ADIRONDACK MAGNETIC IRON ORES 135 



have been put down somewhere in the vicinity of the pit, though 

 their exact location is not now known. 



Within the limits of the exposures the ore exhibits much uni- 

 formity. This feature is naturally of prime importance to the 

 economic working of a low grade body such as the present one. 

 Occasional stringers of pegmatite and a fine reddish granite are 

 encountered which carry little magnetite, but they have not proved 

 a serious obstacle to exploitation. In the previous working, the 

 deposit was quarried without leaving any waste and the entire 

 output was sent to the mill. 



The deposit has apparently undergone little disturbance in the 

 way of faulting. A slip seems to have taken place near the hanging 

 wall at the pit entrance parallel to the strike of the ore body, but 

 it is probably slight, as there is ore showing on both sides with no 

 marked brecciation. A thin dike has been intruded along the 

 fault fissure. The ore next to the fault has been partially altered 

 to martite. 



Character of the ore. The minerals accompanying the magnetite 

 are quartz, feldspar, garnet, biotite, pyrite and apatite. Quartz 

 and feldspar constitute the matrix for the most part, while the 

 magnetite functions as a binding material. The feldspar is mainly 

 the orthoclase variety. The pyrite and garnet are intimately 

 associated with the magnetite, the former occurring as small 

 included grains and the latter as rims on the borders of the magne- 

 tite particles. From the manner in which the magnetite and pyrite 

 are intergrown, it is evident that they have been deposited at the 

 same time. The garnet, however, is a later crystallization formed 

 by a reaction between the magnetite and the feldspar in which the 

 chemical constituents of both have been combined. It is a red 

 garnet and responds strongly to tests for manganese. As a rule 

 the ore is rather fine grained, though coarser in this respect than 

 the country gneiss. Like the latter it shows a gneissoid texture. 

 Occasionally the magnetite is segregated in thin bands interleaved 

 with the silicates. 



The following analyses give details as to the chemical composition 

 of the ore. No. i is the result obtained from a sample of the ore 

 exposed in the present workings, the sample being made up of 

 numerous specimens selected so as to give an average for the entire 

 face of the quarry. The sample was gathered and analyzed by 

 E. Touceda. No. 2 represents a sample of concentrates, an average 

 of 132 cars; and No. 3 a sample of concentrates recently taken 

 from a small lot in the storage bin at the mines. 



