SECTION II.
TOPOGRAPHICAL AND GEOLOGICAL OUTLINE OF THE MINE COUNTRY.
The district of country formerly known as the lead-mines of Louisiana, extends from the head waters of the St. Francis, in a north-west direction, to the Maramec, a distance of seventy miles, by about forty-five in width, having the Mississippi on its eastern borders. It is included, very nearly, between 37° and 38° north latitude, and comprises an area of about three thousand square miles. Most of the mines are situated within a circle of this general area, of which Potosi and Mine à Burton constitute a centre.
The rock formation of the country appears to be simple and uniform. At the lowest depths observed in valleys, there is a crystalline sandstone, which often consists of transparent quartzose grains, adhering by the force of aggregation. The lead-bearing limestone reposes upon this. Both formations are deposited in perfectly horizontal strata. Valleys which carry streams have been worn down into this formation, presenting this order of arrangement very satisfactorily. A stratum of red, marly clay, spreads over the limestone. Above this, constituting the top layer, or surface soil, rests a bed of diluvial materials, filled with broken-down fragments of rock, masses of radiated quartz, and chips of hornstone. Vegetable matter and black sand form a covering over such parts of this diluvial deposit as constitute valleys and agricultural plains. The Mississippi river lays open this formation along its western banks, from the influx of the Missouri to Cape Girardeau.
Beneath this metalliferous column lie the primitive rocks. The most striking feature of this kind is found in the occurrence of a primitive formation at the sources of the river St. Francis. My attention was arrested by this fact, soon after I began to examine the mine country. This formation consists of sienite, rather than granite; the mica beinggenerally replaced or represented by hornblende. The feldspar, which constitutes three-fourths of the mass, is of a dull red hue. The rock in connection is greenstone trap, which is sometimes porphyritic. I observed small masses of sulphuret of iron in some parts of this rock. The upheaval of this formation appears to have been of the most ancient era of geological action; for the stratified limestones and sandstones, which lie upon or in juxtaposition to these elevations, have not been disturbed in their horizontality. The altitude of this primitive tract does not probably exceed one thousand feet above the waters of the St. Francis river. Vast blocks of the red sienite have been detached, and scattered southwardly over the secondary rocks, apparently by the force of some antique deluge, setting from the north. The whole series of formations may be judged of by the following diagram:
Formations
The general aspect of the country is sterile, though not mountainous. The lands lie rolling, like a body of water in gentle agitation. In some places they rise into abrupt cliffs, where the rock formations appear. Generally, they present the form of diluvial ridges, sparingly covered with forest, and bearing a growth of prairie-grass and herbage. The western banks of the Mississippi, between St. Genevieve and Herculaneum, present a mural front to this district, in a series of elevated perpendicular cliffs of compact limestone. The whole coast extending to St. Louis, appears to be sufficiently elevated to have served as a former barrier to waters covering the low grounds of Illinois. The strata exhibit ancient water-marks of a diluvial character. They are broken through, from the west, by small streams draining the mine country.
No indications of lead-ore have been found in these cliffs. The mines are situated at considerable distances west of them; and when the observer has arrived at their localities, he finds the ore often lying in the unconsolidated soil. This soil is a stiff, reddish-colored clay, filled with fragments of cherty stones, quartz, and small gravel, clearly attesting its diluvial character. This soil extends to the depth of from ten to twenty feet, or more, and is based on limestone rock. It is so firm, in some places, as almost to resist the pick-axe; in others, it partakes more fully of marl, and is readily penetrated. The ore lies in this marly clay, andis often accompanied by sulphate of barytes and calcareous spar. The country is particularly characterized by radiated quartz, which is strewn in detached pieces over the ground, and is also found imbedded in the soil at all depths. This substance is here calledblossom of lead, ormineral blossom. Pyrites, and some other ores of iron, are also found in detached masses upon the surface, and, very rarely, lead-ore.
Such is the general character of the mineral lands, which are covered with a stunted growth of oaks, denominated post-oaks. Walnut is found in some instances out of the valleys. A ridge of yellow pine extends west of the mines, between the St. Francis and Maramec, and is more decidedly barren than the grounds covered with oak. All the open, elevated tracts, are clothed with herbage, which hides their flinty aspect, and gives the country a picturesque appearance. The minor slopes and ravines are often rendered almost impassable by hazel, vines, and other bramble, which appear to be indicative of a better, or rather a deeper soil. The whole area of upland soil, which rests as a mantle over the rocks, is a diluvium, which must, we think, be referred to an early period of diluvial action.
The only true alluvium of the mines appears to be confined to the valleys or plains, which are, consequently, the principal seats of cultivation, and thus derive an additional value from their contiguity to the barren tracts. This alluvium rests on the red marl-clay, or mineral diluvium; the latter of which is uniformly found on penetrating it. Some of the mines exist in, and have been pursued beneath, this top alluvion, across the valleys. Others are seated beneath an arable soil, bearing a forest. Many of the most barren and stony parts of the elevated lands are, on the contrary, destitute of mines. The depth of the mineral soil varies exceedingly. It barely conceals the rock formations in many of the more elevated positions, and frequently does not conceal them. It is deepest in the plains and depressed grounds, being accumulated much in the manner we should expect, on the supposition of a general diluvial submersion.
