BATTLE MOUNTAIN MINES, WEST GROUP, AND OUTLYING PROSPECTS. 481 
On level 4, about 50 feet east of the Ajax shaft, is a north-south phonolite dike 
which forms practically the eastern boundary of a large ore body in granite. The 
same dike also forms the eastern boundary of another ore body lying under the one 
just referred to, or on level 5. 
FORM AM) STRUCTURE OF THE ORE BODIES. 
The greater part of the ore of the Ajax mine is in the granite, occurring, as a 
metasomatically altered and mineralized form of that rock, in large very irregular 
bodies between levels 3 and 8. One of these bodies, on level 4, lies about 100 feet 
northeast of the shaft and has been stoped from north to south for a length of about 
60 feet. Its width is about 30 feet. The ore lies mainly on the west side of a north- 
south phonolite dike and is practically bounded on the north by the granite-breccia 
contact. The altered, mineralized granite which constitutes the ore was irregu¬ 
larly fissured prior to mineralization, the dominant fissures running generally paral¬ 
lel with the phonolite dike. The ore body ends abruptly on the south, not against 
any discoverable fissure, but by a rather rapid change from mineralized to unaltered 
granite. A few irregular fissures continue southward from the ore body into this 
granite. This large ore body has been stoped upward for 50 feet or more, but does 
not appear at all on the level above. Neither does this ore body continue below 
level 4, though another similar body does occur on that level nearly under the stope 
just described. The two masses of ore are separated by barren granite. 
On level 5 the main ore body occurs a little farther west, the shaft penetrating 
its western part. The same phonolite dike noted above here also limits the ore on 
the east, while on all other sides the ore passes irregularly through mineralized 
granite into unaltered country rock. This ore body continues with a southwesterly 
pitch down to a point about half-way between levels 5 and 6, where the ore ends near 
the east side of the basic dike. A short distance west of this dike, however, a third 
ore body was found which on level 6 is rudely elliptical in plan, with its major diam¬ 
eter lying north-northeast and south-southwest. The length of this ore body on 
this level is about 150 feet, and its width about 25 feet. It pitches southwest and 
has been stoped to level 7, where it has a length of about 100 feet and a maximum 
width of about 50 feet. Below level 7 the large irregular mass of ore divides into 
smaller bodies, which though of variable width are so closely related to distinct zones 
of Assuring as to be practically lodes. These lodes will presently be referred to again. 
The great ore bodies in the granite thus occur in a northeast-southwest zone 
passing through the Ajax shaft. Their aggregate length is about 400 feet and 
their vertical range about the same. They pitch generally to the southwest, so that 
the highest bodies occur northeast of the shaft and the lowest bodies southwest of it. 
O 
Below level 8 they are succeeded by narrower deposits of distinctly lode type. 
The occurrence of these large bodies of ore is clearly related to the intersection 
of the two northeast-southwest phonolite dikes by the numerous northwest-south¬ 
east fissures, which has been referred to as the southwest zone, and it is probable 
that this relation is a genetic one and was largely effective in determining points of 
ore deposition within the granite. 
