Notes on the Dressing of Tin Ore. 



101i 



Chapman, of Hobart. The work of calcining, crushing, and 

 disintegration was conducted under the immediate super- 

 vision of Mr. Rees Davis, the well-known engineer. 



The stone was calcined, without previous breaking, in a 

 kiln belonging to the Victorian Patent Freestone Company, 

 and was found to be rendered very friable ; even the finest 

 ore could be easily separated from the quartz and other 

 minerals. The ore was then passed through one of Hope's 

 stone-breakers, at the rate of about half a ton in rather less 

 than five minutes. 



The result of this was- 



Coarse, roughly-broken 

 Ore 



\ to T V-i n - in diameter 



1 o ?? 

 2V V 



4 » 6 5? 



less than -gL- 



Class in 

 p. c. 



56-0 



22-0 



15-5 



2-5 



2-5 



1-5 



P. c. of Tin 

 Ore found. 



4-28 

 13-77 

 29-7 

 39-5 

 37-0 



P. c.of free Tin 



Ore in Sand under ■ 



J-in. diameter. 



2-04 

 4-95 

 1-78 

 2-37 

 1-84 



12-98 

 This 12-98 per cent, of clean tin ore gave on assay 69 per 

 cent, of pure tin, which would be equal to 8'99 per cent, on 

 the ore reduced to less than J-in. in diameter. 



Owing to the want of suitable sieves, the whole of the ore 

 from the stone-breaker was sent to the disintegrator,, instead 

 of sending only those portions, Nos. 1 and 2, which contain, 

 attached or enclosed tin ore. 



The disintegrator used was one made by Mr. Buncle as a 

 bark mill. The rate of disintegration was as nearly as pos- 

 sible 1 cwt. of ore per minute, but even this rate and the time 

 taken by Mr. Hope's stone-crusher is only approximate ; the 

 feeding was done by hand from bags, and was irregular. 

 With a proper regular feed the work would be done with, 

 much greater rapidity. 



From the disintegrator we obtained the following sizes of 

 material :- — 



Grains over to of an inch in diameter ... IS 5 per cent. 



30-0 

 140 

 18-5 

 110 



130 „ 

 Mr. J. L. Morley washed (without further crushing) a 



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