HYDRAULIC MINING IN CALIFORNIA.

Tuapeka Times, Volume II, Issue 70, 12 June 1869, Page 5

HYDRAULIC MINING IN CALIFORNIA.

, An- interesting account is given man ettraet from " GPhe Resources of California, by JohnS. Hjttdl," of the manner in which sluicing operations are carried on ia- California, and the following remarks by Mr. William P. Blake, quoted by Sir Wilfiam E. Logan, L.L.D., P.E.S., F.Gr.S., jn his progress report on the geological survey of . Canana, will furnish dsba-fifoin- which conclusions may be diawn as to the probable value of oar abandoned workings. Speaking of " Hydraulic Mining " in California, he says :—: —

In this method the force of a jet of water, with great pressure, is made available, both for excavating and washing the auiiferoys earth. The water issuing in a confcijHi'ous stream, -with great force, frpm a large hosepipe like that of a fire-engine, is directed against "the base of a bank of earth and gravel, arfu teats" it away. The bank is rapidly undermined, the gravel is loosened, violently rolled together, and cleanse^ from any adhering particles of gold, *vhile the fine clay and sand are cai*ricd off by the water. In this manner hundreds of tons of earth and gravef" may be moved, and all' the gold which they contain liberated and secured with greater ease and expedition than' ten tons could be excavated and washed in the old way. All the and gravel of a deposit is moved^jvftshed, and carried off through long slujCKkbjLtbe water, leaving the gold behin«Lj|ihnare acre? of earth on the hij|P^es^maytirus be swept away intc^^e^^ 0^ without the aid J "trf^a J picK s '.or shovel in excavation. Water performs all the labour, moving and wasting the earth in one operation ; while in excavating by the hand, the two processes are of necessity entirely distinct. The value of this method, and the yield of gold by it, as comparecfcijAvith the older oite, can hardly be The water acts constantly, uniform effect, and can be brought to bear upon' almost any point, where it would be difficult for men to work. It is especially effective in a region covered with trees, where the tangled roots would greatly retard the labour of workmen. In such place the stream of water washes out the earth from below, and tree after tree falls before the current, any gold which may have adhered to the roots being washed away. With a pressure of sixty f^et, and a pipe of from one and a hs:lf to two inches aperture, over 1000 bushels of earth can be washed out from a bank in a day. Earth which contains only one twenty-fifth part of a grain of gold, equal to one-fifth of a cent, (halfpenny) in value to the bushel, may be profitably washed by this method ; and any earth or gravel which will pay the expense of washing in the old way, gives enormous profits by the new process. To wash successfully in this way requires a plentiful supply of water at an elevation of from fifty to ninety feet above the bed rock, and a rapid slope tfr descent from the base of the bank of earth to be washed, so that the waste water will run off through the sluices, bearing with it gravel, sand, and the suspended clay. In the case of a deposit in North Carolina, where ten men were required for thirty-five days to dig the earth with pick and shovel, and wash it in sluices, iwo men, with a ' single jet of water, would accomplish the same in a week. The great economy of this method is manifest from the fact that many old deposits in the river beds, the gravel of which had been already washed by hand, have been again washed with profit by the hydraulic method. .

A Eepob^eb's Stratagem. — An exchange paper relates that during the war a certain document of great.importance was submitted to the Grovernment printer with strict orders to allow no person to communicate its contents to any of the public newspapers,, and every compositor was searched before leaving the composingr,oom to see he did not conceal any proof sheets about .his person. Journalistic ingenuity was put to the test, but it proved equal to the occasion. A correspondent bribed one of the typos to wpar a pair of white overalls, to watch his chance, and when he got a opportunity, to ink the £ ti&pe,' and then seat himself upon it. '£Fhis done, he" left the office for a few f&inutes, and appeared in- an alley near bv^ Inhere a' faithful scribe was in "readiness to copy the w.ords printed «s.oji &&jessJjof the white, breeches, and lo^iid them instantly to New York jbV'Telegritph.-iAinericari paper.