As representative of wet-dressing practice, the Anaconda scheme may be noted, as summarised below. There are eight mills, each treating 1,000 tons of ore per day, and conducting the— Coarse crushing in Blake crushers. Coarse sizing by trommels. Coarse separation on Harz jigs of 1¼-inch and ⅞-inch feed. Middlings crushing in rolls. Middlings sizing by trommels. Middlings separation on fine jigs of 7, 5, 2½, 1½, and 1 millimetre feed. Finest crushing in Huntingdon mills. Fines settling by spigot settlers. Fines separation on Wilfley tables (471 are in use on the plant). The muddy water goes to enormous settling ponds, where the slime settles down, gradually drains, and dries, and it is afterwards used for various purposes during the smelting operations; being dug out in the form of a fine clay. A new form of centrifugal apparatus (the Peck) is now being installed for the separation of this material. The subsequent treatment of the products from the concentrating operation is indicated in the diagram (fig. 12), from which it will be seen that the— _Coarse Concentrates_, 1¼, ⅞ (and ⅜) inch size, are smelted in the blast furnaces. _Fine Concentrates_, 7, 5, 2½, 1½, and 1 millimetre size, pass to the roasters, and thence to the reverberatory furnaces. _Slimes_ are used for briquetting, and several other operations. _Tailings_ pass to the dump. [Illustration: Fig. 12.—Outline of Smelting Scheme at the Anaconda Smelter, Montana, U.S.A.] _B._ =Agglomeration of Fines.=—It has just been seen that the wet concentration of ores (considered advisable in a large number of cases) results in the production of a considerable quantity of fine concentrate, a form of material not well suited for immediate blast-furnace treatment. In addition, smelters often receive considerable amounts of fines in the smelting-ore supply, which it is not unusual to screen out and to treat separately from the coarser materials.[4] The alternatives for the treatment of fines, and more particularly of fine concentrate, include smelting in reverberatory furnaces (usually after roasting); blowing into the converter (a new process still in the experimental stage); and blast-furnace treatment after suitable preparation. Blast furnaces have many advantages which lead to their extended use in copper smelting practice, but one important feature, which also applies to the smelting of other metals, has always to be borne in mind in this connection—viz., _that material in a finely divided state cannot be treated directly in a blast furnace without heavy losses_, and the working of the furnace on such charges is not efficient. No material less than ¼ to ⅜ inch in size, especially when in the form of sulphides, should be fed as such into a modern blast furnace. Fines in the furnace lead to—