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involving large expenditure been entered upon without calculations based on reliable data having first been made, and the whole committed for execution to careful and experienced management. It is not the custom now to build expensive mills or reduction-works without something having been first ascertained as to the capacity of the mine whence ores are expected to be obtained for supplying them. Indeed, a good degree of development is insisted upon as a condition-precedent to considering the question of erecting reduction-works, while in most of our large mines extensive deposits are held in reserve, and exploratory labors maintained well in advance of extraction. In strong contrast with the unfortunate results of the large enterprises set on foot a few years since, are those generally reached by companies who have more recently engaged in quartz and placer mining on a large scale. Then failure was the rule, and success the exception, a condition of things which is now almost reversed, more especially in the State of California. Parties operating in mining stocks continue, as they ever will do, to meet with disaster. Corners are made and the venturesome and unwary are caught, as they ever will be, by their more vigilant and astute adversaries. Reckless ventures and wild speculation are as rife as ever, bringing fortune to some and discomfiture to others, while certain mines are managed, as before, in the interest of selfish rings and combinations. But all this has, it is needless to say, no necessary connection with legitimate mining, which should in no sense suffer disparagement from practices so detrimental to its best interests and so foreign to its objects.
Causes of past failure.-A practical miner of many years' experience in California and Nevada, in investigating the causes of disaster to so many of our mining operations in years past, says failures have often been attributed to the high rates of labor, but a critical investigation would show that it was to be attributed more frequently to other causes, which he thus enumerates: 1st. Too extensive as well as too expensive machinery on too small developments of positive property. 2d. Too much expenditure in corporate associations for speculative purposes, and too little for practical mining. 3d. Too small a percentage of metal saved after heavy expenditure for extracting and raising ores.
In seeking for the cause of many early failures much stress has been laid on the defective and careless manipulation of our gold ores—errors which, now that attention has been so strongly called to them by the press of the State, are rapidly being remedied by experiment and invention. On this subject I quote the following extracts from a series of articles on the "Wastage of the Precious Metals," written for the Mining and Scientific Press by Almarin B. Paul, of San Francisco:
The fact that a high percentage of the precious metals is lost in the manipulating of ores by the present modes of working, no one for a moment questions; but when it comes to any special data, but little has been presented to the public. Some assert their loss to be only a trifle, while others, who more closely investigate, know it to be greater than it should be. Having closely investigated the subject for the past two years, I find the average loss, especially in California, so great, that really I think, if there is not more care taken in the husbanding of our riches, when extracted from the earth, that the Government should take measures to do so.
There is an idea that all gold is readily amalgamated, and therefore it is not necessary to be so particular; consequently there is an unwarrantable degree of carelessness. I have learned, by practical working in both gold and silver, that a higher percentage of silver is more readily obtained by the known system of working for silver than the percentage of gold by its most advanced system, showing that gold milling is far behind silver working, although, as before remarked, gold is considered so "readily amalgamated." Yet to adopt the systems for gold that are used in silver affords no especial relief.
That my readers may have some data, as a corner-stone, to build their ideas upon,
before I go too far in my general observations, I will give a few tests of the many which I have made in the last two years, and intersperse with them, as additional evidence, tests of other parties. And here I would call the reader's especial attention to the fact of a goodly percentage of silver in all of our California ores; and I will also remark that the assay of tailings does not even show what percentage of silver the ores may contain, as some may be in the form of chlorides which move off in the water. But to the tests of our gold mining.
Test No. 1. Average yield of ore in mill, $18.60. Wastage after complete washing, including concentrating-silver, $3.14; gold, $10.04; total, $13.18.
Test No. 2. Same mill-tailings 350 feet from mill: silver, $3.93; gold, $5.02; total, $8.98; showing that a percentage secreted itself in its passage down stream.
Test No. 3. Average yield of 150 tons, $3.50. Assays of tailings carefully sampled : silver, $6.28; gold, $13.55; total, $18.83. Silver, $6.28; gold, $8.79; total, $15.07. The above bad results were occasioned by the extreme fineness of the gold. And even the above does not show the full wastage. To corroborate this I will give some admirable tests made to get at the question of "float gold."
