Mance: Quarry Industry of Southern Indiana 117 



planes or horizontal joints. TYiqy usually are responsible for the 

 loss of from 3 to 6 feet of stone on either side of the seam. 



In at least three of the quarries the stone shows a tendency 

 to split up in irregular blocks as soon as quarried, and this splitting 

 results in the loss of many valuable blocks of stone. The cracks 

 seem to be present in the stone before it is quarried, but do not 

 open until the stone is removed from its bed. This condition 

 probably results from geological movements within the earth, 

 and the resulting stress set up causes the stone to crack or at 

 least develop lines of weakness. In one quarry all these cracks 

 were in a horizontal plane and may have been caused b}^ a settling 

 of the formation as a result of the removal by erosion of the 

 underlying beds since the trouble existed only along the edge of a 

 hill and the cracks decreased in extent as the operations were 

 carried farther into the hill. 



The present methods of handling stone in the quarry result in 

 much waste that could be avoided. ^lost of the operations in 

 the quarrj^ are performed by unskilled labor, because the quarry 

 work is less desirable than the mill work. As a result the quarrj^ 

 laborer is underpaid and careless. The channeler, drill, and 

 scabbling machine each cause some waste, and if the work is not 

 well done the irregular breaking of the blocks will represent 

 another important source of waste. 



The Oolitic limestone is of two shades of color known to the 

 trade as "buff" and "blue" stone. The difference is caused by a 

 chemical change in the small amount of iron compounds present 

 in the stone. The original color of all the stone was blue, but 

 the oxidation into ferric compounds of the iron which was pre- 

 sent originally in the form of ferrous compounds has caused the 

 blue shade to turn to a light grey or grejdsh brown known as buff 

 stone. When the quarry block is entirelj^ buff or entirely blue, 

 it can be sold at full price; but the line of separation between the 

 buff and blue stone is usually very irregular, and consequently^ 

 there are blocks in which the colors are both present with the 

 result that this mixed stone has to be sold at a much lower price, 

 some of it being rejected altogether. There is a growing tendency 

 in the stone trade to disregard the difference in color of the 

 rtone, for the stone will take on a uniform color after a longer 

 or shorter period of exposure to the ,^atmosphere. If a block of 

 blue stone be exposed to the sunlight and atmosphere for a month 

 it is diflB.cult to tell whether it was originally buff or blue without 

 chipping into it. A building made of the mixed stone, altho 



