Figure 3.Ground Plan.a, the eye or arch in front.b b, the side walls.c, the hearth.d d, the ledges.
Figure 3.Ground Plan.a, the eye or arch in front.b b, the side walls.c, the hearth.d d, the ledges.
Log Hearth FurnaceLog Hearth FurnaceFor Smelting Lead Ore
Log Hearth FurnaceFor Smelting Lead Ore
The process of charging the furnace may be mentioned. Three large oak logs, rolled in from the back side, and resting at each end on these ledges, fill up the width of the furnace; small split logs are then set up all around on the two sides and front; the ore is then piled on until the furnace is full, and logs are then piled over it, beginning at the back, and continuing over to the front, so that the ore is completely surrounded by wood. This furnace is always built on the slope of a hill, as represented in Plate I., Fig. 1; and the hearth is laid on an angle of 45°, so that it falls four feet in a distance of eight. Two furnaces of the size here described are generally built together, by which there is a saving of the expense of one wall, and the work is rendered stronger, one serving as a support to the other. Not only so, but the same number of hands will keep a double-eyed furnace in blast, which are required at a single one. It takes three hands, one to cart wood during the day-time, and the other two to relieve each other alternately, every twelve hours, at the furnace. When a charge is melted off, the furnace is cooled, newlogs and upright pieces put in, and the whole operation begun anew. Twenty-four hours is the time generally allotted for each smelting, but it often takes thirty-six; and when there is bad wood and want of attention, it requires still longer, and indeed the result is never so good.
The ore is estimated to yield, in the large way, fifty per cent. the first smelting. A considerable portion of what is put in, however, does not become completely desulphurated, and is found in the bottom of the furnace after cooling. This is chiefly the smallest lumps, which have fallen through the apertures that burn between the logs, before they were thoroughly roasted, and thus, getting out of the way of the heat, lie entangled with the ashes. Some lumps, which are too large, also escape complete desulphuration, and either remain unmelted, or else, when the fire is raised, melt altogether into a kind of slag, and produce little or no metallic lead. This constitutes what are called the lead-ashes. The larger pieces, consisting of ore but partially desulphurated, are carefully picked out from among the ashes, and added at the next smelting in the log furnace; while the remainder is thrown by in heaps for further examination.
The lead-ashes are still rich in lead, and, when a sufficient quantity has accumulated from repeated smeltings, it is taken off to a proper place contrived for the purpose, and separated from the cinders, wood-ashes, and other adhering impurities. This is done by washing the whole inbuddles, one set below another, in the manner of the potter, when it is necessary tosearchhis clays. The ashes, which consist of clotted lumps of a moderate hardness, are first pounded to a gross powder, and then introduced into the water through a sieve. The wood-ashes and other impurities, being lighter, swim on the top, and, by letting off the water, are thus carried away. Fresh water is added, the ashes briskly stirred with a hoe, and the water again let off, carrying a further portion of impurity with it. By repeating this operation several times, the lead-ashes are brought to the required degree of purity. Thus washed, they are carried to a furnace of a different construction, called the ash furnace (see Plate II.), and undergo a second smelting.
Plate II., Figure 1.A Perspective View of the Ash Furnace.
a, the ash-pit, 2 feet wide, 6 feet long, and 20 inches in height.
b, the mouth of the fire-arch, a foot square.
c, the mouth of the flue, where the charge is put in.
d, the iron pot for the lead to flow in, when the furnace is tapped.
Figure 2, is a longitudinal section through the furnace, at right angles with the front, showing the curve of the arch, flue, &c.
a, the ash-pit.
b, the grates, 10 inches square, and 3 feet long; these are pieces of hewn stone.
c, the mouth of the fire-arch.
d, thesantee, consisting of two stones, 3 feet long, and 3 feet 6 inches wide, with a thickness of 6 or 7 inches. They reach from the bottom of the ash-pit to a foot above the basin-stone, the interstice between them being rammed full of clay, and the whole measuring 18 inches across. (This keeps the lead, slag, &c., from running into the fire-arch, and is an important part of the furnace, requiring considerable skill and accuracy in the construction.)
e, the basin-stone, 4 feet square, and 1 foot thick.
f, the flue, or throat, 10 feet long, 22 inches wide, and 11 inches in height. This must be continued a foot and a half over the mouth of the flue, or apron, making the whole length eleven and a half feet; some prefer the flue twelve and a half feet.
g, the mouth of the flue or apron, where the furnace is charged; this flares from 22 inches to 3 feet, in a distance of 3 feet, (as shown in Fig. 3.)
h, the fire-arch, 3 feet high in the centre, 18 inches high where the arch begins to spring, and the same over the centre of the basin-stone.
