KEL.J 
NEW YORK. 
263 
The materials used are limestone and clay. The former is of Tren- 
ton age, and is obtained from the Glens Falls quarries. Considerable 
care is required in selecting and mixing the stone from the various 
layers, in order to obtain a suitable and uniform product. A very 
clean and uniform clay, overlying the limestone in this area, is the 
other ingredient. The composition of these materials is shown below. 
Analyses of cement-making materials used at Glen Falls, N. Y. 
Silica (Si0 2 ) 
Alumina (A1 2 3 ) 
Iron oxide (Fe 2 3 ) 
Lime (CaO) 
Magnesia (MgO) 
Sulphur trioxide (S0 3 ) 
Carbon dioxide (C0 2 ) 
Organic and water 
Limestone. 
Clay. 
3.30 
55. 27 
1. 30 
28. 15 
52. 15 
5.84 
1.58 
2.25 
.30 
.12 
40.98 
8.37 
The limestone and clay are separately dried, and crushed in Blake 
j crushers and rolls. After being weighed on automatic scales, the 
j materials are mixed dry and reduced to a line powder in Griffin mills. 
] The powder is then fed into wet mixers, where sufficient water is 
• added to allow it to be made up into bricks. These are dried in tun- 
nels heated by waste heat (from the boiler) driven through the tunnel 
i system by blowers. After drying, the bricks are burned in Schoefer 
kilns, coal being used as fuel. The clinker is passed first through 
Smidth ball mills and finally reduced in Davidsen tube mills. 
An average analysis of the Iron Clad cement is given below. 
Analysis of cement made at Glen Falls, N. Y. 
. 21.50 
1 10.50 
i Silica ( Si0 2 ) • 
} Alumina ( A1 2 :< ) 
J Iron oxide (Fe 2 3 ) 
Lime (CaO) 63. 50 
ji Magnesia (MgO) 1. 80 
| Potash and soda (K 2 Q and Na 2 0) 40 
Sulphur trioxide (SO,) 1. 50 
HELDERBERG CEMENT COMPANY. 
The plant of the Helderberg Cement Company is located at Howe's 
Cave, Schoharie County. Quarries in the Salina or Waterlime group 
at this point have been long used for the manufacture of natural 
cement, while quarries higher up, both geologically and topographic- 
ally, furnished a very pure limestone, which was burned into lime. 
