The Elk Mountain pilot., 1881-09-01
THE PRECIOUS METALS.
And How They arc Obtained, ETC., Etc
CONTACT VEINS.

Ohte@S| NAiAo etiS il\AS tWN
kinds Of rock come together, as por-
phyry and limestone, or porphyritie
trachyte and other rock, as at Lead
vile, there is often a well defined
crevice between flied with rich ores.
Such are contact veins" Nearly
all the carbonate mines in Western
Utah are Of this class, and at Jacob S
canon the miner goes in by such a
gentle incline that mining is compara-
lively simple for the first two or three
hundred feet But on entering a
mine of this class we see at once that
there is an irregularity, and generally
the scientific surveyor cannot promise
permanence. Indeed it is often ap-
parent that the formation is the result
of a "slide" from some mountain
which once toward far above. The
crevices may be such as are natural to
stratihed rock, or they may have re-
sul.ed from fracturlng force which,
while it would have broken straight
aero massive rock, very naturally
follows pre-existing lines of cleavage
when it enters strati6ed rock. To
understand this, the reader need only
bear in mind the axiom of mechanics
that force once set up will take di-
rectiOn along the line of least resist
ance. So it will make one defined
crevlce in the body of a granite noun
tain, but "shatter into hundred
little crevlces at the surface; and
even SO, in stratifed rock, it will
make crevices along the lines Of STRAIT
ihcation.
But the most noted contact veins in
the world just now are those of Freyer
Hill, at the magic city Of Leadville.
There the ore is found in crevices, or
deposits, with porpifyry ab0ve and
limestone below-sometimes a sort of
porphyritic trachyte-while in few
places the ore seams are found with
porphyry or iron between them. The
crevlces ore of various sizes, the ore
seams of every thickness, from that of
knife blade to ten feet, and the ore
of every variety of richness, from S
up to s., 900 per ton. Add to this
that there is no science of developing,
nothing for it but to dig till you find
or can't find it, and the glorious un-
certainty of the thing is apparent, and
its irresistible charm for the true mi
ner. 1t is a bewildering, a dazzling
uncertainty. Your claim may be
worth anything from cent to mil
lion dollars, and who can wonder that
adventurous spirits from all the world
are there, and that handsome city
of $4,000 people has sprung up as
with the touch of Aladdln's lamp: In
the year 1879 this region yielded a
little over SI1, 100000, and from its
discovery to 1881 Its total yield is at
least SIS, 900, 900.
The ore is carbonates for the most
part, easily mined and easily smelted
And this may be as good place as
any to define the most common terms
in ore, as miners use them. (Whether
it agrees with the chemistry of the
books, | don't know.) If the term
ends in ide, it means a combination
of oxygen, or some gas with the metal
Thus we have oxyde of silver, etc. !;
chloride Of silver, a chemical union Of
chlorine and silver, very rich and
easily reduced, it being already in ia
vorable combination with salt. If the
termination is uret, it means union
of the actual substance with the silver,
as sulphuret, a combination of sulphur
and silver sulphuret of zinc, zinc and
sulphur, etc. If it is ate, it means the
acid combined with the mineral,
making an entirely new compound !;
and of all these carbonates, of lead
and silver, are most familiar to the
miner, and generally most welcome,
being so easily reduced. OF the car
Donates of Ophir district, it is said
that they run through a smelter like
molasses, and those of Leadyllle are
reported even more tractable, where
there is lead enough in the combina-
ton. Many mines there have an ad-
ditional element of iron, which is said
to add to the ease of treatment Ca