680 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



Plate XXXII), and are connected with the dust-chamber represented iu Fig. 4. A 

 longitudinal or side elevation of the furnace, shown in front elevation iu Fig. 1, is seen 

 iu Fig. 3. The hearth A is very similar to that of the furuaces at Smelter C, already 

 described; it is liued with fire-brick, and the siphon-tap Lis confined within the hearth- 

 plates; but here the bullion is ladled out direct from the siphon-tap. The hearth- 

 plates are braced by one row of braces, Q'. The hearth is also confined within the 

 hearth plates, as was the case at smelter 0, and does not project out, as in other fur- 

 naces. The water-jackets B are made of riveted steel boiler plates and are braced by 

 tie-rods Q. There are only four jackets: one in frout, one at back, and one large one 

 ou each side. The circulation of water in these jackets is similar to the one adopted 

 with cast-irou jackets; the water is introduced by means of the pipe M, and the hot 

 water comes out at the open outlets R, provided with outlet-pipes 8. The back water- 

 jacket is provided with two tuyere-holes, which are uot used, and the side jackets with 

 four holes, in each of which a tuyere is placed; so that each furnace is worked with 

 eight tuyeres. 



The pillars P do uot rest on the ground, as is the case with all the furnaces thus- 

 far described, but on the lining of the crucible. Another peculiarity is that there are 

 six of these pillars, instead of four as in most furnaces. The capitals are supported 

 on the pillars by means of brackets t. The main cast-iron plate support is of unusual 

 thickness, being four inches thick. The use of a plate of such unusual dimensions 

 is necessitated by the fact that the masonry does not rest directly on the pillars, as in 

 other furnaces. 



The masonry consists of fire-bricks, as usual, but is entirely surrounded by a 

 wrought irou jacket, J'. At the throat there are two feed-holes U, provided with slid- 

 ing doors S'. 



Dust-chamber. The sheet iron stack of each furnace, which is a prolongation of 

 the jacket, is connected by means of the flues F 1 F" with the sheet-iron dust-chamber, 

 formed of a cylindrical portion D 1 and a conical portion D". The fumes escape through 

 the sheet iron stack. The dust is withdrawn from this chamber by means of sliding 

 valve S, and falls from the aperture Z into a wheelbarrow, T. At smelter D flue-dust 

 is not mixed with lime, as at most smelters, nor spread over ore-beds or mixed with 

 smelting charges; it is simply moistened with water and throwu in the furnace in the 

 proportion of one shovelful to every two smelting charges. The smelting capacity of 

 each furnace is 24 tons of ore per 24 hours, or one ton per hour. The pressure in 

 blast-pipe R 1 is regulated by a damper placed at its extremity. The length of runs at 

 this smelter is about two months. 



SMELTER E. 



Disposition of works. These works, situated on Big Evans gulch, are, like all the 

 smelters erected on this gulch, divided into two levels only. This smelter is small, but 

 well managed, and is one of the most successful of its size. The pressure of the steam 

 in the boilers is 70 pounds to the square iuch; they supply a 40 horse-power engine, 

 which drives two Baker blowers, a set of Cornish rolls, two Blake crushers, and the 

 pumps feeding the water tanks. The ore and fuel bins are inclosed in the main build- 

 ing, through which runs a wagon-road, and fuel reserves are placed at the back, out- 

 side of the works. The offices, provided with Fairbanks scales, and the laboratory are 

 situated in a detached building a short distance back of the main building. 



