THE DECOMPOSITION OF WOLFRAM. 



251 



sides to slightly altered wolfram assaying over 70 pel cent. W0 8 - 

 The analysis, by H. "R. Pepper, was as follows 1 :— 



Bin O 90-88 



W0 3 



Al 2 0, 



Si 0, 



Total 



4-20 

 400 

 1-80 



100-38 



At the head of a narrow valley on a certain mine in Tavoy, 

 where the detrital deposits have been sampled as systematically 

 and carefully as this kind of work can be done, the concentrates 

 from the ground assay 55*7 per cent. W0 3 and 16'4 per cent. Sn. 

 The veins which are shedding the minerals yield a concentrate by 

 mining containing 61*5 per cent. W0 3 and 4*8 per cent. Sn. The 

 valley is steep and about 500 yards long. Approximately half 

 way down its length, the detrital from the slopes, tested in a number 

 of places, averages 41*6 per cent, WO3 and 23 per cent. Sn. Close 

 to where the valley joins the main stream, the composition changes 

 to 40-5 per cent, W0 3 and 2G"5 pel cent. Sn. 200 yards down the 

 main stream sampling gives a concentrate with 302 per cent. W0 3 

 and 35-8 pei cent. Sn. 150 yards further down stream the composi- 

 tion is 15*4 per cent. \V0 3 and 51 G per cent. Sn. Further still down 

 stream, actual working produced some tons of concentrate of a 

 composition G per cent. W0 3 and 64 pel cent, Sn. 



The following .analyses of general representative samples from 

 of the Hennyingvi Mine are also instructive:— 



various par 



General sample of concentrate from veins worked 

 in No. 419 Adit.. Big Hill. All these veins are in 

 sedimentary rocks. 



General sample of concentrate from sluicing detri- 

 tal slope deposits derived from veins in sedi- 

 mentary rocks. 



Similar to No. 2, except that the veins are in 

 granite. 



General sample from an old talus deposit at foot 

 of slope. 



General sample from the stuff overlying the old 

 talus deposit of No. 4 and doubtless much more 

 recent and subjected to more intense weathering. 



Sn. per 

 cent. 



13-50 



27-80 



20-50 

 41-40 

 59-80 



i W. R. Jones (16), p. 320. 