The principal objection to a general diluvial action, involving the whole Mississippi valley, appears to arise from the admission of the limestone rock's being the true locality of the ore. But we think there are too many facts in support of this opinion, to leave any reasonable grounds for questioning it. Several of the mines in the mineral soil have been traced down into the rock, and have been pursued through apertures, closing and expanding in the manner of true veins. In the numerous cases where the rock has put a stop to further mining, and it has exhibited no signs of ore, it may be supposed that the ore has been moved, by diluvial force, from the original position of the mine, and been finally deposited, with the soil, upon unmetalliferous portions of the rock. And could we with certainty determine the course of diluvial action, the principles of mining might be, in some respects, employed in searching forthe original vein. It is evident, from the unscratched and unbroken surface of much of the ore and its spars, that it could not have been transported far; while the portions of it called gravel ore, which evince its diluvial character, are manifest proofs of a change, more or less extensive, in the general position of the ore.
With respect to the character of the limestone, we have been perplexed with its protean character, and, to avoid apparent contradictions, were led, at first, to adopt distinctions of strata, which we very soon saw were untenable. It is evidently the American equivalent for the metalliferous limestone of England, and, as a formation, is of the transition era. In a specimen of this rock, now before us, taken from a fresh excavation at Potosi, forty feet below the surface of the soil, and thirty-one feet below the original surface of the rock, the structure is in part compact, and in part granular; the compact portions having minute shining crystalline points, and the granular being without any appearance of crystallization, but changing, in the width of about forty lines, from compact granular to a dull arenaceous structure, quite friable between the fingers. Part of the mass is vesicular, and the vesicles are studded over with minute crystals of white opaque quartz. The two extremes of this specimen have the appearance of totally different formations, yet are both calcareous. By experiment, I found a portion of the lower arenaceous part almost completely soluble, in the cold, in nitro-sulphuric acid; and the actual residuum was, in part, owing to a defect in trituration.
Most of the limestone rock disclosed by excavation in the mines, is of the granulated kind; while the structure of the rock above the surface, where the strata are exposed to the weather, as in cliffs and hill-sides, is of the solid, glistening, pseudo-compact variety. Both these varieties, as shown in the specimen, are geologically identical, notwithstanding their striking differences in hardness, structure, colour, and particularly in crystalline lustre. This lustre is, however, as shown by examination with the magnet, owing almost exclusively to minute facets of calcareous crystals, which render it rather sparry than crystalline.
We have examined large portions of this rock, in all its varieties, for organic remains; but have not succeeded in finding any well-characterized species, although a further and fuller search might, and probably would, disclose some species. We observed a single mass of the rock, an imperfectly columniform structure, apparently organic. The rock is rather vesicular than cavernous in its structure. The heavy deposit of diluvium conceals the surface. But if the appearances in the mine-diggings are to be received as general indicia, the surface of the concealed rock is extremely rough and irregular, standing up, in the mineral soil, in huge lumps, which renders the general depth at which it may be reached, a question of great uncertainty.
It has been intimated that the sparry-compact, and the dull granulated varieties of the limestone, are often contiguous; and we have seen, bythe examination of a hard specimen, that they are geologically identical as a formation. If this compact variety from the mines be compared with the principal formation in the precipitous cliffs forming the western banks of the Mississippi, in front of the mine tract, they will be found to coincide in so many points, that these two localities may be deemed parts of the same formation, and as being identical in age. The principal differences consist in the occurrence of organic remains in the strata along the banks of the Mississippi; a discovery attributable to the more full exposure of these cliffs to observation. There is also an apparent absence of the granulated, or sand-lime variety. These two calcareous tracts are not, however, continuous, being separated by a formation of granular quartz, or white crystalline sandstone, which runs nearly parallel with the Mississippi for a distance, a few miles west of it. This stratum of rock, which appears to be rather a quartzose sandstone than a granular quartz, reappears west of Potosi, in the barren area called the Pinery, and is also apparent at several localities between the waters of the Maramec and the St. Francis.
At a point thirty miles west of the Mississippi, in about the latitude of St. Genevieve, the primitive formation reveals itself in a series of mountain masses of granite, which cover a comparatively extensive area. This tract appears to be the nucleus of the country, rising through the great secondary formations which intervene between the Alleghany and the Rocky mountains. Its western limits have not yet been explored; but it probably covers an area of not less than a hundred square miles. The mines lie north of it. This granite is composed almost exclusively of reddish feldspar and quartz. The proportion of mica is small, and this mineral is often absent. It has been employed as a material for millstones. It is connected with greenstone, which is sometimes porphyritic.