Figure 3.Ground Plan.
Fromatob, 8 feet; frombtoc, 8 feet 6 inches; fromatod, 8 feet 6 inches; frometof, 6 feet; frometog, 13 feet.
h, the basin, 4 feet long, and 22 inches wide, except in the centre, where it is 24 inches wide.
i, the flue.
k, the mouth of the flue, or apron, 3 feet at the front, and 22 inches in the rear.
l, the santee.
m, the fire-arch, with grates at bottom. (This is 22 inches wide at each end, 24 inches in the centre, and 5 feet long from the inside of its mouth to the santee.)
n, the mouth of the fire-arch.
o, the iron pot for the lead to flow into, set in the curve made in the wall for convenience of tapping.
p, the curve in the wall for drawing off the slag.
Figure 4, is a perspective view of the mouth of the flue where the furnace is charged.
Fromatob, 6 feet; fromatoc, 5 feet; fromatod, 1 foot.
c, the mouth of the flue, 22 inches wide, and 11 high. (This flares out to 3 feet in the distance of 3 feet, the flue covering half of it, so that the heat may be thrown down on the ashes.)
Ash FurnaceAsh FurnaceFor Smelting Lead Ashes. Missouri.
Ash FurnaceFor Smelting Lead Ashes. Missouri.
One of the principal points to be attended to in building an ash-furnace is the elevation of the flue. It should rise 5-½ feet in 10; some prefer 5-½ in 11. If the ascent be too steep, the ore will run down into the basinbefore it gets hot, which is detrimental. If the ascent be too low, the bottom of the flue next to the basin will soon be eaten away by the heat, and thus in a short time undermine and destroy the furnace.
The flux employed is also a matter of moment. Sand, and pulverized flinty gravel, are mixed with the lead-ashes before smelting. The object of this is to promote the vitrification of the slag, which would otherwise remain stiff; the particles of revived lead would not sink through to the bottom, but remain entangled with it, and thus be lost. Lime is also sometimes employed for the same purpose; and indeed any earth would operate as a flux to the scoriaceous part of the lead-ashes, if added in a due proportion, particularly the alkaline earths. Lime and barytes, both of which are afforded in plenty at the mines, might therefore be advantageously employed, when no sand or easy-melting silicious gravel could be obtained. Good fusible sands are readily attacked and liquefied by submitting to heat with oxides of lead, alkaline salts, or any other alkaline or metallic flux; hence their extreme utility in glass, enamels, and all other vitrescent mixtures. When, therefore, silicious sand can be obtained, it will be found a more powerful flux to lead-ashes than either gravel, lime, spars, or any other substance, if we except the fluor spar. This is probably better adapted as a flux than even silicious sands; but it has not yet been brought to light at the lead-mines. Perhaps the lower strata of the earth may afford it. It is found at a lead-mine near Cave-in-Rock, on the right bank of the Ohio river, in the State of Illinois, and, with the exception of a little found at Northampton, Massachusetts, is the only place where this rare, useful, and beautiful mineral, occurs in the United States.[17]
The situation for an ash-furnace is always chosen on the declivity of a hill, as represented in the plate. The inside work, or lining, consists of slabs of hewn limestone, laid in clay-mortar, and backed by solid masonry. Although a stone less adapted for furnaces could hardly be found, yet it is made here to answer the purpose, and is an evidence of the ingenuity of men in making a bad material answer when a good one cannotbe found. No sandstone or freestone, of that refractory kind used in glass and iron furnaces, is afforded in this vicinity; and the smelters seem to prefer rebuilding their furnaces often, to incurring the expense of transporting good infusible sandstones from a distance. It is not perhaps duly considered, that a furnace built of refractory materials, although expensive in the erection, would be sufficiently durable to warrant that expense, and outlast several built of limestone, which burn out every blast, and have to be rebuilt from the foundation.
