[Dan De Quille, The Comstock Vein, Daily Alta California, 3 May 1885] 

 

THE COMSTOCK VEIN.

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The Old Lode Still "Alive" and Growing.

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THEORY OF MINERAL VEINS.

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Features of the Comstock and Steamboat Springs Compared – The Birth of a Lode – Curious Incidents.

[WRITTEN FOR THE ALTA BY DAN DE QUILLE.]

            There can be little doubt that the Comstock lode is still growing, or in other words that the causes which produced the great vein are even to this day in operation, though evidently with diminished activity. The lode was probably millions of years in reaching the condition or state of growth to which it had attained when it was first discovered and the extraction of its stored wealth commenced ; in millions more (if left undisturbed by man) all the great chambers that have been robbed of their ore might again be filled. There is good evidence that the material within and about the Comstock is still "alive " and sensitive, and this being the case it is doubtless fulfilling its proper functions and doing its appointed work. In all things that have life we observe that Nature makes an effort to heal wounds and to advance growth. Let the flesh of man, or of any living creature, be wounded and Nature exerts her powers to repair damages. It is the same in the case of a wound to the bark or wood of a tree, or to the stalk or leaf of a plant. While there is life Nature puts forth her powers to heal, but let the man, animal, tree or plant be dead when the wound is inflicted and the injury remains the same until that which has suffered it crumbles and resolves into the dust whence it came.

THE COMSTOCK STILL ALIVE.

            We have said that the ground in and about the Comstock is still " alive," and the proof of the truth of this statement is found in the fact that in it Nature still exerts her formative energies and her inherent puissance for the healing of its wounds. It is found that in all the softer ground along the Comstock (its flesh) where a drift is run (a wound inflicted) a movement is seen toward the closing of it. The adjacent parts begin moving toward each other, and the healing process has commenced. This movement is called by the miners the " swelling " of the ground. If left to itself— to the kind solicitude of Nature— the wound soon closes and eventually perfectly heals. In many places this movement amounts to more than a mere swelling of the ground — amounts to a degree of motion that is almost startling in its energy. Belts of a peculiar kind of clay that have been cut by drifts have been known to rise from the floor day by day until more than thirty feet have been cut away. The clay in the roof (the lopped member) remains stationary, dead, while that in the floor long continues to be pushed up from its root. In the work now being done in the old upper levels of the Consolidated Virginia has been encountered a very interesting exemplification of the healing processes of Nature as referred to above. Drifts that were run some years ago in porphyry, not in clay or ordinary soft ground, are found to have closed so effectually that timbers sixteen inches square have been compressed to about three inches. It is necessary to again blast out the material, so thoroughly has the ancient wound " healed," and but for the presence of the compressed timbers it would be difficult to convince the observer that the ground had ever before been opened. In the same mine, on the 1,200 level, are drifts that were years ago filled with waste which are so effectually closed and solidified (healed up) that in opening them it is now necessary to blast as at first. Not only are the contents of these drifts agglomerated by compression, but they are also agglutinized and brought to the greatest possible degree of homogeneity through the condensation in their midst of vaporous emanations and gaseous exhalations from heated subterranean depths. But for the finding of occasional remains of timbers in these drifts, or of fragments of rock showing the marks of tools, the present miners would see no trace of their predecessors of less than a score of years ago. The broken parts have united and knitted like the sections of a fractured bone.

THE GROWTH OF QUARTZ AND MINERALS.

            In openings where quartz — in place — was exposed by former operations, it is not improbable that a close examination might show some slight evidences of increase of mass. As " like begets like," and like consorts with and cleaves to like, the minerals with which the ascending gases and vapors are charged seek their affinities. The nobler parts, which belong to quartz and the metals, go to and unite with quartz and the ores of such metals as are forming in and about that rock, while the baser constituents go to build up porphyry, lime rock and similar formations. Quartz and the metals are necessarily of much slower growth than the commoner rocks, as the proportion of quartz and the metals to the meaner rocks in the earth's crust is as one to many millions ; yet in what may be set down as exceptionally favorable situations, both quartz and some of the metals have been known to exhibit a perceptible growth.

