THE LODES, I ] 



wall rock near the lode and, owing to the liability of the rock to break 

 along these seams, a common cause of "heavy ground " and falls of 

 rock (especially in the Ooregum Mine) ; chlorite, an alteration product 

 of the hornblende, sometimes found in films in the quartz itself 

 (Nundydroog Mine) ; epidote> another alteration product, associated 

 with the calcite (Mysore Mine). Fibrous asbestos associated with 

 a clayey matter occurs as a casing to the lode, and where this is the 

 case the quartz is often replaced by a brown or green opaline variety 

 oj silica (Nundydroog and Champion Reef Mines). In the Champion 

 Reef Mine small veins of black fibrous tourmaline are occasionally 

 found, similar to that already described by Judd * from Kolar. The 

 quartz of the Oriental vein worked by the Nine Reefs and Road Block 

 Companies contains a much higher percentage of pyritic constituents 

 (iron pyrites, pyrrhotite and mispickel) than the Champion lode and 

 consequently is more refractory to treat. The West Balaghat, on the 

 other hand, is more allied to the Champion lode as regards its freedom 

 from base minerals. 



As has already been remarked, the veins follow the foliation of 

 the schist beds, in places bulging to big bodies {e.g., 30 to 40 feet 

 wide in Crocker's chute, Mysore Mine), in other places thinning to 

 mere stringers. The walls of the lode are, as a rule, well-defined, 

 especially where the quartz occurs in one solid vein ; and the separa- 

 tion of the lode from the country rock is easily accomplished. But in 

 places the vein is split into numerous small stringers alternating with 

 layers of the country rock ; the whole width of ore-body has then to 

 be stoped in the mines and the waste country rock picked out after- 

 wards on the sorting floors. In such places the stoping width may 

 be considerable, although the pay quartz remaining after the value- 

 less country rock or "waste " has been picked out on the sorting 

 floors, is only perhaps 30 to 50 per cent, of the ore broken down in 

 the stopes. This is more especially the case in the mines situated in 

 the northern part of the field (Coromandel, Balaghat, Road Block, 

 Nine Reefs). 



Min. Mag., Vol. XI, pp. 61—63 (1895)- 