A friend of mine, having somewhat similar ideas to my own, concluded to test the question of float gold as well as he could at the time, and embraced the opportunity of cleaning up the slum from a water-tank for supplying the battery, where the water was used over and over again in consequence of its scarcity. The ores were worked after the usual wet method for gold ores. The water and pulp were first passed through a sluice to tailing bed, 190 feet. The tailings being deposited, the water was drawn off at the top, flowing into a well, where it was raised and passed through a sluice 120 feet to tank at battery. This is the tank cleaned up.
The residue was amalgamated in a tub quite rudely, but with a large body of mercury and chemicals. The result was $33 in silver and $56 in gold, making a total of $89 per ton. It will be observed that there were two chances for the metals to precipitate previous to reaching this tank: first, in the tailing reservoir, and second, in the well.
This "float"-metal question is further established by a system of tests made by Mr. G. McDougal, of Grass Valley, who very kindly allowed me to extract the same from his books of tests. And here let me say that these tests are made from water flowing from mills at a point three-fourths of a mile below the mills.
1st test of 20 gallons of water gave.
It was estimated that 576,000 gallons of this "muddy water" flowed by every 24 hours, which, according to these tests, contain $339.84. Let us carry this calculation a little further.
The average amount of ore worked in 24 hours was given as 58 tons. that $5.85 per ton "floats," which probably is at least 20 per cent. of the yield. Let us run this loss a little further. Suppose the two mills run 250 days in each year, which is not unreasonable, and we have a yearly loss in "float gold” alone, to say nothing of loss by imperfect pulverization and general wastage, of $84,960 from two single
Extend the test as far as you may, on a smaller or larger scale, and wastage stares one badly in the face at every turn.
I made a test of 50 pounds of tailings for a party who took them a mile below his mill, and the return was 55 per cent. of what was his average working. I also made a test of three-fourths of a ton, and the result showed the loss in the mill-working to be 63 per cent. From what attention I have given the subject in actual labor, as well as collecting all the data attainable from others, I know that the loss as a whole is fully per cent., and, in the majority of mills, all of 60 per cent. of what the ore contains. From these data of loss we must come to the conclusion that gold mining, not only in California, but elsewhere on the Pacific slope, as all are operating on about the same system, is not up to the point it should be. In fact, so imperfeet is it, that it has been
H. Ex. 211-2
said that our gold mining enterprises, as a whole, may be set down as a failure, when the question of profit in all is considered.
One step in advance would be, taking more care. There is too much slashing about in our gold mining. There is enough in silver, but no comparison between the working of the two metals. This plan of seeing how much can be pounded up and rushed through every 24 hours, is a false, wasteful, and ruinous system.
The profit will be found in how well and how cheap it can be done. It is in the right direction, certainly, to reduce ores expeditiously and cheaply, but not to as expeditiously wash everything away, having an eye more to pounding up the rock than to taking up the metal.
That our gold ores are so readily amalgamated, is one of the ruinous ideas extant. The majority of California miners are, in fact, but little experienced in all the troublesome accompaniments of even gold ores, considering that if the rock does not pay, it cannot certainly contain it. All, however, admit it to be difficult to extract the gold from iron sulphurets, forgetting that even a small percentage of lead, copper, arsenic, or antimony, which is to be found in nearly all the gold ores of California, vitiates the mercury in a little while, rendering it quite inefficient in collecting even the gold that otherwise from gravity might be taken up. It is too universal to consider that it is only necessary to rig up a set of stamps, apply the power, and let them rip away, smashing rocks, to wash over blankets and copper plates; and all is done with a stream of water to wash the sands off, forgetting that it is equally as potent to wash off the smaller particles of gold.
Some will say, it is all well to talk about loss of metal, but how can we prove it, and where is the remedy?
