Page:The American Cyclopædia (1879) Volume XI.djvu/588

570 MINE the power of Eome the important mines of Sardinia, Sicily, and Spain. Subsequent con- quests added those of Asia Minor, Macedonia, and Greece, and still later the remaining mines of western Asia and those of Egypt were ac- quired by the armies of Pompey and Augustus. Those of Gaul yielded to Caesar. The tin mines of Britain were their latest conquests of this sort, and Rome was then mistress of all the important mines of the ancient world. Under the republic the mines were worked by lessees, who employed numbers of slaves, and subjected the mineral deposits of the prov- inces to rapid and reckless robbery. During the period from the first Punic war to the empire there was an immense production of metals, and many of the mines were exhausted. The emperors established governmental super- vision, and worked the mines through regularly appointed officials. Mining in the countries belonging to the West Roman empire declined rapidly from the 3d century, and after the 5th it ceased entirely. The Byzantines gradually surrendered their mines to the Arabs; those of Asia Minor, Thrace, and Greece were the last which the eastern empire retained. Mining is known to have been carried on at Andreas- berg in the Hartz since the year 968. The famous Rammelsberg mines were discovered in 972 by the pawing of a steed named Ram- mel, tied to a tree in the forest. The Freiberg district was discovered about 1165, and has been steadily worked since 1547. Traces of ancient mining in the United States are con- fined to the copper region of Lake Superior, and to certain districts in New Mexico. In both cases the implements seem to have been rude hammers of stone. In New Mexico there is a large excavation known as the Turquoise mine, from which a trachytic rock, carrying turquoise in seams, has been laboriously ex- tracted by a race of whom not even a tradi- tion now exists. In ancient times muscular force, assisted only by applications of fire and occasionally by the power of water, was the miners' resource. A most suggestive picture of rude mining operations is given in the book of Job, xxviii. 1-11, of which Conant's trans- lation brings out the beauties very strikingly : "For there is a vein for the silver, and a place for the gold, which they refine. Iron is taken out of the dust, and stone is fused into cop- per. He puts an end to the darkness; and he searches out, to the very end, stones of thick darkness and of death-shade. He drives a shaft, away from man's abode; forgotten of the foot, they swing suspended, far from men ! The earth, out of it goes forth bread; and undent is destroyed as with fire. A place of sapphires, are its stones ; and it has clods of gold. The path, no bird of prey has known it, nor the falcon's eye glanced on it; nor proud beasts trodden it, nor roaring lion passed over it. Against the flinty rock he puts forth his hand; he overturns mountains from the base. In the rocks, he cleaves out rivers ; and his eye sees every precious thing. He binds up streams that they drip not ; and the hidden he brings out to light." Pliny ("Natural History," xxxiii., 4) gives a similar descrip- tion of shaft-sinking operations: "Elsewhere pathless rocks are cut away, and are hollowed out to furnish a rest for beams. He who cuts is suspended with ropes. . . . For the most part they swing suspended, and fasten up lines for a pathway. They go where there is no place for the footprints of man." The re- moval of surface material by sluicing was also practised in ancient times in Spain. The op- erations of mining may be comprised under four heads: 1, the discovery of mineral de- posits and the testing of their value; 2, the establishment of access to such deposits; 3, the extraction of the mineral ; 4, the protec- tion of the works and workmen. I. DISCOV- ERY AND TESTING OF MINERAL DEPOSITS. For a description of the modes of occurrence of the rocks and minerals which are objects of mining, see MINERAL DEPOSITS. The presence of such deposits is indicated by various signs. Sometimes the veins themselves, if harder than the enclosing rocks, crop out at the surface unaltered. More frequently the outcrop is indicated by decomposed rock, which when ferruginous is called "gossan." Loose pieces of gangue and ore, known to western miners as "float quartz," and found upon the surface and in the soil, frequently lead to the discov- ery of veins. The lead miner of the limestone districts of the Mississippi valley is guided by depressed lines upon the surface, indicating the existence of fissures. The magnetic needle is employed in the discovery of certain ores of iron, and the ancient superstition of the di- vining rod for the discovery of hidden springs and mineral veins is not yet extinct even in this country. (See DIVINING ROD.) "When the neighborhood of a mineral deposit is sus- pected and no certain indication of its exact locality appears, it is sought by prospecting pits, cuts, drifts, or borings. Prospecting pits are commonly dug upon the supposed outcrop of a deposit, to test its dimensions and quality. Open cuts are usually run on the surface at right angles to the prevailing course of the veins of the district, and are excavated down to the solid rock for the purpose of exposing the veins which they may cross. This is called " costeening." Boring is employed for deter- mining the character of rock strata, and the position of mineral deposits in them. It has been usually applied to coal beds or to strata containing salt or petroleum deposits. In the latter cases the bore-holes subsequently serve for the extraction of brine or oil. The inven- tion of the diamond drill (see BORING), by means of which holes can be driven in advance horizontally for hundreds of feet, has greatly enlarged the applications of boring as a means of exploration. Horizontal adits, or crosscuts, driven into the sides of hills at right angles with the veins known to exist in them, are the