Friday, January 24, 2014

A Day in a Life of a Driller

A crucial job that is integral to the design and construction of the Calaveras Dam Replacement Project might surprise some: the driller. During the design phase of the project we drilled more than 11,000 linear feet of core samples to characterize the subsurface ground conditions in and around the location of the replacement dam.

And we didn’t stop there. We are still drilling on the project to clarify the geologic conditions specifically on the left abutment (or adjoining wall) of the future new dam. Skill is key in exploratory drilling. We are lucky to have incredible personnel on site. We’d like to introduce you to one now - one of our lead drillers - Bay Area resident Will Halai.  He has been performing this type of work on construction projects for more than six years.

Will immigrated to the United States in 1992 from Tonga, a country in the South Pacific, to make a better life here for his family.  He works daily with his assistant Fine Taufatofua, also of Tongan descent, who has been drilling for the last four years of his career.  Both are members of the Operating Engineers Local 3, the union which represents heavy equipment operators and construction workers.

Typically, each drill advances a bore hole 40 to 60 feet per day.  The 4-inch diameter drill holes average about 100 feet in depth, while the rock core they extract is 2.5 inches in diameter.  After the borings are drilled, many are logged with a televiewer, which provides a continuous image of the inside of the borehole to allow the identification (and orientation) of important geologic features.  On average, five to six core borings are completed per week.  All of this information helps to ensure that the new Calaveras Dam, when built, will sustain a maximum credible earthquake on the nearby Calaveras Fault.

Will works with Bill Henrich of Norcal Geophysical during televiewer logging,
which is used to obtain important data from the core boring

Union Local 3 Operating Engineers Will Halai & Fine Taufatofua
from drilling work at Calaveras Dam 

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