What type of drills were used to build the Hoover dam and Mount Rushmore?
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Mount Rushmore National Memorial, History/Culture
9 years ago
69 Answers
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The process for creating both collosal structures was very different, however both required an extensive use of dynamite. 

Borglum's "powder men", former miners and dynamite experts, were said to be able to blast within four inches of the finished surface of the rock. From there, air powered tools were used to drill holes in a process called honeycombing, and excess granite was removed with hammer and chisel. Finally, a process known as "bumping" was used with pneumatic tools to smooth the surface down to that of what we see today. Considering the dangers of this job, no workers died in construction! For more information, check out our extensive page on the making of Mt. Rushmore.

The Hoover Dam also used extensive amounts of dynamite to carve out weathered rock and erosion soils down to bedrock. Over 1,500,000 cubic yards of materials were removed from the build area. Diversion tunnels were bored to direct the Colorado River away from the build site, and two cofferdams were constructed. Jackhammers and various pneumatic tools were used by the workers, and just about every kind of drill and hammer were employed in the various needs throughout construction. Here is a link to an image of a "jumbo rig" used to drill the diversion tunnels. You can see that they made an earth moving machine several stories high for multiple jackhammers to be used in concert.

9 years ago
40 Answers
5Helpful Answer Rating

 Mount Rushmore National Memorial in South Dakota was sculpted one head at a time. The tools used in the sculpting of the mountain were drills, air powered tools, and dynamite. After mountain was scaled to projected size of the monument, the dimensions were marked on the mountain. It was obvious then to the team of carvers the problem of removing massive unwanted granite from the face of the mountain. At first, Borglum resisted the idea, but blasting the mountain with dynamite was the only way to do it. After marking oval shapes for each head, dynamite experts blasted the rocky surfaces to the estimated final measurements. The dynamites used in the carving of the Mount Rushmore National Memorial were prepared by John Johnson.  

9 years ago