WorldWide Drilling Resource

O..O..OKLAHOMA...WHERE THE WATER EXPERTS GATHER Jan Allen, Public Relations Professional, WorldWide Drilling Resource ® It may have been a little windy, but the Oklahoma Ground Water Association put on a great conference and trade show in Norman, Oklahoma. Registration was brisk for the events, and everyone was very patient. Such a great turnout is very rewarding to the staff and assis- tants who work so hard to put the conference together. Seminars were well attended. Topics were diverse and interesting. The keynote speaker, a native of Central Oklahoma, was greeted with warm enthusiasm. Each speaker was well-informed and knowledgeable on the information presented. Want information on a specific topic or issue next year? Be sure to let the association staff know! The exhibitors were well received and the atmosphere was very upbeat. It was great to see so many of the younger generation in attendance. Everyone was treated to a great feast, especially in the dessert arena! Of course all the calories had been removed! The WWDR Team thanks the staff for a great time and looks forward to next year’s show! Photos are compliments of WWDR . Geotechnical Study Begins on the Alto Tunnel Compiled by the Editorial Staff of WorldWide Drilling Resource ® The Marin County Department of Public Works (DPW) in California, has started a geotechnical study of the 132-year-old Alto Tunnel. Originally opened in 1884, the tunnel utilized timber supports and functioned as a railway passage from Mill Valley to Corte Madera, but was closed in 1971 because of a series of internal collapses and subsequent engineered stabilizations. Engineering reports state the timber supports are now in an advanced state of decay. In an effort to slow further collapse, the north end was lined and plugged with low-strength con- crete. The investigative project of the 2200-foot tunnel would be the first look inside its corri- dors in more than 35 years. This investigation follows a 2015 study, which assessed the tunnel’s right-of-way. The purpose of the geotechnical study is to observe the structural condition of the previously uninspected areas and assess the feasibility of reconstructing the tunnel. If reconstructed and reopened, the tunnel would operate as an alternate and more direct route between central Marin and southern Marin for bicycle and pedestrian use. The Mill Valley to Corte Madera Corridor Study cost estimates for the Alto Tunnel and path would range from $40-50 million. However, these numbers were based on a $21 million cost estimate with 2% escalation, a 35% cost contingency, a 20% accuracy allowance, and an additional $15 million for “Non Construction Project Cost.” The results of the geotechnical investigation are required to identify the true scope of improvements needed to reopen the tunnel, so a more accurate and up-to-date cost estimate can be produced. “Being able to actually see inside the tunnel and assess the geotechnical issues is an important step,” said Bob Goralka, DPW principal civil engineer. “Having a tangible understanding of what’s going on inside will help guide future decisions.” Engineers will not actually physically enter the tunnel; instead, they will study the interior sections from two sites above the tunnel. The fieldwork will require DrillTech to drill five holes, each four inches in di- ameter, at the two sites. McMillen Jacobs Associates will lower laser scanning probes into the tunnel, which will create images of its interior. The boreholes will be lined with steel as they are drilled then sealed with a permanent cap to ensure safety and secu- rity. By using advancedmapping technology rather than cutting a portal and physically entering the tunnel, the project will avoid higher costs and impact. The laser scanning will also provide the least impactful conse- quences to the surrounding community and result in only minor traffic disturbances. The north entrance, courtesy of Marin County. Congratulations to: Ed I ls ley Thet ford Ct r , VT Thet ford Ct r , VT Winner for May! Time for a Little Fun! May Puzzle Solution: Filmark Products, Inc. Allegheny Instruments Win a prize! Send your completed puzzle to: WWDR PO Box 660 Bonifay, FL 32425 or fax to: 850-547-0329 Can you identify which ads in this issue these two photos came from? 54 JUNE 2017 WorldWide Drilling Resource ®