BATTLE MOUNTAIN MINES, WEST GROUP, AND OUTLYING PROSPECTS. 469 
FORM AND STRUCTURE OF THE ORE BODIES. 
All of the Strong ore occurs in the form of lodes or veins and most of it within 
two pay shoots in the main Strong lode. One of these pay shoots near the shaft 
is known as the south shoot and is separated from the north shoot on all levels 
by a greater or less interval of barren ground. 
The south pay shoot has been stoped almost from the surface to level 9. It 
attains its maximum length (about 550 feet) on level 3. On all levels above the 
eighth this ore body extends both north and south of the shaft, lying chiefly, 
however, on the north side. Practically no ore has been found south of the shaft 
on levels S and 9. As no stope maps are kept, the shape of this pay shoot can only 
be surmised from what is visible in the drifts. It appears to be on the whole nearly 
vertical, tapering irregularly almost to a point on level 9. It is essentially a min¬ 
eralized sheeted zone in granite. On level 1, however, the main phonolite dike 
forms the east wall of the lode. On level 5 the lode and the basic dike are coin¬ 
cident for nearly 300 feet. The ore, however, occurs entirely within the granite, 
alongside the dike, the latter being waste. On levels 6, 7, and 8 neither phonolite 
nor “ basalt ” occurs with the ore. 
As no work was being done on the south pay shoot at the time of visit the mode 
of occurrence of this ore could not be satisfactorily studied. The pay shoot is 
said to have been rather narrow, but richer on the whole than the north shoot. 
There were no definite walls to the ore, which passed through low-grade ore into 
the granitic country rock. The lode appears to have been intermediate in character 
between those like the Dorothy of the Gold Coin mine, where the value is practically 
confined to the actual fissures, and those like the Diamond of the Portland mine, 
where the metasomatically altered granite between the fissures is also ore. 
The north pay shoot apparently first becomes of importance near level 4, though 
a small chimney-like body of ore is said to have extended from the south end of 
the pay shoot up to level 2. On levels 5 and 6 the north pay shoot is respectively 
200 and 400 feet long and is typically developed. The main phonolite dike, about 
7 feet wide, is here closely followed by the basic dike. The latter lies usually on 
the west side of the phonolite, sometimes in contact, but frequently separated by 
a few feet of granite. At one place on level 6 the “basalt” cuts across to the east 
side of the phonolite, follows the east contact for about 125 feet, and then again 
crosses the phonolite to the west side. The ore closely follows the “basalt,” which, 
however, is itself of no value. The phonolite dike also appears to have influenced 
in some way the ore deposition, for it is noticeable that the ore very rarely accom¬ 
panies the basic dike when it diverges for any considerable distance from the phono¬ 
lite. The ore occurs almost wholly in the granite. Where the two dikes are in 
contact, side by side, the “basalt” constitutes a definite wall, limiting on one side 
ore which on the other sides grades indefinitely into the granite. Where the two 
dikes are not in contact, the intervening slab of granite is usually mineralized and 
constitutes ore. Such ore has two definite walls—the phonolite dike on the one 
side and the basic dike on the other. The latter dike at such places thus has ore 
on both sides. The cases where the phonolite is sufficiently mineralized to be ore 
