21 
appearance as regards being auriferous. Glacial conglomerate forms a 
considerable area of the floor on which the auriferous gravels rest, and 
as the top portion decays into a tough clay, the gold is arrested, and it 
forms a good bottom. But the glacial conglomerate is non-auriferous, 
and, therefore, does not contribute gold to the gravels. The Ordovician 
rocks do contribute gold to the gravels, and already the drives put through 
the sandstones and slates have cut veins of auriferous quartz, so the Hon. 
Drysdale Brown, M.P., informs me. 
It is noticeable that the timber in the glacial conglomerate which is 
impervious to water, decays 'more rapidly than the timber used in the 
Ordovician rocks through which water percolates freely. Much of the 
timber is thickly covered with fungoid growth, although it has only been 
a short time in the mine, and the question arises whether , by spraying 
with , perhaps , an arsenical solution , the fungoid growth could be arrested. 
In May, 1902, when the present company took charge of these mines, 
the pressure of the water in the main drives was 98 lbs. per square inch. 
By continuous pumping, this has been reduced to 10 lbs. per square inch. 
An intermediate level is now being driven along the reef level at the 
Charlotte Plains mine, so that at an early date a drive may be run out 
into the wash-dirt itself. 
Valuable data respecting the curves that form the water level from the 
pumping stations should be secured from the records being made at the 
above mines. These curves represent the resistance offered by the 
material through which the water flows in seeking the lowest level, and, of 
course, they will be affected differentlv, according to the material to be 
traversed. 
In magnitude, the present operations eclipse all, previous deep alluvial 
mining in the State, and the result of these operations must exercise a 
potent influence on the gold mining industry in the near future. If suc¬ 
cessful, a great expansion of deep alluvial gold mining will take place, 
and there will be room for the employment of thousands of miners. 
As a great deal of driving would take place in the slate and sandstone 
beds, auriferous reefs would no doubt be discovered, as was the case in 
the Sebastopol and other alluvial mines. 
When the water has been lowered sufficiently at Charlotte Plains to 
allow of the removal of the wash-dirt, a considerable length of drives 
through the drift will be necessary before the average value of it can be 
determined, owing to the sorting process that goes on during the deposition 
of gravel in a stream bed. 
Where a stream takes a bend, the gold and heavier materials are 
deposited on the inner side of the bend at A, thus— 
The reason is that there is considerable scouring on the outer side of 
the curve, as the velocity is greatest there. On the inner side, the water 
flows with less velocity, and in some cases forms dead water; in such 
places heavy material is deposited. 
The above diagram shows the position (A) in which gold is deposited 
along the banks of a stream. In the case of these deep leads, the whole 
