coal-seams that occur above and below. As the 

 exhaustion of the thick coal proceeded, the mines 



