LIST OF ABBREVIATIONS. Ann. Mines.-Annales des Mines. Ann. Rep. R. Cornwall Pol. Soc.-Annual Report of the Royal Cornwall Polytechnic Society. B. u. h. Z.-Lerg- und hüttenmännische Zeitung. Bull. Soc. Ind. Min.-Bulletin de la Société de l'Industrie Minérale. Coll. Guard.-The Colliery Guardian. Comptes Rendus Mensuels, Soc. Ind. Min.-Comptes rendus mensuels de la Société de l'Industrie Minérale. Eng. Min. Jour. or E. M. J.-The New York Engineering and Mining Journal. Jahrb. f. d. Berg- und Hüttenwesen im K. Sachsen.-Jahrbuch für das Bergund Hüttenwesen im Königreiche Sachsen. Jahrb. f. Geol. Min. Paläont.-Jahrbuch für Geologie, Mineralogie und Paläontologie. Jour. Roy. Inst. Cornwall.-Journal of the Royal Institution of Cornwall. Jour. Soc. Chem. Ind.―Journal of the Society of Chemical Industry. Min. Stat.-Mineral Statistics of the United Kingdom. Neues Jahrb. f. Miner. Geol. u. Paläontologie.-Neues Jahrbuch für Mineralogie, Geologie und Paläontologie. Oest. Zeitschr. f. B.- u. H.- Wesen.-Oesterreichische Zeitschrift für Bergund Hüttenwesen. Phil. Trans.-Philosophical Transactions. Proc. Fed. Inst. M. E.-Proceedings of the Federated Institute of Mining Engineers. Proc. Inst. Civil Eng. or Proc. Inst. C. E.-Proceedings of the Institution of Civil Engineers. Proc. Inst. Mech. Eng. or Proc. Inst. M. E.-Proceedings of the Institution of Mechanical Engineers. Proc. Min. Inst. Cornwall.-Proceedings of the Mining Institute of Cornwall. Proc. South Wales Inst. Eng.-Proceedings of the South Wales Institute of Engineers. Quart. Jour. Geol. Soc.-Quarterly Journal of the Geological Society. Rec. Geol. Survey, India.—Records of the Geological Survey of India. Rep. Miners' Assoc. Cornwall.-Report of the Miners' Association of Cornwall and Devon. Stat. Min. France.—Statistique de l'Industrie minérale en France. Trans. Amer. Inst. M. E.-Transactions of the American Institute of Mining Engineers. Trans. Inst. Eng. and Shipbuilders in Scotland.-Transactions of the Institute of Engineers and Shipbuilders in Scotland. Trans. Inst. Marine Eng.-Transactions of the Institute of Marine Engineers. Trans. Manch. Geol. Soc.-Transactions of the Manchester Geological Society. Trans. Min. Assoc. and Inst. Cornwall.-Transactions of the Miners' Association and Institute of Cornwall. Trans. Min. Inst. Scotland.-Transactions of the Mining Institute of Scotland. Trans. N. of Eng. Inst. Min. Eng.-Transactions of the North of England Institute of Mining and Mechanical Engineers. Trans. R. Geol. Soc. Cornwall.-Transactions of the Royal Geological Society of Cornwall. Trans. Technical Soc. Pac. Coast.—Transactions of the Technical Society of the Pacific Coast. Zeitschr. d. d. geol. Gesellsch.-Zeitschrift der deutschen geologischen Gesellschaft. Zeitschr. f. B.- H.- u. S.-Wesen.-Zeitschrift für das Berg- Hütten- und Salinenwesen im preussischen Staate. A TEXT-BOOK OF ORE AND STONE-MINING. INTRODUCTION. THE art of mining, in the broadest sense of the word, consists of the processes by which the useful minerals are obtained from the earth's crust. This definition is wide, for it includes under the term "mine" both open and underground excavations; but it excludes subterranean workings which are simply used as passages, such as railway tunnels, sewers, and galleries for military purposes. 66 The word "mine" is derived from a low-Latin verb meaning to lead, and equivalent to "ducere; " we have the French word "mener," from the same source. No doubt originally the mineral deposit itself was called the "mine" or "lead," and this signification has not been entirely lost, for we still find the word "mine used as a synonym for seam " in the case of coal and ironstone. I must remark that the word "mine," or its equivalent in other languages, varies in signification in different countries on account of legal enactments or decisions which define it. In the United Kingdom it is the nature of the excavation, and not the nature of the mineral, which decides whether the workings are a mine or not. For legislative purposes the term "mine" is restricted to workings which are carried on below ground by artificial light; but in common parlance this rule is not observed, and the word used depends upon the mineral itself. Thus the underground workings for building stone near Bath, and for slate at Festiniog, are usually spoken of as quarries, but are treated legally as mines. In Belgium, France, and Italy, on the other hand, the workings for mineral are classified according to the mineralogical nature of the substance wrought. The French law of 1810 makes three classes of workings: mines, minières, and carrières. Deposits of gold, silver, lead, copper, sulphur, coal, and beds or veins of iron ore form