75 



greatly in different parts of the same deposit, the general 

 average approximating 4 per cent. The gold and silver 

 are negligible in some of the ore bodies and important 

 in others. Besides the copper minerals, serpentine, 

 calcite, clinochlore, and other secondary minerals, as well, 

 rarely, as pyrrhotite and sphalerite, occur associated 

 with the magnetite. 



Hematite masses are much less common than those 

 of magnetite. The Pueblo deposit is the only large body 

 known, and is over 300 feet (91 m.) long and 170 feet 

 (52 m.) wide near the centre. This differs from the 

 magnetite ore bodies principally in the greater oxidation 

 of the copper minerals. Some chalcopyrite survives in 

 portions of the deposit, but no bornite in known to have 

 been found. 



Deposits characterized by a garnet-augite-tremolite 

 gangue are numerous wherever the lime-granite contact 

 is exposed. They vary from low grade deposits containing 

 only a sprinkling of copper minerals to considerable lenses 

 of shipping ore, such as those developed on the Grafter, 

 Copper King, War Eagle, and Valerie. All the important 

 ore bodies of this class, so far discovered, occur in the 

 limestone close to the granite, and are often separated 

 from the granite by a zone of more or less completely 

 replaced limestone. The valuable minerals are similar 

 to those in the iron masses, and consist mainly of bornite 

 and chalcopyrite. At the Valerie, bornite is absent, and 

 the chalcopyrite is associated with mispickel, the only 

 known occurrence of this mineral in the camp. The 

 siliceous ores contain, as a rule, a higher copper percentage 

 than the iron ores: those shipped up to the present time 

 probably average over 8 per cent. The precious metal con- 

 tents are moderate, seldom exceeding $3 per ton (-907 

 tonne). 



The development work on the different properties 

 has been practically all performed at or near the surface, 

 little work having been performed at a depth exceeding 

 100 feet (30m.) With the exception of the Pueblo, the 

 development work other than surface cuts, pits, etc., 

 has been performed by ordinary shafts, tunnels, drifts, 

 etc. On the Pueblo, two shafts have been sunk, but the 

 bulk of the ore has been obtained from the surface by the 

 open-cut or "glory-hole" method, much resembling quarry- 

 ing. During the summer of 1912, previous to September 

 1st, over 22,000 tons (19,958 tonnes) of ore had been 



