35 



MEDIAN MINE, HERBERTVILLE, AMADOR COUNTY. 



This mine was located in 1852, under the name of Lea & Johnson, and during 

 1853 a small amount of work was 4one upon it. In 1854 it passed into the 

 hands of the present parties, holding it by purchase. The latter part of the year 

 was spent in exploring the mine and the extraction of ore preparatory to reduc 

 tion. During the past year the company have erected their reduction works and 

 other necessary buildings, at an expense of $10,000; the power employed being 

 water. During the past year the lower south level has been driven ninety feet 

 and a shaft sunk to the depth of seventeen fathoms. From the bottom of this 

 shaft, which is used for hoisting the ore from the mine by a horse whim, a level 

 has been driven fifty feet, and the distance between levels is sixty feet. 



At this mine the sulphuret of molybdenum occurs associated with lead, and 

 usually combined with the sulphuret of iron containing the gold. 



The characters of the ores have changed materially at the depth of seventeen 

 fathoms. From the surface down to the depth of twelve fathoms the pyritous 

 minerals were much decomposed, and at times a considerable amount of red 

 oxide of iron impregnated the ore. At the present time the ores comport in 

 their dark blue color with those of the surrounding district, being highly charged 

 with pyrites which develops gold after calcination. 



The shafts and levels on the east side of the hill are not used at present on 

 account of their distance from the reduction works, as a greater amount of 

 mineral is obtainable from the workings in close proximity to the mill, the power 

 of which latter is used to raise the ores from the mine, and a heavy item of 

 expense is thus saved in teaming. 



The failure of water to supply power during the past summer, prevented the 

 reduction of ores beyond the period of four months, which constituted the entire 

 running of the mill for 1855; but this failure will probably be obviated the 

 coming year by the introduction of a greater amount of water from other sources. 



The walls of the lode are of graphic slate on one side and an impure serpentine 

 rock on the other; this latter is highly pyritous, and in the adjoining Herbertville 

 Mine has proved highly auriferous. An examination of this rock will be found in 

 the table of analysis and assay. 



No statistics can be given of receipts and expenses, from the short period that 

 the mine was reducing ore. 



RECAPITULATION OF WORKINGS. 



Feet. 



1 adit 60 



1 level 90 



1 50 



2 levels, 1854 '. 30 * 



Whole amount levels and adit 230 



Fathoms. 



1 shaft 8 



1 17 



Whole amount shafts 25 



Strike, north and south; dip, east 70. Power, 9 feet. 



