498 GEOLOGY OF OHIO. 
ores somewhat similar to the Ohio limonites and carbonates are found. 
With many of the Coal Measure ores used in Ohio, considerable 
low grade material and clay are mixed. The introduction of such 
material into the furnace tends to bring down the value of the whole 
charge and to increase the cost of smelting per ton of iron, to diminish 
the effective capacity of the furnace and to render the quality of the 
iron less uniform. ‘‘ Washing,” where practiced, consists in a treat- 
ment of the ore by a stream of water, either over revolving screens or 
in sluices, by which the clay and other lighter and injurious material is 
removed. ‘The charcoal furnaces of Northern Alabama have adopted 
in some cases this method of treatment, and it possibly could be used 
in the case of some of the Ohio ores with benefit, though their low per- 
centage of iron would forbid any expensive treatment. The roasting 
of the iron ore previous to smelting is practiced throughout the State 
of Ohio. The method in almost universal use is of roasting in open 
piles, of which the dimensions vary greatly from district to district with 
the character of the ore. The limestone ores and brown hematites of 
the southern districts are roasted, either with charcoal breeze or with 
raw coal slack. The ore is usually roasted at the furnace, but not in all 
cases; sometimes, as at several points on the Iron Railroad near Jron- 
ton, the ore is brought over to the most convenient distributing point, 
and there made into piles and roasted. A similar arrangement is em- 
ployed by the mining company known as J. R. Buchtel & Co., in Vin- 
ton county. This company owns lands along the lines of the Ohio and 
West Virginia Railroad, in Vinton and Hocking counties, located 20 
or 30 miles along the railroad. The company is composed of a number 
of the furnace owners of the Hocking Valley, united under the above 
name. The ore is mined at various points, roasted, and sent to the 
furnace from three or four stations along the line of the road. The 
piles of ore at the Lawrence county charcoal furnaces are built on a 
leveled space, generally on the bank above the furnace, on an under- 
stratum of wood; above this the ore is piled, with alternate layers of 
finely broken charcoal, resulting from the screening of the charcoal 
used in the furnace. The pile is built to a height varying from five or 
six to ten or fifteen feet, and covering a space of ground about ten feet 
in width by sixty or more in length. Frequently several such piles are 
built side by side, and in this way cover a square of ground possibly 
thirty or forty by fifty or sixty feet. ‘The pile is fired at the bottom. 
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