Slike strani
PDF
ePub

breaking the crust, numerous fissures and small cavities, lined with sulphur crystals of great beauty, were brought to light. Through the fissures, which seemed to communicate with the depth below, hot aqueous vapors and sulphurous fumes constantly escape. The fused mass, covering many acres and exhibiting a bluff front some forty feet high, is exceedingly compact and ponderous in structure; of various shades, from yellow to almost black. It seems to be very pure sulphur. The quantity is enormous, and at no distant day may be made available.

“From the “sulphur bank’ I again turned my attention to the ravine. The water, as I had before ascertained, was strongly impregnated with boracic acid, in a free state. The stream is small, yielding only about three gallons per minute, and is soon lost in the sandy soil, in its progress toward the margin of the lake. From the porous nature of the ground surrounding the spring, and saturated with the same kind of acid water, it is probable a large quantity escapes without making its appearance on the surface. The soil for some yards on either side of the ravine is, to the depth of an inch or two impregnated with boracic acid in summer. Sulphuretted hydrogen escapes in continued bubbles through the water, a feature common to all the borax localities I have yet found; in some places, however, the carburetted takes the place of the sulphuretted hydrogen. The head of this ravine is about three hundred yards from the margin of Clear lake, winding around the base of the “sulphur bank, receiving some small springs in its course, which seem to have their origin beneath the sulphur. The flat land bordering the lake, some eight acres in extent, through which the ravine runs, shows a strong impregnation of boracic acid in its soil. The point where the ravine enters the lake is marked by a large quantity of water of a boiling temperature, issuing through the sand, a little within the margin of the lake. This percolation of hot water covers an area of one hundred and fifty by seventy-five feet. This fact I observed on my second visit, but not until the third or fourth visit did I ascertain that the water contained a considerable

quantity of borax, along with an access of boracic acid. From a gallon I obtained four hundred and eighty-eight grains of solid matter, consisting of borax, boracic acid, and a small portion of silicious and other earthy impurities. On digging to a slight depth just outside the lake, the hot water burst up and ran off freely. From one of these places a stream issued of sixty gallons per minute. I have estimated the entire quantity at three hundred gallons per minute, and feel very confident of being largely within bounds. The stream seems to come from the direction of the sulphur bank, and it would probably be easy to intercept it be fore it enters the lake, by digging a little above high-water mark. It may be well to note here, that the difference between high and low water marks in Clear lake is never more than three feet.

“The enormous amount of borax these springs are capable of yielding would equal half the quantity of that article consumed both in England and America. The large quantity of water in which it is dissolved would, of course, involve the necessity of extensive works for evaporation. Graduation, as a cheap and effective method of evaporation, would be exceedingly applicable here, from the continued prevalence of winds throughout the entire year. These winds blowing almost unceasingly from the west, form a peculiar feature of the country about Clear lake.

“There is nothing to hinder the manufacture of many million pounds of borax per annum, at a cost but little beyond that of producing salt by graduation. Fuel for final evaporation could be had in any quantities from the extensive oak forest in the immediate vicinity. With these observations I dismiss this locality, adding, however, that Mr. Joseph G. Baldwin located this with a four hundred and eighty acre school land warrant, for the benefit of a borax company.

"Having wandered from my story of my second visit to the 'sulphur bank,' and blended with it observations made in several subsequent examinations, I now turn to my second visit to · Alkali lake, or Lake Káysa, as the Indians call it. I need only say, however, I became fully satisfied of the great value of the locality, the extent of which has only been recently developed. I observed that the lake itself contained but little water, but that wells dug anywhere near its margin immediately filled with the same kind of water; the conclusion, therefore, was, that an almost inexhaustible supply was obtainable. I learned, too, that what seemed to be mud at the margin and shelving off and covering the entire bottom to the depth of some feet, was a peculiar jelly-like substance of a soapy feel and smell. This matter I found to be so rich in borax, that I supposed it might be advantageously used for the extraction of the mineral. Thus satisfied of the value of the lake, I little thought that within a few yards of me lay an additional value in the form of millions of pounds of pure borax crystals, hidden by the jelly-like substance I was then contemplating. This important fact was not observed until some six months afterwards.

