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LAFAYETTE AND HELVETIA MINE. 







This mine is located in Grass Valley, and the diagram of their workings is taken 

 from the lode on Lafayette Hill, one and a half miles southwest of the town. In 

 this mine is found a heavy east and west vein, having a dip of about thirty-eight 

 degrees, witli a power of four feet at eight fathoms. The lodes of this hill have 

 been fairly opened, and thus far present a somewhat envious feature to neighbors. 

 The present depth of the workings are about eleven fathoms at the deepest point, 

 the lode in the greenstone, with the above power and a tendency to advance from 

 the latter. The underlie of the vein for about one hundred feet and immediately 

 adjoining the walls, is a bed of hydrosilicate of magnesia of an extremely fine tex 

 ture, containing gold. And the adit level of the mine, exclusive of the team-road 

 for conveying the cattle to the mine-yard, is in its total length 1200 feet. Not in 

 creased from last year, it will be seen, in consequence of the change in the 

 course in which they have been driving daring the past year on the east 

 and west lode. The working on the latter is near one hundred and forty feet, 

 and thus far proved a fine quality of ore 



During the past season the company have erected a new mill directly upon the 

 last lode. This is a most judicious movement on their part, as it will be the ' 

 means of saving the neat sum of eleven thousand dollars each year which has 

 been heretofore paid out for teaming. The arsenical ores do not increase much 

 from last year, and the sulphuret of iron containing and investing the metal, is 

 more abundant than formerly. The reduction works are carried by a twenty-five 

 horse-engine, with a double battery of nine stamps each, and when in full opera 

 tion is capable of reducing about thirty tons of ore per day. This mine employs 

 twelve miners on the lode, day and night, while the aggregate of the other labor 

 ers amounts to twelve more ; making a total of twenty -four. 



The use of Cram's cylinder and Berdan's amalgamating apparatus, have been 

 thrown aside as of little use, and inferior to the more simple and far less expen 

 sive methods that have been suggested from practical experience in this district. 



OSBORN HILL MINE. 



This mine is located two miles east of Grass Valley, on the above hill, and the 

 Lawrence Hill adjacent. Vein has a strike north and south, with an easterly dip 

 of forty degrees. The workings of 1853 have been abandoned for the purpose of 

 attacking the lode at a lower point, some six hundred feet to the north of the 

 latter, and thus drain the southern part of the lode. This has been accomplished 

 by the sinking of their water-shaft to the depth of one hundred and sixteen feet, 

 and which is fifty-one feet deeper than their former shafts of the old workings, 

 and cuts the lode about 80 feet below the greatest depth reached at any former 

 period. The amount of levels driven on Osborn Hill, and principally south of 

 the deep shaft, exclusive of the extreme south workings, is four hundred and fifty 

 feet, and upon Lawrence Hill three hundred feet ; making a total of seven hun 

 dred and fifty feet thus exposing a heavy bed of good ore. The amount of 

 shafting on both hills is near that of the levels ; the mine is thus well ventilated. 

 The power of the vein is three and one half feet, at the depth of twenty feet into 

 the solid greenstone. Arsenical pyrites are plentiful among the ores of this mine. 

 The full complement of laborers at this mine engaged in the lode, is thirty-two. 