mines. Under the head of minières, for which we have no equivalent word in English, are included bog iron ore, pyritous earths fit for working, sulphate of iron, aluminous earths and peat, whilst the carrières, or quarries, comprise workings for stone, clay, sand, etc., whether above or below ground. The statute of 1866 has assimilated the minières to the quarries, and the law now becomes very like that of Italy (1859), which distinguishes simply mines (miniere) and quarries (cave). Deposits containing metallic ores (excepting metal-bearing sand or earth), sulphur, bitumen, coal, or lignite are worked as "mines," whilst pits from which sand and gravel are obtained become legally "quarries." The consequence is that what is merely an underground stone quarry in France would be a mine in England; whilst open workings for iron ore, such as those of Northamptonshire, would be true mines under the French or Italian laws. In a general text-book upon mining, it is therefore necessary to go beyond the British definition of a mine and to include the methods of working minerals in excavations open to the daylight, as well as in those which are purely subterranean. The mining of coal is a subject of so much importance, especially in this country, that it requires a special treatise; this has been prepared by my friend, Mr. H. W. Hughes,* and my task consists in describing the methods of winning and working all other useful minerals, whether solid, liquid, or gaseous. Furthermore, as it is customary for the miner to cleanse or prepare his ore or stone for sale, I shall explain the processes which are usually carried on at the mine, and can be fairly included under the convenient term " dressing." Finally, a few remarks will be made concerning legislation affecting mines in the United Kingdom, the condition of workmen, and the accidents to which they are exposed. The subject has been divided into the following chapters:(1) Occurrence, or manner in which the useful minerals are found in the earth's crust. (2) Prospecting, or search for minerals. (3) Boring. (4) Excavation. (5) Supporting excavations. (6) Exploitation, or working away of minerals. (7) Haulage, or transport along roads. (8) Winding, or hoisting in shafts. (9) Drainage, or removal of water. (10) Ventilation. (11) Lighting. (12) Descent and ascent. (13) Dressing. (14) Principles of employment. (15) Legislation. (16) Condition of workmen. (17) Accidents. A Text-Book of Coal Mining, London, 1892. (3) CHAPTER I. MODE OF OCCURRENCE OF MINERALS. Classification of mineral repositories.-Beds.-Veins.--Masses.-Causes affecting the productiveness of veins.-Theories concerning the formation of veins.-Examples of mineral deposits arranged alphabetically.-Faults or aislocations. CLASSIFICATION. Various conditions may be taken as the bases of classification of the rocks which form the crust of the earth. One striking characteristic is the presence or absence of beds or layers. A rock made up of parallel beds, or layers, or strata, is said to be stratified; a rock in which no such structure exists is called unstratified. When we examine the stratified rocks closely, we find that, as a rule, they have been formed at the bottom of seas, lakes, or rivers by the gradual deposition of sediment, by precipitation from solutions, and by the growth or accumulation of animal or vegetable organisms. As instances may be cited beds of sandstone or clay, formed by particles of sand or mud settling down in water; beds of rock salt, resulting from the gradual drying-up of inland seas; beds of limestone, formed out of old coral reefs; beds of coal, due sometimes to plants growing upon the spot and sometimes to plants washed into lakes or estuaries. The unstratified rocks are frequently crystalline. In the case of recent volcanoes we see molten rocks issuing forth from the earth, spreading over it, and consolidating into a crystalline mass, and we may fairly assume that many of the crystalline rocks now met with at the surface were at one time in a soft fused condition. Internal evidence leads to the belief that the process of consolidation often took place at a very great depth, and on this account geologists have subdivided the crystalline unstratified rocks into volcanic, which hardened like recent lavas near the surface, and plutonic, which became solid under the heavy pressure of thick masses of superincumbent strata. One class of crystalline rocks has given rise to much controversy, viz., the rocks in which the crystals of the constituent minerals are arranged in roughly parallel layers. The rock has a flaky structure, and is known as a crystalline schist. Some crystalline schists have all the appearance of being altered sedi |