Limestone is a combination of the pure earthlimewithcarbonic acidandwater; it is a carbonate of lime. When subjected to a red heat, it parts with its carbonic acid and water, and, if the operation be continued long enough, is converted into quicklime. This effect, therefore, takes place as well in the lead-furnace as in the limekiln, and with this difference only—that in the former it is laid in a wall, protected in some degree from the heat, and will not part with its carbonic acid readily; while in the latter it is broken into comparatively small lumps, exposed to the heat on all sides, and is easily and readily converted into quicklime.
Nevertheless, although this calcination is constantly progressing, an ash-furnace will last from fifteen to twenty days, according to the skill which has been displayed in its construction, and the particular quality of the stone employed. When the stone partakes of clay (alumina), it runs into a variety of argillaceous limestone, and is manifestly better adapted to resist the effects of fire. Whenever the furnace is cooled, so that the stone can attract moisture from the atmosphere, it falls into quicklime. This change does not, however, take place rapidly; for the burning has seldom been uniform, and the stones have either been over-burned, or not burned enough; so that it requires several days, and even weeks, to assume the powdery state.
An ash-furnace, built of limestone, is estimated to cost a hundred dollars. This includes every expense, and such a furnace lasts during one blast, say fifteen or twenty days; perhaps, with great care, it will run a month. During this time, from sixty to ninety thousand pounds of lead ought to be made.
When a furnace is completed, it requires several days to dry it, and bring it to the proper state for smelting. About ten days are usually spent in this. The fire is begun very moderately at first, being only the warmth of a hot smoke, and is kept so for the first five days, by which means the moisture of the mortar and stone is gradually expelled, and without any danger of cracking the stone, or otherwise injuring the furnace. It is then raised a little every day until the furnace is brought up to a full red heat, when it is ready for the first charge of ashes.
The operation begins by shovelling a layer of ashes on the mouth of the flue, then adding a thin layer of sand or flinty gravel as a flux, and then more ashes; and so adding gravel and ashes alternately, until the required quantity is shovelled up. This is suffered to lie here and growthoroughly hot before it is shoved down the flue into the basin; for, if introduced cold, it would check the heat too suddenly, and prove injurious in the result. When hot, the charge is shoved down the flue with a long-handled iron hoe, and another portion of ashes and gravel immediately shovelled on the mouth, suffered to heat, and then pushed down as before. This operation of heating and charging is continued until the furnace has a full charge, which may require about six hours, and in two hours more the furnace is ready for tapping. The slag, which is in a very fluid state on the top of the lead, is first drawn off, and the aperture closed up with stone and mortar. The smelter then goes to the opposite side of the furnace, and prepares for drawing off the lead by driving a stout sharp pointed iron bar through the side of the furnace, at a particular place contrived for this purpose. On removing the bar, the metallic lead flows out into a large iron pot set in the ground, and accompanied by a considerable quantity of a semi-metallic substance, calledzane. This is lead not perfectly revived, being combined with some earthy particles, and oxide of lead. The zane occupies the top of the pot, and is first ladled out into hemispherical holes dug in the clay near by. This substance is of the consistence of the prepared sand used by brass-founders when hot, but acquires considerable solidity when cold. The metallic lead is then ladled into iron moulds of about eighteen inches in length, and yielding a pig of lead of about fifty pounds each. The quantity of zane made at each tapping is about equal to that of metallic lead. This is afterwards taken to the log furnace, and readily converted into lead. The lead made at the ash-furnace is not thought to be of so pure a quality as that of the first smelting made at the log furnace. It undoubtedly contains any other metals that may be combined with the ore, and is therefore more refractory. Such lead is thought to be a little harder, and some pretend to discover a lighter color.
The lead-ashes are reckoned to yield fifteen per cent. of lead (zane and all), which, added to the first smelting, makes an average product of sixty-five per cent. This estimate will hold good uniformly, when the ores have been properly dressed, and the smelting well performed. Any spar adhering to the ore, renders it refractory; blende and pyrites have the same effect. The latter is particularly injurious, as it consists chiefly of sulphur; a substance known to render all ores refractory.
