654 



GEOLOGY AND MINING INDUSTRY OF LEADVtLLE. 



constitute the slag, containing about '2 per cent, of lead, or 15 pounds, and the loss in 

 fumes is equal to about four pounds of lead per charge. Each charge gives about 5.07 

 parts of slag for one part of bullion. The furnaces run about two hundred charges in 

 24 hours, yielding: Bullion, 16 tons; slag, 80 tons; and consuming: Rich ores, 63 

 tons ; fuel, 20 tons ; charges, 143 tons. 



SMELTER D. 

 Smelting charges made in August, 1880. 



Ore, 700 pounds. 



Flax, .130 pounds. 



Fuel, 160 pounds. 



Orebeds 500 ; Dolomite 80 Charcoal 95 



Various ores 200 Hematite 170 Coke 65 



' Old Blag* 80 



Charge (ore and flux), 1,030 pounds. Smelting charge (ore, flux, and fuel), 1.190 pounds. 



In the preceding smelting charges the proportions are 



Flux to ore 47 



Fuel to ore 22J 



Fuel to charge l&J 



The composition of this smelting charge is a normal one. The composition of 

 the average smelting charge, calculated from the data given in Table IV, is the fol- 

 lowing: 



i i 



Ore, 7CO pounds. Flax, 170.3 pounds. Fuel, 133.4 pounds. 



Various ores 700 Dolomite 41.65 Charcoal 89.6 



| Hematite 48.65 ! Coks 43.8 



! Old ("lags - 



Charge (ore and flux), 870.3 pounds. Smelting charge (ore, flax, and fuel). 1,003.7 pounds. 



In the average smelting charge the proportions are 



Flnxtoore 24$ 



Fuel to ore 19 



Fuel to charge l"t 



The percentage of fuel is the smallest which has been yet observed, and this last 

 smelting charge would prove the most perfect if it were not for the important ele- 

 ment, time, which has been purposely neglected. The question will be discussed after 

 exhausting the composition of smelting charges of the various smelters, and it will 

 be seen whether it is advisable to aim at the lowest percentage of fuel in smelting 



charges. 



SMKLTER E. 



Smelting charges made in Aagnst, 1880. 



Ore, 300 pounds. 



Flux, 80 pounds. 



Fnel. 73 pounds. 



Ore-Bed 200 Dolomite 15 " Charcoal 36.5 



Variousores 100 Hnmatite 15 Coke 36.5 



Old slags 50 



Charge (ore and flux). 380 pounds. Smelting charge (ore, flux and fuel), 453 pounds. 



