Mount Monjan Gold Mine. 355 



enormously enriched from <idld in solution leached out of the 

 oxidised ores and re-deposited in the secondary ore. The pold 

 in a very pure and crystalline state in the secondary ore would 

 be one strong means of extracting the gold from any solutions 

 carrying gold that came in contact with it ; also the conditions 

 prevailing in these beds of secondary ore were no doubt just 

 those that would in other ways conduce to the deposition of 

 whatever gold was in solutions passing through them. 



The chemical reactions that were brought into play under such 

 conditions as existed at Mt. Morgan when the sea or fresh or brack- 

 ish water came into contact with the sulphides, must necessarily 

 have been of a very complicated nature, and tliese would form a 

 most interesting subject for some chemist to investigate. It would 

 not only be of interest from a scientific point of view, but 

 also from an economic point, for the question arises from the 

 present position of this great mine whether it would be possible 

 to imitate nature's processes in working the abundance of low- 

 gi'ade sulphides encountered in the depths of the Mount. 

 Possibly some electrolytic method might prove even more 

 effective than pyritic smelting, because fuel at Mt. Morgan 

 will be an expensive item. 



In conclusion, although the writer differs from Dr. Jack as 

 to the causes that have produced Mt. Morgan as we know it, it 

 is a pleasure to him to bear ample testimony to the faithful 

 and accurate descriptions of the Mount supplied by Dr. Jack 

 in his reports. 



Specimens of the Mt. Morgan rocks and ores obtained by the 

 writer are in the collection of the Mines Department of Victoria, 

 at the Exhibition Building. To Mr. Kicliards, the (TPueral 

 Managei', the author is indebted for samples of ore and the 

 statistics used. 



DESCRIPTION OF PLATES. 



No. XXI. — Plan of Mt. Morgan Gold Mine, Queensland. 

 XXII. — Section thrcni<fh the same. 



