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Inquiry Question

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Illustrations 1a and 1b
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Photo 4



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Visual Evidence

Photo 5: Dragline at Work, 1918

[Photo 5: Dragline at Work] with link to larger version of photo.
(National Archives and Records Administration; Photographer Unknown.)

Construction techniques and technology changed rapidly during the years the Rio Grande Project was under construction.  Reclamation was quick to take advantage of these changes.  Because it was working on so many projects, it may actually have encouraged innovation by providing a market for the new technologies. 

Questions for Photo 5

1. Look carefully at this photo. How would you describe the piece of equipment shown? How big is it (use the man standing between the tracks for comparison)? What kind of work does it appear to be doing?

2. The machine shown here is a dragline, which is an excavator used to dig surfaces that lie below the level at which the machine sits. It consists of a large bucket suspended from a long metal boom by a heavy wire hoist rope that raises and lowers the bucket. The operator uses a second wire rope, the dragrope, and chains to manipulate the bucket. The hoist rope and the dragrope are attached to wheels and drums operated by a large motor mounted behind the cab of the dragline—the heavy motor also stabilizes the dragline machine by acting as a counterweight to the boom, the bucket, and its contents. The cab and boom are mounted on a platform that can swivel, and the whole mechanism is on a chassis with wheels or tracks so it can move along the work site. Can you find these features in the photo? What advantage do you think a machine like this would have in excavating canals? What disadvantages?

3. In a typical cycle of excavation, the operator positions the dragline's bucket above the material to be excavated. He then lowers the bucket, pulls the dragrope to drag the bucket along the surface of the material, and then lifts the full bucket by using the hoist rope. The operator then swings the boom and the bucket to the place where the material is to be dumped and releases the dragrope, causing the bucket to tilt and empty. How much skill do you think it would take to operate a dragline? Do you think it might be dangerous to work around one of these machines? Why or why not? Do you think one of them ever tipped over? Imagine the noise and the smell of fumes coming from the motor, and the squeal from all the moving parts.

4. Reclamation put its first dragline to work on the Rio Grande Project in April 1916. Four gasoline-powered draglines were delivered in mid-1917. Reclamation ordered four more in the following summer. By 1919, there were 15 draglines at work on the Project. Why do you think Reclamation invested what must have been a substantial amount of money to purchase so many machines?

5. During the early years of the Rio Grande Project, most of the canals were excavated using metal "Fresno" scrapers pulled by teams of horses or mules. The cost of excavation by contractors using teams of horses averaged 26 cents per cubic yard during the 1918-19 fiscal year. Two years later, excavation done by Reclamation employees using government draglines cost an average of 7.6 cents per cubic yard.8 What do you think might have accounted for this difference?

Click for a larger version of Photo 5.


8 Eighteenth Annual Report of the Reclamation Service, 1918-1919 (Washington, DC:  Government Printing Office, 1919), p. 265; Twentieth Annual Report of the Reclamation Service, 1920-1921 (Washington, DC: Government Printing Office, 1921), p. 274.

 

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