Mance: Quarry Industry of Southern Indiana 181 



siderations are so important that the location and supply of fuel 

 becomes more important than the location of the deposits of 

 cement material. As mentioned before, the cement deposits 

 are located near the Indiana coal fields, but at the present time the 

 plants of Indiana are using Pittsburgh coals. This difficulty 

 could be remedied by the use of producer gas in the kilns. In 

 fact, the use of gas is increasing even in the coal districts of West 

 Virginia and Pennsylvania. The advantages of the use of pro- 

 ducer gas as a fuel for the manufacture of lime or cement are 

 many and the use of gas as a fuel in both industries is sure to 

 grow rapidly. Producer gas is better than coal for the following 

 reasons : 



1. The absence of ash in the burned product. In the pro- 

 ducer gas the ash remains behind and only the combustible gases 

 are passed into the kilns to burn, thus insuring a purer product. 



2. The presence of a great amount of water as the gas burns. 

 A large percentage of the gas consists of hydrocarbons and hydro- 

 gen and the combustion of these gives water. This is of especial 

 advantage in the manufacture of lime. 



3. The high heating value of the gas. 



4. The ready control of the point of burning and the tempera 

 ture. 



5. The fact that any coal can be utilized in the manufacture 

 of gas. 



Cost of Cement Manufacture. The cost of the raw ma- 

 terials varies greatly in the different districts. Estimates on the 

 loss of weight due to burning the raw material to cement clinker 

 are: for dry, hard limestone and shale about 33| per cent, that 

 is, 1,000 pounds of the mixture of limestone and shale will give 

 about 665 pounds of cement clinker. A barrel of Portland 

 cement weighs about 380 pounds and Eckel (op. cit., p. 59) states 

 that if the losses of manufacture are included, it is safe to say 

 that 600 pounds of raw material will produce a barrel of cement. 

 The cost of excavation and delivery is given as from 8 to 15 

 cents per barrel. That represents a cost of from 27 to 50 cents 

 per ton of raw material at the mill. Since it takes from four to 

 five carloads of limestone per carload of shale and the price of 

 limestone, delivered in the quarry district is very low, the shale 

 could be brought quite a distance without exceeding this figure. 



As has been already stated, the fuel cost is a more important 

 consideration than the cost of raw materials. In the use of 



