The Daily state register. [volume] (Carson City, Nev.) 1870-1872, 1872-01-26
WITH WHAT ARE THE STRATA
ABOUT PRODUCTIVE LODES MIN
ERALIZED!

GhALlZEU
This is a question which is being
discussed at length by the English
mining journals. The London Min
ing Journal contains several commu-
nications on the subject, evinclng
considerable learning. but all of
them failing to furnish a satisfactory
answer. One of the difficulties at
the threshold of the investigation
arises from the uncertainty OF the
actual composition of the minerals.
The belief is expressed that facts
viii soon demonstrate that the met
ais are not elements but compounds.
A thorough chemical analysis of the
rock adjoining ore-producing veins,
it is thought, by these writers can
only furnish a solution of the per-
picking in~terroSatory. BY this
mode the miner would be guided in
forming an opinion as to the prob
able productiveness of the mineral
vein. 1t is urged that 1.-THE preva-
lence of certain metallic minerals in
particular kinds of rock is well
known, and if 1t can be shown that
the presence of such minerals is due
to the existence of one or nor
chemical elements in the rock then
the advantageo of analyses Of the strata
cannot be over-estimated."
The occurrence of certain minerals
with an abundance of various chemi-
cal elements peculiar to the strata,
is noted. illustrations are given, Is
in the case of galena, most frequently
found with Iimestones or clay states,
consisting Of considerable quantities
of lime. The belief is expressed
that the proportion of lime materi-
ally influences the quantity of lead
ore found in the vein or bed. A
writer says
~ series of careful analyses would
very possibly establish Il connection
between the occurrence of argeutIter-
Gus galena and the existence of some
particular chemical substance, as pot
ash lin addition to the limel in the adj
Joining rock. As for copper pyrites,
it is difficult to say with what substance
it Is usually associated, except that
magRe>ia would appear to he very
abundant in the ground in which it Oc-
curS-aS in ~greenStoneS, &c. Manga
nese occurs most abundantly near
trappean rocks, through which it was
probably disseminated at the time OF
their intrusion. beng afterwards taken
up in solution, and deposited i'll veins
and assures. Trappean rocks consist
of silicates OF lime. magne>ia- potash,
iron. and alumiua; but there is no
evidence to show that the prepOnder-
of any of these is favorable to its
occurrence"
This concurrence of certain metals
and certain rock may be due to the
presence of some peculiar ~precipi-
tating element. This idea is illus
trated in the following paragraph:
We may advance variGrls hypothesis
to account for the appearance of par
metallic ores in rocks contain
certain chemical matters. For in
stance, assuming that the minerals
infinitely disseminated through
Dut the strata previously to the forina-
ion of the lodes, and being subse-
1ueHtly dissolved and circulated in
veins in a fluid state, a deposit of
ore might take place owing to certain
substances having the prop
erty of precipitating 1t from solution
the sides Ofthe vein. Thus, lime
stone might precipitate a solution of
i'll which caSe the occurrence
If the two minerals together would be
for; or mineral being held
solution by a certain substance
might be deposited in a bed of rock,
md afterwards on the formation of a
vein it would be carried away and de-
therein. The existence, in the
rock, of the substance in
which the mineral was originally held
n solution would serve as an indica-
ion of the presence OF the metallic ore
n the lode.
In forming an opinion of the pros
oects of a mineral vein being remuner-
to mine, it is, ofcoUrse, necessary
take into consideration the physical
conditions under which it exists.
However highly mineralised the add
strata nay be, it is quite pos
'ible that, from mechanical causes,
my chemical action was Intellectual,
the metallic ores were unable to
ind their way into the vein. on the
,ther hand, a vein most promising to