326 BROWN & HERON: GEOLOGY AND ORE DEPOSITS OP TAVOY. 



A dredge was built in Melbourne and erected at the site. It com- 

 menced working in October 1911 and continued until the outbreak 

 of war in 1914, shipping, it is said, in all about 200 tons of cassiterite. 

 At the end of 191 4: the Company went into voluntary liquidation 

 and at a later date the dredge was purchased by Messrs. Booth 

 and Milne. They started work again in 1916 with considerable 

 success and sold the property and machine to the present owners, 

 the Indo-Burma Tin Corporation, Ltd., in 1918. This is a Calcutta 

 concern with an authorised capital of Rs. -45,00,000, of which 

 lis. 36,75,000 are issued. Operations are being continued with 

 the old suction dredge while others of the bucket type, formerly 

 used for gold dredging in the upper reaches of the Irrawaddy, are 

 being transported to, and erected on, the Taimgthonlon area. 

 The following particulars of the first dredge are of interest : — 

 Type. — A revolving cutter and suction. Casey's Patent Pon- 

 toon with a deck of 100' X 40', and depth of 6' 6" forward 

 and 8' 6" aft. Draws 4' of water with tin saving sluices 

 loaded. 

 Main Pump. — A 12" Gravel Pump by Thompson & Co. of Castle- 

 maine, driven by a 75 B. H. P. Belliss and Morcom 

 high speed compound condensing engine. This pump -raises 

 1,500 gallons water per minute, and 1 yard of ' solids.' 

 with a ' Duty of Water ' of 10. 

 1,500 gallons of water weigh approximately 6|- tons, 

 1 cubic yard of ' solids' weigh approximately lj tons, 

 so that the total lifted per minute is approximately 8 tons 

 altogether. 

 Service, or * Auxiliary ' Pump. — A 10" centrifugal driven by a 

 25 B. H. P. high speed Belliss and Morcom compound 

 condensing engine. 



The dredge is fitted with a surface condenser and an Edwards' 

 air pump. Steam is supplied at 150 lbs. pressure by a Babcock 

 and Wilcox water-tube boiler, with integral superheater. 



Sluices. — These are 8 in number, 90 feet long and 4 feet wide 

 each. When loaded the incline is 3 per cent. 



The main sluices have 4" stops or ri flies every 8' of run and this 

 height of stop is not added to, as the clean-up takes place every day. 



The cross sluices, under the screen, feeding the main sluices, 

 are stopped up 2" every 4 hours during working so that at clean-up 

 every day there are 12" of stops in the cross boxes. 



