CraneE.| Prospecting, Mining and Milling Machinery. 301 
TOP 
SECTION 
Fig. 74. Pointed box hydraulic classi- 
fier — vertical section. 
Fig. 73. Pointed box hydraulic 
classifier — plan. 
FEEDING APPARATUS. 
In connection with all concentrating works are to be found 
various forms of devices employed in feeding, either auto- 
matically or otherwise, the various machines. These feeders 
are intended primarily to regulate the amount of material 
fed, as well as to maintain aconstant supply. Usually, how- 
ever, the regulation of the feed is conducted at the reduction 
end of the system, and, when the ore is fed by hand, this can 
be done with comparative ease, especially if there is a large 
amount of material on hand, so that the feeders do not have 
to wait. In this district, as the feeding is done entirely by 
hand, no forms of feeding devices are employed within the 
main concentrating works. With the introduction, however, 
of slime-washing machinery there has been a demand for 
some form of feeding appliance which would save the hand- 
ling of a large amount of waste material. This is especially 
the case with the slime-treating apparatus, which are located 
in separate mills and treat almost entirely the waste product, 
such as tailings and refuse sand, etc., from other mills. A 
form of automatic feed was employed at a slime-treating plant 
in which Wilfley tables were the special form of apparatus 
employed in the concentration. 
A side view of the automatic feed employed in this mill is 
shown in plate XXXVII, and was operated as follows: A 
long rectangular bin with a sloping bottom was constructed 
with the feed end facing the mill. An elevated road was built 
