Part IV. Utilization of Waste 



CHAPTER vn 



Quarry Waste 



General Discussion. The largest industries of the country 

 have all been developed by improved methods of the utilization 

 of waste. The success of the Standard Oil Company and the 

 meat-packing industries is directly traceable to their close utiliza- 

 tion of the waste products of their business. The stone industry 

 has been one of the most backward of all industries in its use of 

 the waste stone that results from the operation of quarry and 

 mill. 



During the operations of quarrying the loss of stone will reach 

 from 30 to 50 per cent of the solid cut, and' one operator who was 

 working a quarry where there was no adequate covering over the 

 building-stone layer estimated that as high as 60 per cent of the 

 solid cut of his quarry was wasted. The quarr}^ in which 70 

 per cent of the solid cut can be put on the market is an exception- 

 ally good quarry. The probable average of waste for the whole 

 quarry district is 38 per cent to 45 per cent of the solid cut. 



The causes of this great amount of waste stone are many, 

 but the most important may be grouped under the following 

 heads: (1) the texture of the stone, (2) mud seams and joints, 

 (3) the character and amount of the overburden, (4) irregularities 

 in the stone, (5) crackings in the stone due to geologic causes, 

 (6) carelessness in the handling of the stone in the quarry, (7) 

 variations in the color of the stone. 



The general texture of the stone is granular and a wide varia- 

 tion in the coarseness of grain may occur even in a single quarry. 

 This variation may appear in the different beds or even in different 

 parts of the same bed. Stone of too coarse texture has to be 

 discarded because there is no demand for the coarse-grained stone 

 in the trade. On the other hand, when the grain of the stone is 

 very fine it may be harder and more difficult to work. It follows 

 therefore that the medium-grained stone is the most desirable 

 and gives a larger profit to the quarryman. In many places the 

 stone contains small crystals of calcite, and when these crystals 

 are numerous they produce what is known as ''glass^seamg". 



(115) 



