Proper washing apparatus

—For washing the ore after sifting it, the running buddle already described is employed, along with several chests or buddles of other kinds. 1. The trunk buddle is a species of German chest (see Metallurgy and Tin ) composed of two parts; of a cistern or box into which a stream of water flows, and of a large tank with a smooth level bottom. The ore to be trunked being placed in the box, the workman furnished with a shovel bent up at its sides, agitates it, and removes from time to time the coarser portions; while the smaller are swept off by the water and deposited upon the level area. 2. The stirring buddle , or chest for freeing the schlamms or slimy stuff from clay, is analogous to the German chests, and consists of two parts; namely, 1. a trough which receives a stream of water through a plug hole, which is tempered at pleasure, to admit a greater or le current; 2. a settling tank with a horizontal bottom. The metallic slime being first floated in the water of the trough, then flows out and is deposited in the tank; the purest parts falling first near the beginning of the run. 3. The nicking buddle is analogous to the tables called dormantes or jumelles by the French miners. See Metallurgy . They have at their upper end a cro canal or spout, equal in length to the breadth of the table, with a plug hole in its middle for admitting the water. Alongside of this channel there is a slightly inclined plank, called nicking board , corresponding to the head of the twin table , and there is a nearly level plane below. The operation consists in spreading a thin layer of the slime upon the nicking board , and in running over its surface a slender sheet of water, which in its progre is subdivided into rills, which gradually carry off the muddy matters, and strew them over the lower flat surface of the tank, in the order of their density. IMG:4147767755307473660_illo0751.png:Dolly tub 4. The dolly tub or rinsing bucket, fig. 630. , has an upright shaft, which bears the vane or dolly A B , turned by the winch handle. This apparatus serves to bring into a state of suspension in water, the fine ore, already nearly pure; the separation of the metallic particles from the earthy ones by repose, being promoted by the sides of the tub being struck frequently during the subsidence. 5. Slime pits. —In the several operations of cleansing ores from mud, in grinding, and washing, where a stream of water is used, it is impo ible to prevent some of the finely attenuated portions of the galena called sludge , floating in the water, from being carried off with it. Slime pits or labyrinths , called buddle holes in Derby shire, are employed to collect that matter, by receiving the water to settle, at a little distance from the place of agitation. These basins or reservoirs are about 20 feet in diameter, and from 24 to 40 inches deep. Here the suspended ore is deposited, and nothing but clear water is allowed to escape. The workmen employed in the mechanical preparation of the ores, are paid, in Cumber land, by the piece, and not by day’s wages. A certain quantity of crude ore is delivered to them, and their work is valued by the bing , a measure containing 14 cwt. of ore ready for smelting. The price varies according to the richne of the ore. Certain qualities are washed at the rate of two and sixpence, or three shillings the bing; while others are worth at least ten shillings. The richne of the ore varies from 2 to 20 bings of galena per shift of ore; the shift corresponding to 8 waggons load. 1. The cleansing and sorting of the ores are well performed in Cumber land. These operations seem however to be inferior to the cleansing on the grid steps , grilles à gradin , of Saxony (see Metallurgy ), an apparatus which in cleaning the ores, has the advantage of grouping them in lots of different qualities and dimensions. 2. The breaking or bruising by means of the crushing machine , is much more expeditious than the Derby shire proce by buckers ; for the machine introduces not only great economy into the breaking operation, but it likewise diminishes considerably the lo of galena; for stamped ores may be often subjected to the action of the cylinders without waste, while a portion of them would have been lost with the water that runs from the stamp mill. The use of these rollers may therefore be considered as one of the happiest innovations hitherto made in the mechanical preparation of ores. 3. The brake sieves appear to be preferable to the hand ones. 4. The system of washing used in Cumber land differs e entially from that of Britt any. The slime pits are constructed with much le care than in France and Germany. They never present, as in these countries, those long windings backwards and forwards, whence they have been called labyrinths; probably because the last deposits, which are washed with profit in France and Germany, could not be so in Cumber land. There is reason to believe, however, that the introduction of brake tables , ( tables à secou es , see Metallurgy ) would enable deposits to be saved, which at present run to waste in England. 5. From what we have now said about the system of washing, and the basins of deposit or settling cisterns, it may be inferred that the operation followed in Cumber land is more expeditious than that used in Britt any, but it furnishes le pure ores, and occasions more considerable waste; a fact sufficiently obvious, since the refuse stuff at Poullaouen is often resumed, and profitably subjected to a new preparation. We cannot however venture to blame this method, because in England, fuel being cheap, and labour dear, there may po ibly be more advantage in smelting an ore somewhat impure, and in losing a little galena, than in multiplying the number of washing proce es. 6. Lastly, the dolly tub ought to be adopted in all the establishments where the galena is mixed with much blende (sulphuret of zinc); for schlich (metallic slime) which appears very clean to the eye, gives off a considerable quantity of blende by means of the dolly tub . While the vane is rapidly whirled, the sludge is gradually let down into the revolving water, till the quantity is sufficiently great. Whenever the ore is thoroughly di eminated in the liquid, the dolly is withdrawn. The workmen then strike on the sides of the tub for a considerable time, with mallets or wooden billets, to make the slime fall fast to the bottom. The lighter portions, consisting almost entirely of refuse matter, fall only after the knocking has ceased; the water is now run away; then the very poor slime upon the top of the deposit is skimmed off; while the pure ore found at the bottom of the tub is lifted out, and laid on the bingstead . In this way the blende, which always accompanies galena in a greater or smaller quantity, is well separated.