{"id":27896,"date":"2020-05-26T10:53:55","date_gmt":"2020-05-26T16:53:55","guid":{"rendered":"https:\/\/www.boartlongyear.com\/?p=27896"},"modified":"2025-03-10T14:14:42","modified_gmt":"2025-03-10T20:14:42","slug":"bridging-the-past","status":"publish","type":"post","link":"https:\/\/www.boartlongyear.com\/fr\/insite\/bridging-the-past\/","title":{"rendered":"Un pont vers le pass\u00e9"},"content":{"rendered":"
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Drilling has many purposes and the name Boart Longyear is often tied to drilling for core samples in mineral exploration, dewatering for groundwater control, and water well drilling for municipal and industrial applications. The company has been all about drilling since its beginnings in 1890, when founder Edmund J. (E.J.) Longyear sank his first diamond drill hole on the Minnesota Mesabi Iron Range in the midwestern United States.<\/p>\n<\/div><\/div><\/div><\/div>\n\t\t\n\t\t\n\t<\/section>

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What many people may not know is that the drillers and engineers of Boart Longyear have been involved in some exciting historical drilling projects in a variety of other applications, too. Drilling equipment for moon exploration is one such example (read Drilling Beyond Earth<\/a>); but closer to home, the company has assisted with projects to explore and define foundation and structural integrity below the earth or even under bodies of water.<\/p>\n<\/div><\/div><\/div><\/div>\n\t\t\n\t\t\n\t<\/section>

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Test drilling for transportation tunnels<\/span><\/h3>
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In the late 1920s, members of the Longyear team were contracted to test drill the route of a proposed vehicular tunnel under the East River to connect Manhattan to Brooklyn in New York, USA. The tunnel was intended to reduce transportation congestion due to the slow and unreliable ferry service that existed at the time. The Longyear company provided preliminary boring samples used to determine what was beneath the surface of the river. Characterizing the samples\u2019 type of rock and its hardness allowed geologists and engineers to determine what equipment should be used for tunneling, how long it should take, and at what cost. Although the initial tunnel project didn\u2019t receive support and funding, it laid the groundwork for a later project\u2014the Brooklyn-Battery Tunnel\u2014which was started in 1940 and opened in May of 1950.<\/p>\n<\/div><\/div><\/div><\/div>\n\t\t\n\t\t\n\t<\/section>

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Boring for foundation samples for the Golden Gate Bridge<\/span><\/h3>
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A similar challenge of traversing a wide body of water required assistance from the Longyear team in 1929. Joseph B. Strauss, a visionary engineer, was tasked with his team to design the proposed Golden Gate Bridge in San Francisco, California, USA. As chief engineer, Strauss requested the services of Longyear to investigate the rock formations beneath the San Francisco Bay where the bridge would be constructed. Longyear started boring in the Bay in November 1929 along the sites of the proposed piers and anchorages. [i]<\/a><\/p>\n<\/div>

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Due to the turbulent waters of the channel, the drillers had to be creative as to how they would retrieve the core samples beneath the tumultuous surface. Strauss was big on safety, requiring bridge workers use safety lines, work over safety nets, and even wear some of the first hard hats. The Longyear crew constructed a platform over the water supported by a boom\u2014an A-frame\u2014and guy-wires anchored to the shore. The platform allowed the team to suspend their drilling equipment securely on top and safely above the bay. Despite the problems of deep water, ocean traffic, storms, and tidal movement, the team was able to finish the work on schedule with complete core sample recovery.<\/p>\n

The geological samples and subsequent data supplied to Strauss proved that the rock formations could bear the weight of the foundations and enable the huge bridge structure to be built. The information was provided in a full report to the board of engineers in February 1930 and the bridge was determined to be \u201cfeasible economically and structurally.\u201d<\/p>\n<\/div>

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This great news meant Strauss and his design team could move on to the next phases of engineering and constructing the Golden Gate Bridge. In gratitude for Longyear\u2019s contribution, Strauss wrote, \u201cThe work done by your company, having been entirely satisfactory, and the relations between us and your drillers having been cordial and pleasant, I am glad to make immediate payment of the balance due.\u201d [ii]  \n

Payments received by the company totaled close to $15,000 for the boring contract. It wasn\u2019t for another three years (January 1933) that construction began and a groundbreaking ceremony for the bridge was held. The Golden Gate Bridge was completed in May 1937 at a total cost of $35,500,000.<\/p>\n

Click below images to view larger.<\/em><\/p>\n<\/div><\/div><\/div><\/div>\n\t\t\n\t\t\n\t<\/section>

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From left to right<\/strong><\/em><\/span><\/p>\n

Images 1 and 2: \u201cEngineers Speed Plans for Golden Gate Bridge\u201d<\/strong> - A Pacific Street and Road Builder article from March 1930 stating \u201ctest borings reveal solid rock foundations and showing a photo of boring operations at the Lime Point side of the bridge in Marin County, California.<\/em><\/span><\/p>\n<\/div>

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Image 3: \u201cBorings Started for Gate Span\u201d<\/strong> \u2013 Photos shows in the Vallejo California Chronicle, Sebastopol California Times, and Cresent City Triplicate newspapers on November 29, 1930. The article shows a photo of Longyear\u2019s diamond-tipped drills used for bore sampling the rock at the San Francisco end of the bridge, next to Fort Point.<\/em><\/span><\/p>\n<\/div>

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Image 4: \u201cGetting Down to Bedrock\u201d<\/strong> \u2013 A San Francisco Examiner article, dated February 14, 1930, picturing engineers, including Strauss, inspecting boring samples from the Golden Gate Bridge project.<\/em><\/span><\/p>\n<\/div><\/div><\/div><\/div>\n\t\t\n\t\t\n\t<\/section>

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A truck-mounted LS600 sonic rig<\/a> taking core samples near a dam site.<\/em><\/span><\/p>\n<\/div><\/span>

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Testing for hydro dam safety<\/span><\/h3>
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Shortly after the Golden Gate boring project, the Longyear company became involved with drilling projects for the construction of hydro dams around the country. In the 1930s, Longyear drillers did test borings for several of the twenty planned dams under the jurisdiction of the Tennessee Valley Authority. These dams were part of a comprehensive plan for the reclamation and development of the Tennessee River\u2014covering an area of more than forty thousand square miles and over seven states.[iii]<\/p>\n

Later twentieth-century construction-type projects for Longyear drillers included boring for core samples for the Missouri River Project, and the first foundation test borings for the Fort Peck Dam in Montana\u2014the project\u2019s first major hydro dam.<\/p>\n<\/div><\/div><\/div><\/div>\n\t\t\n\t\t\n\t<\/section>

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Sonic drilling advancements for today\u2019s construction projects<\/span><\/h3>
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Today, Boart Longyear continues to assist with construction and rehabilitation projects around the world using even more advanced technologies and equipment. The company regularly uses sonic drilling technologies<\/a> which are ideal for avoiding many of the challenges experienced with conventional drilling methods.<\/p>\n<\/div>

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Sonic drilling offers quality control in conjunction with the production and installation of geotechnical construction elements. The sonic method can actually eliminate the need for circulation-type drilling allowing the driller to work safely in situations that involve sensitive structures, vulnerable site conditions, difficult geology, or have restrictive conditions. Sonic drilling also provides measurements and samples to evaluate actual conditions across a given site during the progress of exploration and construction.<\/p>\n<\/div>

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A few examples of Boart Longyear\u2019s sonic drilling assistance with tunnel, bridge, and hydro dam projects in the twenty-first century include: [iv]<\/p>\n<\/div><\/div>

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