I was recently thinking of my early days in this industry. In 1977, I was a young chemical engineer working in a chemical plant for the DuPont Company when the boss walked in one day and asked me if I would like to sell explosives. My initial thought was that I didn’t really want to be a salesman. After thinking about it a minute, I decided that dealing with explosives might be really fun and I accepted his offer. I’ve never regretted it.
My first day on the job, traveling with an old experienced salesman, I was surprised to see some guys pouring fertilizer from 50# bags down a bunch of holes in the ground. I was really clueless about blasting and how it worked. However, DuPont was very good at training its salesman and I soon began to understand what it was all about. I fell in love with the problem of how to harness explosive energy and make it do what I wanted it to do. I still love that problem today.
When I started out, it was a different world. Mines and quarries were typically far out of town and no one really cared if they made a lot of noise and shook things up. In fact, they represented Concrete Sealing jobs, income, and security. The presence of a mine nearby meant that people could buy coal and rock cheaply. It was a time when businesses were honored as a source of support for families and considered cornerstones of our society.
Consequently, while the safety of the company’s employees and neighbors was always of great concern, little thought was given to such things as ground vibration and air blast (noise). Since that time, cities have grown larger and in many cases have encroached upon or surrounded long existing mine sites. Many of these operations now have very close neighbors and fall within city limits. Fortunately, better knowledge of blasting effects and new techniques have mitigated many of these problems and allowed operations to continue even in crowded areas.
The understanding of what causes ground vibration increased dramatically in the 1980s. Studies by the U.S. government, explosives manufacturers and private companies documented the effect of different variables on ground vibration. The industry began to understand the effects of such variables as timing between holes and blast geometry on vibration. Extensive testing by the U.S. Bureau of Mines quantified the impact of ground vibration on residential and commercial structures. The need for better control of the timing between blast holes led to the development of sequential blasting machines, non-electric detonators that could be connected in series and more accurate timing for detonators. Results began to improve dramatically. Each one of these developments was the result of research and extensive testing by the explosives companies with the cooperation of major customers. Everyone in the industry was committed to minimize the impact of blasting operations on nearby neighbors and businesses.
I was fortunate to be involved in many of these developments as I had positions in marketing, distribution, manufacturing and technical development with DuPont, at the time the nation’s largest explosives company. I worked routinely with our technical representatives, salesman and research engineers. I ultimately became a Technical Manager for DuPont’s explosives business and all of DuPont’s technical development programs fell under my purview. I had a dream job. I was pretty much free to work on those things that interested me so I spent a lot of time studying new explosive formulations and ground vibration theory.