We have now three formations of rock, as constituting the mine series; and it only remains to point out their relative position and extent, with the best means at our command. This might seem to be a very simple process, and would indeed be so, were it not that the area over which the formations extend is extensive, and is covered with deep formations of the diluvial and alluvial character, bearing a forest. The primitive is immediately succeeded by the two latter. Mine à La Motte is situated in the mineral diluvium, and is distant about two miles from the granite on Blackford's fork. The first appearance of rock, in situ, north of this point, is at Rock creek, a few miles distant, where the granular quartzose sandstone appears. There is no further appearance of rock in this direction for many miles. The white crystalline sand-caves of St. Genevieve are seated in this formation. It is again disclosed on the Platten creek, and in the elevations west of the Joachim creek, called Fort Rock, and in the white sand-caves near Herculaneum. Whether it is continued farther in the approach to the Maramec, cannot be stated; but the line of country which is thus traversed by it, is probably sixty miles. Theonly point where this rock appears on the banks of the Mississippi, is in the range of the Cornice Rocks.
Proceeding west across this formation, the mineral diluvium succeeds, and conceals the rock formations; but, wherever they are disclosed by the action of the streams, and by excavations, the metalliferous limestone appears, which constitutes the lowest stratum yet found in the mine region proper. But it is to be observed, that no excavations of any considerable depth have been made; the rock has not been penetrated to any great depth. The principal seat of the mines consists of the area included within the circuits of the Grand river and Mineral Fork, constituting the main tributaries of the Maramec. These streams extend something in the shape of a horse-shoe around the mines. Immediately west and south-west of this area, the white sandstone reappears, extending south towards the granite. The position of the two formations may be represented by a pair of expanded dividers, opening northward; the two shanks of which denote the sandstone ridges, and the head, or rivet, the primitive.
The most valuable mineral products of the mines, in addition to lead, are iron and salt; the latter of which is made, in limited quantities, at a saline spring at Madansburgh, in the county of St. Genevieve. Other indications of it exist at one or two localities in the township of Bellevieu, and on the Maramec river, where efforts were formerly made to manufacture salt.
Iron-ores are found at numerous points; but no body of the ores of this metal is known, comparable, in extent or value, to the locality of Bellevieu, called the Iron Mountain. The ore exists, at this place, in a very massive form. It is in the state of a micaceous oxide. It has been tried in a slag furnace, and smelted easily, without a flux. The iron obtained was of a very malleable quality, and spread freely under the hammer. This locality is embraced by the waters of Cedar creek, which, at the distance of seven miles, are stated to afford a water-power adequate for the reduction and working of the ore. About five miles distant, at Stout's settlement, occurs another body of this ore.
Zinc is found, in the form of a sulphuret, in small quantities, at several of the lead-mines in Washington county. A single mass of the sulphuret of antimony has been discovered in the granitical district, which affords also a locality of coarse graphite, and some other minerals, which will be noticed in the sequel.
A sulphur spring exists a few miles west of the Mississippi, in Jefferson county. The water issues, in a copious stream, from an aperture, situated near a cliff of the compact limestone. It is of a bright, transparent quality, but indicates, by its taste, its sulphureous impregnation, and deposits sulphur, in a whitish pulpy form, on the pebble-stones and fallen vegetation of the brook which issues from the spring.
Topographically considered, the mine country is a hilly and uneven tract, having a considerable elevation above the waters of the Mississippi. It is well watered, with numerous springs, brooks, and streams, and, from the prevalence of a firm diluvial soil, affords facilities for roads. The climate is favorable to health. The manner in which the smelting of the ores is performed, being in the open air, is probably less injurious to those engaged in it, than if the furnaces were enclosed with buildings.
Some losses are sustained in the death of cattle, which die with a disease called the mine sickness. Cows and horses, which are frequently seen licking around old furnaces, often die without any apparent cause. Cats and dogs are taken with violent fits, which never fail, in a short time, to terminate their lives. This is usually attributed, by the inhabitants, to the effects of sulphur, driven off from the ores in smelting. It is more probable that it arises from the sulphurous acid in its combination with barytes, which may operate as a poison to animals. The sickness is wholly confined to quadrupeds.[16]
The soil thrown out of the pits, at the abandoned mines, is found to produce some plants, and even trees, which are not peculiar to the surface. Such are the cotton-wood and the beech-grape, species which are usually confined to the arenaceous alluvions of valleys. And we think their growth here is not promoted by the mineral clay, which is manifestly of a fertilizing property, when cast on the surface; but to the disintegration of the sand-lime, producing a soil favorable to such productions. The sensitive brier, observed in the mine district, is evidently not of this class, as it is found remote from any mine excavations.
SECTION III.
LOCAL POSITION OF THE SEVERAL MINES.
