108
GOLD MIXING IX GEORGIA.
in the riffles of the mine-sluices, the remainder being obtained in the mill.
HISTORICAL NOTES.
The Dahlonega method first originated in 1868 by sluicing the material from the mines to platforms near the mill, from where it was hauled to the mill in carts. This was improved by placing bins, with perforated bottoms, in the stamp-mills, from 4 to 5 feet above and back of the mortars; underneath this bin was a settling-box, in which the sandy material settled and the slimes overflowed. At the Child's mill, near Xacoochee, a plant was erected, consisting of a series of washing and sizing plate-screens, in which three sizes, coarse, medium and sand, were made and milled separately. It is stated that all the millable ore was saved in this way, in a clean shape, free from mud.
The present practice is to flush the material on to the mill floor back of the batteries, this space in the mill-house being practically arranged as a large bin with a slat screen (distance between slats about -J- inch) at one end. Frequently a Y-shaped storage-tank is situated outside of the mill, where the material is collected and flushed into the mill as occasion requires.
THE WATER-SUPPLY.
The system of reservoirs, ditches, etc., in this district is by far the most extensive and best equipped in the Southern gold-belt. The principal water-line is known as the Hand and Barlow ditch, having a total length of 31 miles, the main canal being 20 miles long, 6 feet wide and 3 feet deep, and furnishing 800 miners' inches. The grade averages 5 feet to the mile, being i^ feet on straight lengths, with slightly steeper grades on bends. The cost of digging this canal was about $1 per rod; the total cost, including trestling, etc. (excluding syphon-line I, was $1000 per mile. The canal crosses the Yahoola valley about 1 mile northeast of Dahlonega, in a wrought-iron syphon-tube (see Plate YIII) 2000 feet in length. The difference in level of the two end- is about G feet, and the pressure at the lowest point is 90 pounds per square inch. The inside diameter is 3 feet, the thickness of the pipe being T:^ inch in the upper and ยง inch in the lower part. It was built in IsGO.
Four miles from Dahlonega the water is carried across a similar depression in a wooden tube which is f- of a mile in length and 3 feet in outside diameter. It is made of 3 by 5-inch staves, trimmed so as to make a tight fit. These staves are laid in wrought-iron hoop-, funning alternate joints; the last stave is driven in with a maul. This tube was built in 1868, and is still in good condition.
Auxiliary ditches run off from the main canal to the various mines. A portion of this water was formerly leased out at the rate of 12 cents per miner's inch for 21 hours. The present owners, Hie Hand &
