Gcoiotjij of the Diamond Creek Area. 351 



the reefs are within the ilykc. When tlie reefs wander out intu 

 the slate or breccia, iiu nutieoable increase in values utxurs, an(.l, in 

 fact, lu sucli cases there seems to be ratiier a uecrease in values. 



The ett'ect of the " diagonal "^ veins. Bedded reefs are loniniun 

 at the mine, but their effect, if any, on the gold values is not rlear. 

 A very interesting case of local enrichment occurs in the oOU feet 

 level north near the intersection of the dyke, with the nearly verliial 

 shale reef before mentioned. Here a very rich pocket of gold oc- 

 curred in the very fractured dyke. This fracturing in parts ap- 

 pears to antedate the formation of the quartz veins, as no definite 

 reefs exist here, the dyke being simply veined by numerous very rich 

 stringers of quartz. Three possibilities exist for the localisation of 

 the gold at this point : — 



1. Action of the shale reef. 



2. Effect of pre-existing fractures. 



3. Secondary enrichment. 



The first effect may probably be omitted, for the same leason 

 that the effect of certain bands of tlie country is out of question. 



A section was made of the ore from here, and it was seen that the 

 gold and stibnite were intimately associated, although botii were 

 .secondary in relation to the quartz. The stibnite was seen to con- 

 sist of agg)'egates of needles, and not to be like the usual secondary 

 sulphides that occur in some mineral helds, such as Bi-oken Hill, 

 near the water level. Very little information could be gained 

 regarding the character and value of the ore above the -{OO feet 

 level at the mine, as tliis was worked in the early days of the fii-ld. 

 No great variation in values, as far as could be learned, oci-urred 

 in going down from the surface. The evidence appears insuthcient 

 to justify us drawing any extensive conclusions witli regard to 

 secondary enrirlnnent. The presence of senarniontite in the lower 

 levels does not necessarily mean that the zone of oxidation reached 

 that depth, but probably that sueh ore was near fractures <lo\vn 

 which surface waters percolated. Tlie evidence, sueh as it is. tnids 

 to support the view that secondary enrichment has occurred to a 

 limited extent. The great amount of strata removed since foldingv; 

 would tend to concentrate the gold, Mhile the dense character and 

 small size of the quartz reefs would exclude any large circulation 

 of solutions. Tn the neighbourhood of faults, enrichment has occa- 

 sionally been noted. In the Union mine, the gold-1)eai-ing stone was 

 mainly the footwall stone, ^ and the hanging Avail st(uie was hardly 



1 " DiajfOiial " is the miner's term for the slate \ oitis. 



2 JutBoi). c, p. h'i'K 



3 Oiinii. Op. cit. 



