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They first erected two steam engines of 36-inch cylinders each, which freed the mine from water to a depth of 324 feet under the adit; at this point another one was required and erected of 54-inch cylinder, by which the working was carried to 724 feet under the adit; but here again the engines were overpowered, and still another engine of 75-inch cylinder was erected. Mr. John Buchan, the superintendent of the mine, in one of his reports, made in 1852, says: "After the mine had reached a depth of 710 feet under the adit (1,310 feet below the surface) the difficulties of drainage had so increased, both from augmented quantity of water and the greater height to raise it to the point of discharge, that three powerful steam engines could barely stem the coming waters of the mine.

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With the increased difficulty of drainage. seeing three bunches of ore worked out, and a debt of $5,000,000 still outstanding, it is not surprising that the energy and perseverance of the English adventurers were at last exhausted."

"Had the company prosecuted a projected deeper drain tunnel, it would have secured the continued prosperity of the mines for many years to come. It will be remembered that the first Count of Regla distinguished himself and made the fortune of his family by driving the present adit; the second count reached down 324 feet below it, being the limit to which the mines could be worked with profit by horse power drainage. The English company, by the powerful aid of steam machinery, carried down the workings to 720 feet below the adit; but here we find another limit to profitable working, as the deeper excavations of the Biscanya vein are again abandoned to fill with water.

"A deeper adit, which had to be driven a distance of 13,500 feet, had been commenced by the second count. The English company unfortunately adopted the more speedy plan, as it was supposed, of employing steam engines, instead of the slower but surer plan of driving home the deep adit, which could have been done with the investment of but little more capital than that expended in applying steam engines, and would no doubt have given a very different turn to the fortune of that company."

Mr. W. P. Robertson thus relates the financial history of this company:

"The London Real del Monte Company cominenced working on a magnificent scale ; then, under the influence of a panic, suddenly deserted, in the most critical time, their judicious and indefatigable agent at the mine, and the result has been unmitigated ruin. The mania in London at the time (1823 to 1825) was so strong and so general that no expenditure was for a moment grudged. People thonght they were laying out tens to receive back thousands, so they paid up their tens with surprising alacrity. The management in London of many of the new companies under the reaction was miserably bad, and in the end many of the shareholders were completely ruined and retired to cottages, there to abandon forever their Chateaux en Espagne.'

"In 1825, the late Mr. Kinder, the enthusiastic leader of the Real del Monte Company, was offered $5,000 for each of his 30 shares of $500 paid up in that concern: he refused to sell, that is, he would not take $240,000 for what had cost him $15,000. The reaction set in, and down went all shares. In 1845-'46, those of Real del Monte were to be had at $12.50 each; that is, Mr. Kinder's 30 shares, which in 1825 were worth $240,000, had gradually dwindled down to $375! The company was all but bankrupt; no more assessments were listened to; and the debts could not be paid with unsalable engines, though they kept up the steam, nor yet with stones, although silver was in them. The shares have since gone to nil; no one will have then fenced in, as they are with unknown responsibilities and debts. In vain did their new, active, intelligent, and enterprising, though prudent manager and agent, Mr. Buchan, write to the shareholders to take heart and not to throw away their property. They had been panic-stricken in the first instance, they had got sick of the business in the second, and in this last and most helpless fit, they entered into negotiations for the sale of the property to a Mexican company. A bargain was struck, and the perpetual lease of Real del Monte, with everything on it, passed from the hands of the Real del Monte bondholders for an old song. The entire sum paid was $130,000, for a business on which $7,000,000 had first and last been expended: and even of the mite to be recovered, threefourths were not to go into the hands of the bondholders at all, but to be appropriated in Real del Monte itself in the liquidation of sums still due to the servants of the old company. What a winding up! Shares once worth $8,000 each, now not worth 30 cents! and the actual movable property on the estate, in houses, workshops, machinery, crushing establishment, timber, wood, iron implements, utensils, steam engines, horses, horned cattle, mules, and many valuable miscellaneous materials, must be worth altogether some millions of dollars. The house of Regla alone cost a million and a half, and now is valued at a million of dollars-all gone for $130,000.

"Thus did Real del Monte pass from the Counts of Regla in Mexico, and thus has it passed from the luckless shareholders in London-the first paying the penalty of personal extravagance, the other an equally severe one of wild speculation and injudicious manageIt is now in wiser hands than theirs, and prosperity dawns again on this almost national establishment or colony."

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This lustory of the Real del Monte mine teaches a valuable lesson, confirmed by the result of almost every similar enterprise in Mexico. They show that after a certain depth has been reached and no drain tunnels constructed, the mines have been abandoned and the proprietors ruined.