I will tell you how to prove it, but each must work out his own remedy. For my part, I have worked out the loss by what I consider the remedy-dry amalgamation; but our subject now is loss, not remedy. To awaken the mind for improvements, and be interested in a remedy, miners must first realize their loss. I contend there are several ways of working our gold ores better than the one now universally used in California. If you want to get a clear comprehension of your loss, take, say, 5 tons or more, not less. Reduce the ore dry through say No. 20 wire-cloth screens; mix all thoroughly, then spread it out upon a floor about two inches thick. Lay it out in 12-inch squares, take a smaller quantity from each square, take samples thus obtained, and again mix them. Again spread out, say, one inch thick, laid out into 4-inch squares, taking a smaller portion from each. Reduce this sample to powder; if too much for average assays, sample again as before. Get 3 or 5 assays from reliable assayers, average the assays. Work your ore by your mill process; compare the results with assays; and in nine cases out of ten every one will find he possesses more riches than he thought he had. Any other system of testing is unreliable. Pieces of rock can be had to assay more or less, as you want. To get at the value of your mine, the testing of tons by this mode is the only safe one.
Mr. Paul further calls the attention of our miners to the existence of a large percentage of silver associated with the gold-bearing quartz:
That there has been still too great a wastage of precious metal, all admit; not only is this in our gold in gold mining, but in the silver associated with the gold. This fact is not generally understood, as California miners are not accustomed to getting silver with the gold, a thing precluded by their present mode of working. An investigation will disclose the fact that nearly all the gold ores of California contain no meager percentage of silver. The same may be said of the "gold ores" of other States and Territories. By way of illustration the following assays are given:
The yield of Quartz Mountain ran 9 per cent. silver. The ores of all the counties of California carry silver, and my experiments show they run from 3 to 50 per cent. of the yield.
The closer the concentration from batteries, the higher is the percentage of silver. It is time we were investigating more closely, and outgrowing this rushing system of mining, and, instead of sluicing our silver and gold down streams, seeking modes of working that will produce less wastage. As far as California is concerned, I am satisfied that not more than 40 per cent. of her gold is extracted. The fact is, as before expressed, we are not working for gold or silver, but to crush rock.
Mr. Paul's opinions on the condition of the gold are given in the following extracts:
Our present general system of gold mining is based upon the idea that gold is mainly coarse, while examination will show that the high percentage is in atoms finer than flour itself. In my experiments gold has been taken up so fine that in distilled water it would not precipitate in less than from five to ten minutes. Can you save gold of this kind by running water down stream? Again, can you obtain the gold of this fineness, without minute reduction? Therein lies the secret of high assays before working, and small returns after.
Gold in its matrix, according to the highest authorities, is in a metallic condition. Such being the case, the first requisite is minute reduction, to the fineness of the gold itself, in order to release it. Gold in quarte of gravity enough to resist the pressure of any stream of water is the exception, and this is the aggregating of finer particles, the primary simple condition, in my opinion, being flour or powder of gold. It is the flour of gold we must seek to obtain, to get the wealth of our ores.
