MATERIALS USED IX SMELTING. 641 



CONSTRUCTION MATERIALS. 



Common brick — The biiclis used iu the constriictiou of outer walls and dust- 

 cLambers arc made fiom clays fouud iu California aud Big Evaus gulcbes. They are 

 made in a very simple way: luto a woodeu mold (Figs. 9 and 10, Plate XLIV), divided 

 into tbree compartments having the shape and dimensions of bricks, a lump of the 

 clay, brought to the proper degree of consistency, is jammed atone blow without sub- 

 sequent eflort or pressure. The excess of clay, represented by c in Fig. 9, is cut off by 

 means of an iron wire, both ends of which are fixed to a wooden handle (Fig. 11, Plate 

 XLIV). The mold is then reversed and gently shaken. The detached bricks are 

 dried as usual in long rows iu the air. They are then piled uji in large stacks and 

 burned. 



Fire-brick. — The fire-bricks used for the lining of furnaces are sent to Leadville 

 chiefly from the niaiiutactory of Messrs. Evans & Howard, St. Louis, Missouri, and 

 also from the Cambria Fire-brick Company, Golden, Colo., and from the Denver Fire- 

 clay Company, Denver, Colo. 



Tapping clay — Good plastic aud refractory clay is ueeded for tymp stones, tap- 

 boles, tamping, aud steep (brasque) used iu the lining of furnace crucibles. The fol- 

 lowing analysis of tapping clay found in Big Evans gulch and used at the Gram 

 smelter was made by Dr. M. W. lies, of the Grant Smelting Works: 



Analysis A'll. Tappin'g clay. 



Silicate of aliiiuiua 74. "> 



Water 14.0 



Oxiile of iroii 3. 



Magnesia Trace 



Carbonate of lime 6. 8 



Free silica 1.0 



Other materials — Wheu the smeltiug works are erected on the plans of sujier- 

 intendents, the smelting implements are derived from various sources. The cast- 

 ings, however, such as water-jackets, iron pillars, plates for supports and frames 

 of crucibles, ingot-molds, slag-pots, etc., are generally made by Messrs. Hendey & 

 Meyer, of Denver; while the boilers and engines are made by different foundries. In 

 many cases smelters have found it more convenient and advantageous to obtain the 

 whole of their smelting plant from Messrs. Fraser & Chalmers, of Chicago, 111., who 

 are prepared to furnish a complete smelting outfit, from the crushers and turnace 

 down to ingot-molds and tamping-rods. 



FUELS AND FLUXES. 



Coke — Coke is made iu El Moro, on the Eio Graude Eailroad, from Cretaceous 

 coals found there ; it is known iu Leadville as El Moro coke. It is also made iu Como, 

 on the South Park Eailroad, from Como Cretaceous coals, aud is then known in Lead- 

 MON xti 41 