Since the first discovery of lead in this Territory, the number of mines has been much increased, and hardly a season passes without some new discovery. Every discovery of importance soon becomes the centre of mining attraction. As the ore is found in the diluvial soil, it is generally exhausted on reaching the solid rock; and after penetrating a considerable area of the surface with any, or but partial success, the locality is abandoned, and a new one sought. As the mines are worked without capital, and the ore is dispersed over a wide area, the number of localities is almost indefinite. Upwards of forty principal sub-districts are known, most of which are appropriately denominateddiggings. The earliest discovery, at Mine à Burton, has been one of the most valuable, and still continues to afford the ore. Mine à La Motte has also proved an extensive deposit, and is still unexhausted. New Diggings, Shibboleth, and Richwoods, are among the discoveries of later date, which have yielded very large quantities of ore. But the mode of mining in the diluvial soil must exhaust it of its mineral contents, and direct miners, in after years, to the true position of the ore, in the calcareous rock. So long as the search continues in the soil, the business will partake of the uncertainty which now attends it, and which renders it rather an object of temporary enterprise, than a fixed employment.
In the search for ore in the soil, scarcely any uniform principles can be certainly relied on. Generally, rocky and barren localities are avoided, and large and deep beds of the red metalliferous clay sought for. The occurrence of crystallized quartz, or spars, on the surface, is regarded only as a general indication, but cannot be depended on to ensure local success. These masses are found to be distributed on and through the top soil, as other debris, being sometimes contiguous to, and sometimes remote from, ore. But they are never, so far as I have observed, found with the ore.
The method of searching for and raising the ore, is simple. Having fixed on a spot for digging, the operator measures off about eight feet square. A pick-axe and shovel are used for removing the earth. A practised hand will pitch the earth from a depth of eight or ten feet. A windlass and bucket are then placed over the pit, and the excavation thus continued. Small detached masses of ore, or spars, are often found in the soil, in approaching a larger body. The ore is the sulphuret, or galena. It has a broad, glittering grain, and is readily divisible into cubical fragments. It occurs in beds, or detached masses, which are deposited horizontally in the soil. They are often accompanied by the sulphate of barytes, or by calcareous spar; sometimes by blende, or ironpyrites. The ore is often connected with the barytic spar, indicating the latter to be a true matrix. The direction of these beds of ore appears to be irregular. Veins of ore are confined to the rock.
The variety of ore calledgravel ore, differs from the preceding chiefly by its marks of attrition, and connection with diluvial pebble-stones. No spars have been noticed in these gravel-beds, although it is probable that a careful search might detect them.
The calcareous spar is most abundant in connection with rock diggings. It is translucent, or transparent, and often exhibits the property of double refraction. The miners, who employ their own conventional terms, call this substanceglass tiff, to distinguish it from the sulphate of barytes, which is denominatedtiff. Much of the radiated quartz of this district bears the marks of diluvial action. It is not uncommon to find masses of it, in which the angles of the crystals are quite defaced. Veins of ore in the rock correspond generally, in their course, I think, with the cardinal points, in the instances of their being pursued horizontally. But they dip at various angles with the plain, or sink perpendicularly into the rock.
The horizontal position of the ore-beds in the red clay soil, may be regarded as an evidence of its being a diluvial deposit.
The metalliferous, red, marly clay, is, in fine, the most interesting geological problem connected with the mines, and is calculated to show us how little we know of the true eras of the diluvial deposits. After every examination which we have been able to make, we are decidedly of the opinion that this formation belongs to the diluvial, and not to the alluvial era. It seems, indeed, to assert a claim to be considered, among the western strata, as immediately succeeding the secondary. It lies directly next to, and upon, the limestone rock. We have witnessed the progress of an excavation on the public square of Potosi, in which the soil was removed down to the rock, and a clean area of its surface was exposed. There was no other stratum below it, and between the clay and rock. And such we believe to be its general position. The radiated quartz and pebble drift is above it, and, consequently, constitutes a subsequent deposit. And hence it is that the numerous fragmentary masses of the former, calledmineral blossom, are no sure indications of the subterraneous presence of ore. The gravel-ore and mixed diluvial gravel is likewise a newer deposit, coinciding with the era of the primitive and secondary boulders. No large primitive boulders, however, exist in the mine district, if we except the angular fragments of granite, south of St. Michael, which are, indeed, just without the lead-yielding area. Pebbles of common quartz, granite, and greenstone, are found in the surface soil, and are also to be observed, in accumulated masses, in the beds of brooks. Occasionally an orbicular mass of these rocks, of the size of a melon, is observed. It is evident, from these appearances, that no formations of the primitive exist, towards the sources of the Mississippi, for a greatdistance, as it is from this direction that diluvial action appears to have been propagated. This clay soil is free from boulders, and is of a homogeneous texture. It partakes, in its qualities, so largely of marl, as to operate as a manure, on being thrown out of the pits, and, after a few years, is covered with a very rank growth of trees, vines, &c. This is a characteristic trait of the locality of abandoned diggings.
The following is a catalogue of the mines. It comprises those of most note, which are now worked, or have been at some former period.
