A curious fact is mentioned by Mr. Schoolcraft, respecting the Elliott's mines. "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 are frequently observed in this vicinity on the approach of night."[25]
It seems there is a considerable quantity of a greyish white sublimate collected at the log hearth furnaces, and rejected by the workmen upon the supposition that it is sulphur and arsenic; but Mr. Schoolcraft, by unquestionable experiments, ascertained that it was lead, as would appear, in the form of a carbonated oxide. A considerable loss is in this manner sustained, and in a more advanced state of the metallurgic operations of these mines, the author's valuable suggestions will not be neglected. There is one mine (M'Kain's) where the ore is of the steel-grained variety—it is said to yield less lead, and is inferred to contain more silver than the common ores; we are aware that this is the common impression, but our own experiments on different varieties of lead ore would induce us to think that it cannot be relied upon. We have examined fine steel-grained ore which contained very little silver; in one specimen only one five-thousandth part, and in another, and that a foliated specimen, we found three and a half per cent, of silver.
The methods of digging for the ore are sufficiently simple. "A pick-axe and shovel are the only tools used for removing the earth, and the drill, hammer and priming rod are added when it is necessary to blast." The process is carried on as in digging a common well.
We must refer our readers to the book itself for a clear account of the furnaces and furnace operations, employed for smelting the lead; it will be the more intelligible, as it is accompanied by two good plates containing views and sections of the furnaces. A circumstance which appears very extraordinary is, that the furnaces are most commonly built of limestone, which is of course calcined, and brought to the condition of quicklime by a few blasts, and then it crumbles and the furnaces must be rebuilt.
The ore yields at first fifty per cent., and then the ashes give fifteen per cent, more—sixty-five[26] in the whole.[27]
Custom, says the author, 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 claiming 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 his 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.
Mr. Schoolcraft, from various particulars, infers that the average annual produce of the Missouri lead mines, as mentioned before, is three million pounds per annum, and the lead was worth in 1819, at the mines, four cents per pound. For the last three years, up to 1819 inclusive, the produce of the mines was estimated at three million seven hundred twenty-six thousand six hundred and sixty-six pounds per annum of pig lead, which the author supposes to be not more than one half what the mines are capable of yielding.
The number of miners is between eleven and twelve hundred, and the number of hands employed in labor at different mines is from twenty to two hundred and forty, including in both cases persons of all descriptions.
Many miscellaneous topics connected with the general subject of his work, are introduced by Mr. Schoolcraft, such as the sections relating to the manufactures, and uses of lead, &c., but it is not our object to advert to these topics.
Among the miscellaneous mineral productions of the western regions, there are some that are interesting; and it will be seen from the author's table of minerals, that the list is various. There are several caverns which produce nitrate of potash by the usual treatment; and Ashley's Cave, about eighty miles from Potosi, is said to be one of stupendous size, and to "afford native nitrate of potash in beautiful white crystals."