308 PROCEEDINGS ‘OF SECTION C. 
AN INTERESTING OCCURRENCE OF GOLD IN 
VICTORIA. 
By Henry C. Jenkins, A.R.S.M.,-Assoc. M.Inst., C.E. 
At Clombinane, about six miles from Wandong, on the 
Melbourne to Sydney Raiiway, there are two mines—the 
“Golden Dyke” and the “ Golden Dyke Extended ”—that 
present some features of interest, as bearing upon the general 
problems connected with the occurrence of gold in Victoria. 
The mines are both in a true dyke, cutting roughly east 
and west across Upper Silurian country. Its width is from 
50 up to 200 feet, and it belongs to the so-called intermediate 
class of rocks. The present workings. of the two mines 
cover about a quarter of a mile in length; along the dyke, 
and midway between them, there is a-gully that has been 
very rich in alluvial gold, just where it crosses the line of 
dyke, the gold being evidently derived from the denuded 
dyke-mass, which latter so readily decomposes and softens 
that, at the time of my first inspection, I could not obtain 
any satisfactory specimens for slicing; it is, indeed, only 
very recently that some have come to hand from the deeper 
workings—too late for full examination and analysis.* 
The general mass of the dyke is quite worthless as a gold 
ore, notwithstanding that it carries arsenical pyrites in its 
partings, but transversely across the dyke, and nearly at 
right angles from wall to wall, numerous groups of small 
cross-seams occur; these extend vertically or else are re 
placed by others, so that each level in the mine presents some- 
what similar features to those of its neighbour. The veins 
are found by driving levels along the line of the dyke, and 
they are stoped from crosscuts along them as they are found. 
The workings are now about 360 feet deep from the surface 
at their deepest part. 
The veins are filled in with quartz, limonite, stibnite, and 
derived oxide of antimony, and are rich in gold. They can 
be followed across the dyke up to the wall of the same, 
where they disappear rapidly, and within a foot or so of the 
contact-plane, just as though they only occupied fissures in 
the dyke-mass caused by a shrinkage of the same, such as 
would be produced by cooling. Some of the quartz is 
beautifully crystallised, and gold is found upon and in it; 
*The rock proves on examination to be an andesite almost 
rape composed of minute felspars, with phenocrysts, also of 
elspar. 
