. The prospector's field-book and guide in the search for and the easy determination of ores and other useful minerals. it. The remaining sponge-like massof amalgam must be retorted to extract the gold. Washing the dirt is also affected by sluices havingan inclination of about 8 feet in 12 feet. Thesesluices consist of a series of troughs formed byplanks nailed together, the length of each beingabout 10 or 12 feet, the height 8 inches to 2 feet,the width 1 to 4 feet. By making one end. of thebottom plank of each trough 4 inches narrowerthan at the other, the troughs can be telescoped intoone a
. The prospector's field-book and guide in the search for and the easy determination of ores and other useful minerals. it. The remaining sponge-like massof amalgam must be retorted to extract the gold. Washing the dirt is also affected by sluices havingan inclination of about 8 feet in 12 feet. Thesesluices consist of a series of troughs formed byplanks nailed together, the length of each beingabout 10 or 12 feet, the height 8 inches to 2 feet,the width 1 to 4 feet. By making one end. of thebottom plank of each trough 4 inches narrowerthan at the other, the troughs can be telescoped intoone another and so a sluice of very great length can GOLD. 115 be formed. Across the inside of the bottom-planks,small, narrow strips of wood 2 inches or so thick,and 3 or more inches wide, are fixed across, or some-times at angles of 45° to the side of the trough,at short intervals apart. Running water washesdownward the earth thrown into the sluice, whichis open on the top side, and the gold dust accumu-lates, sometimes assisted by the aid of mercuryallowed to trickle out of a vessel from riffle to riffle, Fig. in front of the bars, while the lighter matter iswashed downwards. A still more effective method is what is calledhydraulic mining, and under favorable circum-stances, such as a plentiful supply of water withgood fall and extensive loose auriferous deposits, avery small amount of gold to the ton can be madeto give paying returns. The water is conducted influmes or pipes to a point near where it is required,thence in wrought-iron pipes gradually reduced in 116 prospectors field-book and guide. size and ending in a great nozzle somewhat likethat of a firemans hose. Figs. 43 and 44 show thearrangement. Fig. 43 exhibits the mouth-piecemovable at A B in an ascending, and at C D in aninclined, direction. E is a lever loaded with
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectprospec, bookyear1903
