WorldWide Drilling Resource

This month, we’ll look at borehole recla- mation, which is an important part of any drilling operation. We’ll define it, examine the need, and present some examples to achieve it through my past field experiences. Each agency and/or firm in the nation has their own procedures and there are many local, state, and federal regulations related to this necessary last step in the drilling process. Borehole reclamation refers to the plugging or sealing of borings after the work has been completed. If these boreholes are not plugged, it may become a public health and/or safety hazard, and may threaten the quality of the groundwater resources. Therefore, proper borehole reclamation procedures are a necessary critical final step in any type of drilling operation (e.g. geotechnical, geothermal, water well, etc.). The agency I work for focuses on the geotechnical shallow exploration as it relates to road and/or bridge con- struction, and often forensic determinations when problems occur after construction activities. Proper borehole reclamation accomplishes the following: 1) Eliminates the physical hazard of a borehole itself. 2) Eliminates contamination. 3) Prevents hydrologic changes in groundwater systems. The proper reclamation method will depend on both the reason for borehole abandonment, condition, and construction details of the boring. During my past field experiences, the drilling operations occurred either on the road or on open ground situations. For on-the-road drilling or taking pavement cores, we mostly used a cold, asphalt patch material after abandonment. Sometimes, an asphalt overlay was additionally applied to the road at a later date for maintenance purposes or part of a planned project. In the case of an open ground situation, the geology and groundwater sources are identified, and we usually employed the use of medium-sized bentonite chips recommended for sealing shallow boreholes. This type of bentonite is poured directly down the borehole. These chips are natural sodium bentonite screened to 1/4-inch to 3/8-inch in size, and are certified to NSF/ANSI Standard 60, Drinking Water Treatment Chemicals - Health Effects [NSF International/American National Standards Institute]. Consult search engines for more information and regulations on this topic. Be sure to provide in-house training on this subject to all drill operators and crews to maintain the proper borehole reclamation methods when drilling work is completed. Scott Scott Cosby may be contacted via e-mail to michele@worldwidedrillingresource.com Road drilling. Borehole Reclamation by Scott Cosby 44 MAY 2016 WorldWide Drilling Resource ®