COPPER. 75 



The principal Pashok mine is on the hill-side above the Rangiak 

 stream. It was worked in Dr. CampbelFs time 

 by a man named Rajman, who is said to have lost 

 heavily by it ; afterwards by Bhotu, and lastly by another Rajman, by 

 whom it was abandoned three years ago after the discovery of the Mang- 

 phu mine. The cupriferous stratum is quartzose hornblende-schist, 

 dipping south-west at 15°, through which the ore, with mundic, is 

 very sparsely disseminated. Mr. Piddington's assay of a sample from 

 this locality yielded only If per cent, of copper.* There is another older 

 mine, close to the bank of the Rangiak, which has entirely fallen in. 



The Pashok and Mangwa copper localities appear to be on the 

 same horizon as the Mahanaddi and Rani Hat. 



Copper is said to have been recently found near the head of the 

 Rangbong, west of Pashok, but I did not hear 

 of it until after I had left the neighbourhood. 



The Rattu mine is in Independent Sikkim, but I visited it as it 

 was being worked at the time. The rock is grey 

 clay-slate with interbanded lenticular layers of 

 quartz, through both of which the ore occurs, but chiefly in the latter. 

 The strata dip at high angles, and vertically, with an irregular strike 

 from north-east — south-west to north — south. The mine is in a ravine 

 which runs nearly parallel to the direction of the strike, so that the 

 entrances cut across the bedding, but inside there are also drifts rami- 

 fying parallel to it. The mine is extremely wet, with rivulets of water 

 running down some of the passages. The men are therefore unable 

 to sink below the level of the stream outside into which the water 

 drains. 



The ore here is the best I have seen, and occurs in considerable 

 quantity, as evidenced by the extent of the excavations. Several heaps 

 of good picked ore, very free from mundic, were lying about ; a care- 



* Journal, Asiatic Society, Bengal, Vol. XXIII, p. 477. 



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