BATTLE MOUNTAIN MINES, WEST GROUP, AND OUTLYING PROSPECTS. 477 
ticularly by the Black Diamond, which divides it into north and south portions. 
The underground workings are all in the irregular fractional part of the claim lying 
north of the Black Diamond. The mine is worked by lessees. 
UNDERGROUND DEVELOPMENT. 
The Dillon workings comprise a vertical shaft about 800 feet in depth, with 
eight short levels. The main drifts, as a rule, run a little west of north and east of 
south. The longest drift is about 450 feet, on level 8, which has been run south¬ 
ward into the Black Diamond claim. 
LODE SYSTEMS. 
There is no dominant or persistent lode known in the Dillon mine, unless a 
phonolite dike east of the shaft, which carries bunches of ore, may be so called. 
The chief characteristic of the mine is a number of short, nearly vertical sheeted 
zones in granite, ranging in strike from north to northeast and carrying bunches 
of ore at their intersections or junctions. In this respect the mine resembles the 
Abe Lincoln. (See p. 277.) There are at least four of these sheeted zones exposed 
in the northwestern part of level 3. The westernmost, known as the Stonehouse 
vein, strikes northwest, seems rather more persistent than the others, and is known 
in the Monument mine. 
GEOLOGICAL FEATURES. 
The general country rock of the Dillon is the familiar porphyritic granite of 
this vicinity, cut by dikes of phonolite and basalt. One phonolite dike striking 
about X. 15° W., and with variable but, on the whole, nearly vertical dip, lies about 
75 feet east of the shaft. The width of this dike varies from 6 to 8 feet. There 
is also an east-west dike with northerly dip, lying south of the shaft and well ex¬ 
posed on level 7. This is very probably the same phonolite dike known in the 
southern parts of the Granite and Dead Pine mines. (See pp. 472 and 485.) 
The Dillon shaft was sunk on a basalt dike which strikes X. 20° W. The 
dike, on the whole, is about vertical, though on some of the levels it lies as much 
as 10 feet on one side or the other of the shaft. It is usually from 2 to 3 feet in 
width and is soft and decomposed. 
FORM AND STRUCTURE OF TIIE ORE BODIES. 
The ore of the Dillon occurs in irregular bunches in and alongside the phono¬ 
lite dike east of the shaft and in the short sheeted zones in the granite of the north¬ 
western part of the mine. The ore occurs chiefly in bunches at the intersections 
of these lodes, and has been found mainly above level 3. The ore associated with 
the phonolite dike does not apparently follow any very distinct sheeted zone, but 
occurs at points where local irregular fracturing has provided spaces in the phono¬ 
lite or adjacent granite for the deposition of tellurides. 
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