1. Mine à Burton.24. Tapley's Diggings.2. Mine à Robino.25. Lambert's Diggings.3. Mine à Martin.26. Old Mines.4. New Diggings.27. Mine Shibboleth.5. Citadel Diggings.28. Elliot's Mines.6. Perry's Diggings.29. Belle Fontaine.7. Hawkins's Mine.30. Cannon's Mines.8. Rosebury's Mine.31. Little Diggings.9. Austin's Shaft.32. Becquet's Diggings.10. Jones's Shaft.33. Mine Liberty.11. Rocky Diggings, (Prairie de Roche).34. Renault's Mines.12. Gravelly Diggings.35. Miller's Mine.13. Brushy-run Diggings.36. Mine Silvers.14. Stricklin's Diggings.37. Fourche à Courtois.15. Bibb's Diggings.38. Pratt's Mine, Big river.16. Tebault's Diggings, (Pinery).39. Lebaum's Mine, Richwoods.17. Mine Astraddle.40. Mine à Joe, Flat river.18. Masson's Diggings, or Partney's.41. Bryan's Mines, Hazel run.19. J. Scott's Diggings.42. Dogget's Mine. Hazel run.20. T. Scott's Diggings.43. Mine La Motte, St. Michael.21. Micheaux's Diggings.44. Gray's Mine, Big river.22. Henry's Diggings.45. M'Kain's Mine, Dry creek.23. Moreau's Diggings.
The most noted mines are Mine à Burton, New Diggings, Shibboleth, Richwoods, Old Mines, and the numerous mines on the waters of the Mineral Fork of Grand river. Mine à La Motte, Mine à Joe, and Bryan's Mines, are east and south of the principal group of mines in Washington county, and at a considerable distance from them. A few general remarks may be applied to all these mines.
The mines possess one general character, although there are some peculiarities which I shall hereafter mention. The ore is found in detached pieces and solid masses, in beds, in red clay, accompanied by sulphate of barytes, calcareous spar, blende, iron pyrites, and quartz. The ore is of that kind called, by mineralogists, lead-glance, or galena, and is the sulphuret of lead, of chemistry. As it is dug up or quarried from the adhering spar, it presents a very rich appearance. It has abroad, glittering grain, of a lead-gray colour, which passes into a bluish shade. The ore is easily broken by the blow of a hammer, and may be pounded to a fine powder, still preserving its glittering appearance. In breaking it, it always separates in cubes. Sometimes detached lumps of four or five pounds weight, of a cubical form, are found imbedded in the clay. Its primitive figure of crystallization is particularly observable after the ore has been desulphurated by heat, which, at the same time, increases its splendor, and renders the lines of intersection between the facets more plainly discoverable.
The clay, or red earth, in which the ore is found, appears to partake largely of marl; and a difference of quality is to be observed at the different mines. It all, however, operates more or less as a stimulant to vegetation, on being thrown out of the pits. Mixed with the clay are innumerable pieces of radiated quartz, very beautiful in appearance. This forms the first stratum, and is about fourteen inches in depth; then succeeds a stratum of red clay, four or five feet thick, and sparingly mixed with substances of the same kind; after this, a layer of gravel and rounded pebbles, of a silicious character, ensues; these are about a foot in depth, and lead-ore, in small detached lumps, is then found. This is of the description called gravel-ore, and no spars are found accompanying it. The greatest proportion of lead-ore is, however, found imbedded in marly clay, accompanied by the sulphate of barytes, and resting on limestone rock. The rock is struck at a depth of from fifteen to twenty feet, and is a metalliferous limestone, of a semi-crystalline structure, lying in horizontal beds. It is traversed by veins of lead-ore. Sometimes these expand in the shape of caves, where masses of galena occur.
The most valuable substance accompanying the lead-ore, is an ore of zinc, which is found at several of the mines. Another substance, found with the ore in considerable quantities, is the sulphate of barytes. This is sometimes in immediate connection with the ore, but more frequently in contiguous masses, in the clay.
The sulphate of barytes, calledtiffby the lead-diggers here, is the same substance calledcawkby English miners. It is very white, opaque, and very heavy, and may be considered as the proper matrix of the lead-ore.
There are also found considerable quantities of calcareous spar, particularly in the caves and veins in rock. This substance is often observed in large orbicular or irregular masses, which have the appearance of external attrition. On breaking them, they fall into rhombs, which are very transparent and glittering; in color, they are either white, or honey-yellow.
Pyrites are common at the mines, sometimes crystallized in regular cubes of a beautiful brass-yellow color, and, at others, found in tabular masses, or mixed with blende, sulphate of barytes, or calcareous spar. Quartz is found throughout the whole mine district, both on the surfaceof the ground, and at all depths below. It is generally in the form of tabular pieces, whose surfaces are thickly studded over with small pyramids of transparent rock-crystal, and present an appearance of the utmost beauty and splendor, looking like so many diamonds set over the surface of white stone. These crystals are frequently grouped in the form of a hemisphere, circular, or oviform, solitary or in clusters, forming the different varieties of mamillary and radiated quartz, and, when met with in their pristine beauty, present a very rich and brilliant appearance. It has acquired the popular name ofblossom of lead, or mineral blossom, a term perfectly significant of its supposed affinity.
