96 
MINING GEOLOGY 
The White Stone antimony deposits have special bearing upon 
the theme of depths at which mineralization takes place and con¬ 
tact sulphides of the metals are formed. Of late it is the custom 
to regard garnet-contact ores, for example, as taking place only 
under such high temperatures as the critical point of water, or 350 
degrees, and under great pressure of not less than 200 atmo¬ 
spheres, or a rock cover four to eight miles thick. While these 
figures appear to be excessive in some cases, the White Stone 
mineralization indicates that the process of contact-ore forming 
may at times go on also at relatively shallow depths. 
In some respects antimonic alteration of wall-rock is different 
from mineralization by some of the other metallic ores.* Anti¬ 
mony volatilizes at temperatures so low, that in the manufacture 
of the oxide white the comminuted ore is passed slowly over 
plates heated to dull redness. It may be for reason of this very 
fact that in veins of complex ores the antimony easily separates 
from the other metals and collects very close to the surface of the 
ground, at depths measurable in tens or hundreds of feet, instead 
of thousands of feet, or miles, as theory demands. 
Vein-filling in the White Stone Peak deposits is thus caught in 
one of its very earliest and incomplete stages, a stage long since 
lost in most veins that we know. With depth we might expect in 
the White Stone veins change to a lead facies, then to silver-lead 
tenor, and perhaps then to copper and gold. So it is probable 
that, according to the amount of denudation experienced in the 
region, all of these stages may be revealed in the same district. 
Launay’s pregnant suggestion concerning the effects of profound 
erosion in uncovering those parts of veins which were originally 
great distances from the surface has therefore vast practical pos¬ 
sibilities in local ore developments, despite the circumstance that 
so many mining men have accepted literally the theoretical ex¬ 
tremes. By slight modification of the premises ore exploration in 
veins may still be vastly promoted and results precisely predicted 
by proper attention to the theoretical requirements. 
