518 TH1-: 



The proximity of the lodes to the tin-lodes and their occur- 

 rence in the same rock, suggest some relationship. A complete 

 series of types of lodes has been made out, between the tin- 

 veins proper and the complex ore-bodies of the Borali Creek 

 Lodes. The ores contained in the mine are arsenopyrite, zinc- 

 blende, chalcopyrite, stannite, and galena. The ores are the same 

 ill both lodes, but rather more stannite is present in the Conrad 

 than in the King Conrad Lode. In the Conrad Lode the clay- 

 selvage is present, sometimes on one side, sometimes on the other, 

 and occasionally on both sides of the lode. This does not occur 

 in the King Conrad Lode. The ores are very uniformly dis- 

 tributed througli the mine, botli along the lode and in depth. 

 There is practically no oxidised zone and the sulphide ore out- 

 crops in the bed of Borah Greek, the direction of which has 

 been determined by the lode. There are two fairly well defined 

 shoots in the mine, a small one occurring in the King Conrad 

 Lode, and a larger one in the Conrad Lode. These are shown 

 by the shaded areas in text fig. 2. 



The order of deposition of the minerals, which form symmetri- 

 cal zones in the fissure, is arsenopyrite, stannite, pyrite, zinc- 

 blende, chalcopyrite, galena, and finally quartz. This normal 

 order is frequently disturbed by the reopening of the fissure, and 

 also by the rejuvenescence of the depositing solution. The 

 deposit is a very typical, banded fissure-lode, and very little 

 metasomatic replacement occurs, though it was carefully sought 

 for. The country-rock has been feebly altered for a few inches 

 from the lode, the replacing constituents being chiefly arseno- 

 pyrite and sericite. Two well-marked t-xamples of replacement 

 of the vein-material were observed. At A in text-fig.2, the 

 galena forming one of the zones in the lode has been replaced by 

 quartz, which has retained to perfection the cleavages of the 

 original mineral. This change has been effected by surface- 

 waters. At B, in the same figure, beautiful examples of i-eplace- 

 ment of quartz by zinc-blende are abundant. This change has 

 probably been effected by rejuvenated, ascending solutions. In 

 the bottom drive of the mine, at the spot marked D, warm 



