752 



Popular Science Monthly 



roads. These trees must usually be 

 planted where the conditions are not 

 favorable to them. Where such adverse 

 conditions are encountered, better results 

 in the growth of the trees are obtained 

 when each hole is blasted. 



In heavy road construction the steam 



Appropriate method of loading 

 for side hill cut and fill 



Loading for side hill cut when 

 material is to be wasted 



shovel is playing an important part. 

 Light tractor rigs are employed. These 

 dig slowly and with difficulty in hard 

 ground. On actual count it was found 

 that under such condition the dipper 

 was not filled more than one time out of 



A common road trouble and the remedy- 

 five. This slowed up the work. Blasting 

 ahead of the shovel will loosen the 

 ground so that it can work to capacity. 



The demand for hard surfaced roads 

 creates a need for millions of tons of 

 crushed stone. This is blasted out of 

 the quarries. In some sections remote 

 from operating quarries, the stone is 

 obtained by blasting hard boulders out 

 of the fields. Occasionally a rock cut 

 affords an excellent source for stone, 

 and gives the additional advantage of 

 cheapening the cost of construction by 

 making use of the most expensive 

 material to excavate. 



When crooked or shallow streams are 

 paralleled or crossed it is often cheaper 

 to correct the stream than to elevate the 

 road to a sufficient height to keep it out 

 of trouble. 



A great part of the filling up of stream 

 courses is caused by logs and other 

 floating material 

 forming rafts and 

 sand bars in the 

 channels. Another 

 fruitful source of 

 trouble is from 

 outcrops of rock 

 which divert or 

 impede the nor- Loading a rock- 



mal flow of the ledge outcrop 



current. Overhanging stumps and trees 

 along the banks lend still further ob- 

 struction. Sharp bends in the course of 

 the stream check the current and cause 

 trouble by forming sand bars. 



Any and all of these troubles may be 

 overcome quickly and at reasonable 

 cost by the use of dynamite for shooting 

 out the rafts and logs, and blasting a 

 sufficient channel through the confining 

 rock. A well-placed blast will cause the 

 overhanging stumps to vacate immedi- 

 ately. 



Cutting off sharp turns in the channel 

 will take a little more time and should 

 be well done in the beginning. Locate 

 the line of the new cut-oft' and blast a 

 ditch that will at all times carry a part 

 of the flow. When this is done and the 

 rafts and logs are out of the way above 

 and below, all there is left to do is to 

 wait for heavy rains to flood the streams. 

 The increased velocity of flow will 

 cause the water to cut and wear away 

 at the bottom of the channel as well as 

 at the sides. From time to time it will 

 be best to go over the stream and make 

 sure that no new obstruction is being 

 formed. 



A good use for blast 

 holes 



Loading top-rot- 

 ted stump 



