126 Journal of the Mitchell Society [. November 
somewhat upon exposure to the weather so that the recovery 
by cyanide was very good. 
The old cyanide plant had four iron tanks 5)4 feet deep and 
30 feet in diameter and supposedly the necessary other tanks 
and apparatus. When the tailings were exhausted the mine 
was sold to the Colossus Mining Company, a London corpor- 
ation, which proposed to put in an immense plant to treat 
the entire zone. This zone had previously been cross cut by 
two trenches somewhat over 20 feet deep, but it was never 
properly sampled, for although there are many fairly rich 
streaks, the general average value is only 40 to 50 cents a ton. 
The tanks of the old mill were made a part of the new big 
mill, so the original arrangement of this successful plant 
could not be learned and also no one could be found to give 
information about the successful treatment. There is now a 
Ledgerwood cableway for economical handling of excavated 
rock. This dumps the skips of rock upon the feeding plat- 
form of a very large gyratory crusher discharging into a 
trommel. The coarse rock from the trommel goes through a 
smaller gyratory crusher into the bin cotaining the finer rock. 
From this bin it is hoisted to a long, rotating cylinder dryer 
discharging to the first of a pair of Allis rolls working in 
series with necessary screens and elevators. The fine mate- 
rial from these rolls is divided among three ball mills of pecu- 
liar design. They have a vertical axis bearing arms which 
push a number of six inch iron balls around a horizontal run- 
way. 
There are at present no screens on these, and the product 
contains a good deal of troublesome dust or slimes, and some 
sand too coarse for successful cyaniding. From the ball 
mills a fine set of conveyors carry the dry material to any one 
of the leaching tanks. There are six tanks 5)4 feet deep and 
40 feet in diameter, and four tanks 5)4 feet deep by 30 feet in 
diameter, all in the open air; and the necessary solution, 
gold and slump tanks. The mill is very badly designed since 
the rolls have scarcely capacity for 75 tons per day and the 
ball mills were so overworked that much coarse sand passed 
