TIN DEPOSITS OF THE MALA V PENINSULA 



153 



often been indurated by infiltration of iron compounds, while it 

 also often contains masses of the original tin-bearing rock from 

 which the cassiterite has not yet been liberated, so that crushing 

 becomes necessary. At Sorakai, roasting, crushing, and concen- 

 trating machinery has been introduced by the Sorakai Tin Min- 

 ing Co., an English corporation, to handle the ore mined in the 



Fig. 9. — Women washing tin ore near Lahat, Perak, Malay peninsula. 



granite at that locality, the roasting being necessary to drive off 

 the arsenic in the ore. At Tronoh, some of the alluvium con- 

 tains much clay which adheres closely to the tin, and the mate- 

 rial is treated in large tanks with revolving paddles inside. 



The tin was formerly smelted largely at local works in the 

 various mining districts, and some of it is still treated in this 

 way, but most of it is now smelted by the Straits Trading Co., 

 which has a large smelting plant at Singapore. This company 

 has great influence throughout the peninsula, and has established 

 numerous agencies where tin is bought from the miners and sent 

 to Singapore. The total production of tin on the Malay penin- 