The slag created by the ash-furnace is a heavy, black, glassy substance, well melted, and still containing a portion of lead. Some attempts have been made to obtain a further portion of lead from it, by smelting with charcoal in a blast-furnace; but the undertaking has not been attended with complete success, and is not generally thought to warrant the expense. The per centage of lead recovered from the slag is not estimated at over ten, and, with the utmost success, cannot be reckoned to exceed twelve.
Some practical and miscellaneous observations may here be added.Metallic lead in the pig is now (Feb. 1819) worth $4 per cwt. at the mines. It sells for $4 50 on the banks of the Mississippi, at St. Genevieve and Herculaneum; for $5 50 in New Orleans; and is quoted at $6 in Philadelphia. This is lower than has ever been known before, (except at one period,) and a consequent depression in the mining business is felt. There is a governmental duty of one cent per pound on all bar and pig lead imported into the United States; but it does not amount to a prohibition of foreign lead from our markets. Perhaps such a prohibition might be deemed expedient. It is what the lead-smelters here call for; and certainly the resources of this country are very ample, not only for supplying the domestic consumption, but for exportation.
Those who dig the ore do not always smelt it. The merchants are generally the smelters, and either employ their own slaves in raising the ore, or pay a stipulated price per cwt. to those who choose to dig. For every hundred pounds of ore, properly cleaned, the digger receives two dollars. He works on his own account, and runs the risk of finding ore. It is estimated that an ordinary hand will raise a hundredweight per day, on an average of a year together. This, however, depends much upon luck; sometimes a vast body is fallen upon, with a few hours' labor; at others, many weeks are spent without finding any. He who perseveres will, however, generally succeed; and the labor bestowed upon the most unpromising mine, is never wholly lost. The above average has been made by those long conversant with the business, and upon a full consideration of all risks.
Custom has established a number of laws among the miners, with regard to digging, which have a tendency to prevent disputes. Whenever a discovery is made, the person making it is entitled to claim the ground for twenty-five feet in every direction from his pit, giving him fifty feet square. Other diggers are each entitled to twelve feet square, which is just enough to sink a pit, and afford room for throwing out the earth. Each one measures and stakes off his ground, and, though he should not begin to work for several days afterwards, no person will intrude upon it. On this spot he digs down, but is not allowed to run drifts horizontally, so as to break into or undermine the pits of others. If appearances are unpromising, or he strikes the rock, and chooses to abandon his pit, he can go on any unoccupied ground, and, observing the same precautions, begin anew. In such a case, the abandoned pit may be occupied by any other person; and sometimes large bodies of ore are found by the second occupant, by a little work, which would have richly rewarded the labors of the first, had he persevered.
In digging down from fifteen to twenty feet, the rock is generally struck; and as the signs of ore frequently give out on coming to the rock, many of the pits are carried no further. This rock is invariably limestone, though there are many varieties of it, the texture varying from very hard and compact, to soft and friable. The former is considered bythe diggers as a flinty stone; the latter is called rotten limestone; and, from its crumbling between the fingers, and falling into grains, there is a variety of it called sandstone. It is all, however, a calcareous carbonate, will burn into quicklime, and, as I find on experiment, is completely soluble in nitric acid. As no remains or impressions of shells, animalculæ, or other traces of animal life, are to be found in it, I conclude it to be what geologists term metalliferous limestone; a conclusion which is strengthened by its semi-crystalline fracture. It exhibits regular stratification, being always found in horizontal masses. How far this formation extends, it would be difficult to determine; but, so far as my observation goes, it is invariably the basis on which the mineral soil at Mine à Burton, and the numerous mines in its vicinity, reposes. It is overlaid by secondary limestone in various places on the banks of the Mississippi, between Cape Girardeau and St. Louis. It is also seen passing into a variety of secondary marble, in several localities. I have seen no specimens of this mineral, however, which can be considered as a valuable material in sculpture.
I have already mentioned the per centage of lead obtained by smelting in the large way. I shall here add the result of an assay made on the ore. One hundred parts of ore yielded as follows:
Metallic lead82Sulphur driven off by torrefaction11Earthy matter, and further portion of sulphur, either combined with the scoria, or driven off by heat7by estimation100
The ore experimented upon was the common ore of Mine à Burton, (galena.) I took a lump of the purest ore, completely freed from all sparry and other extraneous matter, beat it into a very gross powder, and roasted for an hour and a half in a moderate heat, with frequent stirring. On weighing the mass, it had lost 11 of sulphur. I now beat this to a very fine powder, and treated it with a strong flux of nitre and dry carbonate of soda, adding some iron filings to absorb the last portions of sulphur. The whole was enclosed in a good Hessian crucible, previously smeared with charcoal, with a luted cover, and exposed for twenty minutes to the high heat of a small chemical blast-furnace.
