WorldWide Drilling Resource

Focus on SEDC Hurry up and make plans to attend the 50 th Annua l SEDC ( S h a l l o w E x p l o r a t i o n Drillers Clinic). Hosted by the South Dakota Department of Transportation and the South Dakota Geological Survey, this milestone event is set for April 7-9, at the Sioux Falls Convention Center in Sioux Falls, South Dakota. On Tuesday, a three-hour workshop sponsored by the National Dri l l ing Association will run from 1:30-4:30 p.m. Wednesday is packed with informa- tional sessions of exploration procedures and related equipment, including sonic drilling technology; grouting equipment selection and guidelines; groundwater sampling; and drill rig maintenance and safety. Ample breaks give time for visi- tors to speak with others, see the prod- ucts and services on display, and ask questions of the representatives on hand. Some of the topics for discussion on Thursday include plugging test holes, as well as soil and rock sampling. Don’t miss your chance to partici- pate! WWDR will be there. For more details, visit http://sedc.unl.edu or e-mail molly.haines@state.sd.us Rob was there for Diedrich Drill at the 2014 SEDC. WWDR photo. 28 APRIL 2015 WorldWide Drilling Resource ® Open-Cut Project at Pinkerton Tunnel Part 2 Adapted from an Article by Dale L. Ramsey which Appeared in The Journal of Explosive Engineers Phase I: Mass Rock Loading Plan Due to geologic conditions, and water and hole diameter restrictions, repumpable emulsion was chosen as the primary explosive, along with cast boosters and shock tube initiation. The north and south slopes of the Pinkerton overcut were prespl it for slope overbreak control using 3-inch diameter holes loaded with 7/8-inch cont inuous prespl i t , and holding a stemming collar of 4 feet. After excava- tion was complete, a final wall inspec- tion was conducted, and rock anchors and shotcrete were installed in softer rock strata zones of concern, such as coal and shale. Several monitoring methods were employed. Seismographs were used to monitor vibrations. Borehole cameras were used to assist in identifying void- space volumes and geologic anomalies. Due to coal seams, methane detectors were used to monitor for potential gas buildup in holes and void spaces. Given the age of the tunnel and its unknown integri- ty, a post-blast walk-through inspection was conducted after each blast. Phase II: South Notch Drilling and Blasting Plan Once drilling and blasting operations reached an elevation of 1710 feet, the project switched into Phase II. The plan included developing a notch to the south of the existing Pinkerton Tunnel, and installing a temporary runaround track to move rail traffic outside the tunnel. Once rail traffic was relocated, the tunnel was imploded and retreat excavated. Phase III: Tunnel Removal Once mainline traffic was shifted outside the tunnel onto the newly in- stal led runaround track, focus was directed to removing the tunnel. This phase involved an entirely new set of challenges. The runaround track was within 15 feet of the north slope high wall. Once again, maintaining rail traffic and rail curfews was imperative. To maximize the track curfew, blasting mats topped with steel impact plates were used to protect the track Due to continued concerns about void spaces, the tunnel location was outlined on the surface, and equipment was never allowed to encroach on that limit. A blast was fired to collapse the north tunnel wall, leaving the south tun- nel wall and a 15-foot rock rib on the south wall protecting the track from debris. The track was mechanically moved following the blast. Conclusion When the Pinkerton Tunnel open- cut project began, blast vibration levels were the main concerns for protecting the tunnel. Looking back, the greatest challenge to tunnel integrity was water infiltration from excavation above. The entire construction team agreed this was the most challenging, and at the same time most rewarding project they had ever worked on. CSX estimates money spent on the National Gateway Clearance Initiative will create about 50,000 jobs in a 30- year period, 10,000 of which have already been created during the con- struction phase. According to CSX, haul ing double stacks between the east coast and Midwest, which pro- vides a l ink to the west coast , wi l l reduce traffic route miles in the U.S. by more than 14 billion miles, saving more than 2 billion gallons of fuel. An eastbound train travel- ing in the south notch of the Pinkerton open-cut project on the runaround track installed to move rail traffic outside the Pinkerton Tunnel. This photo by Dale Ramsey won Best of Show in the 21st Annual Photo Contest in The Journal of Explosive Engineers. “Burdening people with debt is an old deal, not a new deal.” h Henry Ford