18 Scientific Proceedings, Royal Dublin Society. 
consist of two independent reef series ; however, shaft-sinking has 
proved it to be a case of overthrust faulting. Similar faulting may 
also be encountered at the Robinson and the Langlaagte Royal, 
establishing the same deduction. I could multiply instances, all 
pointing to the same conclusion. 
Treatment of the Ore-—The ore having been brought to the 
surface in the “ skip”’ is sent to the sorting machinery. Circular 
sorting tables are mostly in use. Kafirs stand around these tables 
and reject all country rock, quartzite, &c. The reef matter is 
thrown into the crushing machinery, which reduces the ore to 
fragments representing about 2-inch cubes. 
This product is carried forward in trucks driven by wire- 
haulage to the “ stamp-battery,” where it undergoes crushing to 
about “ four hundred mesh,” the standard of fineness of the mesh 
differing in many mines. 
The crushed material passes over copper plates amalgamated 
with mercury, which seizes the free gold. The residue (or 
‘“tailings”), which contains about 33 per cent. of the total gold, 
is then subjected to the cyanide treatment, by being pumped (or 
elevated by a wheel) into the Spitzlutzen or hydraulic classifiers, 
which separate the coarser sands and pyrites from the finer sands, 
or slimes, the latter flowing away into the slimes-dam, to undergo 
further operation, whilst the coarser sands are dealt with in the 
cyanide tanks, which consist of wooden structure, as in the older 
establishments, but which are being discarded by the more modern 
undertakings in favour of iron tanks. 
Tn these tanks the material is treated with cyanide of potassium 
solution for a few days, after which it is drawn off and passes 
through wooden boxes charged with zinc shavings, resulting in 
the precipitation of the gold in the form of fine black slime, which, 
having been dried and calcined, is smelted in graphite crucibles, 
yielding “cyanide gold,” containing an average of 750 “ fine,” in 
which form it is exported to the English refiners. 
In many mines electrical precipitation by the aid of lead plates 
is rapidly becoming availed of, which effects a saving of the 
cyanide. The gold is deposited on lead plates, which are after- 
wards subjected to cupellation. 
The Occurrence of Gold in the Transvaal and Swasieland.—In the 
first portion of this communication I dealt with the occurrence of 