The richest species of galena, of which we have any account, is that of Durham, England. An analysis of a specimen of this ore by Dr. Thompson, gave the following result:
Lead85 13Sulphur13 02Oxide or iron0 598 65
Many of the English, and nearly all the German ores, are, however, much poorer. Of five several experiments made by Vauquelin on ores from different mines in Germany, sixty-five per cent. of lead was the richest, and all were united with uncommon portions of carbonated lime and silex.
The button of metallic lead found at the bottom of the crucible in chemical assays, contains also the silver, and other metals, if any should be present in the ore. So also, in smelting in the large way, the metallic lead is always united with the other metals. When ores of lead contain any considerable portion of silver, they assume a fine steel grain; and the crystals, which are smaller than in common galena, oftener affect the octahedral, than the cubical figure. They are also harder to melt; and the lead obtained is not of so soft and malleable a nature as that procured from the broad-grained, easy-melting ore.
The proportion of silver in lead varies greatly. It is sometimes found to yield as high as twelve per cent., and is then called argentiferous lead-glance; but, in the poorest ores, it does not yield more than one ounce out of three hundred. To separate the silver from the lead, a process is pursued called the refining of lead, or cupellation. This is effected by exposing the lead to a moderate heat in a cupel, and removing the oxide as soon as it forms on the surface, until the whole is calcined, leaving the silver in the bottom of the cupel. The lead in this process is converted into litharge, the well-known substance of commerce; and the silver is afterwards refined by a second process, in which the last portions of lead are entirely got rid of. This process is known at the German refineries under the name ofsilber brennen, burning silver.
The rationale of cupellation is simply this. Lead on exposure to heat, with access of air, is covered by a thin pellicle or scum, called an oxide; and by removing this, another is formed; and so, by continuing to take off the oxide, the whole quantity of lead is converted into an oxide. It is called an oxide, because it is a combination of lead with oxygen (one of the principles of air and of water.) By this combination, an increase of weight takes place, so that a hundred pounds of bar-lead, converted into the state of an oxide, will weigh as much over a hundred, as the weight of the oxygen which it has attracted from the atmosphere. Silver, however, on being exposed to heat in the same situation, cannot be converted into an oxide; it has no attractive power for oxygen. Hence, when this metal is contained in a bar of lead, the lead only is oxygenated on exposure in a cupel; whilst the silver remains unaltered, but constantly concentrating and sinking, till the lead is all calcined. This is known, to a practised eye, by the increased splendor assumed by the metal.
I do not think the ore of Mine à Burton contains a sufficient quantity of silver to render the separation an object. This is to be inferred from its mineralogical character, from the mathematical figure and size of thecrystal, its color, splendor, &c. The territory is not, however, it is believed, deficient in ores which are valuable for the silver they contain. The head of White river, the Arkansas, the Maramec, and Strawberry rivers, all afford ores of lead, the appearance of which leads us to conclude they may yield silver in considerable quantity.
SECTION V.
ANNUAL PRODUCT, AND NUMBER OF HANDS EMPLOYED.
On this head, it is very difficult to procure proper information. The desultory manner in which the mines have been wrought, and the imperfect method in which accounts have been kept, when kept at all, with other circumstances, which are in some measure incidental to the operations of mining in a new country, oppose so many obstacles in the way of obtaining the desired information, that I find it impossible to present a correct statement, from authentic sources, of the annual product of the mines for any series of years. When Louisiana was first occupied by the United States, Mine à Burton and Mine La Motte were the principal mines wrought; but the few Americans who had emigrated into the territory, under the Spanish government, were fully aware of the advantages to be derived from the smelting of lead, and, united to the emigrant population which shortly succeeded, made many new discoveries, and the business was prosecuted with increased vigor, and to a much greater extent. The interior parts of the country, and such as had before been deemed dangerous on account of the Indians, were now eagerly explored; and the fortunate discovery of several immense bodies of ore near the surface of the ground, whereby the discoverers enriched themselves by a few days' labor, had a tendency greatly to increase the fame of the mines, and the number of miners. But, as generally happens in new countries, among the number of emigrants were several desperate adventurers, and men of the most abandoned character. Hence, the mines soon became the scene of every disorder, depravity, and crime, and a common rendezvous for renegadoes of all parts. It is by such persons that many of the mines were discovered, and several of them wrought; and it is, therefore, no subject of surprise, that, on inquiry, no accounts of the quantity of lead made, and the number of hands employed, are to be found.