In commenting on the disasters that have so often overtaken mining enterprises on this coast, too much stress has sometimes been laid upon a presumed gross mismanagement, or a willful purpose to defraud. To these much of the failure and loss heretofore sustained is undoubtedly due; yet it should be recollected that mining for the precious metals was a business with which our people were wholly unacquainted at the outset. When we embarked in this pursuit, one naturally beset with obstacles and full of inherent difficulty, we had everything to prepare and everything to learn. Not only so, but we had to make our first trials under circumstances that rendered the mining and metallurgical knowledge gained elsewhere of little avail. The experience obtained in the Old World and the rules laid down in the books could not be applied here to advantage. The high prices of labor, the want of material, the character of the ores, the climate, and, in short, all the conditions, were so unlike those to which the experts of other countries had been accustomed, that they, of all others, proved the most inefficient and helpless. In attempting to adapt themselves to surroundings so new and strange, none found themselves at so great a loss or blundered more widely than they. Of all failures, those of our scientific men from abroad were at the first the most signal. Our sins were, therefore, at first, mostly the sins of ignorance, and our errors, the errors of judg ment. If, in a few instances, deliberate frauds have been committed, it is no more than has happened in the conduct of many other kinds of business not accounted specially difficult or hazardous. Or if it should appear that there has been some extravagant and even culpable expendi ture incurred on mining account, it may yet be claimed that we have introduced many valuable improvements into this business, and advanced it with an energy that more than atones for these wasteful and unwarranted outlays. It is now generally conceded that we have, in the matter of mechanical contrivance, if not also in metallurgical skill, advanced this industry in all its branches far beyond the point where we found it, and even beyond its present status in almost any other country. In the adaptation of means for washing auriferous earth, in the use of hydraulic power, in our ore crushing machinery, our roasting-furnaces, our concentrators and amalgamators, and in much of our other milling-apparatus and appliances, we can point to improvements that leave us without a rival elsewhere. Both as regards the exploitation of the mines and the beneficiating of the ores, we can justly claim to have reached as great perfection as any other nation in the world, having contributed our full quota towards the wonderful advancement that this branch of mining has undergone during the past quarter of a century.
Present and prospective production.-With so much progress made and
so large an aggregate of improvements effected, a large and profitable production of bullion has ensued, leading to heavy investments in mining properties on both home and foreign account, and to an unwonted activity in every department of this industry. The yield of the precious metals for the entire coast has, of course, been greatly curtailed in consequence of the restricted amount of rain that has fallen for the past two years; the effect of which has proved more disastrous to the mining interest of California than of any other portion of the Pacific slope, as we have here many quartz mills dependent on water for their propulsive power, while placer washing constitutes, in favorable seasons, our most prolific source of gold production. But despite this serious interference the California yield for the current year is probably $20,000,000, a sum that would, with the ordinary supply of water, have been increased fully one-fourth. Owing to the introduction of improved machinery and modes of washing, as well as to the employment of more efficient metallurgical processes and labor-saving contrivances, the profit margin is being steadily enlarged in mining operations even while working a lower grade of material; much auriferous gravel being now washed and ore milled with satisfactory gains that would not a few years ago have paid working expenses. Hence the maintenance of such a high rate of production in the face of a drought almost unexampled for its long continuance and severity. During the prevalence of the drought our hydraulic and placer miners have been engaged in the extraction and accumulation of dirt, and in running deep-drainage tunnels, until they have now large quantities on hand, ready for washing as soon as the rainy season will permit. As we have now had three dry years in succession, we may safely count on the incoming winter being a wet one, affording the waiting miner all the water that his needs require. Should this prove to be the case, a heavy yield of gold will be speedily gathered, insuring for next year larger product than has been realized in California for several years past.* Indeed, a heavy annual increase of bullion in this State may be calculated upon for an indefinite period to come, in view of the impulse lately given to mining enterprise through the liberal investments of capital and other assistance brought to its aid. In the construction of capacious hydraulic works, looking to vastly increased supplies of water, in the extensive opening up of the old river-channels and gravel-banks and in the erection of many large mills and reduction works, to say nothing of the favorable developments being everywhere made in our mines, we have ample assurance of the largely augmented production that awaits us in the future. There is good authority for believing that with the usual supply of water the yield of the California mines alone would be increased $500,000 per month. With all the water available for that purpose introduced into the mines at the head of the State Creek Basin, Sierra County, it is computed that two million dollars could be annually taken from that locality more than it affords at present. With the Von Schmidt ditch completed according to the original plan referred to elsewhere in this report, the gold-producing capacity of the country to be supplied by it, already one of the most prolific in the State, would at once be more than doubled. In El Dorado County the California Water Company are constructing a system of ditches and reservoirs which will furnish from 30,000 to 45,000 inches of water, miners' measurement, and open a large section of gravel country hitherto untouched or worked only on a small scale; while at Parks Bar in
*Since writing the above my anticipations have been more than realized, as the rainfall for December has been almost unprecedented, giving promise of a year of abundance to both the miner and the agriculturist.