MINES 



257 



Tons 



Railways and canals, 1872, increased . . 4,600,000 



Exports, 1872, increased .... 450,505 



Iron and other metallurgies, 1872, increased . 6,073 



The quantities used at collieries and in mines, 



estimated increase 10,000 



Coal carted, or sent by private rail- or tram-roads, 

 to iron-works, manufacturers, and towns, 

 which does not appear in the above returns, 

 estimated increase. ..... 250,000 



Coastwise shipments, decrease 



5,316,578 

 300,214 



Actual estimated increase in 1872 over the production 



of 1871 5,016,364 



Production of the principal Minerals raised in the United Kingdom during 

 the four years ending 1872. For 1873, see p. 246. 



MINERAL TALLOW. See HATCHETTINE. 



MINERAL WATERS. See SODA-WATER ; and WATER. 



MINES. (BergwerJce, Ger.) The miner, in sinking into the earth, soon opens 

 up numerous springs, whose waters percolate into the excavations which he digs. 

 When his workings are above the level of some valley and at no great distance, 

 it is possible to get rid of the waters by leading them along an adit-level or gallery 

 of efflux. This forms always the surest means of drainage ; and, notwithstanding 

 the great outlay which it involves, it is often the most economical. Many adit-levels 

 are several miles in length, and are so contrived as to discharge the waters of several 

 mines, as in the Gwennap district of Cornwall, and in the environs of Freiberg, in 

 Saxony. Such an amount of slope should be given them as is barely sufficient to make 

 the water run, at the utmost from ^ to 4 ^, so as to drain the mine to the lowest pos- 

 sible level. 



Whenever the workings are extended below the natural means of drainage, 01 

 below the level of the plain, recourse must bo had to mechanical aids. In the first 

 place, the quantity of percolating water is diminished as much as possible by plank- 

 ing, walling, or tubbing, with the greatest possible care, those pits and excavations 

 which traverse the water-levels ; and the lower workings are so arranged that all the 

 waters may unite into sumps or wells placed at the bottom of the shafts or inclined 

 galleries ; whence they may be pumped up to the day, or to the level of the gallery 

 of efflux. In most mines simple lifting-pumps are employed, but in those districts 

 where the necessity of raising large volumes of water from great depths has led to 

 improvement, forcing-pumps or plunger-Ufa are introduced, placed over each other 

 at intervals of from 180 to 240 feet, although, for convenience, a lifting-pump or 

 drawing-lift occupies the deepest extremity of the shaft, whence it raises the 

 water to the first plunger, q,nd that again forces the stream upward through the 

 column, or trees, to the one next above it, and so on up to the adit-level, or to 

 the surface. 



These draining-machines are set in motion by that mechanical power which happens 

 to be least costly in the place where they are established. In almost the whole of 

 England, and over most of the coal-mines of France and Silesia, the work is done by 

 steam-engines ; in the principal metallic mines of Franco, and in almost the whole of 

 Germany and Hungary by hydraulic-machines ; and in other places, by machines 

 moved by horses, oxen, or even by men. If it be requisite to lift the waters merely to 

 an adit-level, .advantage may be derived from the waters of the upper parts of the 

 mine, or even from waters turned in from the surface, in establishing in the adit-level 



VOL. III. S 