The exterior stratum of red clay, with its ores and minerals, will be best understood by comparing it to a garment thrown over the rock-formations of the country. The search for ore has been generally confined to these clay diggings, which are pursued, very much, with the apparatus of common well-digging. If, on reaching the rock, no vein of ore is discovered, the work is generally dropped.
On viewing the district on a large scale, this external clay stratum appears to have originally derived its mineral contents from veins in the calcareous, lead-yielding rock. This metalliferous rock has evidently, in former ages, been scooped out by rivers and streams, forming valleys and vast diluvial plateaux, where the abraded materials were deposited. The original subterranean veins were concealed by these geological changes.
Some of the mines exhibit traits that may be mentioned. Mine La Motte is one of the oldest mines in the Territory, having been discovered in 1720, by the person whose name it bears. The mines are very extensive, and a large quantity of ore is annually raised. They are situated within two miles of St. Michael, Madison county, and on the head-waters of the river St. François. No spars are found accompanying the ore; iron pyrite is occasionally met with, and plumbago is found in the vicinity. The ore, which is less brilliant, and differs in other characters from any other in the mine tract, is at the same time more refractory; in some instances, the greatest difficulties have been experienced in the smelting. Hence, an idea has originated that it is combined with other metals; but no experiments, I believe, have been made to ascertain this point.
On a visit to these mines, I observed the inside of the ash-furnace beautifully tinged with a blue color of considerable intensity. This furnace is built of a white sandstone, which becomes vitrified on the surface, forming glass. We are acquainted with no substance which will communicate a blue color to glass in fusion but cobalt; hence, it is not unreasonable to infer that this metal is volatilized during the smelting, and is thus brought into contact with the liquefied surface of the stone, imparting to it the color noticed. That the ores of La Motte contain an unusual portion of sulphur, is very probable. I draw this inference both from its refractory nature and dull appearance. Sulphur always renders an orerefractory; for, when it is expelled by torrefaction, the ore melts easily. Its dull aspect is not less conclusive; for, the more an ore is roasted, and the more sulphur there is driven off, the brighter it grows. This is evident to every smelter, who cannot fail to observe the surprising brilliancy the ore assumes after it has gone through the first operation in the log furnace. That the difficulties daily experienced in smelting the La Motte ores are, therefore, attributable to the extraordinary quantity of sulphur they contain, is extremely probable; for, even if they were united with other metals, with silver or with cobalt, these would not increase their infusibility, except by the extra quantum of sulphur they brought with them. At least, we have no facts to prove that a simple alloy does not melt as easily as a pure metal, while there are many to show that alloys are of the most easy fusibility.
The quantity of ore raised at New Diggings has been very great, a regular vein having been found; but they were abandoned several years ago on account of the water, which rushed in with such rapidity, that to remove it every morning with a common windlass and bucket was found a work of such labor as to render the business unprofitable. The mines were left with the most flattering veins of ore in view. The general character of these mines is such as to justify the erection of a steam-engine, and other works for prosecuting the business on an extensive scale; and their revival at some future period may be confidently looked for.
Mine Renault is situated about six miles north-north-west of Mine à Burton, in a very rocky part of the country, which affords some of the most picturesque views of mountain scenery. The region is strongly marked by mineral appearances, rendering it probable that other substances of value, besides lead, may exist in that vicinity. Ores of zinc are abundant at this mine, and a body of micaceous oxide of iron is found in the neighborhood.
Bryan's Mines are seated on Hazel run, and are among the most recent discoveries of consequence. Near a million pounds of lead were made here during the first year of the discovery. The mine is characterized by yielding no heavy spar; sometimes a little calcareous spar is found, and then adhering to the ores; a circumstance which I have nowhere else observed. Much of the ore of these mines is found in tabular pieces, which are sonorous in a considerable degree; the ore is brilliant, and smelts readily, yielding the same as at Mine à Burton.
Gray's Mine, situated on Big river, in the northern extremity of the mine tract, is remarkable for a body of white clay, which was discovered in searching for ore. In sinking several pits at this mine, a stratum of clay of an unusual appearance was struck at the depth of from eight to ten feet, and no ore was procured at those places; the diggings were abandoned in consequence of the clay, which covers a considerable area of ground on the banks of Big river. This mineral substance bears a striking resemblance to specimens of a pyrous crucible clay.
Elliott's Mines lie upon the Mineral Fork, and are characterized by the abundance of pyrites, and the beauty of the calcareous spar found there. Considerable quantities of blende were also met with, and strong indications of the existence of copper are furnished. During the remarkable earthquakes of 1812, a fine spring of water at the mouth of the mines suddenly became warm and foul, and in a few days dried up entirely, and no water has run there since. Illuminations in the atmosphere (arising doubtless from phosphorus) are frequently observed in this vicinity on the approach of night.
