Sharing Insight

The Minnesota Ground Water Association (MGWA) will hold its annual Fall Conference on November 13. The MGWA Conference will focus on recent advances in the collection of ground water field data. WSB Geologist BJ Bonin, GIT will share his insight on “Double Duty: Using Vibration Monitoring to Improve Construction Methods”.

Vibration monitoring is commonly used to monitor well construction activity, especially blasting used to develop a bedrock well. The purpose of vibration monitoring is usually to ensure that vibration levels fall below those that could potentially damage adjacent facilities. This study investigates the relationship between vibration monitoring data and conditions in the well and aquifer and how the data can be used to adjust construction techniques in order to improve the well’s future operating conditions. Two boreholes in the Jordan Formation were subject to blasts by explosives at similar depths during well development. The vibrations generated by the blasting were analyzed and then compared to measurable post-development well conditions such as specific capacity and borehole morphology. In addition, vibration analysis during construction was studied and able to identify which portion of the borehole was more likely to have a higher specific capacity as well as structures that may increase the likelihood of future sand pumping before actually pumping water from the well. Construction techniques were then adjusted based on the data.

Translation: For two wells in the Jordan Aquifer and of similar depth, BJ used the vibration monitoring that is normally done for well construction and used the data to take some measurements of the aquifer to predict conditions in the well while it is being constructed, and then used these predictions to modify construction to improve the development of the well. BJ verified his predictions in these two wells using the MDH mandated video inspection. To his knowledge, nobody has done this before. And better yet, this was done within the normal budget for blasting and video inspection of a well. That is why his presentation is titled Double Duty. The monitoring and the video are both common practices, this just uses that data for an entirely different purpose to benefit our client at no additional cost.

The Minnesota Ground Water Association is a non-profit, volunteer organization dedicated to the following primary objectives:

• Promotion and encouragement of the scientific and public policy aspects of ground water;
• Establishing a common forum for scientists, engineers, planners, educators, attorneys, and other persons concerned with ground water;
• Education of the general public regarding ground water resources;
• Dissemination of information on ground water through meetings of the membership

For more information visit www.mgwa.org.