72 GEOLOGY AND MINERAL RESOURCES OF SIKHIM. 



Tuk, Bhotang, Ratho, and Pachi — are certainly the most promising 

 in all Sikhim. They work, however, in a primitive fashion, and the 

 depth of the drifts which they run for the ore is limited by the water 

 level of the nearest stream. As soon as a drift fills in with water 

 which cannot be easily let out, it is abandoned. The deepest mine 

 scarcely ever goes down below 70 feet from the surface ; that at 

 Pachikhani has scarcely reached this depth, and the miners intend 

 abandoning it already, owing to the difiBculty of draining it, though 

 the ore is found to get richer with depth. It was chiefly this difficulty 

 of draining that led to the abandonment of Tukkhani, Bhotangkhani, 

 and partly also of Kathokhani. I have no doubt Pachikhani also 

 will be deserted as soon as the surface ores have been worked out. 

 Deep mining on modern methods at these places, especially at Pachi- 

 khani, is likely to yield a very fair return. 



Of the four places just mentioned, Pachikhani appeared to me 

 the most promising. This may partly be due to the fact that, owing 

 to the works here being in progress, I could see for myself the exact 

 mode of occurrence of the ore. However, as the existence of at 

 least one good lode here is known, this place ought to be tried first, 

 in case Sikhim should attract mining enterprise, which it is likely to 

 do in the near future. There are other reasons also in favour of 

 Pachikhani. A sample taken from the lode just mentioned yielded 

 20-31 per cent, of copper; and from what the miners told me the 

 average yield from the entire mine is about 12 per cent, (five seers 

 of copper from one maund of ore). On the other hand, the picked 

 ore from Rathokhani was found by Mr. Mallet to contain not more 

 than 8 or 9 per cent, of copper. At Bhotang, the ore appeared to me 

 to contain rather too much mundic. From what the miners who 

 had worked at Tukkhani told me, the ore there at the point where 

 it was given up was richer even than that of Pachikhani. I would 

 not place much reliance upon such a statement uncorx'oborated by 

 samples. Still from all accounts, Tukkhani would be a very favour- 

 able place for trial, after Pachikhani. 



Of the other localities the surface indications at Rhenock appear 

 to be rather favourable. 



Iron 

 Occurs chiefly as pyrites in association with chalco-pyrito. It is 

 most plentiful at Bhotang, where magnetite also occurs. The iron 

 ores have nowhere been put to any economic use. 



Lime. 

 There is a vein of calcite in the gneiss at Lingtam, about 

 three miles north-east of the Ronglichu rest bungalow. Lime was 