At Mine à Burton, there is found adhering to the sides of the log-hearth furnace, a grayish-white sublimated matter, of great weight, which I take to be a sublimate of lead. It is considered as chiefly sulphur or arsenic by the lead-smelters, and is thrown by as useless. It is found at every furnace, and a very large quantity could be annually collected. This induced me to undertake some experiments on the subject. I was convinced, on reflection, that there could be no sulphur, at least no considerable quantity of sulphur, in it, from the fact that all sulphur, or other inflammable matter, expelled from the ore in the furnace, would undergo immediate combustion. This is also observable in the color of the flame while the ore is torrified. Indeed, every person conversant with the nature of this substance must know that it cannot be otherwise. The furnace is entirely open, and does not rise over seven or eight feet in height; consequently, there is no opportunity for it to condense. That the sulphuric acid is driven off, is undoubted; for, whenever sulphur is burned, this acid is set at liberty; but it has no opportunity for entering into a new combination within the body of a log furnace.
The idea of arsenic in the substance alluded to, is perfectly erroneous, and has originated in an ignorance of the nature of the ores of these mines. It is thesulphuret of lead, and not thearseniate. That there is a small portion of silver and antimony in combination with the ore, is probable; but they too are mineralized by sulphur. Reflecting on this, I became convinced of the popular error, and, to ascertain the point, made the following experiments:
A. I took a lump of the sublimated matter, freed from adhering impurities, and reduced it to the state of a fine powder by pulverizing in an agate mortar, and trituration. Of this I mixed six parts with four of pulverized borax, and a little charcoal, and submitted it to the intense heat of a small chemical furnace. On removing the crucible, I found a button of metallic lead in the bottom, weighing nearly four.
B. Dissolved a quantity of the powdered sublimate in nitric acid; it effected a ready solution, with violent effervescence. Poured on liquid carbonate of potash until no more precipitate fell. I then collected the precipitate, and washed away the superfluous alkali by clear water, and dried it in the shade. The result was a very fine, and a very white powder, of considerable weight. This was a carbonate of lead (white lead).With a quantity of the white lead thus made, I mixed linseed oil, and painted a board. The color was of the most delicate white, and it gave a good body. On inspecting this board several months afterwards, I found the color inclining a little to yellowish. But perhaps it stands as well as any white lead would, prepared from litharge, by solution in nitric or acetic acids, and precipitation by carbonated alkali.
C. Mixed eight parts of sublimate with twelve of muriate of soda, and fused in a crucible, with a tight cover, in a high heat. Result, a yellow, hard, heavy, vitrified mass, resembling muriate of soda and lead.
M'Kain's Mine is situated on a small stream called Dry creek, running into Big river not far from its junction with the Maramec. The mine is worthy of remark only on account of a body of steel-grained lead-ore found there. This ore is found to yield less lead in smelting than the common broad-grained ore, and, as may be inferred from its texture, contains silver.
So little has been done, of late years, in mining in the rock, that the character of the veins must be judged of from limited facts. But there can be no question, from what is known, that the true scene of mining operations is the rock.
Along the west banks of the Mississippi, and also in some of the interior valleys, we observe that the metal-bearing limestone rests on crystalline sandstone. Both preserve a horizontal position, and both are deposited, at the distance of about seventy miles south of Potosi, upon pre-existing formations of sienitic granite, embracing hornblende rock; some of the latter of which is porphyritic.
These primitive formations mark the geography of the country at the sources of the St. Francis. They form alpine peaks, through which the river forces its way. Mine à La Motte is within two miles east of this tract. These peaks have been raised to their present position without disturbing the horizontality of the limestones and sandstones. Hence the conclusion of their prior elevation.
At a still further southern point, and before reaching the banks of the St. Francis at Bettis's ferry, the horizontal rocks again appear. But, in this instance, sienitic and granitic boulders are scattered over the southern series of the calcareous strata, showing, with equal clearness, that the geological era of the boulder stratum was posterior to the deposition of the horizontal strata, and that the force which scattered the boulder stratum was from the north.
SECTION IV.
METHOD OF WORKING THE MINES.
The method of raising the ores, and the processes pursued in separating the metal, are, upon the whole, extremely simple. A pick-axe and shovel are the only tools in use for removing the earth; and the drill, rammer, and priming-rod, are added when it is necessary to blast. Having determined on the spot for digging, the process commences by measuring off a square of about eight feet, and throwing out the earth, spar, and gravel, until the miner sinks beneath the depth he can throw the earth. An expert hand will pitch his earth clear out of the pit from a depth of ten, twelve, and even fifteen feet. At this depth a common windlass and bucket are placed over the centre of the pit, and the digging continued by drawing up the earth, spar, and ores, if any are found, in the manner pursued in sinking a well. During his progress, the miner is notified of his approach to a body of ore, by small detached lumps occasionally found imbedded in the soil, within a few feet of the surface. Sometimes lumps on the top of the ground determine on the place for digging. The spar is also a sign by which he judges, as there is seldom a body of spar found without lead-ore. There are also other signs by which an experienced digger is advertised of his prospects, and encouraged to proceed with cheerfulness in his work. These are, peculiar appearances in the texture of the spar, and sometimes minute specks of ore scattered through it, the changes in the color, and other qualities of the earth, gravel, &c. If these appearances are promising, and bits of ore are occasionally met with, he is encouraged to sink down a great depth; but if they should fail, he is generally induced to abandon the pit, and commence at another place.
