346 Repori S.A.A. Advancement of Science. 



vantage of all the latest development of mechanical skill. The gold 

 mines have had the benefit of the advice and supervision of the l)est 

 mining engineers, consequently all appliances are up to date, and 

 there has been a great advance in the knowledge of cyanide work- 

 ing. The problem there of the immediate future is as to the best 

 methods of working, and knowledge of hoisting ore from depths than 

 has. up to now been attempted in mining; we may look forward 

 shortly to the time when those who wish to take up mining as their 

 jirofession will go to learn their lessons at the Rand. 



COAL. 



The requirements of the mines have resulted in the opening up 

 of portions of the great coal deposits of the country, and it is worthy 

 of notice that whilst the cost of coal mining varies consideral)ly, coal 

 is now produced at one or two mines in the Transvaal for four 

 shillings a ton at the pit's mouth, which compares favourably with 

 anvthing achieved in Europe, though it is not .so cheaj) as in some 

 of the Pennsylvanian Coal Mines, where it is said to be put on trucks 

 for a total cost of 2s. 6d. per ton. 



The coal production of the world is estimated to be aljoul 800 

 million tons, of which the United States produces al^out _'6o million 

 tons, the United Kingdom about _\30 millions, and Germany 150 

 millicms. 



Science and Chemistry have achieved important results in the 

 last few years, first, in reducing waste, and. secondly, in utilizing the 

 bv-products in all manufactures, notabK in the manufacture of coke 

 in the ovens of the Otto Hoffmann, and the bauer, Breuer and 

 Brunck, and later the Otto-Hilgenstock types, which are everywhere 

 superseding gradually the old wasteful beehive oven. In these new 

 ovens the coal shut up in close retorts and exposed to a high tem- 

 perature gives in addition to the coke the following by-products, viz. : 

 tar, gas-liquor, from which bv distillation sulphate of ammonia i'^ 

 of)tained, largely used, especially in Germany, as a soil fertilizer or 

 manure, and coal gas containing benzol. Attempts are now being 

 made to utilize the waste heat of blast furnace.s ; the importance of 

 this is shown by the fact that although the by-product gas of the 

 f)last furnaces in the Cleveland Iron District in England has been 

 successfully used for years in heating the hot blast stoves, and for 

 raising steam, vet there is still a waste of some 61,000 horse-power 

 in the gases, and Mr. Whitwell goes on to say that the furthei 

 waste of heat in the iron and slag is equal to 276,140 tons of coal, 

 or 31.500 horse-power, making a total i>ower going to waste of 92.5,00 

 horse-power in that district alone ever}' }ear. 



Manv attenijjts have been made to utilize the slag l)y grinding 

 it for mortar, making paving l)locks of it, and using it as a fertiliser, 

 but the commercial result has . not been verv successful so far. 

 Perhaps it mav be the good fortune of this countrv to produce 

 metallurgists and engineers who will solve this problem. 



There are vast deposits of iron in South .Africa unworked except 



