New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1880-08-16

composed of granite, and Others OF quartz ana 1ed-
spar. have been thrown. until IL ~ filled to the sur
| face, and that subsequently cement consisting oi
| feldsite and other VEIN matter has been poured III
| to fill up tho vacant spaces between the Stones
| Suppose also that Mt one place in this vein, adj
| iacent TO the upper or hanging wall. space was
marked out tho surface in the shape OF kidney
seventy-four feet long aud tiry-fOur feet wide nj
the naTrowest point and that there has been poured
IN among the mass Of stones covered by thu figure
instead of feldsite and other barrcn-cangue, mix
ture of these substances and liquid argentiierous
galena which has filled up all the inteIstcos be-
tween the stones to an unknown depth-in some
places he gaena pro dominating and occupying al
most all the space while in others the rock material
ssmply filled with streaks of the silverlead ore.
! II the reader can imagine a mineral deposit of the
kind | have described. he VIII have very correct
idea of the Bull-Domingo ven and mine. only the
material which fills up the spaces between the
| boulders in the vein came in from below and not
| from above.
| have neglected to mention characteristic OF
this remarkable ore-body. AT frequent intervals III
the chimney barren bikes of feldste or granite
push out through the conglomcTaie mass, In some
| places the vein seems TO have turned out for or
been pushed aside by them, but in Others it was 40
strong that it retained its original form and dircc-
|
through into the orc-body. and form what miners
| call L" horses" The the surface is geneI-
| ally carbonate of lead mixed with some galena.
| 1t was all originally galena, but where the air and
rams have mad an opportunity to act upon 1T they
| have desulphurlzed " docoIn posed II, as tie
miners say I'm the surface there Is also compare
| lively little lead and silver. tho former running
| from 10 to 80 per cent, and the later from a few
ounces 10 forty 10 ton. These stained with
OK de Of iron. which give red color. The ore be-
low the point where the air and surface waters have
had an opportunity to act upon them, Is bright
lona carrying silver principally in the form of
sulphide, but sometimes as Il chloride. Many small
cavities are also found in which little wires of ma
| tive silver may be seen running through the ORE
The frsi-class rock which Is taken from the Bull
| Domingo mIne and by that IL meant the entire
| mass of boulders. pebbles and surrounding VEN
matter as IT is broken out, carries from ght
to ifty.sx ounces OF silver TO ton, and contains
from sixty to Sky two-and-a per cent OF lis
own weight OF lead. II is remarkably free from
zinc autlmony arsenic and other troublesome sub
stances which make refractory, and Is, Il ere
fore very easy to reduce aud brings high prices
For instance, lot OF ore sold on the 10Th inst
which assayed fortycight ounces OF silver 10 ton,
and from sxty-One to siXty-two per cent of lead
broU Sht Sj7 80 ton net.
HOW TIE oRfs ARE HAU Ed And CONCENTRATED.
From the description have given of the mine 1t
will hc easily understood that considerable portion
rabout three Ourh) Of the material as II IS mined
and raised to the surface, consists OF the bouders
and pei bes winch themselves contain neither silver
nor lead. They greatly increase the buk OF the
ore without adding to It's value. and as II all has 10
be sent away 10 reduced make the cost OF trans
po;tation Inch is very considerable here, two or
three times n great as 1t otherwise would be. IL
has been found prof able, therefore, TO concentrate
the Bull Domingo ores before they sold. that 49,
| 10 remove a considerable portion OF the waste rock
and to put the valuable part of two aad one-haf or
three tons of ore into ton of cpncentraes ms
Is accomplished oy means of water ilgs which are
constructed on tho same principle which is en-
p!oyed in the anthracite regions Pennsylvania to
separate the slate from the smaller sizes OF coal.
If a sieve flied with stones of different specific
gTayities be held ia water and raised aud lowered
| by a rapid ierky motion, the heavier stones. owing
to their greater specific gravity, Will be collected
topether at the bottom. II tie water at the same
time runs across the sieve with considerable force.
it will gradually carry the lighter stones away.
leaving only the heavier ones in the sieve Galena
ores are so much heavier than OF the rocks with
which they are associated that machinery con-
srrucfed ON the principle just explained viii concen
trate them with great rapidIty aud perfection. The
BulI-Domingo Company is now binding concen-
tratipp works on Grape Creek. IN the valley, in
winch the superIntendent, Mr.. Callahan, expects u
he able TO handle 100 tons of ore n day at an ex-
pense of 81 % ton, 60 cents OF winch
will be the cost OF hauling, and 90
cents the cost of concentrating
| suppose the freight on a ton Of ore sent
TO a srneter in Pueblo or Denver is at least $40. If
three tons of ore are put into the cost OF concen
trating aud shipping 1t at that rate VIII be pIo 10
while the freight on the three tons before concen-
tr,tion would be 800 If the company handles
seventy-hvo tons OF ore day the saving by concen-
tation would. therefore. be IN the neighborhood
of $500 day.
have described the general shape and size of the
ore-body IN this mine. From the surface to depth
of about seventy or eighty feet most OF the ore
| WAS taken out through the old shaft What was
left i'm former workings is now beng removed Inc
PRINCIPAL operations of the mine are now the new
| shaft. which has already been sunk to depth OF
$50 feet and it was IN the crosscut at the bottom
of this that the measurements showing the size of
the body of ore already gwen made AS no stop
ing has been done from these lower workings the ore
remains untouched from the elghty-foot level 10 the
| bottom of the shaft, distance OF seventy ieet'
fine shaft-houso just completed, has been suppiied
with hosting machinery, cages, etc. OF the pest
| character by which from eighty to 100 tons OF ore
can be raised III a day. The present product OF the
| mine was stated to me at go tons week. Con-
siderable denominations Of ore to be seen around
fine mine. The company has good Offices a black
smiths shop, boarding houses and other buildings
which constitute a considerable village about the
| mine uD
In closing may say that there is in the Bull-Do-
mipgo mine larger mass Of galena ore than ever
saw before in one mlnc and know OF no reason
why the company should not begin to pay uiv'd-
ends soon after the completion OF Its concen'ra-
ting works. w.
MIDNIGHT WEATHER REPORI