STATISTICS ON MINERAL PRODUCTION 3 1 



SAND AND GRAVEL 



The sand produced in Florida is used principally for building, 

 paving and road-making, filtering, molding, cutting, grinding and 

 blast purposes. The gravel produced is reported as used for roof- 

 ing material and for railroad ballast. 'Deposits of clayey sands 

 and gra^'els occurring in the southern part of Jackson County have 

 also been quarried and used as road surfacing materials. The total 

 production of sand and gravel for 191 8, as shown by returns from 

 the producers, was 158.489 tons, valued at $48,768. 



The companies reporting the production of sand and gravel 

 in Florida during 1918 are the following: 



Atlantic Coast Line Railroad Company. 

 Akerman & Ellis, Lake Weir. 

 Interlachen Gravel Company, Interlachen. 

 Tallahassee Pressed Brick Company, Havana. 

 Tampa Sand and Shell Company, Tampa. 



SAND-LIME BRICK 



The materials used in the manufacture of sand-lime brick are 

 sand and lime. The bonding power of the brick is due to the chem- 

 ical reaction betw^een these ingredients. The chemical changes oc- 

 cur in the presence of heat, pressure and moisture and result in 

 the formation of hydro-silicates of calcium and magnesium. 



The sand used in the manufacture of sand-lime should be com- 

 paratively pure and preferably with some variation in the size of 

 the grains. The mixture of lime, sand and water is cut in the form 

 of bricks and conveyed to a hardening cylinder. Necessary heat 

 and pressure are obtained in the hardening cylinder adapted for 

 the purpose. The sand-lime bricks are placed in this cylinder and 

 subjected to a pressure and temperature which vary according to 

 the method of treatment. 



Two companies were actively engaged in the manufacture of 

 sand-lime brick in Florid^ during 1918 as follows: 



The Bond Sandstone Brick Company, Lake Helen. 



The Plant City Composite Brick Company, Plant City. 



The production of sand-lime brick in Florida during 1918, al- 

 though not separately listed, is included in making up the total min- 

 eral production of the State. 