St. Clair Duport, who published a work on the mines of Mexico in 1843, gives a general sketch of mining operations, which is a perfect representation of recent experience in California and Nevada. He says:

"Opening a mine by accident, somebody discovers, guided by the croppings elevated above the soil, quartz containing some metal. He exposes some pieces to white heat, and if he discovers thereon globules, or pearls of silver, he takes up the claim. The discoverer now seeks partners with capital to work this claim, as generally the means of one man are not sufficient for such an enterprise. At first they generally seek to extract the ore by fol lowing down on the vein, and open a number of shafts along its course; but in the same ratio as these shafts increase in depth the water increases too; galleries and new shafts become necessary, and finally, as is generally the case when the largest portion of the yield has been expended in such operations, particularly in mines which are not extraordinarily rich in minerals, the work has to stop on account of bad air and abundance of water, the improvements being of no further use.

"The owners now look for new partners; if the vein presents probabilities of richness at a greater depth, persons can be found who, for a portion of the stock, generally for half, advance the necessary means, which is to be repaid out of the first yield of the mine.

"After the water has been removed, and the shafts and galleries are made, and really rich ore is found, then commences the good time of the mine. Arrived at a depth where silver generally is abundant, and when the expenses to bring the water and ore to the surface are not too great, mining is a good paying business; that is what is called in the miner's language la bonanza.' This time is hoped for with ardent desire, not only by the owners of the mine and the miners employed, but also by the entire neighborhood. In this case labor, and all necessary articles for mining, are in demand, and well paid for; the money earned with ease is spent freely, and everybody in the whole mining region having any claims is full of hopes to strike it equally rich. The buildings for the reduction of ores are now erected, and very often in a style altogether too costly for their use. Next, underground works are constructed to facilitate the hoisting of ore and water. In case the mines in bonanza' belong to private individuals, these works are executed on a substantial basis, with a view of usefulness for the future. But in most cases, when a mine is divided amongst a number of shareholders, they present such a diversity of ideas that they often cannot agree upon anything at all, except to extract the most money from their mine in the shortest time possible, without even looking ahead for a few months. For this reason we cannot find one single wellworked gallery in such mines. The richest ore is torn from the mine, and less rich ore remains untouched to be taken out when la bonanza' ceases. It is difficult to understand why in times of prosperity a small portion of the yield is not spent to make new developments. ABANDONMENT OF THE MINE.-"The pay streak once traversed, and the increased depth rendering the price of extraction too considerable, the 'bonanza' ceases. The less rich ore left in the mine is now taken out, and one of the greatest expenses being the keeping down of the water, the lower qualities of ore are abandoned.

"The reserved middle class of ores will pay expenses to explore the mine for a while, but the time arrives when a day's work, or the value of a pound of ore, ceases to pay, and the mine is thereafter entirely abandoned."

The author of the above description of mining operations in Mexico, written 25 years ago, could not have given a more truthful account of operations in the Comstock lode had be spent the last six or seven years in Virginia City. Our mining companies have been pursuing exactly the same course, and have followed in the footsteps of their Mexican predecessors. Ruin of the owners and abandonment of the mines has been the result there; ruin and abandonment must follow upon the suicidal course pursued here.

MINING IN EUROPE.-If we turn to Europe, however, we find that mining is carried on with intelligence, economy, and with a view to permanency. In England but few mines are located at any considerable elevation above sea level, and deep drainage by adits is impossible. But each mine has its adit, however small its depth may be beneath the surface, and in stating the depth of shafts in England they are given from the adit downwards; what is above the adit is not counted at all.

The most remarkable work of this kind in Great Britain is the great adit in Cornwall, of which an English writer says:

"The advantages of working mines by adits are well shown at the United mines, near Redruth, where an adit has been driven, commencing only a few feet above the sea level, which, with its branches, has a length of from 30 to 40 miles, and a depth under the mines of from 180 to 420 feet. By means of this work a saving in the consumption of coal is effected amounting to 24,000 tons per annum. This magnificent undertaking was completed in 1768."

MINES IN GERMANY.-The mines in Germany present by far the finest field for studying mining operations reduced to a science. There mining schools and learned professors have for years prepared young men, who were to be placed in charge of mines, with a thorough knowledge of all the varied branches required of mining engineers. It is owing quite as much to intelligent management as to the low rates of wages that mines are profitably worked in Germany which would be considered valueless in California or Nevada. There we see the most complete systems of drainage and ventilation, and mines placed beyond the

usual contingencies of such enterprises, yielding nearly uniform dividends, and regarded by capitalists as good security for investment.

