266 BROWN & HERON: GEOLOGY AND ORE DEPOSITS OF TAVOY. 



terite in them are common, but special mention must be made of 

 the veins of drusy quartz, which are of very exceptional occurrence 

 in the district. In these crystallization seems to have set in from 

 the walls with the result of a mass of more or less imperfectly formed 

 quartz crystals, growing horizontally towards the centre. The 

 metallic minerals have tended to deposit between the bases of the 

 crystals and the mica walls, and in druses amongst the crystals 

 themselves. As will be demonstrated in a later chapter these veins 

 are probably of hydrothermal origin. 



At Kanbauk there is definite evidence of the occurrence of 

 wolfram in shoots, which are often well demarcated, although 

 the mineral also occurs disseminated elsewhere *in the veins. The 

 wolfram of the Kanbauk veins is coarser than usual and its crystal- 

 line habit is typical. The veins themselves vary from 3 to 24 

 inches, with an average of about 10 inches, in thickness. Thus 

 they follow the general rule that veins in the sediments are thinner 

 than those in granite. They also follow another general rule and 

 form thin overlapping lenses, the duplication taking place in a 

 left-handed direction. At least one natter vein cuts the more 

 steeply inclined ones in Kanbauk proper. It is said to be richer 

 than the others and to go straight through them without displace- 

 ment. Evidences of deposition of wolfram on the vein walls are 

 common. Sometimes the mineral has to be broken away when 

 the vein quartz is removed, often it is wedged in between the wall 

 and the terminations of quartz crystals. At other times it is 

 splashed irregularly in small crystalline aggregates in the matrix. 



Associated minerals are pyrite, chalcopyrite, galena, marmatite 

 and native bismuth. Fluorite and siderite have been found. 



Mining and milling. — The veins are systematically opened op 

 and stoped by a series of drives from 60 to 100 feet apart vertically. 

 Two main low level adits have been driven which give a maximum 

 of backs of about 100 feet. Temple-Ingersoll electric rock 

 drills are used in the harder country rock. The ore is trammed 

 to gravity inclines and thence to the mill, which was erected in 

 1914 and consists of 10 heads of stamps of 1,100 lb-, dropping 8 

 inches, with a screen aperture of } inch. There are four Wilfley tables 

 of Nos. 5 and 6 types. The installation is driven by a Pelton wheel 

 wnen water is available and by a 32 b.h.p. Hornsby engine, assisted by 

 a 12 h.p. portable engine and boiler, at other periods. 