To secure the public interest, and remedy, in some degree, the irregularities practised at the mines, a law was passed in Congress, a few years after the cession of Louisiana, reserving all lead-mines, salt-springs, &c., which should be discovered on the public lands, subsequent to that period; and the Governor of the Territory was, at the same time,authorized to grant leases to discoverers for three years. The great defect of that law appears always to have been, that a specific agent was not at the same time authorized to be appointed for the general superintendence, inspection, and management of mines—an office which, from its nature, can never be properly incorporated with that of the territorial executive, and which, with every inclination, it is presumed his other avocations would prevent him from discharging either with usefulness to the public, or satisfaction to himself. But, whatever be the defect of the law, certainly the advantages which the government proposed to derive from it have not accrued. No revenue, it is understood, has yet been realized under it, and we are now as much at a loss how to arrive at a true statement of the mineral product of Missouri, as if the mines had never been a subject of governmental legislation.
When a discovery of lead has been made, the miners from the neighboring country have flocked to it, and commenced digging as usual, no one troubling himself about a lease; and thus the provisions of the act have been in a great measure disregarded. Men of respectability, and of sufficient capital to carry on mining in a systematic manner, have, it is believed, been frequently deterred from making applications for leases, from the short period for which only they can be granted. It would not warrant the expense of sinking shafts, erecting permanent furnaces, galleries, and other works necessary for prosecuting the business to advantage; for, no sooner would such works be erected, and the mines begin to be effectually wrought, than the expiration of the lease would throw them into the hands of some more successful applicant.
But, although we have no data to form an authenticated schedule of the annual product of the mines for any required number of years, there is something to be obtained by collecting and comparing facts, detached and scanty as they are. Something also is to be acquired by consulting the books which have been kept of late years in the warehouses on the Mississippi, where the lead is sent for exportation, and some information is also to be gleaned from various other sources. It is from information thus obtained that I proceed to an enumeration of the products of the different mines, and the number of persons to whom they furnish employment and support, satisfied, at the same time, that although the information may not be all that could be desired, yet it is all which, without the most extraordinary exertions, could be obtained.
The amount of crude ore delivered at the furnaces of Mine Shibboleth, during one of its most productive years (1811), was something rising of 5,000,000 of pounds. The ore of this mine is estimated to yield, in the large way, from 60 to 70 per cent., reckoned at 62-½, which is probably a fair average. The product of the mine in 1811 was 3,125,000 pounds. Shibboleth is, however, one of the richest mines in the Territory, and this is the product of one of those years in which it was most profitably worked. It was then a new discovery, vast bodies of ore were found nearthe surface, and the number of miners drawn together by the fame of its riches was uncommonly great. It has since declined, although the ore is still constantly found; and I am informed by Colonel Smith, the present proprietor, that the product this year (1819) will be about one million of pounds.
The number of persons employed in digging lead at Mine à Burton has been constantly lessening for the last four or five years; and this celebrated mine, which has been worked without interruption for more than forty years, and is stated to have yielded as high as three millions per annum, is manifestly in a state of decline. During the last summer (1818), the greater part of which I resided at that place, there were not more than thirty miners employed; and the total product of the different pits, shafts, and diggings, composing this mine, did not exceed half a million of pounds. Of this quantity, Messrs. Samuel Perry & Co. were the manufacturers of about 300,000 lbs. They contemplate realizing an increased quantity during the present year. John Rice Jones, Esq., is also engaged in penetrating the rock in search of ore, with the most flattering prospects, and is determined, as he informs me, to sink through the upper stratum of limestone, and ascertain the character of the succeeding formations. It is highly probable, reasoning from geognostic relations, that the lower formations will prove metalliferous, yielding both lead and copper; a discovery which would form a new era in the history of those mines. The present mode of promiscuous digging on the surface would then be abandoned, and people made to see and to realize the advantages of the only system of mining which can be permanently, uniformly, and successfully pursued, viz., by penetrating into the bowels of the earth.