            An old Comstock miner, to whom we have read the foregoing, informs us of an instance of an interesting example of the formation of a quartzose mass on the surface of the earth and in the open air. He says that in June, 1876, he and a friend were following the line of the Chollar croppings southward, toward Crown Point ravine. While on the southern slope of Mount Davidson they sat down upon the ground to rest and speculate upon the probable course of the vein. His companion presently declared that he felt warmth in the spot of ground on which he was seated. An examination showed there to be at the place a considerable accumulation of quartzose material. Looking more closely, a faint jet of vapor was observed to be escaping through a small opening in the midst of the growing mass. Our informant revisited the spot about eighteen months ago and found that the mass of mineral matter had considerably increased in size, and was evidently still growing. Mr. Havenor, Deputy Commissioner to the World's Exposition at New Orleans, has in his collection of specimens from the Comstock a piece of quartziferous material that was deposited upon a timber in the Yellow Jacket mine. A small jet of steam from the subterranean depths of the mine probably issued from a vent in the rock against which the timber rested. While this quartzose formation was doubtless different from the quartz formed in confined places and under pressure, it is probable that it is not very dissimilar to much of the material that forms the filling of many parts of the Comstock lode — those parts in which a considerable amount of lime is observable.

A CURIOUS INCIDENT.

            In a chamber in a mine in Grass Valley, California, that had for many years been flooded, it was found upon renewing operations, about 15 years ago, that a drill hole in a vein of quartz had healed up around a small rod of iron, or "spoon," that had been left in it, and that several clusters of small crystals had shot out in a fractured portion of the vein. Also, in a copper mine of Cornwall it was found on draining a shaft, which had long been flooded, that there had been so great a growth of metal and pyrites as to completely involve and cover tools left behind by miners in their hasty flight This, however, is nothing very wonderful, as it is a fact well known that iron deposited in the water flowing from a copper mine soon accumulates a heavy coating of metallic copper. The noble metals are undoubtedly of much slower growth.

            A few years ago a paragraph went the rounds of the newspapers, apparently on the authority of a man of science in one of the Atlantic States, that a particle of gold imbedded in a lump of iron pyrite, that had a place in his cabinet, had grown perceptibly and taken upon itself the form of a tendril. It is needless to say that in a situation of the kind such growth was an impossibility. The pyrites had perhaps slacked and fallen away leaving more of the thread of gold visible than was at first seen. Such a nucleus of gold would doubtless increase in size in the course of ages, if left in its matrix in the depths of its native mine where it would be exposed to the gaseous emanations arising through the fissures of the lode. Indeed, Platner, Danfree, Durocher and others have not only succeeded in producing quartz artificially, but also the ores of iron, lead, tin, antimony, silver and several other metals. This was done through sublimation by heat and condensation in a proper receptacle.

THE FORMATION OF MINERAL VEINS.

            It is now conceded that the majority of mineral-bearing lodes are formed either by sublimation or infiltration, very few persons at present holding to the old theory of the injection of molten matters. Hot mineral springs are important assistants, if not indispensable requisites, in the formation of mineral veins. At Steamboat Springs, in Washoe Valley, the formation of a large mineral vein is now undoubtedly in progress. So slow is the process of formation, however, that to produce a vein such as the Comstock must have required ages, almost beyond computation. At one time, ages and ages ago, the hot water now found at the depth of from 1,500 to 2,000 feet undoubtedly reached the then surface along the line of the lode. Ages ago the subterranean fires and forces directly beneath and all about the Comstock were undoubtedly much more active than at present. The burnt and discolored hills in various directions, particularly on the east side of the lode in Flowery District — where were the latest vents for the heat, heated vapors and hot water of regions beneath — still mark points where almost volcanic activity once existed. Indeed, on the west side of Mount Davidson and above American Flat are to be seen the craters of two extinct volcanoes.  

            All lodes, however, have not been formed in the same manner. Not a few show that they owe their existence principally to aqueous solutions, while in others evidences of condensations from sublimations or gaseous emanations predominate. In great veins like the Comstock, there are nearly always to be found proofs of the work of formation having been performed at widely different times, as well as through different agencies; aqueous forces being at one time in ascendency, and the gaseous, with sublimations from great heat, predominating at another. Besides all this, all mineral lodes are subject to transformation after formation. Nearly all, therefore, have reached our age after having passed through a variety of influences. Aqueous deposits have been changed by plutonic forces and deposits from sublimations by aqueous precipitations and infiltrations.

THE SLOW PROCESS OF NATURE.

