TABLE OF CONTENTS. XVii 



PAGE 



Quarry practice ." 368 



Working in levels 370 



Use of steam shovels 370 



Costs of steam-shovel work 373 



Crushing and drying in the quarry 374 



Mining 375 



Dredging 375 



Marl pumping 376 



Cost of raw materials at mill 378 



Loss on drying, etc 378 



Costs of quarrying or mining 378 



Costs of marl dredging 379 



References in quarrying, etc 381 



CHAPTER XXIX. 



CALCULATION AND CONTROL OF THE MIX. 



Theoretical composition of Portland cement 382 



Influence of normal constituents on the cement 384 



Maximum lime content of mixture 384 



Minimum lime content of mixture 385 



Magnesia. 386 



Silica 386 



Alumina 387 



Iron oxide 388 



Sulphur 388 



Alkalies 388 



Phosphorus 389 



Influence of intentionally added fluxes 390 



Calculating mixtures of untried materials 391 



Cementation Index. 391 



Use of the formula in proportioning mixtures 392 



Calculating mixtures in current work 393 



Composition of the mixture 394 



Methods of control 395 



Changes in composition during manufacture 395 



CHAPTER XXX. 



PREPARING THE MIXTURE FOR THE KILN. 



Methods of preparation 398 



Dry methods 399 



Drying the raw materials 399 



Percentage of water in raw materials 399 



Methods and costs of drying 400 



Grinding and mixing 404 



General methods 404 



