124 SCIENCE PROGRESS 



2. Pyrite-Smelting at Mount Lyell 

 The Mount Lyell mining-field is, metallurgically, remarkable 

 as the first in which pyrite-smelting has been successful on a 

 big scale. The copper ores are now smelted there without the 

 use of any other fuel than their own sulphur and iron — an 

 achievement due to the high skill and patience of the general 

 manager, Mr. R. C. Sticht. The history of the process has been 

 told by Mr. Sticht, with an historical completeness only too rare 

 in mining literature, in his recent presidential address to the 

 Australasian Institute of Mining Engineers. 1 He traces the 

 development of pyrite-smelting from the first beginning of 

 Roharbeit, or pyritic-smelting, by Barthold Kohler, of Freiberg, 

 in 1555. Mr. Sticht insists on the essential differences between 

 pyritic-smelting, a term introduced by Percy in 1880, and the 

 newer process of pyrite-smelting. Pyritic-smelting is a blast- 

 furnace process, in which iron pyrites is added to form a 

 regulus, in which the precious metals of the ores are 

 collected. The process is adapted to ores which do not con- 

 tain sufficient copper or lead to collect their own gold and 

 silver ; and thus it enables ores to be treated by means of 

 valueless pyrites, which are too poor to afford the use of lead 

 and copper. In this process carbonaceous fuel is used as the 

 main source of heat, and the smelting is conducted in a 

 reducing atmosphere. 



Pyrite-smelting, on the other hand, is the blast-furnace 

 smelting of sulphide ores by means of the heat generated by 

 the oxidation of their sulphur and iron, and not from the com- 

 bustion of carbonaceous fuel, and the smelting takes place in an 

 oxidising atmosphere. A block of wood may be added occa- 

 sionally ; but its function in pure pyrite-smelting is mechanical, 

 as it breaks up the crust in the furnace, and it is not added 

 as a fuel. 



Partial pyrite-smelting is an intermediate process. It agrees 

 with pyritic-smelting in the use of some carbonaceous fuel ; it 

 agrees with pyrite-smelting in the use of an oxidising atmo- 

 sphere in the furnace, and in using all the heat that can be 

 generated by the oxidation of the sulphides in the ore. Partial 

 pyrite-smelting is, therefore, applicable to ores of which the fuel 

 capacity is insufficient for their own smelting. 



1 R. C. Sticht, "The Development of Pyrite-Smelting: An Outline of its 

 History," Proc. Austral. Inst. Min. Eng. vol. ii. 1905, pp. 9-78. 