THE FRIEBERG DISTRICT.-A few years since it was proposed to drain the Frieberg mining district by an adit-level of the extraordinary length of 24 miles, which would cut the vein at a mean depth of 2,000 feet. This plan was vigorously supported by Von Beust and other eminent mining engineers, and received the sanction of the Saxon government. This gigantic work has not yet been commenced, but a deep adit is now being driven, which will drain the mines 400 feet below the present deepest natural drainage, and will have a length of a little over eight miles. It is eight feet wide, nearly 10 feet high, and rises in the whole distance 12 feet 6 inches.

In the Harz district some mines have attained an immense depth. The mine of Andreasberg has a depth of 2,450 feet, being one of the deepest mines in the world: adits have been there for centuries, the largest of which was completed three years ago.

THE ERNST AUGUST TUNNEL.-We make the following condensed extract from a report made by Dr. Geissler concerning this great work, called the Ernst August tunnel, after the late King of Hanover:

"On the 224 of June, 1864, a drain tunnel was completed which may be called the greatest work of the kind ever executed. To explain its objects and importance it will be necessary to give the following details:

"The mines of the Harz were about to be abandoned, or, more properly speaking, about to be drowned out by water beyond redemption. In the course of time the explorations in those mines went deeper and deeper, until they reached a depth of 2,000 feet. While the higher situated galleries ceased to yield pay ore in sufficient quantity, the exceedingly rich ores discovered in the lowest levels could not be reached on account of great bodies of water, which pumps and engines could not master, and the lower levels had to be, for the time being, abandoned.

"There have been drain tunnels in the Harz for a long time, which were used as canals for the transportation of ores. Already at the commencement of the 16th century mechanical means to remove the water from the mines were insufficient, and drain tunnels were constructed at that early period. The first tunnel was commenced in 1525, another in 1548, one in 1551, and still another in 1573. By aid of these tunnels mining was continued in those districts for 200 years, but about the middle of the last century it became difficult again to master the water.

"In 1799 another deep tunnel-having a length, including gaileries, of 57,000 feet, or nearly 11 miles-was completed. But this also, afterwards. was considered insufficient for future purposes, for notwithstanding additional engines might have been used for a while, their dimensions and cost in mines which had reached such an enormous depth would have been very great. And, after all, the surest and cheapest way for water to be removed is by its natural flow; the engines have enough to do in pumping the water up to the Ernst August tunnel, as that gives the deepest natural drainage which can ever be obtained.

DESCRIPTION OF TUNNEL.-"In 1850, after careful surveys and due consideration, the construction of the Ernst August Tunnel was resolved upon; it was to commence at Gittelde, a little town at the foot of the Harz mountains, and it was estimated that 22 years would be required for its completion, but it only took a little over half that time, for it was entirely completed in 12 years and 11 months. Nine shafts had been sunk, from which 18 galleries or drifts were run, and one from the mouth, so that the work progressed from 19 different points. The connections were made with such perfection that they could not be recognized after they were completed.

"This tunnel has a uniform fall of 5 inches to each 630 feet, or 1 in 1,400; its height is eight feet three inches; its width, five feet six inches, and its shape that of an egg. The water has a sufficient depth to allow the use of long flat-boats, for the transportation of ore. A part of the water-course is covered over, to be used as a sidewalk for the miners."

NECESSITY OF A TUNNEL TO THE COMSTOCK LODE.-We have thus far reviewed the results of mining experience where drain tunnels have not been, and where they have been constructed, and the conclusion your committee arrives at is, that a deep drain tunnel to the Comstock lode will not only greatly facilitate mining operations, but is an absolute necessity; the sooner it is constructed the more benefit will be derived therefrom, and without it nothing is more certain than the abandonment of those mines before the lapse of many years.

The necessity of the tunnel having been sufficiently demonstrated, it remains to show that the ore which will probably be obtained from these mines will justify the cost of construction. The first question to be examined is, whether the ore in the Comstock lode extends to an unlimited depth. This question has been so ably handled by Baron Richthofen, an eminent geologist of the highest European reputation, that we content ourselves by giving some extracts from a letter written by him upon this subject, in February, 1865, and published in one of the pamphlets issued by the Sutro Tunnel Company. For a more detailed account of the geology of the Washoe country we refer to his able report, to be seen on the tables of this institute.

