52 



MARBLE SPRING MINE. 



This mine is situated on a "branch of the North Fork of the Merced River, in 

 Mariposa County, and the highly metalliferous character of the quartz and the 

 uniformity of its yield in gold renders it one of the most interesting of the quartz 

 mines of California. 



The ore is a grayish blue quartz, very hard and solid, containing large quanti 

 ties of sulphurets of iron, zinc and lead, the latter predominating. From ten to 

 twenty per cent, of the ore consists of sulphurets. The gold yielded is of a low 

 degree of fineness, not averaging over 790-1000, and giving so great a proportion 

 of silver, that taken in connection with the argentiferous galena produced and the 

 general appearance of the ore, it is not unlikely that the mine may, when more 

 extensively and deeply worked, prove to be a silver mine ; it now bears all the 

 appearance of what the Mexicans call oroche. 



Thie mine was discovered and located in the summer or fall of 1851, by Silcott, 

 Bunyon, McPhane, Harvey, Humphries and Davenport, and by them sold to the 

 Empire State Quartz Mining Company. New claims have been located in con 

 tinuation of the same vein by the present proprietors, and it is now claimed by 

 them to the extent of about 1,760 yards. 



The general course of the vein is nearly north and south, passing along the 

 back of a ridge of high hills, along whose base, Upon one side, flows the Marble 

 Spring Creek, and upon the other, the North Fork of the Merced. 



The vein lies between trap rock upon the upper side and slate on the lower, 

 and all the ore is obtained by blasting. It stands at an angle of about fifty 

 degrees, and . has kept an average width of two to three feet, and increasing in 

 bieadth downward. 



The advantageous position of the vein has rendered it unnecessary to sink 

 shafts. Four tunnels have been run in, each twenty to twenty-five feet perpen 

 dicular hight the one above the other, and starting at the base of the hill and 

 continuing upon and in the direction of the vein, northerly. Their respective 

 lengths, commencing at the lowermost, are three hundred and fifty, two hundred 

 and fifty, two hundred and one hundred feet. They have been opened up, one 

 into the other, and the trap rock taken from above the vein has been used to stow 

 away in the place of the quartz taken out, leaving the tunnels about six feet high 

 and five feet wide, for the conveyance of the ore from the drifts. The ore is con 

 veyed in cars upon train ways from each tunnel direct to the mill, which stands 

 within one hundred yards of the mouth of the openings. 



The total amount of ore taken out, to the commencement of the present work 

 ing season, has been 1,300 tuns,, the whole of which has been reduced without 

 selection, and has yielded $56,197 in gold, being an average of forty-three dollars 

 per tun of 2,000 pounds. 



The ore is delivered in the mill at a cost of about five to six dollars per tun. 

 The works at the mines, in addition to the necessary out-buildings, smith-shops, 

 etc., at this time consists of a steam mill, having an engine of fifteen-horse power, 

 running ten stamps of five hundred and thirty pounds each, and capable of reduc 

 ing to a fine powder ten to fifteen tuns of crude ore per day of twenty hours. 



The process of collecting the gold consists of blankets, Goddard's Amalgamat 

 ing Tubs, and lastly, a newly 'invented riffle box. 



The fuel used is pine wood, of which great abundance is found in the imme 

 diate vicinity, and is deliveied at the mill for four to five dollars per cord. 



The number of hands required and the wages paid are as follows : 



