156 ECONOMIC GEOLOGY OF SILVERTON QUADRANGLE, [bull .182. 
with the Silver Lake can be seen on level 2, At the junction the 
quartz of the two lodes is separated by a narrow seam of gouge. 
Together they constitute a solid vein of low-grade ore about 10 feet 
wide. The E. G. S. has contained some of the richest pockets of ore 
encountered in the mine, but its value falls off, like the other veins of 
Group II, as it approaches the Silver Lake. The L. A. S. is another simi- 
lar small vein, which was not worth working until level B was reached. 
It illustrates the fact, thus far exemplified in this mine, that the small 
veins of Group II may prove more valuable and have longer ore 
bodies as they are worked downward and as their junctions with the 
Silver Lake are carried farther and farther to the northeast on account 
of the relatively flat dip of the latter lode. 
The Silver Lake mine is worked by overhand stoping, the ore being 
broken down onto canvas, and the stopes are filled with waste as the 
work is carried up. Siemens and Halske electric drills are used in most 
of the stopes. They are portable and convenient, but somewhat too 
lightly constructed for the work required of them. The ore from the 
various levels is all dumped into bins at the central station on level 1, 
that from the lower levels being raised through a vertical shaft by a 
cage and an electric hoist. From the central station the ore is drawn 
out in trains of cars by mules to the mill at the mouth of the adit. 
At the mill it is sorted, the larger and heavier pieces of nearly solid 
ore being sent down the tramway as crude, or shipping, ore. The 
equipment of the mill is 2 Blake crushers, 50 stamps, 4 sets of rolls, 10 
Wilfley tables, 8 Hartz jigs, 8 Woodbury tables, and 18 "end-shake" 
slime tables. Power is furnished by three 100-horsepower boilers and 
a 150-horsepower engine, and the mill has a daily capacity of about 
200 tons. The water for milling is pumped from the lake, into which 
the tailings are allowed to run at another point. A new mill is now 
in progress of erection on the Animas River, at the lower terminal of 
the tramway. 
As already stated, the ore of the mine is low grade. Ore running 
$10 a ton can be worked, but even $8 ore is often run through the 
mill with the better grades. About half the total value of the output 
is in gold, the rest being in silver, lead, and copper. Free gold is 
very rarely seen, and no attempt is made at amalgamation. The con- 
centrates are said to average about 145 per ton. The crude ore and 
concentrates are carried down from the mill on a substantially 
constructed Bleichert tramway to a large terminal station near the 
mouth of Arrastra Gulch, furnished with capacious bins. From 
these bins the ore is loaded directly onto the railroad cars. A second 
tramway from the Unity tunnel was completed in October, 1900, and 
will soon handle the bulk of the ore. 
Power for hoisting, pumping, and lighting the mine and buildings 
is generated by dynamos run by two Pelton waterwheels located on 
the Animas opposite the mouth of Boulder Gulch, the water for this 
