90 



low grade. An average analysis of the ore from the large 

 producers gives — gold 0-5 oz. per ton, silver 0-3 oz. per 

 ton, copper 0-9 per cent, iron 22 per cent, silica 37 per 

 cent, sulphur 10 -8 per cent, lime 4-2 per cent, alumina 

 14-9 per cent. The ore from near the surface yielded the 

 higher values, but the proportion of free gold does not 

 appear to decrease with depth and high grade ore bodies 

 are still encountered at the lowest developed levels. 



Oxidation extends downwards only a few feet from the 

 surface. Secondary enrichment is a minor feature but is 

 found at several points well below the zone of weathering. 



Lodes. 



The chief lodes or veins have a general easterly 

 trend and northerly dip with an associated fault system 

 trending north and south. The LeRoi-Centre Star main 

 and south lodes and the Josie lode strike about N. 60° E. 

 The LeRoi north vein, the War Eagle vein, and the Centre 

 Star north veins strike N. 70° W., and appear to be ofif- 

 shoots of the main lodes. The dips are to the north ranging 

 from 60° to 70° with local flattenings. 



The main LeRoi-Centre Star lode is at least 4,000 feet 

 (1,219 rn.) long, with a thickness varying from a mere 

 crack to over 130 feet (39-5 m.) The maximum thickness 

 cannot in many instances be determined owing to the lack 

 of sharply defined walls. Between ore shoots it is some- 

 times very difficult to trace the lode, particularly where 

 the continuity is broken by faults and dykes. 



Ore Shoots. 



The ore shoots vary greatly in size and shape, len- 

 ticular bodies being the more common. Some are 

 very irregular at one termination especially when 

 forming against a dyke or fault. In such cases the shoot 

 either develops an enormously increased thickness or an 

 L-shaped body is formed by the ore turning sharply and 

 following the plane of the fault or dyke. The pitch varies 

 from vertical to a pronounced easterly or westerly direction 

 dependent upon purely local conditions. In size the shoots 

 vary from a foot (30 cm.) to 130 feet (39-5 m.) in thickness 

 and from 50 to 500 feet (15 to 152 m.) in length. One of 