Several other persons of intelligence and capital are also engaged in mining at this place, and it is probable that the total amount of lead manufactured at this mine during the year 1819 will fall little short of one million of pounds.
It is not to be inferred, however, that because the number of miners at Potosi has decreased, the mines are exhausted. On the contrary, there is reason to conclude, as already mentioned, that the principal bodies of ore have not yet been discovered, and that it is destined to become the seat of the most extensive and important mining operations. The ore heretofore raised at these mines has been chiefly found in the stratum of earth which forms the surface of that country, and is bottomed on the limestone. This stratum consists of a stiff red clay, passing in some places into marl, and in others partaking more of the silicious character forming a loam, and imbedding the ores of lead, accompanied by the various mineralogical species before mentioned. These minerals are often of a very attractive character for cabinets.
The depth of this soil is sometimes thirty feet; and in this the diggings have been chiefly done, requiring no other machinery than isused in well-digging; and the stratum of rock has generally put a stop to the progress of the miner, although veins of ore penetrating it have often invited him in the pursuit. But it requires different tools, machinery, and works, for mining in rock; the process is also more tedious and expensive, and is considered especially so by those who have been accustomed from their youth to find bodies of ore by a few days' digging in the earth, and who, if they should work a fortnight at one place, and not fall upon a bed of ore, would go away quite disheartened. The principal search has therefore been made in the sub-stratum of clay, where large bodies of ore are sometimes found by a day's, and sometimes by an hour's work. Hence, in the neighborhood of Potosi, the ground has been pretty well explored, and more search and labor is required to find it than in other and more distant places, where new mines continue annually to be discovered. But, with the exception of Austin's shaft, who sunk eighty feet, and the mines opened by Jones, the rock at this mine remains unpenetrated. Austin found large quantities of ore filling crevices in the rock, and the appearances were flattering when the last work was done. In sinking down, a change in the rock was experienced, passing from compact solid gray limestone, by several gradations, into a loose granulated limestone, very friable, and easily reduced to grains. This stone was in some instances completely disintegrated, forming a calcareous sand; and the most compact bodies of it, on a few weeks' exposure at the mouth of the shaft, fall into grains. These grains are, however, wholly calcareous, and readily soluble in nitric and muriatic acids. The portion which I submitted to experiment was taken up completely, nor was any sediment deposited by many months' standing. On going deeper, the rock again graduated into a compact limestone, very hard, and of a bluish-gray color, in which were frequently found small cavities studded over with minute pyramids of limpid quartz. These variations in the structure of the earth and rock in that place, are still observable by the stones, spars, and other minerals, lying around the mouths of the mines; and, upon the whole, the appearances are such as to justify a conclusion that the lower strata of rocks at Potosi, and the numerous mines in its vicinity, are of a highly metalliferous character, and such as to warrant the expenditures incident to a search.
From a statement lately drawn up, and certified by the proprietors of warehouses at Herculaneum, it appears that the total quantity of pig and bar lead, and shot, exported from that place, from January 1, 1817, to June 1, 1818, a period of eighteen months, was 3,194,249 pounds. Herculaneum may be considered the depôt for the lead of Mine Shibboleth, Richwoods, Bellefontaine, a portion of the lead of Mine à Burton and Potosi, and a few other mines in that neighbourhood. Perhaps nearly or quite half of the whole quantity of lead yearly smelted at the Missouri mines, is shipped from this place. Here then is an average product of2,395,667 pounds per annum, for the years 1817 and 1818, from those mines which send their lead to Herculaneum.
Assuming the ground that these mines produce only half of what is annually made at the whole number of mines, which I conclude may be a true estimate, we shall arrive at the conclusion, that the annual product of the Missouri mines for those years was four millions, seven hundred and ninety-one thousand, three hundred and thirty-four pounds. This, estimated at the present price of four cents per pound, gives us a sum of one hundred and ninety-one thousand, six hundred and fifty-three dollars. This is the produce of one year; and supposing the mines to have produced the same average quantity during every year since they have been in possession of the United States, we have a sum of three millions, sixty-six thousand, four hundred and forty-eight dollars; which is more than the original cost of Louisiana, as purchased from France during the administration of President Jefferson. Let those who have any doubts of the value of our mines, reflect upon this, and consider that it was the product of a year when the mines were in a manifest state of decline, and wrought wholly by individuals, with a foreign competition to oppose, and without the benefits resulting from a systematic organization of the mining interest.