            To say nothing more about the formative processes by means of which the Comstock lode was filled and mineralized, it is evident that some of the causes through which its production was effected are still in operation; that it is still " alive " and sensitive to wounding and encroachment. The internal fires beneath the earth's crust are still active ; heated water is still being forced up and put in circulation among the rocks as a solvent, and the rocks themselves are kept at a high temperature, which all chemists know is favorable to condensation by crystallization. As the machinery in the workshops is still in operation, it must be that some work is being done. The progress of this work, however, may be so slow as to be almost imperceptible and incapable of computation through measurement, unless a special study of it should be made, extending over a great number of years — perhaps from generation to generation of man and age to age of the earth. But if we are enable to note and measure the work accomplished in a given number of years, we may readily find and study the evidences that it is still in progress. The closing up of the ground where openings are made and the cementing of materials loosely deposited in such openings into a homogeneous mass, are evidences that the heat of the water and rocks, and the various emanations from the bowels of the earth are still exerting their procreant influences. The heated waters are doubtless still dissolving oat of the rocks their metalliferous contents and depositing them in a more condensed form, but the rate at which this deposition proceeds is so slow that during the period alloted as the life of man it would probably not exceed in thickness a sheet of ordinary writing-paper.

THE U. S. GOVERNMENT INTERESTED.

            Recently our Government has shown a disposition to investigate this interesting and instructive matter of the formation and growth of mineral veins, and last year sent a competent corps of engineers and scientists to Steamboat Springs, where Nature has in her laboratory in process of evolution a quartz lode of great size — a twin of the Comstock. The results of the observations of the geologists and chemists of the corps will be published in a year or two, and the conclusions arrived at will undoubtedly be of great interest and value to the world of science. At an early period of its existence the apex of the Comstock probably presented much the same appearance as now does the fuming and fissured ridge forming the apex of the range of hot springs at Steamboat. Had the Government scientists then been in existence to have studied the Comstock in embryo, or in its swadling clothes, they would probably have seen nothing more than they saw last Fall at Steamboat Springs.

FORMATION OF THE COMSTOCK.

            They would also, it is almost certain, have found the embryo Comstock situated upon a plain as low as that now occupied by Steamboat Springs, if not at the bottom of a lake. The broken and confused condition of much of the upper portion of the Comstock lode shows that it was raised to its present height and position by the same great upheaval, or succession of upheavals, that produced Mount Davidson and the range of igneous hills that lies between Washoe Valley and the valley of the Carson River. As landmarks of this period of upheavals and subterranean convulsions are left the two craters mentioned above. These probably contained active volcanoes for some time after the range attained its present altitude ; that above American Flat undoubtedly did, as lava from it overflowed the adjacent Plutonic rocks. Good evidence of this upheaval is found near American Flat, where, on the top of one of the highest surrounding hills, is to this day to be seen a bed of washed gravel, doubtless brought up from the bed of an ancient lake or stream at the time the mountain was raised to its present height. Although these cobble stones show outwardly the polish attained by attrition, all have been subjected to each a degree of heat (apparently a cooking in hot water or mud) as to destroy the cohesion of their atoms, and inwardly they are as rotten as a ball of clay.

DISPOSITION OF ORES.

            By the upheaval and consequent fracturing of the young lode many fissures and openings were undoubtedly made which afterward became the receptacles of ore deposited by ascending currents of mineral-charged gases and vapors ; for which not a few of them, by their form, would be peculiarly fitted. Observations in all parts of the world have shown that the disposition of ores is not only affected by the kind of rock forming the wall of a vein, bat also the accidental conditions of that rock — as roughness, smoothness, solidity and form— irrespective of its nature and components. Thus, in fertile portions of the Comstock it has been found that wherever a portion of the hanging wall so inclines forward toward the foot wall as to form an arched cavity, resembling what would be represented by the half-opened hand, in that place will be found an unusually thick and rich deposit of ore. It would seem that the mineral-charged vapors in their upward rush impinged upon their projections, and were so far detained as to cause larger deposits to be made than in places where the wall rock presented no such obstructions. Aqueous vapors no doubt contribute most to the formation of quartz, and gaseous and sublimated emanations most to the formation of minerals, though much in the way of mineral matter is undoubtedly deposited from solutions of minerals in heated waters.

            In what is said above about the Comstock being "alive," it is not of course meant that this life very nearly approaches the kind or degree of life that is observed in men, animals and plants, but life is contradistinction to the apparent condition of our satellite, the moon. The lode is one of those places in which our planet still manifests its creation, or rather formative powers, and gives those signs of the life within its bosom which appear only at wide intervals on the surface.

            These indications of inward life and formative activity are still more apparent at Steamboat Springs, where we have an embryo mineral lode, as perhaps the foetus of a lode. It has probably not yet attained to a proper growth to be ejected from the womb in which it now lies quickening, but the time will come — as it came to the Comstock—when by a great throe of nature, manifested in old mother earth, it will be thrust forth and its crest will rest hundreds of feet above its present position— will rest upon the bosom of a range of igneous hills raised from the depths as a nurse for its support and sustainance.