“ This locality is by far the most important of any I have yet discovered. It is situated, as may be seen by reference to the accompanying map, in the angle formed by the two prongs into which Clear lake is divided at its eastern extremity. The elevated hill land that fills the angle separates into two sharp ridges, each following its division of the lake and leaving a valley between, of a triangular shape, near the apex of which lies Alkali lake. Clear lake is, therefore, on two sides of it, distant to the north about a mile, and to the south about half the distance. The open part of the triangular plain looks to the east, and expands into an extensive valley, from which it is cut off, partially, by a low volcanic ridge running across from one hill to the other, and thus enclosing the triangle

" This ridge is composed of huge masses of rock resembling pumice-stone, which flvat like cork in water. A thin stratum of ashy-looking soil, scattered over with obsidian fragments, covers the ridge and affords root to a stunted growth of manzanita shrubs.

“ The whole neighborhood bears marks of comparatively recent volcanic action. Indeed, the action has not ceased entirely yet; hot sulphurous fumes issue from several places on the edge of the ridge just named, on the side next Alkali lake.

“ The • lake,' as it is called, is rather a marsh than a lake. In winter it covers some two hundred acres, with about three feet depth of water. In the dry portion of the year it shrinks to some fifty or sixty acres, with a depth of only a few inches. The ó soapy matter' covers the entire extent with a depth of nearly four feet, the upper part, for a foot in depth, being in a state of semifluidity, the lower having the consistency of stiff mortar. Beneath this is a rather tenacious blue clay. This water was nearly as highly charged with solid matter as that of the lake in its highest summer concentration; the proportion of borax to other substances being greater. The soapy or gelatinous matter, however, presents the greatest feature of attraction, being filled with the prismatic crystals of pure borax. They vary from a microscopic size up to the weight of several ounces. These crystals are semi-transparent, of a whitish or yellowish color. The form is an oblique rhomboidal prisin, with replaced edges and truncated angles. In some cases the edges are bevelled, and in others the unmodified hexahedral prism exists. Beneath the gelatinous matter, and on the surface of the blue clay, and from sixteen to eighteen inches in it, crystals of a similar form, but much larger, are found. They weigh from an ounce, and seem to have been formed under different circumstances from the other crystals. My first impression was that they had been formed in the upper stratum, and, sinking by their own gravity, had found their present position. An examination proves, however, that they were formed where they lie, as particles of the blue clay are found enclosed in their centres, which could not have been the case had the upper crystals been their nuclea, for no blue matter is ever found in them.

[ocr errors]

“The first inquiry of practical interest relates to the quantity of borax already formed. On this subject I cannot speak with perfect confidence. The quantity is very considerable, but I do not look on the experiments heretofore made to test this matter as conclusive. The area covered by the crystalline deposit is not coextensive with that of the lake, but has been found over a space of about twenty acres in the examination made so far. A very valuable collateral product, iodine, with the compounds of which the water seems to be exceedingly rich, could be made a source of revenue with but little additional expense. With regard to the quantity of iodine I cannot speak positively, not having isolated the product, but from the brilliant reaction with the qualitative tests, there can be no doubt of its being great. Should this article be manufactured largely the sulphuric acid required might be made on the spot from the products of the “sulphur bank,' one and a half mile distant. With this I leave

Alkali lake. I would state that I located this place in my own name for the company.

"There is yet another important borax locality in the same vicinity, resembling much the foregoing in its more prominent features. It consists of a pond of water of about twenty acres.

