FiNLAYSON. — Geology of the Reefton Gold-veins. 



95 



The vein lies in a zone of soft crushed slate, surrounded by harder sand- 

 stone. Down to No. 6 level it has a dip of 60° to the south ; below that 

 it flattens out, and from No. 8 to No. 11 level — a distance of 400 ft. vertical 

 — it made 1,500 ft. of base. It is worked by two shafts — one, the eastern, 



opens up 5 and 6 levels; 

 the other, the western, 

 opens up the deeper 

 levels. The shaft-head 

 is 1,600 ft. above sea- 

 level, and No. 11 is 

 1,460 ft. deep. 



Except in the harder 

 sandstone some dis- 

 tance from the reef, the 

 country is soft, and 

 stands badly. The es- 

 timated annual cost of 

 timber in this mine 

 during the last ten 

 years has been £3,000. 

 The walls are gene- 

 rally poorly defined, 

 and rarely do a foot 



Fig. 12. — Section of Workings, Globe-Pbogress. 



wall and hanging-wall occur together ; they are often obscured, while quartz 



merges gradually into slate. 



The quartz occurs in lenses of varying size and value, frequently much 

 disturbed by small faults. The following varieties of ore are met with : — 



(1.) Seamy : The most characteristic form. It is seamed with strings 

 of pyrite and mullock, and is nearly always gold-bearing. 



(2.) Brecciated : This is only occasionally found. 



(3.) White glassy or *' dog's-tooth " quartz : This varies in its gold- 

 content. In blocks of this quartz which have been regarded as poor or 

 barren, gold is frequently found in good payable patches. Miners claim 

 that it is possible to distinguish good and poor ore in this mine by means 

 of its appearance to the naked eye ; but this is very doubtful. Frequently 

 quartz set down as poor has been found to give good returns. 



The difference between the seamy and white glassy varieties seems 

 to be largely due to processes of replacement in the former case, and to 

 simple deposition without replacement in the latter. 



The quartz blocks are in the main low-grade throughout, and poorer in 

 the lower than in the upper levels. The gold is patchy in its distribution, 

 does not run in shoots, and is very fine. This vein carries the finest gold 

 on the field. It occurs both free and involved with pyrite, which is the 

 common sulphide. 



Stibnite occurs, frequently and patchy. In places it has been found 

 in seams up to 30 ft. thick, but of low-grade (30 per cent.) ore. In this 

 mine antimony-ore is found generally to accompany poor values in gold. 



The blocks or lenses of quartz follow in the main three roughly distinct 

 shoots, which all show a certain pitch to the south-west. They are all 

 fairly continuous, though with frequent pinches and makes. 



The main shoot has been worked right down to No. 11 level. Between' 

 8 and 11 it flattened considerably, as shown in figure, and in No. 11 it lies 

 practically horizontal. This is the most peculiar feature in this mine. 



