CEI^TEAL AND EASTERN NEVADA. 299 



the shaft had passed through the lower limit of the ore-chimney. At the 

 point where the vein ceased to be ore-bearing in the shaft, a drift was subse- 

 quently run westward some 80 or 100 feet, which was reported as being in 

 good ore for the whole distance. 



The ore is of a peculiar character. It consists chiefly of the oxides 

 of lead and antimony, carrying a small percentage of silver, averaging, by 

 assay, about $80 per ton. The ore, as it now exists, is evidently the 

 result of decomposition or alteration of other and more familiar forms 

 of silver-bearing, antimonial ores. It is sometimes hard, massive, and com- 

 pact in character, while the larger proportion is friable, showing a fibrous 

 structure, apparently the form of its pre-existing condition. The harder 

 variety is usually next the hanging wall and needs blasting, while the other 

 kind, lying on the foot-wall, may be removed without the aid of powder. The 

 former is said to be the richer. An analysis of a piece of this ore, made by 

 Mr. William Gr. Mixter, assistant at the Sheffield Laboratory, Yale College, gave 

 the following results : 



Antimonic acid, SbOj • 51.94 



Oxide of lead, PbO 40.89 



Silver, Ag 33 



Sesquioxide of iron, Fe203 .60 



Insoluble residue 1.66 



Water : ■ 4.58 



100.00 



The above composition, together with the physical characteristics of the 

 ore, identify it with bindheimite, a mineral described by Dana, occurring 

 in Cornwall, Siberia, and other localities, and derived from the mineral 

 jamesonite by decomposition. A few fragments of undecomposed mineral, 

 strongly resembling jamesonite, were found by the writer in the ore at Oreana. 



Thus far the extraction of the ore has been a simple process of quarrying in 

 the open cut, and has been done very cheaply. It is said to cost not more than $2 

 or $2 50 per ton for extraction ; mining, and hauling to the furnace, costing, in the 



