152 



R. A. F. PENROSE 



range from a few feet to several hundred feet in length, as the 

 case may require, and are either made of wood or are cut in the 

 sandy clay of the region. After a certain number of hours, the 

 stream is stopped and the material at the bottom of the sluice is 

 still further concentrated by hand panning in a flat wooden bowl 

 not unlike in shape the ordinary sheet-iron American gold pan. 



Fig. 8. — -Washing tin ore near Tronoh, Perali, Malay peninsula, 



(See Fig. g.) The final process in the preparation of the ore 

 is the separation, by hand-picking or by very expert panners, of 

 the particles of magnetite and other heavy minerals associated 

 with the tin, finally leaving a product varying from 69 to 73 per 

 cent, in metallic tin. This ore is then sacked and hauled to 

 market. 



At Gopeng, the Gopeng Tin Mining Co. is using hydraulic 

 monitors to handle the alluvium, in the same way as they are 

 used in the gold placers of California. At Cacha, an English 

 company has also erected a stamp mill with concentrating tables 

 to crush and concentrate masses of ore. The alluvium here has 



