Mount Morgan Gold Mine. 347 



appeared even below where the iron sulphides still survive, but 

 that a zone has now been reached where the ores are in the 

 condition as oria'inally deposited. From an industrial point of 

 view, this chanpfe in the character of the ore is serious ; for, 

 whereas the ores first worked were for jrold only, tlie future 

 development of the mine must be as a copper and gold proposi- 

 tion, the copper greatly outweighing the gold in importance. 

 Eventually it is likely that the mine may become a copper 

 mine, the gold being merely a by-product. Necessarily following 

 this change in the nature of the ore is an entire alteration in the 

 plant and methods involving heavy expenditure. 



Origin. 



As to the origin of this great body of siliceous and sulphide 

 ore, there is some obscurity. Its gi'eat mass and its relations 

 to the surrounding igneous rocks differentiate it from ordinary 

 lodes. Besides, at the Sugar Loaf another similar body of ore 

 exists also with similar surroundings, and still others in the 

 neighbourhood. Whether it resulted from igneous agency or 

 not has yet to be worked out, but the intimate manner in 

 which similar cavernous siliceous material was blended with the 

 felspathic material at the archway that formerly stood at No. 

 3 level as observed by the writer seemed to point this way. 



Dykes of various dimensions cut through the siliceous sul- 

 phides in many places, and the rock is not as altered as at 

 higher levels. 



In the upper levels, besides the friable siliceous material, 

 very extensive bodies of kaolin ore were also met with, and ex- 

 tensively mined. Although the kaolin ore in some cases was 

 undoubtedly produced from the decomposition of dykes of 

 felspathic rock that were not necessarily auriferous originally, 

 but that may have become so through the decomposition of the 

 auriferous sulphides in the siliceous ore around them, and the 

 gold derived from the pyrites in solution may have been re- 

 deposited in the kaolin, it is not certain that all the kaolin 

 could be thus accounted for. In some parts the ore itself 

 appears to carry much kaolin, but this point will be far clearer 

 in the lower levels now being opened out. 



