310 PHOCEEDIXCS OF SECTION C. 



9.— FUKTHEE OCCURRENCES OF TANTALUM AND NIOBIUM IN 

 WESTERN AUSTRALIA. 



By EDWARD S. SIMPSON, B.E., F.C.S., Govenimnit Minc,-alo<ji.',t (iiilI .4.ssny,T 0/ WVsf 



Ansfralia. 



At the Adelaide meeting of the Association, in 1907, I had the 

 honour to present a paper embodying all the then available informa- 

 tion with regard to the occurrence of tantalum and niobium in 

 Australia. Whilst no new finds of minerals containing the.se metals 

 in the Eastern States have come under my notice in the meantime, a 

 considerable amount of further information has been collected with 

 regard to West Australian occurrences, which it is the object of this 

 paper to describe. 



U«til quite recently it was a matter of impossibility to separate 

 occasional fragments of black tantalates and niobates from parcels 

 ol black stream tin except Avhere the}' showed Avell-developed crystal 

 faces or other prominent characteristics. The publication, in Volume 

 YIII of the '■ Journal of the Chemical, Metallurgical, and Mining 

 Society of South Africa," of Prof. G. H. Stanleys " New Test for 

 Cassiterite," has veiy materially alte-red the aspect of affairs. This 

 method is invariably used by the author in his examination of tin ox-es 

 for rare minerals. A shallow dish about 4 inches by 3 inches is made 

 by turning up the edges of ^ a piece of stout sheet zinc ; in this are 

 placed the concentrates in the foi*m of sand or coarse fragments up to 

 •J inch diameter, and then cover'ed with dilute (5E) hydrochloric acid. 

 In about one or two minutes the acid is poured off and replaced with 

 water, when all fragments of cassiterite which have been in contact 

 with the zinc are found to be coated with a bright deposit of metallic 

 tin so that they can easily be picked out, leaving a residue of other 

 minerals which are not appreciabl}' affected by the short immersion in 

 dilute acid. This residue is submitted a second time to the same 

 process, as possibly it may contain some fragments of cassiterite 

 which are not coated because they have not been in contact with the 

 zinc. After diying the final residue, it is freed from mag-netite -with a 

 hand magnet, and if necessary" from ilmenite by a weak electro- 

 magnet. Hand-picking will remove quartz, monazite, &c. The final 

 residues are then examined by chemical and physical tests for the 

 tantahnn minerals, tantalite, euxenite, &c. 



If the method here outlined were applied to all samples of tin 

 concentrates in the possession of members of the Association, it is 

 possible that our knowledge of the distribution of tantalum and 

 niobium in Australia Avould be greatly extended. 



MooLYELLA. — In my previous paper mention was made of the re^ 

 cognition of two small pieces of mangano-tantalite in Moolyella stream 

 tin ore, whilst it was suggested that in such material others might 

 easily be overlooked. During the collection of exhibits for the Franco- 

 British Exhibition some most interesting bulk samples of concentrates 

 came to hand from Moolyella. One Avas marked " Sluice-box residues, 

 Macdonald's Lead ", and subsequent inquiries elicited that it was 

 representative of the lighter waste material obtained by resluicing the 

 first concentrates obtained from the sluicino; of alluvial tin w^ash. 