The bottom is covered with the same soaplike substance, but seems to contain no crystals. The water contains less solid matter in solution, but the percentage of borax is greater in proportion to the other substances than in the Alkali lake. The borax separates readily by crystallization, and forms about thirty-three per cent. of the whole matter. Like the foregoing, this pond has no outlet and no visible source of supply; yet it is said never to be dry, although the water is never more than three feet deep. It would perhaps be a profitable source of borax if the millions of pounds the before-described localities are capable of yielding be not enough to supply the demand. It is in the midst of a magnificent grove of pines and oaks.

This place was taken by Mr. Archibald Peachy, by the location of a three-hundredand-twenty-acre school land warrant. The borates are also known to exist in other localities between Clear lake and Napa City. In Siegler valley there is a hot spring, in the waters of which I detected borate of strontia and other borate salts. Near Napa there is a borate spring, and one in Suisan valley, near the marble quarry. None of these places are important. The foregoing are the only borax localities known in the northern part of this State ; and I feel confident there are no others in that quarter that can ever compete with the inexhaustible stores of the Alkali lake and the hot springs. I had expected to find something worthy of attention at or in the neighborhood of the geysers, but there was no trace of borates in the hot waters of those springs, nor anywhere totally in the surrounding district. The geological features of the country were so different from those of that where I had theretofore found the borates, that I was able to predict as soon as I saw it that nothing of the kind existed. In a hasty reconnoissance of the great Tulare valley I found traces, but nothing more, of these substances. I have reasons for doubting the existence of any large quantities in that region. That portion of the valley bordering on the Coast range might be worth examining further. It is there, if anywhere, valuable deposits may be looked for.

“ There probably are as many as three districts in the lower part of the State presenting the borates. One or more valuable localities may probably be found

among them.

4.--PRODUCT OF BORAX IN CALIFORNIA.

Up to this date but one borax company has been formed in California. There was some talk of organizing another company eight or nine months since, the parties interested having discovered on the shores of Owen’s lake, in the southern part of the State, a substance resembling the borate of lime of South America

but an analysis of some specimens and of the waters of the lake showing no trace of borax, the project was abandoned. The California Borax Company is the only company on this coast of which I have any knowledge. This company produces at present about two tons of crude crystals daily. Their process is simple, the entire machinery consisting of six small coffer-dams, six feet square each, open at top and bottom. By means of floats these coffer-dams are sunk in the mud; the water is then bailed out, and the finer crystals extracted by washing, as in placer gold-washing.

5.-PROCESS OF WORKING.

The mud taken from different parts of the lake after the crystals have been extracted in this primitive way give, by analysis, from 11.9 to 18.7 per cent. of prismatic borax, and from virgin mud, partially dried, from which the borax has not been extracted, a result of 31% crystallized borax is obtained. Several tons of the mud, which had been worked over by the coffer-dams, were treated practically by lixiviation, and gave the following results :

Fine prismatic borax, 15 per cent. ; carbonate of soda, 281 per cent. ; common salt, 84 per cent.; equal to 513 per cent. Thus yielding in the three salts more than one-half the weight of the whole. The mud partially dried lixiviates easily, and the salts are separated without difficulty.

When the company's works are completed the present mode of production will be discontinued.

The fine crystals are found in the upper layer or stratum of soft mud to the depth of about six feet. They dissolve easily, and are subsequently reformed in large crystals by the process of boiling and crystallization. Below the first stratum is a stiff, blue mud containing the largest crystals, which are picked out by hand, the mud being too stiff to be treated by washing. The quantity obtaived by the present process could be increased by increasing the number of coffer-dams. This has not been done for the reason that the company have been engaged during the summer in the erection of expensive works for the treatment of the mud by lixiviation, having found by analysis and by actual experiment that for every pound taken out by the coffer-dam washing process fourteen or fifteen pounds go back into the lake, where it is held in solution or in minute crystals by the liquid mud. It is expected that they will be in successful operation by next spring, when, it is confidently anticipated, the capabilities for production will be practically unlimited. Borax lake covers two hundred and nineteen acres in the latter part of the