Nearly all the lead smelted at the Missouri mines is transported in carts and wagons from the interior to St. Genevieve and Herculaneum. As it must necessarily be deposited for storage at those places, it was naturally expected that authentic accounts of the lead manufactured in the Territory for many years, might be obtained on application. But in this, I experienced some degree of disappointment. At St. Genevieve, although a warehouse has been kept at the landing for many years, the lead sent to town has not all been stored. From the earliest time, and before the establishment of a warehouse by Mr. Janies, the French inhabitants of St. Genevieve had all been more or less engaged in the storage, purchase, and traffic of lead. Every dwelling-house thus became a storehouse for lead, and, in these cases, no regular accounts were kept of the quantities received or delivered. The same practice has, in some measure, continued since, so that it is impossible to obtain, with any precision, the amount shipped from this place. At Herculaneum, a warehouse has been kept since the year 1816; and on application to Mr. Elias Bates, the proprietor, he was so obliging as to allow me permission to peruse his book of receipts, for the purpose of making extracts. The following details embrace the receipts of lead at that place for a period of two years and eleven months, ending May 18, 1819.
I.A Series of Receipts, from June 16, 1816, to December 31 of the same year, being a period of six months and fourteen days.Fol. 1.Aggregate of receipts52,781lbs.2.57,0973.55,0394.58,8925.50,6396.63,7877.55,6638.47,287Aggregate of separate individual acc'ts during same period.322,134Total.763,319II.A Series of Receipts from 31st Dec. 1816, to 31st Dec. 1817.Fol. 1.Aggregate of receipts.12,375lbs.2.51,5213.49,0234.60,5765.54,2426.47,3217.60,9568.51,4209.43,77410.42,69411.47,95812.15,482537,343Aggregate of separate individual acc'ts during same period.501,903Total1,039,246III.A Series of Receipts from 31st Dec. 1817, to 31st Dec. 1818.Fol. 1.Aggregate of receipts24,261lbs.2.45,9813.31,0414.39,4245.34,7116.44,2667.31,3158.56,4429.33,932341,372Aggregate of separate individual acc'ts during same period.112,203Total453,575IV.A Series of Receipts from 31st Dec. 1818, to 18th May 1819.Fol. 1.Aggregate of receipts14,764lbs.2.44,3233.44,628103,715Aggregate of separate individual acc'ts during same period.26,211Total129,926RECAPITULATION.1816763,319lbs.18171,039,2461818453,5751819129,926Total2,386,066
During eighteen months of the same period, from Dec. 31st, 1816, to June 1st, 1818, there was deposited with, and shipped by, sundry other persons in Herculaneum, as ascertained by Colonel S. Hammond and M. Austin, Esq., 517,495 pounds of lead, together with patent shot, manufactured by Elias Bates and Christian Wilt, to the amount of 668,350 pounds. For the remaining part of the estimated term, (two years and eleven months,) it is reasonable to presume that a like quantity of lead was exported through private channels at Herculaneum, and a like quantity of shot manufactured by Messrs. Bates and Wilt. This will make the quantity of pig and bar lead shipped by individuals, 1,034,990 pounds, and the quantity of patent shot manufactured, 1,356,700 pounds; which two sums, added to the receipts of Mr. Bates's warehouse, as detailed above, gives us an aggregate amount of 4,757,990 pounds, for the period of two years and eleven months. St. Genevieve, as has already been mentioned, is probably the storehouse for one-half of the mines, and may therefore be estimated to have received and exported the same quantity of pig and bar lead during the same period, making a total of 9,515,512 pounds, which gives an average product of more than three million of pounds of lead per annum.
It would be interesting to know in what proportion the different mines have contributed to this amount. The above details show us their collective importance; but we should then be enabled to estimate their individual and comparative value. With this view, I have compiled, from the best information, the following: