Caribou silver mines: report, The

THE

CARIBOU

SILVER MINES

REPORT OF

PROFESSORREGIS CHAUVENET,

PRINCIPAL STATE SCHOOL OF MINES,

GOLDEN, COLORADO.

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REPORT

ON THE

CARIBOU SILVER MINES,

Grand Island District,

BOULDER CO., COLORADO.

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u Caribou" property, and whose general location IS

named above, are ten in number, viz. :

1. Caribou,

.V.

2. No Name, v'" 77

3· ^Sherman,

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4· Nederland. '35

5· _Socorro,

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6.Kalamazoo, . 76

7·^{Federal, ~.} 91

8. Columbia, / 167

9· ^Spencer,

.v

10. R. G. Dun,

(Numbers of patents in right hand column.)

The surface lines of these claims, being fully described in the surveys and patents, need not here be described in detail. All the claims, except the R. G. Dun, a recent loca-

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tion (patent applied for), were located under the old law limiting width of claim to fifty feet. The R. G. Dun claim is one hundred and fifty feet in width.

The two veins which have so far been the most produc- tive, are the Caribou and the NoN ame. The remaining veins are for the most part parallels to one or the other of these two, thus forming two crossing systems, of 200 and

150feet in width. Thus the Caribou, with an east-western course, has north of it the Sherman and Nederland, and south of it the Socorro. The No Name, with a north-east south-western course, has south of it the Columbia and the Spencer. The Kalamazoo is nearly parallel to the No Name, but its side lines are not identical with those of any other claim. The Federal is a fraction, probably purchased to consolidate surface ground, while the R. G. Dun, whose discovery was made overground at joe-foot level (and sub- sequently legalized by a surface discovery), lies outside o~

most of the consolidated ground.

Caribou Hill, upon which all of these claims are located, is one of the most remarkable of the mineralized mountains of Northern Colorado. Silver was discovered here in T859, but at that time free gold ores alone could be

mined for treatment, and no developments were made. Ten years later, when local treatment and purchase of are by smelting companies were introduced, the deposits attracted great attention, and numerous locations were made, the

" Caribou" being the earliest.

The "country rock" is granite, but divided into true

" structureless " granite and schistose gneiss. The line of

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demarcation, whose general course is nearly east and west, can be readily seen on Caribou Hill, and many of the prin- cipal veins are found parallel to that line. These veins dip more or less to the north.

A second system of veins have a north-eastern south- western course, dip north-west.

The" Caribou" belongs to the first, the «No Name"

to the second system.

A third, but much less prominent set, have a nearly north-western south-eastern course. -I-h-a-ve -beaed -Gf--&€l

<Ie¥e-l<>pm€~nt-"f.-.i.mllQIla.=e--U~p"~"hheJaffe'ro ~ Judging by the intersections, the east-western mines are older than the north-eastern south-western veins. Thus the" No Name" holds its course thr~ugh the" Caribou,"

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0-1 and has no value and little extent south (south-east) of the

"No Name," if indeed we can identify it at alL

The gangue is principally quartz. Ca1cspar is found only sparingly.

The ores are silver glance, stephanite, grey copper, argentiterous galena and chalcopyrite. Native silver is very common. (It is said that chlorides were found in the upper workings, but I saw none during my examination.) Prous- tite (" ruby") is disseminated in many parts of the " Cari- bou " ore bodies.

Chalcopyrite is found only in limited quantities and in cehain localities. It usually bears a considerable amount of silver. Pure argentiferous galena is not abundant, being usually mixed with cupriferous ores, producing minerals of

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~Ancertam type, which though ofhigh assay, cannot be aiel to Ie 1resent any distinct mineral speci . The most dis- tinctly crystallizedof the ores is the" ruby" silver, of w hich beautiful specimens are obtainable from the lower levels of the" Caribou."

It is not within the scope of the present report" to glVe/

a detailed history of the" Caribou" and "<No Name"

rnmes. itwould not be a pleasant task, for hardly in the history of Colorado mining has fraud reigned so supreme as during the middle and later periods of the Dutch manage- ment. There are few mining men who would not believe that of the tw~ millions or over raised here, one-half should have found its way to the pockets of the shareholders. That it did Dot was no fault of the property. As a resident of Colorado, I can only congratulate myself that the foreigners (after discharging their best men) sent over their own thieves, who pillaged at will, and wasted what they could not steal. That it should survive in the memory of the Dutch shareholders as a great" American" swindle is per- haps natural, certainly not just.

After prolonged litigation, arising from a dispute between the" Caribou" and "No Name," the veins in question, and all the others named on page r , were acquired by Mr. R. G. Dun, the consolidation quieting all the vexa- tious questions of priority, or of main veins and spurs.

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The property, now in poor condition for immediate production-its upper levels stoped out, its lower ones un- developed, its west ground unexplored-was allowed to . b-ecome flooded (1882-83). Mr. James Cowie was put in

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charge of the machinery and mill (at Nederland, four miles distant), and nothing ~lore wa1. ^{done until 1886, when it}

was resolved to pump out the mine and develop the lower levels.

(My examination was made in the latter part of August, 1887, and lasted about a week. Considering the condition of the mine when work was resumed, the long delays of a difficult pumping job, and the danger always involved in cleaning out and resetting timbers, its present condition is

\ most flattering, both to the property itself and to the man- agement.

The relation of the" Caribou" and ^(lNo Name" veins \ (is this. The "Caribou," course east-west, dip north, inter-

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sects, or at least makes into the hanging walls of the" No Name," whose course is north-east south-west, dip north/

west.

But the "Caribou" is a nearly vertical vein, while the

"No Name," though steep -fperhaps 20° from vertical for an average), is flatter than its companion. The result is that the intersection of the two increases rapidly in depth in proportion as we go west or south-tacst,

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w ^CARIBOU.

1. Surface relation of Caribou and NoN arne .

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w ^{C A} E

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F K

. 520^T

D B

980'

II. Plane of Caribou vein looking north. E VV,surface; (]

CD, Caribou main shaft. A,intersection of No Name at surface; B, do. at 980 feet.

In II.,"A B (in plane of Caribou vein) represents line

of intersection of" No Name" vein. Thus, at the surface, the

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intersection is over 500feet east of the main shaft of the

"Caribou," while at the.bottom of the main shaft (980 feet)it is not over forty feet east of same. At greater depth the intersection will doubtless be found west of the main Caribou shaft.

The" main shaft" above spoken of, follows, in the

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main, the ,. Caribou" vein, and is consequently not quite ver- tical. The levels are driven at sixty feet apart. Little need be said of ground above the 530 foot level, as it is nearly all worked out. The levels examined were the 530, 600, 670, 740, 800, 920 and 98o; the first four at 70, the last five at

6o-foot intervals.

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The levels all lead east into the" No Name" work-

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ings. The ^I'No Name" shaft is north-east of the surface intersection of the veins. At the 530 level the main (Caribou) shaft is about 300feet from the intersection, and /(J each level as we go down shows a decreasing distance, until at 980 the junction is close to the bottom of shaft.

Thus it will be seen that from the main shaft east to

" NoN arne" vein, and from the 520to the 980 level, we have t4';';\

a triangle of Hground" in the" Caribou" vein (F K B inl!!.J sketch 11.), whose side F K is approximately three hundred feet in length, F B being four hundred and fifty feet long.

Surface, 67,500 square feet or 1,875 square fathoms. This, of course, wi thou tl!::.::l:,u:.d~in::,g':..:a~nfy..:o~f~t~h"ec-';:'""N,-,o~N~a"m~e:-:'_'g",r'";'o~

I will speak later of two branches, locally called North and South Caribou, which increase the "ground" to be worked

nt between shaft and intersectio .

Starting east from main shaft along" Caribou" vein, we see the vein in places in the roof, ut the groun a ave as een very largely stoped out, and is not included in any estimate. uch being the case, I omit the few notes mad on this roof The in tersection with" NoN arne" is very)v-J clearly seen, it runs into the north (hanging) wall of the ~

\ latter, but is not found on the south (foot) wall. Not far away, in the foot wall of the "No Name," some rather obscure seams and" stringers" seem to represent all that is left 0

the" Caribou beyond the" No Name" south wall.

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At this point (intersection on 530 of the two veins) we)~ ~ are only sixty feet south-west of the main shaft of the

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"No Name." This shaft is in working order to 600 leveL On the No Name vein, at this level, a drift has been run

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five hundred feet south-west of the main shaft-all in "No Name" vein. At the breast of this drift a stringer of four inches of high grade ore comes into the hanging walL It has hardly been driven on, but seems to be widening, and is a promising prospect?F'Most of this long drift is old work, and the ground is not first-class. Near the main shaft it is stoped out above, and more or less stoping has been done for four hundred feet south-west of shaft. Above the last one hundred feet, and of course' beyond that (south-west) ~

all is virgin granny

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I Have iSOlidtHat the " ground" above this level is

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first-class. But it improves rather suddenly near the breast (i.e. 500feet from shaft) where the spur above mentioned comes in. lIn fact, we find everywhere the best show at or near intersections in tlus hill. Withal, I do not think much of the future of this part of the" No Name."

Six hundred level.-No underhand stoping having been (done from the 530, and the ground above being mostly worked out on the" Caribou," and largely on the" No Name," the new ground begins to show on·ly at the six hundred foot leveL Here, as above, the east drift from

"Caribou" shaft leads into the" No Name," intersection quite distinct, though not so clean ly seen as above.

Here the No Nallle vein has been drifted upon about one hundred and forty feet south-west of intersection. The roof of drift shows fair stoping ground, nothing like the fine , display of the lower levels, but probably all or nearly all

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estimate of " good ground," in concluding portion of report.

The Caribou vein on this level is very good. It is found to be split here however, but the exploration of the two branches is complete enough in the whole ground to enable us to explain the true relation of them. They are called the north and south branch of the" Caribou" (p. 9.)

The main" Caribou" shaft comes in (at 600 level) on the" North Branch." From shaft, for two hundred feet, the ground has been opened, stopes (overhand) started, and ore is being freely extracted. Itwould seem that the pros- pect forOft still further east here is also good. There is at least one foot of high grade ore her~d some of the choicest of the present shipments are being made from these stapes by Jeasers.x This is new ground. f!'he south branch may be considered as stoped out from here upward.) Ore can be sorted and shipped from here ranging from 100to

300oz. Very little is shipped at all, under 100oz.

This ground is best considered in connection with the six hundred and seventy, which though not much developed, shows some good ore, and that too, to the east,i.e. furthest from the shaft. Thus in the 600 the development is in good ground and west (nearest shaft), while in the 670 the good ground found is further from shaft (east). A tendency of the best ore chimneys to dip eastward, as they go down, is found in several other places. Here, however, we cannot say but that good good on670 exists also near to the shaft, the ground is not yet exploited.

Seven hundred and jorry.-Winze is being sunk hence to

800, mostly in pay are. Vein here, as elsewhere, shows

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average of three feet, pay streak variable, seldom under six inches, sometimes over one foot. Less is known of this ~ part of the mine than of any other. ~So far I consi~ the prospects decidedly good, and the sallie m the eight hundred, but the lower part of the mine having attracted the most attention, (as was proper, since its strongest and best founded hopes for the future lie in sinking) no great exploration has been made from 740 to 800. It is below the latter level

\ that we begin to find ground calculated to raise an old time

"excitement "-no offence to the 600 and other levels, which in many mines would be considered as strictly first

\\c1aSS1 but here have toyield the palm totheir betters below.

Eight hundred and sixry.-At this level the" Caribou"

shaft is eighty feet from the" No Name," measuring as before, along course of the" Caribou," to the eastward.

Quite close to the intersection a cross-cut drift has been run west, and a new spur of are found, now ten inches wide and very rich. This is only one of many interlacing spurs-it is not surprising to find them close to intersecting fissures.

An underhand stope has been started from here to the 920. It is in pay ground, and ~hipments being made.

{)<I find in my notes here (I had not yet seen the 920 level) the following~" This is certainly fine ground if the level below shows up as well." As it shows up much better, this ground is correspondingly strengthened and raised to first class" measurable" stoping ground. It is claimed by the superintendent that this work is being done merely for im- mediate supply of are, and in fact it would not seem to be

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warranted on the score of permanently economic working.

Nine hundred and twenty. "No Name" vein.-Close to the intersection an "upraise" has been started-about under the" Caribou" workings above. This is all in good ore-best below, but nowhere playing out. On the 920

level the" Caribou" seems to have been thrown out of its course near to the intersection, but a winze, dropped thirty feet down, and then drifted west, has developed wonder- fully rich ground, and as this is nearly above equally fine ground below, it is evident that this is one of the strongest parts of the mine so far developed .• Here we have five feet of high grade ore-much of it running over $300 to the ton, and no walls found at time of my visit. Of course, .such ground is exceptional, but it will help out a much larger area of ordinary ground, to form a fair average. In the drift I should estimate leasers could pay 6~ per cent. gross for simply drifting, and much more for stoping. I mention this simply to indicate the very high character of this develop- ment, which is as good a show as I have seen in any vein mine in Colorado.

Nine hundred and etgllry.-Here the two veins intersect close to the" Caribou" shaft. They seem to be each repre- sented by an ore streak, one on each wall of the now united vein. The walls are here ten feet apart, and it may be esti- mated that three feet of ore (in the two streaks) and seven feet of low grade vein matter occupy the space between.

The ore proper is of the highest grade and is of course being shipped as sent up.

There is a vast amount of ore in the various levels of

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this mine, which is not classed as shipping ore, and from which, nevertheless, shipping ore can be obtained by sort- ing, washing and screening. I have spoken only of the

"pay streak," i. e.the most solid mineral, but in fact there is a good deal of "pay" outside of it. Three means are employed in sorting the ore-no concentration of low grade has ever been attempted on it-all of the simplest descrip- tion.

As the ore is thrown upon the floor of the top-house (which from its great size serves as engine room, crushing and sorting department, shaft house, offices and carpenter- shop), the heavy lump; are taken to the hand cobbers, who bre<:1:kit, and sort out by the eye. But a great deal of the ore is already tolerably fine, and this is thrown upon a screen, 'which delivers the finest of it already (as a rule) of shipping grade .• This would not work in are of all descrip- tions, but here the are seems to break along its best miner- alized seams, so that the screenings are always better than the coarse stuff.

Much of the ore is crushed, and then screened. A large prop,ortion of mixed are goes to tables where it is first washed by tUI,Ding on water, the fine stuff thus carried off is settled III tanks under the floor of the sorting room, and this also is of quite fair shipping grade. The are thus cleaned off is rapidly picked over by hand, a practiced sorter becoming very dexterous in separating low and high grade.

\( As to the cost of sorting, it must be remembered that there is a class of ore which hardly requires any, though even in the best lots it will usually pay to use the hammer

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to a considerable extent, throwing out the lean streaks.

Eight dollars per ton of shipping ore may be named as a fair estimate on the total product, viz.: 500 lbs. per hand (at $2) per diem, which is rather less than a tolerably skilled hand will accomplish on ordinary material.

All of the work done since the drainage of the mine- or very nearly all-c-has been in the direction of exploitation, so that the present shipments, though amounting to several hundred dollars per diem in gross value, are merely inci- dental. The treatment charge will average $16.50 per ton, freight to Denver about $6.50, subtractions from assay value

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will vary (as per grade) from $5 to $8 per ton. It will be very close to the truth to say that the gross value of the shipments (assay value) will be taxed $30 per ton after leaving the mine.

The" ground" is hard, as a rule. In extreme cases i0

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has cost $40 per fathom to extract the ore." --- Before proceeding to the other claims, a few words as - to the future development of the" Caribou" and "No Name." The rapid improvement in the ground as the veins come together points to the rapid sinking of the present or some other shaft, as the strongest hopes for the future lie at depth. At the same time it would not do to neglect explora- tion along all the veins from 520 downward. Itremains to speak of the drainage question.

The mine is tapped by a cross-cut adit, abOllt 700 feet in length, intersecting the" Caribou" at 3oo~foot level near

* The " fathom" is 36 square feet. Contracts per fathom are quite irrespective of thickness, all shipping ore between walls must be taken.

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main shaft. The total" make" of the mine at present IS

about fifty gallons a minute, say 75,000 per diem. This will increase in spring time probably to two or three times that quantity. The pumps (horizontal Knowles) raise all the water needed for boilers and ore washing, to the surface, all not needed there is discharged through the arlit. Suit- able tanks regulate this arrangement. The steam pipes should be wrapped and all leaks stopped; this would reduce pumping cost considerably. As the pumps are not worked from separate boilers, we can only guess at their consump- tion of fuel at present-I estimate it at two cords of wood a day. As no arlit much lower can be driven, the pumping question becomes an important one for the future. If the property is largely developed, and eventually worked from a vertical shaft entering not far from mouth of the present adit (i.e. several hundred feet north of present shaft) it would be best to introduce a Cornish pump, as a fuel saver.

The adit is patented as a "tunnel" claim. Itcrosses the IIPoorman" lode (~yingHOItl sf th@ R C :bhul-eurTS"o- ....};j,da·~, also the" Sherman" and" Nederland," before

coming into" Caribou" ground proper. It is on this (300) level that the R. G. Dun vein was discovered.

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CARIBOU. ",. "'" W.----E.

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Sketch III does not attempt to give true relative distances of intersections, but merely to show general relation of the newly discovered" Dun" vein to the other three. Its course, as well as it could be observed in the small opened on it; is north, north-east, south, south-west, (N. 22° 30' E. S. 22° 30' \-V.) From its hanging wall, ore carrying chalcopyrite, and running from 30 to roo oz., was taken, streak about six inches in thickness. The intersection with" No Name" is hypothetical, but the vein is seen to cross the "Caribou" in the workings. I attach some importance to this discovery, not from value of the very trivial ground shown up, but because of the gerreral rule of enrichment near crossings.

The" Sherman" vein is cut bythe adit, and at this level seems to be not over fifty feet from the" Caribou." It has never been largely developed. Nothing can be now seen, the workings have not been put in shape cc sinc: the flood." Mr.

Wm. Donald, of Caribou, who has probably had more experience on the property than anyone in the county, and whose estimates may be accepted as certainly honest, and probably nearly correct, thinks thirty thousand dollars a conservative figure on its total record of shipments.

Nothing can be "aid of the" Nederland," except that it helps to "consolidate" the ground constituting the group.

As little can I speak of the ^IIKalamazoo" and

"Federal," though ore has been found in all of these claims.

The" Spencer" seems to be a branch of the" No Name," intersecting, or rather, branching off from it a little south-west of the" No Name" main shaft. Its workings

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extend from surface 300 feet, and it has a considerable record as an ore producer. I could not go below 140 feet, nor can anything of importance be seen in present condition.

I confine my statements to what is now to be seen, though I do not doubt the existence of much undeveloped ore in many of these spurs and crossing veins.

The" Columbia" also diverges from the" No Name,"

(like the" Spencer," from its foot wall) but has no great development. Its working shaft is a little north-west of the

"Spencer," is down some fifty feet. No stopes nor drifts.

Ore was extracted and sent the mill then in operation at

" Nederland."

Of the" Socorro," parallel and south of the" Caribou,"

I can say nothing.

Returning to the main property, the" Caribou," west of main shaft has received little attention. "Shaft NO,5,"

situated on claim 350 feet west of main shaft, has been sunk and levels driven, developing a good deal of are. Of the 225 feet of this shaft I saw only the first 90, ice on the ladders and massed about them rendered examination dangerous as it would have been resultless. I doubt very much if the are found here is from the" Caribou" proper.

It may be a spur or parallel. In any event it lies in the consolidated ground. A good engine and boilers, recently moved up from old mill at Batesville, are on the ground, the boilers are set, the engine and hoisting drum are complete and ready for erection. The shaft, now nearly vertical, should be straightened and retimbered in good style before proceeding with exploitation. By connecting with 300 foot

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level, a good deal of ground could be explored without pumping.

In estimating the value of the" ground" developed in the" Caribou" and" No Name," I first figure out the total number of " fathoms," which I find closely approximates three thousand. But of this not all is well exposed. Four hundred may be thrown out as dubious, and six hundred more as lean or" not proven." Of profitable working ground I do not reckon over two thousand fathoms exposed. If the future shows good ore in my rejected ground (rejected i. e. for the purposes of this estimate), so much the better.

I certainly cannot assert that it contains none.

All told, I consider the gross value exposed is consider- ably over one million dollars. But this includes 19Wgrade bodies, and much" that will not be milled, or which will be culled out and relegated to the dump after being mined.

The important question is, how profitable can the ground be made? You have, in the 2,000fathoms, some that may yield over $1,000 per fathom, others between $500 and $1,000 and a great many from $200 to $500 in gross value of minable . shipping ore. In attempting to average so large an area, caution rather than enthusiasm should rule. Remembering that I am speaking now of the best two-thirds of the ground, I think it should be mined and shipped at an over-all profit of

$100 and over per fathom, a total of $200,000 (two hundred thousand dollars).

I presume the local estimate would be about double this. As I wish success to all legitimate enterprises, I can sincerely say I hope my estimate is badly under the mark!

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But there are many contingencies to be discounted in such estimates, and among them the" personal equation" of hope or expectation, too often allowed to be a prominent factor in estimating output to come.

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ground, and backed bysuch a record, the future or unknown

\ ground adds no value to the property. As a matter of opinion or surmise (not" estimate "-that would be impos- sible) I should value the deeper unexplored ground at more

\ than all the nett values in sight.

<, With regard to equipment, the large and substantial shaft and engine house, measuring 50 x 160 feet, with boiler sheds and blacksmith shop not included, is furnished with very ample conveniences for all the necessary work. Four boilers, each ao-horse powe,r {and two more in good repair but not set), engine (by Gates, Eagle Works, Chicago) 80 horse-power, for hoisting, three drills now working in the mine driven by air compressor (all in good working order), two large crushers, machine sampler, fine lathe and numer- ous other tools, assay office (complete and working), car- penter and blacksmith shop well equipped, pumps ample for present service, additional (working) engine and boiler at "No Name" shaft, and the boilers and engine already mentioned at shaft NO.5.

I do not, however, understand that anything like an

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inventory or evaluation of the "personal" property was\

expected in this report Suffice it that all the heavy appli- ances are on the ground, and of course add their value to the property as a working mine.

The working shaft takes nearly the average dip (north.

ward) of the "Caribou" vein. It is now worked (two com- partments) by buckets, swung to very heavy hemp rope (shortly to be replaced hy wire).

These two compartments, with the assistance of the

"No Name" working shaft, can handle all the ore and do the other hoisting and lowering required, from the 980 level up. But it is a question whether for deeper work, certainly if driven several hundred feet lower, it would not be better to adopt a vertical system at once, sinking a new shaft to the north, and not far from ,the present adit entry. /

The work done since the drainage reflects credit "on Mr. J. S. Oli~, .the Superin~X.dent, and has developed more and better ground than coulJhave reasonably been expected in so short a time. /

Before closing, I must refer to the question of concen-\

tration. The "dump" of the old management, or the

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various dumps, are supposed to contain from thirty to forty thousands of low grade are, and are estimated at an assay value of from three hundred to four hundred thousand dol- lars. Can any of it be regained at a profit? Ifit can, it is evident that much low grape and rejected are (from sorting) can be made valuable in the future.

I will give the results of the few experiments I tried,

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prem,ising that they form too small a basis,

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From a great mass of low grade in 980 level (see p. 15), a lot was taken at random. This was material entirely rejected in working (i. e. not sent to the surface at all, even to be picked over). It assayed six ounces.

Hand-concentrated, failed to yield any satisfactory result, hot yelding over 40 ounces at any ratio of concen- tration, high or low. (Highest tried was 60 into 1.)

A sample was taken by Mr. Cowie (Aug. 23) from ore rejected by sorters. His cut assayed I I ounces. From a sack of the coarse I took two pounds, which assayed 10

ounces or a little over.

Hand concentrated, 16 into I, yield of headings only 41 ounces. Very unsatisfactory.

The third experiment yielded better results. It was made upon screenings of very low grade are. Sample assayed

20ounces. Hand concentrated, 8~ into I, headings assayed 88 ounces, saving slightly over 50 per cent., i. e. perfect concentration, 8)6 into I should have yielded assay 83/zX20

=IJo oz., and the result actually obtained was over half of that.

Trials of this simple "riffle" contrivance, worked by hand on small quantities, show that its results do not much differ from those of the best machines.

At Nederland is a fine water power (part of the prop- erty), ditch, turbine wheel, fifteen stamps, and other appli- ances. I think concentrating contractors could be found to lease the dump, and try their hands upon screenings and

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low grade ore. I would be willing, were the dump my own property, to lease it for 10 per cent. gross proceeds (sales) to any responsible parties.

The altitude of the Caribou shaft house is 10,000 feet above sea level. Altitude of mill at Nederland, 8,300 feet.

Carriage of ere, for large contract, should not be over $1.25.

Distance, four miles.

Some fine bodies of timber belong to the property.

Fuel can be obtained (pine wood) at $3 to $3.50 per cord.

Stulls, 8 to 10inches diameter, I4 feet in length (for two stulls], 6oc. apiece, or slightly over 4C. per running foot.

Poles for lagging, 14 feet long, 15c., or slightly over r c. per running foot.

Freight to Boulder, where ready market for the ore is found, four dollars. But it is higbly; probable that the narrow-gauge railroad now running to Sunset, will soon be extended to a point much nearer to Caribou Hill, and that the total freight can be much reduced.

The" Caribou" mine is certainly the leading property of Boulder County to-day, and it is not an enthusiastic pre~

diction to say that it will again assume its former position as a great producer. In its future at depth, I have great confidence; of the profitable character of the present expo.

s es I have no doubt. /

That capital would be ne}ded to push the initiatory dead work for a great developme~!, is true, and it would be true for any similar case, howev~r\brilliant the prospect.

To assert that no risk would be lincurred, would be saying

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too much. More than a good ,business risk, would be to claim no more than justice for tll\ prospects fairly consid-

ered. /

REGIS CHAUVENET.

STATE SCHOOL OF MINES, GOLDEN, COLORADO,

September 14, 1887.