MINE. The name given generally to every system of subterraneous work or excavation which has for its object the discovery and extraction of the metallic ores or other mineral produce. But in addition to the underground works which constitute the mine properly so called, the term usually comprehends also the ground on the surface, together with the numerous appendages which are requir ed there; as steam-engines, water-wheels, and other machinery for drainage, the extraction of the ores, and their mechan ical preparation, with various buildings and erections. The subject of mines is one of the most important within the whole range of human knowledge : their contents constitute the main-springs of ci vilization ; and the means employed to ob tain them are to be ranked among the most extraordinary instances of human enter prise, patience, and ingenuity. The art of mining has been practised from the earliest antiquity, and has formed a branch of industry to the most barbarous as well as the most civilized communities. It is true that we can scarcely dignify by the name of mining the cperation by which the savage merely collects grains of gold in the sands of rivers, or extracts it by pounding, when mechanically combined with other substances ; but even this simple operation becomes interesting when viewed as the first link in the chain of those elaborate and scientific processes which result in placing at our disposal the metal of any ore, no matter how refractory.
In the lodes, or veins, the principal matters which fill them are to be distin guished from the accessory substances ; the latter being distributed irregularly, amidst the mass of the first, in crystals, nodules, grains, seams, &c. The non metalliferous exterior portion, which is often the largest, is called gangue, from the German gang, vein. The position of a vein is denoted, like that of the strata, by the angle of inclination, and the point of the horizon towards which they dip, whence the direction is deduced.
Penns are merely small lodes, which sometimes traverse the great ones, rami fying in various directions, and in differ ent degrees of tenuity.
A metalliferous substance is said to be disseminated, when it is dispersed in crystals, spangles, scales, globules, &c., through a large mineral mass.
Certain ores which contain the metals most indispensable to human necessities, have been treasured up by the Creator in very bountiful deposites • constituting either great masses in rocks of different kinds, or distributed in lodes, veins, nests, concretions, or beds with stony and earthy admixtures ; the whole of which become the objects of mineral ex ploration. These precious stores occur in different stages of the geological for mations; but their main portion, after having existed abundantly in the several orders of the primary strata, suddenly cease to be found towards the middle of the secondary. Iron ores are the only ones which continue among, the more modern deposites, even so high as the beds immediately beneath the chalk, when they also disappear, or exist merely as coloring matters of the tertiary earthy beds.
The strata of gneiss and mica-slate constitute in Europe the grand metallic domain. There is hardly any kind of ore which does not occur there in suffi cient abundance to become the object of mining operations, and many are found nowhere else. The transition rooks, and the lower part of the secondary ones, are not so rich, neither do they contain the same variety of ores. But this order of things, which is presented by Great Britain, Germany, France, Sweden, and Norway, is far from forming a general law ; since in equinoctial America the gneiss is but little metalliferous ; while the superior strata, such as the clay schists, the sicnitic porphyries, the lime stones, which complete the transition series, as also several secondary depo sites, include the greater portion of the immense mineral wealth of that region of the globe.