The Works Of Messrs. Schneider And Co.

18 MESSRS. SCHNEIDER AND CO.’S WORKS. the Ste. Madeleine heading, at a height of 3,340 ft. In 1893, a new heading called St. Henri, at a height of 2,700 ft., one mile in length, was driven by means of drills worked by compressed air. This gallery also cuts the two veins, and will facilitate the work of extraction for many years to corne. The first vein intersected is 18 ft. to 25 ft. deep ; it yields a foliated ore, largely crystallised, and known as “ maillat ” ore. This quality gives the finest samples from a mineralogical point of view, but it is not the best for practical purposes, as it is not sufficiently rieh in manganèse, does not roast easily, and yields a certain quantity of dust. The second vein, tlïe finest of the whole region, is equal in depth to the “ maillat ” vein. The ore it yields shows smaller scales, and is rieh er in manganèse. The gangue is chiefly quartz ; in some cases it is found to be dolomite, and multiple carbonates of iron, of manganèse, and of lime. The mode of working is by galleries, which divide the veins into a series of levels, one above the other. These levels are reached by shafts, and the veins are worked by inclined cuttings, the excavation being filled up as the ore is taken out. On leaving the mine, the trucks are carried, four at a time, on frames which descend the inclined planes as far as Champ Sappey, near St. Pierre d’Allevard. There the ore is thrown on screens and washed by means of jets of water ; it is then sorted, the largest pièces being broken. with the hammer. After washing, the ore is roasted. Three furnaces of an ordinary type serve for this purpose, and three others built specially are used for roasting the fine ore. The furnaces are heated by gas, which is pro- duced in separate generators. The ore loses 25 per cent, of its weight in roasting, and after this operation, it contains from 4G to 48 per cent, of metallic iron and manganèse The proportion of crude fine ore being rather large, a special plant bas been put down for mechanical préparation and washing. The largest pièces are crushed between rolls, and the whole is then screened. The product is divided into five classes, and is carried to continuons washing machines provided with lateral pistons and sieves. The ore gradually falls to the bottom of the tank, and the waste stone is carried away by the stream from the washers. The finer portion is treated in another type of washing machine. Classification into different sizes is carried on only to facilitate the washing process, and the washed products from the varions screens are afterwards brought together to the roasting furnaces. Fig. 36 is a general plan of the disti’ict of Champ Sappey, and sub- joined is a list of the various installations for treatment of the ores. In this plan the letters refer to the following : A. Weighing machine. B. Sorting and washing small ore. O. Magnetic screens for treating refuse of the heavy roasted ore. D. Roasting funiace for small ore. E. Roasting fumace for heavy ore. F. Screens for heavy ore. G. Roasting furnace for small ore. H. Sorting and screening ore. I. Weighing machine. K. Stores. L. Air compressors. M. Locomotive shed. N. Central electric lighting station. O. Bepair shops. P. Offices. Limestone.—Limestone flux of first-class quality is found in quarries a few miles distant from Creusot. The most important are at Chagny, on the banks of the Canal du Centre. The flux is brought at a very low cost by boat to the port belonging to Messrs. Schneider and Co., at Montchanin. This limestone is also used to make lime of great purity ; it is extremely suitable for furnace linings. The same remark applies to dolomite, fluor-spar, various sands and clay used in the Works, either direct, or after treatment at Messrs. Schneider and Co.’s brick Works at Perreuil.