MINES OF THE COASTAL RANGE. 



269 



the computed average value in wolfram or cassiterite was 1| lbs. per 

 cubic yard, while the acntal return made by sluicing ovei 350.000 

 cubic yards of this material was 3-31 lbs. The exploitation of 

 these unique deposits is undertaken on a large scale by an electrically 

 driven plant designed by the late Mr. C. M. Lyons, O.B.E.. the 

 General Manager of the mine, who for many years advocated and 

 practised scientific mining in Tavoy and who gradually evolved 

 methods which now result in Kanbauk possessing the largest hydrau- 

 lic; mining installation in the Indian Empire. 



The following summary of the methods used in working these 

 surface deposits has been given recently by R. Coleridge Beadon : — 



" Water is brought to the mine by two steel flumes, capacity 

 25 and 35 cubic feet per second respectively, and of a total length 

 of about 3 miles. 



The working pressure varies from 125 to 150 lbs. per square 

 inch, while the equipment includes four 8-inch and two 12-inch 

 monitors with nozzles ranging from 2 to 4 inches. 



Two hydraulic elevators are used to elevate the gravel to heights 

 of 50 and 45 feet respectively, but the former is now being replaced 

 by a 12-inch gravel pump mounted on a pontoon and driven by a 

 Pelton wheel ; this pump will lift a total height of 80 feet and enable 

 deeper ground to be worked. 



The water and gravel is passed over grizzlies with one inch 

 spaces, the stones being passed down a steel chute to the end of 

 the boxes where they join the main flow in the tail race. 



Two main sets of boxes are used. Each contains three compart- 

 ments 12 feet wide and 130 feet long. 



They are cleaned up about once a month by sluicing them out 

 with a fire hose and elevating the concentrates to the cleaning 

 box with a 6-inch hydraulic elevator. 



As the concentrate contains large amounts of magnetite it 

 has to be passed through the magnetic separator. 



As the streams diminish rapidly when the rains cease, water 

 is stored in a reservoir, 2.200 feet above the mine, by means of a 

 " rock-fill " dam 650 feet long and 51 feet high. The dam consists 

 of a reinforced concrete face with a backing of hand-laid dry stone 

 work, and has proved very satisfactory. 



The capacity of the reservoir is 500,000.000 gallons and this 

 together with the natural flow of the stream will enable 1,000 H. P. 



