ADIRONDACK MAGNETIC IRON ORES 53 



bottom on encountering a brecciated zone which probably marks 

 an extensive fault. A drill hole was put down to a depth of over 

 iooo feet but failed to find the continuation of the ore beyond the 

 fault line. 



The North pit is on the ridge above the Penfield. It* is partly 

 an open cut, with a chamber running off to the southeast on the 

 course of the shoot. A curious feature is the pods of ore along the 

 southern edge which were worked through short . inclines driven 

 from the main chamber. Apparently they are squeezed portions 

 of the larger body. 



The Blacksmith mine is based on a comparatively small deposit 

 which lies north of the eastern wing of the Penfield. The ore at the 

 outcrop is from three to five feet thick and dips 30 northeast. 



Exploration. The ore-bearing ground has been tested by the 

 diamond drill, principally with a view to locating the extensions 

 of the larger ore bodies. The drill holes have been mostly limited 

 to depths not exceeding 500 or 600 feet. In the area between the 

 West End and No. 5 workings, ore has been shown to exist in 

 what seems to be a flat sheet at a depth of from 460 to 500 feet, 

 and with a thickness of from 3 to 15 feet or slightly more. Its 

 relation to the contiguous deposits can only be conjectured, but 

 not improbably it represents an extension of the West End. 



So far as has been observed the drills have not encountered 

 any limit of the ore -bearing gneiss in depth. The cores show the 

 rock to be quite uniform in character, the only marked variation 

 being in the grain which at times becomes coarse owing to pegma- 

 titization. The occurrence of red spots and streaks on the other- 

 wise white core is considered a favorable indication of the prox- 

 imity of an ore body; they are due to hematite stain. 



Character of the ore. The Hammondville ore is compact, 

 granular, or more rarely, a platy magnetite. The richest variety 

 in which there is little admixture of foreign minerals is the so 

 called shot ore made up of loosely cemented grains. In average 

 material the iron content is about 50 per cent, the magnetite being 

 associated with quartz, feldspar and hornblende. White vein quartz 

 occurs quite abundantly in segregated masses and stringers. The 

 percentages of phosphorus and sulfur are low. Of the following 

 analyses, Nos. 1 and 2 have been taken from a paper on " The 

 American Iron Trade " by James M. Swank, published in Mineral 

 Resources for 1886. Nos. 3, 4 and 5 are from Maynard's paper 

 "The Iron Ores of Lake Champlain." No. 3 is the result from an 

 average sample from the Hammond mine; No. 4 from an average 