At other seasons it covers quite four hundred acres, of which about three hundred acres may be considered as borax ground. The average depth of the water is about two and a half feet. It is the mud, however, which contains the borax in large quantities. The first eight and a half feet average 15 per cent. borax, 28 per cent. carbonate of soda, and 84 per cent. common salt. Below the depth of eight and a half feet the smallness of the coffer-dams has prevented their working, hence it is not known how much further down this high average will continue. At the depth of sixty feet the mud brought up by an artesian borer give by analysis but 3.51 per cent. of borax. The intermediate points between eight and a half and sixty feet have not yet been tested. The artesian borer was sent up for the purpose of testing the ground at all depths, but, being worked by inexperienced hands, was broken on the first trial after having reached the depth of sixty feet.

An estimate of average workings shows that twenty cubic feet of mud will yield one ton, so that taking the number of square feet to the acre, the number of feet already tested, and the percentage of borax contained in the mud, an approximate idea may be formed of the value of this deposit.

summer.*

* Report of United States surveyor general of California.

The company estimate that if the crystallization which is going on all the time were to cease suddenly, they would still have a deposit of at least two thousand tons of borax and eight thousand tons vf carbonate of soda to the

acre.

Besides the innumerable boracic springs which find an outlet in the bed of the lake, there are other springs on the same property which deposit boracic acid over a large surface of ground. These are not worked for the reason that the lake furnishes the borax itself in such great abundance.

Under the impression that the total consumption of borax in Great Britain was less than 2,500 tons per annum, the company proposed limiting the capacity of their works to about eight tons a day. Recent information, however, satisfies them that the actual consumption in Great Britain is upwards of 11,000 tons. They profess to be able to place borax in London cheaper than it can be manufactured there, which, at the lowest estimate, is five cents per pound. The carbonate of soda will pay the cost of production.

The cost of labor at borax lake is $31 per month. The laborers employed are Chinese, and they find themselves. Fuel is abundant all over the hillsides. Transportation to the bay of San Francisco is $15 per ton.

In 1865 this company exported 1,707 cases of borax, valued at $38,765; and during the first nine months of 1866 they have exported 1,998 cases, valued at $42,235, and there is a steadily increasing demand for it in the markets of the Atlantic States, as its great purity is becoming known. The imports of this article on this coast have nearly ceased since this California product has been introduced. The superintendent of the mint, all the assayers and manufacturers who use this article in their operations, combine in stating that it is far better than any imported.

There are spveral lakes among the Sierra Nevadas in the States of California and Nevada, the waters of which contain large quantities of boracic acid in solution. But the only place on the coast, if not in the world, where it is found in a crystalline form in such abundance, is in the coast range.

6.-DEPOSITS OF SULPHUR.

There are sulphur deposits in many parts of the State, but only one thus far has been worked successfully—that belonging to the Borax Company, near Clear lake, which has been in operation about four months. The capacity of the present refinery is from six to ten tons per day, depending on the variable quality of the material worked.

Along the entire base of the sulphur hills flow innumerable boracic acid springs. Near the shores of the lake are boiling springs of borax.

7.–TIN.

[From the Geological Survey of California, vol. I, p. 180, by Prof. J. D. Whitney.]

The Temescal range was, in 1860 and 1861, the scene of a great excitement on the subject of tin, which metal was supposed to occur here in large quantity, hundreds of claims being taken up, covering all the hills and ridges for miles around. Tin ore was undoubtedly found at one locality in these hills and in considerable quantity, as specimens of it have been seen in various collections from San Francisco to New York. The ore, which appears to be a mixture of cassiterite, (tin stone, or oxide of tin,) with more or less earthy or mineral matter, resembling a mixture of hydrous oxides of iron and manganese, is quite unlike in appearance to any previously seen, and its true character would hardly have been recognized by the most practiced mineralogist. Some specimens, assayed in New York and Boston, gave as much as 60 per cent. of the metal.

The locality from which this ore was obtained was the so-called Cajalco

« PrejšnjaNaprej »