In 1717 iron was exported from Pennsylvania to England; and a few years later an act of Parliament prevented the erection of rolling or splitting mills in the American colonies. The greatest improvement in the manufacture of iron, in America, is in the use of anthracite coal. Previous to 1820, iron was reduced by means of charcoal. About that year anthracite coal was tried, and found to be available; and as soon as it came into general use the business of iron manufacture progressed rapidly.
The working of an iron mine is very much like working a mine of any other character. There are shafts, and tunnels, and levels, just as in a coal mine. The ore must be raised, and the men lowered and raised, just as in any other mine. There are, however, more open worked mines of iron than of coal, for the reason that the veins of iron are generally found nearer the surface than the veins of the combustible mineral. In the Iron Mountain of Missouri, which has already been described, there is no necessity for shafts and levels, for the reason that the mountain is a mass of ore, and the only working necessary is to remove it in an open cutting, just as a bank of earth might be removed in making a passage for a railway.
The only visit I ever made to the Iron Mountain and Pilot Knob region was during the war, when work at the blast furnaces had been suspended. A small party of us climbed to the summit of Pilot Knob, and it was not a great climb, after all. We found that the mine consisted entirely of open cuttings. The ore was drawn away from the cuttings by means of small cars, running upon a track. As the cuttings were partly up the side of the mountain, the loaded cars had a downward grade, so that no power was required to move them. Considered as mines with picturesque cuttings and underground scenes, they were a total failure.
CHASED BY GUERRILLAS.
We looked around among them, and found nothing which we could call sensational. While we were lamenting the absence of something interesting, a small party of guerrillas made their appearance in the valley below. They were armed, and we were not, and they were more numerous than ourselves. They moved straight in our direction, and we began to think that the place might be sensational, after all. We scattered among the oak trees, and disappeared as much as it was possible for us to disappear. The guerrillas evidently concluded that we were not worth attacking,—and they were entirely right in this conclusion,—for they changed their course, and rode away. We immediately abandoned our researches among the iron works, and returned to the railway station, which we considered a much safer place.
INTERIOR OF AN IRON MINE.
In many metallic mines the operations are not conducted exactly like those of coal mines, for the reason that the position of the veins and beds is frequently quite different. Some of the metal lodes are sometimes perpendicular, and generally have a high inclination to the horizon. In such cases, the system of working is by means of steps. Sometimes these steps are direct, or descending, and are made by attacking the ore from above. In other cases the steps are reverse, or ascending, and the ore is attacked from below. In either case the excavations are like steps of stairs. The direct system is not in use in coal mines, because the miner would be obliged to stand upon the coal which he had disengaged; but it is frequently adopted in obtaining metallic ores, which have to be pulverized and dressed to make them fit for the furnace.
Where the metallic ores are in very rich lodes, or thick masses, they are worked by a system of large chambers, or extensive excavations. In this system great chambers are hollowed under the earth and around the masses of valuable ore. In the copper mine of Lake Superior, and in some of the Nevada mines, this system is frequently employed, and sometimes the uncovering of a large mass will require considerable time.