In searching for ore, the soil, the slope of the hills, spar, blossom, trees, &c., are taken as guides, and some are obstinately attached to these signs. Others, who have been fortunate in finding ore where these appearances were least promising, wholly disregard them, and pay no attention to rules. In general, there is a greater disposition to trust to luck and chance, and stumble upon ore, than by attending to mineral character, to be sure of success. As those who search by rules are generally incapable of those minute remarks on the distinguishing character and geological situation of minerals, which are necessary in order to ensure success, it frequently happens that they meet with disappointments. An incident of this kind is enough to perplex a man who has not habituated himself to reasoning on the subject, and to weaken his belief in the affinity of ores and stones. Such a man will not stop to compare and reconcile facts, which are seemingly opposite, or to investigate the nature of general principles.
Hence miners exclaim on the uncertainty of finding ores by rules drawn from the observations of science; that the strata of the earth are irregular, and not to be depended upon like the rock formations in Europe; and that, in fine, we have no guides by which its mineral treasures are to be sought, and that, in so confused a soil, chance is the best guide. Such a man is more ready to follow the mysterious guidance of the divining-rod than the light of reason, and would be easily persuaded that fortune is more surely the result of blind chance, than of feasible schemes, well planned and well executed.
There would be, nevertheless, some truth in the uncertainties and the confusion complained of, were those circumstances among the observations of scientific men. But it will be hazarding little to say, that when such observations are made, there will be found as much regularity, harmony, and order, in the superposition of the strata, as generally exist. The few facts I have noticed, lead to this conclusion.
Having raised a sufficient quantity of ore for smelting, the next process consists in separating the spar, and cleaning the ore from all extraneous matter. This is done by small picks, tapered down to such a point that a careful hand may detach the smallest particle of adhering spar. It is necessary that the ore should be well cleaned, as it would otherwise prove refractory in smelting. If there be any lumps of uncommon size, they are beaten smaller. The object is to bring the lumps as near as may be to an uniform size, so that the heat may operate equally in desulphurating the ore. It is desirable that the lumps should be about the size of a man's two fists, or perhaps fifteen pounds' weight; if too small, a difficulty and a waste is experienced in smelting. In this state, the ore is conveyed to the primary furnace, (see Plate I.) and piled on the logs prepared for its reception. When the charge is put in, which may in a common way be about five thousand pounds, it is surrounded by logs of wood, and covered over at the top, the fire being lit up at the mouth below. A gentle warmth is created at first, which is raised very gradually, and kept at this point for about twelve hours, to allow the sulphur to dissipate; the heat is then increased for the purpose of smelting the ore, and, in twelve hours more, the operation is completed, and the lead obtained. Wood is occasionally added as the process goes on, and there is a practical nicety required in keeping the furnace in proper order, regulating the draught of air, &c., so that some smelters are much more expert, and thereby extract a greater quantity of lead from a like body of ore, than others. This furnace is called the log furnace, and, so far as I know, is peculiar to this country. It is of a very simple construction, consisting of an inclined hearth, surrounded by walls on three sides, open at top, and with an arch for the admission of air below. Upon the whole, it appears well adapted to the present situation and circumstances of the people. It is cheap, simple, may be built at almost any place, and answers the purpose very well. A good furnace of this kind may bebuilt at a cost of from fifty to sixty dollars, every expense considered; and one of the most considerable items in the sum total is the bill of the mason, who cannot be hired, in this region, to work for less than two dollars per day.
Plate I., Figure 1.A Perspective View of the Log Furnace.
a, the front wall, 8 feet long, 7 feet in height, and 2 feet in thickness.
b b, the side walls, 8 feet long, and 2 feet thick.
c, the hearth, 2 feet wide, and 8 feet in length.
d d, the ledges on each side of the hearth, 10 inches in height, and 1 foot wide. These serve to elevate the logs above the hearth, at the same time creating a draught for the air, and passage for the lead.
e, the eye of the furnace, or arch, 2 feet across at bottom, with an arch thrown in a half circle, or a flat stone laid across at the height of the ledges.
f, the iron ladle for dipping out the melted lead.
g, the iron mould. Every bar of lead cast in this, is called apig.
h, the hole in the ground, for the reception of the lead as it runs from the furnace.
Figure 2, is a perspective view of the furnace from the back or open part. The same letters used in Figure 1 apply to the same parts of the furnace in this figure.