18S 



On Certain New Mineral Species associated with 



Carnotite in the Radio-active Ore Body 



near olary. 



By D. Mawson, B.E., B.Sc. 



[Read September 4, 1906.] 



Introduction. 



The occurrence of carnotite, a vanadate of uranium and 

 potassium, was reported by Mr. Chapman, the Government 

 Analyst, as a filmy coating in the crevices of a sample of ore 

 sent to him for analysis. As the yellow powder was scarce 

 his determination rested on qualitative investigation only, but 

 was substantiated by physical tests made by Professor Bragg, 

 who demonstrated its high radio-activity. This information 

 was made public in the daily press of May 3 last. 



The same day Mr. H. Y. L. Brown, the Government 

 Geologist, visited the locality of the find, Radium Hill,* situ- 

 ated 24 miles in a direct line east-south-east of Olary, and IJ 

 miles south-south-west of Teesdale's Dam. In the Adelaide 

 press of May 5 appeared a short report made by him on re- 

 turn to the city. 



Mr. H. G. Stokes, after a visit to the field, made com- 

 ments through the press of May 9, doubting the correctness 

 of the mineral determinations. 



Extracts from the final official report appeared in the 

 Advertiser of May 16, in which announcements were made by 

 the Government Geologist and Government Analyst, 

 and by Mr. G. A. Goyder, Public Analyst. In this 

 report the Government Geologist, suspecting that 

 the carnotite originated as a decomposition pro- 

 duct, states: — 'Tt appears most probable that it 

 has been derived from the solution and redeposition of other 

 uranium compounds below, and that, therefore, such ores, in 

 addition, will be found by exploitation in depth." Both 

 analysts reported the yellow compound to be probably carno- 

 tite. Magnetite and magnetic titanic iron were reported; 

 also gummite. 



Only within the last month have representative samples 

 been obtained at the University. Extreme variation in 

 physical characters, exhibited by "different nortions of the black 

 mineral, at once attracted attention. It was evident that 

 instead of a single black constituent previously described as 



* As this fipot has so far remained unnamed, "T?ndinm FTill' 

 seems appropriate. 



