702 IDAHO MINING DISTRICTS. 



to shot size, and in some of the very rich pockets the oxidation of the pyrites has 

 left a semicrystalline form. It is worth $15 per ounce from the retort, the alloy 

 being silver. The associated sulphides are iron pyrites and galena, and a little 

 zinc blende appearing on the surface as iron oxides and cerussite. From the 

 pure galena silver values as high as 160 ounces per ton have been obtained, one 

 assay showing 0.7 ounce of gold and 44 ounces of silver. The pyrites contain as 

 high as 21 ounces of gold per ton. An assay of clean zincblende contained 1.4 

 ounces of gold per ton. The pyrites constitute from 3 to 10 per cent of the ore 

 as broken; the galena less than 1 per cent. From 40 to 65 per cent of the gold 

 is saved by amalgamation. The values of the milled ore range from $10 to $120 

 in gold per ton, the larger part being between $10 and $35. Concentrates carry 

 about 2.5 to 4 ounces in gold and 5 to 6 ounces in silver per ton. 



The veins of the second class have less development', and with two or three 

 exceptions have produced but little ore. They occur nearly parallel to the fissures 

 at some distance on either side, and differ in having less dip, little or no complete 

 replacement of the country rock, and less regularity to the ore bodies. Generally 

 the values are high. Where they have been productive the veins occur along the 

 line of dike contacts, as at the High Five and Golden Star. The foot wall is here 

 a granitic porphyry and apparently lies parallel with the jointing or sheeting. 



The veins of the third class are the most prominent in the way of outcropping, 

 the hard white quartz having suffered but little from surface decomposition. 

 Occasionally the quartz is heavily stained by the iron oxides, and in places scat- 

 tering pyrites are found, but the values are low. In places along the sides of this 

 "bull quartz " have been found streaks of high-grade ore, but there has been no 

 development to determine whether the hard quartz caps softer ore, as it does in 

 other parts of the State. 



Several prospects are found northwest of Three Point Mountain, in Charcoal 

 Ravine. The main developments have been on the Jackson property a narrow 

 dike, 8 to 12 feet, of quartz-porphyry, with quartz veins on the joint and contact 

 surfaces. The quartz carries a coarse gold, and there is some impregnation of the 

 porphyry mass. 



In the central belt the principal vein is the Homestake-Hidden Treasure. On the 

 Homestake claim one shoot of ore, varying in length from 75 to 125 feet and in 

 width from 4 to 12 feet, has been mined through tunnels to a depth of 350 feet. 

 To the west the vein is cut by a fault, striking N. 19 W. and dipping 60 E. 

 Beyond this fault the vein was recently found again, thrown 100 feet to the south. 

 Four hundred feet to the east, in which distance another shoot is opened, a section 

 of the vein is faulted 200 feet to the north. This faulted section is another ore 

 shoot, and is about 250 long. Beyond this, to the east, another shoot has been 

 mined to a depth of 100 feet. The term "ore shoot" refers only to ores yielding 

 $10 per ton and over; if made to include ores from $5 per ton and up, the vein so 

 far as opened is practically one shoot. The greatest depth attained below the 

 surface is 350 feet. 



On the Hidden Treasure, the easterly extension of the Homestake, the vein has 

 been opened for 450 feet, to a depth of 165 feet, varying in width from 1 to 13 feet. 

 Several small displacements by north-south faults, between 4 and 12 feet, are 

 shown, and one with a displacement of 60 feet. The entire top of the vein has 

 been moved to the south on a fault plane dipping 6 or 8 to the northeast, between 

 60 and 100 feet. In one place this plane was filled with ore. About 90 per cent of 

 the production of the camp has been from these two properties. 



In the High Five and the Golden Star a vein has been opened, with the granitic 

 porphyry for a f oo twall. It apparently dips with the foliation. The high-grade 

 ores occur in lenticular masses of greater or less extent. The value or extent of 

 the rest of the vein material has not been determined. 



