. Discovery. Science. ^'iX'i â -â f'' ^'^' Fig. 2.âview showing METHOD OF WORKING AND EFFECT OF WEATHERING ON CHAI^K. great quarries at Melton Ross situate on the main line between Sheffield and Grimsby, which passes between them on a high natural embankment of chalk that has not been quarried. These quarries, each 175 yards long by 100 yards wide and 50 feet deep, have been worked for many years for whiting, and lime for building and agricultural purposes, but the bulk of the output is used for fluxing steel in furnaces. The chalk, or " Limestone " as it is called locally, is w
. Discovery. Science. ^'iX'i â -â f'' ^'^' Fig. 2.âview showing METHOD OF WORKING AND EFFECT OF WEATHERING ON CHAI^K. great quarries at Melton Ross situate on the main line between Sheffield and Grimsby, which passes between them on a high natural embankment of chalk that has not been quarried. These quarries, each 175 yards long by 100 yards wide and 50 feet deep, have been worked for many years for whiting, and lime for building and agricultural purposes, but the bulk of the output is used for fluxing steel in furnaces. The chalk, or " Limestone " as it is called locally, is won simply by pick and shovel, and occasionally by blasting. It is quarried out in steps or ledges as shown in Figs. I and 2. For making whiting, which is chemic- ally pure chalk, there are pan-mills to grind to a paste the pure white beds of chalk which occur in certain parts of the quarry. The slurry or liquor from the pan-mills is run off into settling-pits, from which the paste is dug out by hand and placed in lumps on shelves in long open sheds where it is dried by the air. A certain waste-product is removed from the slurry before it enters the settling-pits. This product is coarse in grain and cannot be used in the manufacture of whiting, although its chemical composition is identical with that of whiting. The process is quite simple ; but good raw material such as is to be foimd in the " Middle Chalk " is in- dispensable. The manufacture of lime, and of the purer variety of lime for steel-smelting, is also carried out in brick kilns in one of the quarries. The process consists of burning the chalk (calcium carbonate) into lime (calcium oxide)âthe latter, like cement, having the property of forming another hard chemical compound when mixed with water. The flint quarried is ground for poultry grit. Fig. 2 shows the manner in which chalk disintegrates when exposed to the atmosphere for some time, the lines of stratification being almost obliterated. This is see
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