CONTINUITY OF THE COMSTOCK LODE.-The learned Baron says: "The value of a deep tunnel will, of course, chiefly depend upon the question whether those mines will ever be worked to considerable depth; that is, whether the Comstock vein will extend far down, and

whether it will retain its metalliferous character in depth. Both questions will have to be decided from the study of the structure and nature of the Comstock vein, and from compar ing the results with the observations at such mines in other countries which have already been worked to great depth. My experience on the Comstock vein is based on close and repeated examinations of nearly all the mines on its course. I believe I concur with almost everybody who has bad equal experience about them, in the opinion that it is a true fissure vein, of extraordinary length, and extending downwards much further than any mining works will ever be able to be carried on. It would be too lengthy to enumerate the various reasons which lead most positively to this conclusion. It is now assumed almost universally as a fact, and the number of those who consider it as a gash vein, or a system of gash veins, is fast diminishing.

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As to the downward continuance of the ore-bearing character, every instance goes to show that the average yield in precious metals remains about the same at every depth. Some mines had accumulations of ore near the surface, (Ophir, Mexican, Gold Hill:) in others they commenced very near under the surface, (Gould and Curry, Potosi, Yellow Jacket, Belcher;) at others, again, considerable work had to be done before bodies of ore of any amount were struck, (Chollar, the southern part of Gold Hill, Uncle Sam, and others;) and some which had no ore heretofore, appear to have good prospects to find it soon. The fact that some rich bodies of ore, which were found near the surface, gave out at a depth of a few hundred feet, induced the common belief that the Comstock vein was becoming poorer in its lower parts. But the explorations of the last few months have entirely defeated this opinion. On the contrary, the enormous amount of bullion which is being produced by the mines at present may almost appear to prove that the vein is improving in depth. But this conclusion is probably equally fallacious, as it must be borne in mind that many mines have been developed at different levels and ore is being extracted from several of those. Hoisting works and the mode of extracting the ore have also been improved, and of course help to increase the daily produce. This average equality of the produce of the vein at different levels is not only true for the amount of ore extracted but also for its yield. The rich body of ore in the Ophir aud Mexican mines forms the only exception to this rule, as none of equal average percentage in silver and gold has been found again. Even the relative proportion of gold and silver in the ore has not undergone any material change, though the bullion, on account of the more imperfect process of reduction, contained at first proportionally more gold than at present.

"There is no reason to doubt that the equality of average produce and yield throughout the entire length of the vein will continue downward to any depth; besides the very obvious theoretical conclusion that vast amounts of silver could not be carried into the fissure from the overlying or enclosing rocks, but naturally had to rise from unknown depths, through the channel of the fissure itself, to be deposited in it where the conditions for sublimation or precipitation were given in its open space; experience in other countries by no means shows of a regular decrease or increase in yield as of common occurrence, though either of them may happen. More commonly, the produce of true fissure veins in precious metals has been found to be about constant.'

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The Baron wrote the above over two years ago; the explorations made since that time in the Hale and Norcross and other mines, strongly confirm the views expressed by him.

Nearly all writers who have specially studied the question of the continuance of mineral veins in depth have arrived at the same conclusion. We will give an extract upon this subject from an eminent French writer, M. Burat. He says:

"In all countries where isolated veins are worked, a large number of them have been abandoned and taken up again; abandoned because accidents or barren streaks rendered the working burdensome, and afterwards taken up again, when they have, by the aid of capital, been made productive mines. The same veins have been declared to be rich or exhausted for these reasons at different times; exhausted always when the owners were discouraged, and rich after the execution of further works had pierced the barren places. These are the facts of which we will relate several examples, and by which we intend to prove that each reworking of a vein after an abandonment more or less long, bears witness of the continuity of mineral veins in depth."

Burat and other prominent writers recite numerous instances of this kind, but we cannot give place to them in this report.

THE SUTRO TUNNEL.

The proposed tunnel begins 34 miles below Dayton, between Corral and Webber cañons. The distance from the mouth of the tunnel to the Savage Works is a little over four miles, but as the Comstock lode dips to the east, it will be cut in 20,178 feet. It will pass through the different ledges in Silver Star and other districts nearly at right angles. Allowing a grade of one inch in 160 feet, or four and four-tenths feet per mile, it will be 1,922 feet below the floor of the Savage Works. The topography of the country is admirably adapted for sinking shatts, four of which are proposed to be put down. They will not only supply the tum el with fresh air, but will greatly expedite work, as drifts can be run each way after reaching the grade of the tunnel. The distance of the first shaft from the mouth of the tunnel is 4,070 feet; depth, 443 feet; second shatt from first, 5, 159 feet; depth, 980 feet; third shaft from

second, 4,060 feet; depth, 1,436 feet; fourth shaft from third, 4,654 feet; depth, 1.360 feet; from fourth shaft to Comstock lode, 2,244 feet; depth. 1,942 feet. These are convenient distances for working and ventilation. The mouth is about one and a half mile from Carson river, and 150 feet above high-water mark. There is a gradual descent for about one-third of a mile, in which a fall of 100 feet is obtained, giving sufficient area for dumping and mill sites.

The vertical section of the tunnel through rock not requiring any support is a circle of 12 feet diameter, with offsets 33 feet from the bottom, about one foot wide, which support the superstructure of the railroad track to be used for removing ore and debris from the mine. The space under the superstructure is for drawing the water from the lode. Where timber supports are required to sustain the adjacent rock, the top is level, and 10 feet wide, clear of the framing: height eight feet to the bottom of the timbers supporting the railroad, where it is 12 feet wide in the clear. Below this there is a trianguiar space, three feet seven inches in depth, forming the water way.

The estimates of the cost of construction have been very ably discussed in a lengthy report by R. G. Carlyle, esq., covering some 200 pages of manuscript, and illustrated by numerous well-executed diagrams. Mr. Carlyle has resided some years in Virginia City, when he was the engineer of the Gould and Curry Company, and appears to be thoroughly familiar with everything connected with mining in that country. The minuteness with which he goes into the details of the proposed work, the elaborate calculations into which he enters, and the scrupulous manner in which he weighs his conclusions, entitle his report to careful consideration.

It is impossible for us to give more than a condensed abstract of the results he has obtained. The basis of his calculations is the experience of himself and others in mining near Virginia City, and the statements of Baron Richthofen in regard to the character of the material encountered in the construction of the tunnel. The Baron says:

"The facilities of excavating the tunnel would depend mainly upon the quality of the rock through which it will pass." It is a remarkably fortunate incident that the route selected by Mr. Sutro not only gives the greatest depth, is the shortest, has the best facilities for working shafts, but promises also in this respect to be the most advantageous. The first 6,000 or 7,000 feet will be through trachyte and trachytic breccia, which in a broad semicircular belt of prominent hills, swing from Dayton by the Sugarloaf to Washoe valley. Trachytic breccia may easily be worked by the pick, yet is ordinarily solid and dry enough to require no timbering. An idea of its excellent qualities for tunnelling may be formed from the fact that in Hungary wine cellars hundreds of feet in length are with preference excavated in this kind of rock. The solid trachyte is an excellent blasting rock. Its superior qualities have caused its general use in Washoe for building material; it was as such applied in the construction of the solid masonry of Gould and Curry mill. With the use of the drilling machine of Mount Cenis, speedy work will be made in this rock. The next 2,500 feet will, to all probability, exhibit a great variety of rock, some of which will be rather hard. The following 10,000 feet to the cutting of the vein will most likely consist of the same material as is traversed by the numerous tunnels which lead at present to the Comstock vein. This rock (trachytic greenstone) would offer some obstacles if it were in an undecomposed state. But from the general nature of its decomposition, which evidently was performed from below by ascending steams and vapors during a time of volcanic action, we believe we are justified in the conclusion that it will be found for the entire length of 10,000 feet of the same rotten nature as in the shallow tunnels at present in existence, and it may have to be timbered the whole distance."

Mr. Carlyle speaks as follows in regard to his experience with the two principal kinds of rock to be encountered:

"While I was in the employ of the Gould and Curry as their chief engineer, we used solid trachyte for building purposes, taken from a quarry on the side of the Sugarloaf mountain. I had, therefore, considerable opportunity of learning the particular characteristics of the stone. It is not porous, but is very close in its nature, has very few seams, no grains or special tendency to fracture in any particular direction. It is rather soft, and, in consequence, is easily drilled to any desired shape. The rock drills well and blasts freely, as it does not seem to have much cohesion on account of its many component parts. The rock does not airslack; on the contrary, it grows harder by exposure."

This rock is extensively used for building purposes; all the stone buildings in the town of Dayton are constructed of it.

His experience in working greenstone porphyry he gives as follows:

"This class of rock is traversed by several tunnels to the Comstock lode, all of which were easily worked, and they had to be supported by timber. The Gould and Curry lower tunnel is the only exception to this, as it passed through 1,400 feet of undecomposed rock, which was not difficult to work on account of its favorable stratification; powder was used but to a small extent, and this for the purpose only of shaking the mass. The remaining 800 feet to the lode had to be timbered, as the rock would not support itself. The whole length of this tunnel, 2,200 feet, was run from one working point in 46 working days, or 16 months; the work, however, was distributed over a period of two years, as it did not progress steadily. The average daily progress was nearly five feet."

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