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The Britannia main shaft is located on the southern side of Barkly- 
street, overlooking the steep bank of Specimen Vale, a tributary creek of 
the Yarrowee. The shaft is sunk to a depth of 1,060 feet, with levels 
opened out west at 1,040 feet, 940 feet, 830 feet and 720 feet below the 
surface. These levels comprise the main workings at present open, but a 
short cross-cut was put out west at the 630-ft. level, while to the east old 
cross-cuts occur at the 560-ft., 500-ft. and 400-ft. levels. At the 720-ft. 
level, an east cross-cut had reached a point 100 feet east of the shaft 
twenty years ago and was then abandoned, but has recently been extended. 
To enable a correct idea to be formed of this mine or any other in 
Ballarat East, it is necessary that the structure of the held be grasped. 
As a result of the present survey, which has extended over several years, 
it has been found that the gold-held of Ballarat East consists of a series 
of slate and sandstone beds, probably of Ordovician age, acutely folded 
into a series of anticlines and synclines. Certain beds have been dis¬ 
tinguished by the miners on account of the richness of the quartz veins 
crossing them, such as the Duchess, Twelve-foot, Four-foot, Seven-foot. 
&c., among the slates, and the Big Sandstone, the Grit, the Grindstone, 
&c., among the sandstones. Mineralized seams on which exceptionally large 
pieces of gold have been found are known as indicators, of which there 
are several, as The Indicator, the Western Indicator, the Eastern 
Indicator, the Black Seam, the Pencil Mark, the Telegraph, &c. Along 
certain bedding planes occur faults or slips (slides); these are locally known 
as “ piths," and are utilized in identifying various slates. 
As the result of careful survey and inspection and examination of 
the whole of the available workings on the Ballarat East gold-field, I 
have found that the auriferous portion of the field is confined to eastern 
dipping beds. So far, the width of the proved auriferous country is 
about 350 feet; folds occur on both sides of this, but evidence is gradually 
accumulating which shows that these barren belts on either side of the 
auriferous belt are confined to the western dipping strata, and that after 
a repetition of the folding the strata dip east again, and the auriferous 
nature of the beds is again apparent. The result of this is that instead 
of the gold being limited to one belt of 350 feet in width, a similar belt 
may be expected to the east, probably at a slightly greater depth, while the 
western belt at about the same level will be found to traverse the whole 
length of the field. 
The quartz formations of Ballarat East may be classed under the 
following heads:— (a) those associated with the “ leather-jacket ” faults; 
(/;) those associated with the anticlines ; (c) those associated with vertical 
slides; and (d) irregular spurs and veins throughout the whole field. 
Of the quartz formations, those of type (a) are by far the largest, and, 
as they occur at intervals, may be dealt with first. The leather-jackets 
are large faults with a general north and south strike, and they hade 
westwards at about 45 0 . They occur throughout all the mines in Ballarat 
East, and have produced enormous bodies of profitable stone. In width 
the stone on the footwall varies from a few inches up to 40 feet and more, 
with large veins going out into the adjacent strata. The leather-jackets 
occur about 300 feet apart, and I have found that at the depth where one 
leather-jacket is just entering the barren beds another will be found 
entering the favorable zone. With a shaft in a well selected site this means 
that a constant supply of stone can be maintained from close to the shaft, 
while the leather-jackets in the barren country have dipped away from the 
shaft. 
