MINES OF BATTLE MOUNTAIN, EAST GROUP. 
445 
first attained importance between the 220- and 350-foot levels, and have been very 
productive near the 350-foot level. Below the 600-foot level, while the Captain 
Assuring continues, the ore is of low grade, and on the 1,000-foot level such indistinct 
Assuring as persists is associated with but little more value than is found in the 
breccia country rock, most of which in this part of the mine affords assays up 
to S3 in gold per ton. The Xo. 1 Hidden Treasure vein, while recognized on the 
350-foot level, first becomes important between this level and the 500-foot, and 
has been stoped down to the 900-foot. The Xo. 2 Hidden Treasure has been 
productive from the 600-foot to the 800-foot level, while the Xo. 3 Hidden Treasure, 
first stoped above the 700-foot level, has maintained its importance to the bottom 
of the mine. 
Owing to the uncertainty attaching to the identification of individual members 
of these closely spaced Hidden Treasure and Captain groups on different levels, 
the foregoing statement as to the vertical distribution of the various pay' shoots 
may be modified in the course of future underground development. But enough 
is known to bring out the essential fact that the pay shoots in the various bodies 
do not as a rule possess great vertical persistency and may occur at all depths thus 
far explored. There are pay shoots known in depth which do not reach the surface 
and there are pay shoots known at the surface which do not extend to great depth. 
In the southern ore zone the Xo. 2 vein and its branches are the only lodes 
which are of much importance within the breccia. This lode is not definitely 
recognized on the 350-foot level, though a lode stoped above that level and called 
the Diamond vein is probably really the Xo. 2 vein, the Diamond vein proper 
apparently never having been recognized in the breccia above the 600-foot level. 
Between the 500- and 800-foot levels the ore bodies of the Xo. 2 vein have been 
stoped to a width of 40 and occasionally of 60 feet, up to the Stratton’s Independence 
line. The width of this ore is subject to sudden changes, a narrow sheeted zone 
of pay ore 4 to 5 feet wide expanding within a few feet to a width of 50 feet and 
again as abruptly contracting. The wider ore bodies occur near the 600- and 700-foot 
levels, the pay shoots being generally narrower on the lower levels. Toward the 
north the lode appears to split, the Rose and Scranton stopes on the 700-foot level 
being probably on branches of the main zone of Assuring, known as the Xo. 2 vein. 
Lodes formed by mineralization along fissure zones in granite are well exempli¬ 
fied by the Diamond vein and by portions of the Xo. 2 vein. In the granite the 
fissures which served as channels for ore deposition are less conspicuous than in the 
breccia. In the latter rock the valuable constituents of the ore are practically con¬ 
fined to the fissures themselves. Xot so in the granite. Here metasomatism has 
been more active and ore minerals, among which fluorite and pvrite are usually most 
conspicuous, occur distributed through the mass of the rock, in many instances for 
20 or 30 feet from the main fissure zone. As a result of this action, the ore bodies 
are usually of very irregular shape. As a rule there is little or no waste mixed with 
the ore, whereas in the breccia the rock between the joints or fissures is invariably 
worthless. At varying distances from the main fissure zone which was the deter¬ 
minative factor in the formation of the ore body the ore changes to unmineralized 
granite. In some cases the change is abrupt, in some gradual, but only under 
exceptional circumstances is there a distinct wall separating country rock and ore. 
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