269 
THE CORONATION GOLD MINING COMPANY (LATE TUBAL 
CAIN), WALHALLA. 
By W. Baragwanath. 
The workings of the Coronation Gold Mining Company, Walhalla, are 
situated in a large mass of igneous rock known as the Tubal Cain dyke, 
and located on the eastern side of the eastern branch of Stringer’s Creek, 
about 2 miles slightly 'to the east of north from the junction at 
Walhalla.* The chief feature of the Coronation mine workings is 
the occurrence of rich auriferous reefs associated with the so-called “ dyke ” 
outcrop. This “dyke” outcrop is all the more interesting on account 
of its almost circular shape and comparatively large extent, having a 
maximum length of 850 feet by an extreme width of 700 feet, and being 
but slightly indented at one extremity. The shape suggests a neck or plug 
rather than a “ bulge ” or sudden expansion of a continuous line of dyke, 
as in the Wood’s Point district;! no evidence of any such continuous dyke 
could be found. 
In texture the dyke varies considerably, probably through the differen¬ 
tiation of the magma during consolidation; portion of the dyke consists of 
coarsely crystalline rock of granitic appearance, while other portions 
are fine grained, dense, and apparently non-crystalline. The dyke 
decomposes irregularly; in places in the upper or shallow-level 
workings it has decomposed till it is little more than a stiff clay with 
occasional nodules of undecomposed rock, while at other places hard rock 
shows over several feet on the surface. An examination of samples from 
the “ dyke ” is quoted in the above-mentioned report on Walhalla, page 57, 
from which it appears that the “ dyke ” may be classed as an augite- 
diorite. No evidence as to the geological age of the dyke is obtainable, 
except that it is undoubtedly post- Silurian, the surrounding strata through 
which it has broken being of Silurian age. For a distance of 20 to 30 
feet from the edge of the “ dyke,” the strata have been indurated. 
A number of roughly parallel fissures, all having a westerly dip, occur 
within the “ dyke.” These fissures have a general strike of about N. 
45 0 W., and a dip of 30 feet horizontal in 100 feet vertical. Faulting 
appears to have taken place along these fissures, the texture of the dyke 
on opposite sides often differing. Along these fissures the quartz reefs which 
have been worked occur. In the decomposed portions of the dyke the 
reefs are often irregular and spurry but have proved to be very rich in 
places, while in the less .decomposed dyke the nature of the reefs is more 
apparent. 
The character of the quartz is somewhat peculiar. In the decomposed 
dyke, the quartz varies but slightly in appearance, being commonly opaque 
and white, or iron-stained. In the harder portions of the dyke, however, 
the quartz is more vitreous, and ranges in colour from white to black; 
portions of the reef are made up of a semi-opaline mass; other portions 
are more or less ordinary quartz with included fragments of dyke, the edges 
of which often show a gradual transition into quartz, indicative of a 
metasomatic replacement. Much calcite, derived probably from the decom¬ 
position of the dyke constituents, occurs in the main reef channels or along 
* For a locality plan see Report on the Walhalla Gold-field, by H. Herman, Spec. Rept., Dept. 
Mines, Viet., 1901. 
t See The Wood’s Point Gold-field, by O. A. L. Whitelaw, Memoirs Geol. Surv. Viet,, No. 3,1905. 
B 2 
