COSTS AND STATISTICS. 557 



expenses of the plant must be paid in cash. This is particularly the 

 case with regard to quarry and mill labor, an item which alone may 

 amount in a six-kiln plant to from $4000 to $6000 per month. 



For these reasons it is advisable to make a very liberal allowance 

 for the working capital required. A reserve amounting to $20,000 

 to $25,000 per kiln will probably be found sufficient to cover most cases, 

 though in commencing work on absolutely new materials a consider- 

 ably larger reserve will be found advisable. Adding this necessary 

 reserve to the amount required for the purchase of land and the 

 actual erection of the plant, and for ordinary small plants, it will be 

 found that the total working capital necessary will be in the neighbor- 

 hood of $100,000 per kiln. 



Current administrative expenses. This group of expense factors 

 includes the salaries of the administrative officers of the plant and 

 also the expenses of the sales department, including advertising. It 

 is obviously one of the most variable factors in the cost of cement-man- 

 ufacture as between different plants. Even at the same plant it may 

 vary widely from time to time, because its total amount does not depend 

 directly upon the amount of cement sold. In a large plant during a 

 prosperous year the costs chargeable to this group of expenses may fall 

 as low as 5 cents per barrel of cement produced, while in a small plant 

 running undertime they may easily rise as high as 15 cents per barrel. 



Cost of excavating raw materials. This point has been covered 

 quite fully on preceding pages. In the present place it will only be 

 necessary to summarize this information by stating that the total cost 

 of raw materials, delivered at the mill, per barrel of cement produced, 

 will usually fall within the following limits : 



Cost per Barrel. 



Cement rock and limestone. . 

 Pure limestone and clay. . . . 

 Marl and clay or shale 



a. Limestone on property . . $0 . 07 to $0 . 10 



b. Limestone purchased .. . .15 ' .20 



a. Quarried 06 ' .15 



b. Mined 10 ' .20 



a. Both on property 03 ' .05 



b Clay purchased 08 .15 



Total power required. The total power developed in a Portland- 

 cement plant is not far from 1 H.P. for each barrel of cement turned 

 out per day. As most of the power is required continuously, it is safe 

 to figure on a requirement of 20 to 30 H.P.-hours for each barrel of 

 cement. This will include the power used in grinding and mixing the 

 raw materials in running conveyors, kilns, etc., and in grinding the 

 clinker. 



At most American plants all this power is derived from the direct 

 consumption of coal under boilers. At several plants, however, water 



