NORTH IRON HILL. 405 



MINE WORKINGS. 



The underground workings of this portion of Iron Hill are almost 

 exclusively confined to the Argentine and Adelaide mines. 



Argentine. — The Argentine mine is opened by the Camp Bird and Argen- 

 tine tunnels and the Loker and Hjnies shafts. The old Avorkings on the 

 Camp Bird claim are now mostly abandoned. The ore was found quite 

 near the surface, resting on the Parting Quartzite, which is here 30 feet 

 thick and contains, no White Porphyry, as it does in the Argentine. This 

 contact does not seem to have been followed in depth. Indeed, the geo- 

 logical relations of the ore bodies were so little understood in early times 

 that no systematic exploration could be carried on. 



In the Pine claim the main ore body was also found near the surface 

 and above the level of the Argentine tunnel. It was afterwards traced down 

 along the dip southward to a level 80 feet below the Argentine tunnel, 

 then southeastward into the Adelaide claim, following nearly the line of the 

 strike, but rising a little — that is, diverging to the eastward. 



Argentine tunnel. — Ore is extracted through the Argentine . tunnel, the 

 Loker shaft being used simply for ventilation purposes This tunnel is 

 over twelve hundred feet long-, running- first a little east of south and then 

 bending to the west of south. It crosses the Adelaide claim, on agreement 

 with that company, in order to explore the ground beyond. The geological 

 structure, as exposed by this tunnel, was for a long time a complete puzzle 

 to those who were working the mine, owing to the difficulty of distinguishing 

 the difierent rocks from one other when bleached and altered. Even now 

 a chemical test is often necessary. After passing through surface Wash the 

 tunnel crosses the upper part of a body of White Porphyry into White 

 Limestone. About seventy-five feet from the mouth a small gash vein in 

 the porphyry, carrying galena, is said to have been found, upon which a 

 winze was sunk. In the White Limestone a narrow sheet of bluish-gray 

 porphyr)^ is found before the tunnel enters the main body of Gray Por- 

 phyry, Avhich at the contact is quite bleached by decomposition. Some 

 iron-stained vein material is also found on the contact. Beyond, the tunnel 

 again passes through White Limestone for L50 feet, another small sheet of 

 porphyiy being cut about midway in this distance. Parting Quartzite and 



