Bisbee daily review., 1918-09-01

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 is 16 feet, AZ inches. Exclusive of coke, the charge fed per furnace amounts to 996 tons per day, requir- ing 44,169 cubic feet of free air per minute, equivalent to 6S,645 cubic feet per dry ton, the blast being sup piled at a pressure of 27 ounces. The coke used is 12.7 per cent and the dry tons of ore on the charge amounts to S9.7 per cent. The flue-dust produced is 3.4 per cent of the total dry charge.
 There are four all being 100 feet long, and 19 feet wide. The furnace is erected upon deep foundation ot poured slag. On this comes a Ain layer of tamped fire clay, followed by 12 inches of crushed quartz under the matte-bay, and 21 inches under the re- mainder of the furnace hearth. the matte-bay being 20 feet long. The 21 inch I-beams, to take up the thrust at the rear of the furnace, are anchor cd securely by inch rods with 10 inch plates at the end, laid in the poured slag The expansion joints, which are three in number. and are spaced about IS feet center to center, are breaks in the arch ' inches wide at the key line, and tapering to a fraction of an inch at the walls. There are 42 fettle holes on each side, by 6 inches in size and spaced 2 feet apart from center to center. open through the arch close to the inner wall The advantage of fettle-feeding, with details have already ben dis cussed in connection with the smelting ing practice at the plant of the Kansas City Smelling & Refining company at Fl Paso, in the Mining and Scientific Press of May 25, 1918. The prOtec- ton given to the walls is better than when fettling is employed in the old way, and the limits of the bath are more flexible. Thus a better adjust ment to smelling conditions is pos sible than when the bath is held to rigid lines.
 The matte-bay is an interesting de- tail, especially with regard to the eX- pansion of the bath when side-charg- ing is employed It hints at condi tiOns not unlike that would obtain by the enclosure of what is essentially a fore-hearth within the reverberatOry itself. This has been the subject of direct experiment elsewhere The out come of these experiments will be watched with interest. The object is to grade the matte. and 10 permit of continuous discharge of slag. from which the matte may be settled more perfectly than under the old system. One problem, however, is the invari- ability of the arch-temperature. Pe- riodic cooling. at the times of slcg- skimming and of charging, tend to pro long the life of the arch. Indeed, in side charging much of that advantage is sacrificed, and even the feed gen orally contributes heat since the GUS tom prevails. at most plants where side-charging is practiced. of bringing the calcine from the roasting furnaces 10 the reverberatories as hot as pos sible The idea of including the set tier within the furnace suggests the probability of greater fuel-economy. It must be understood that the reference here is merely to the tendency of the bath 10 widen. forming a con5picu- ous embayment, as was explained more fully in discussing the reverber- cioTy practice at the El Paso sme1er. At Great Falls a fore-hearth Is applied to the reye.beratory. placed outside as is done at the blast furnaces; this