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 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.
One common misconception is that a blast consists of a single charge of explosive. In reality, each hole in the blast has a separate charge and is set to detonate at a unique time. Typically, the time between individual detonations is between ten and 100 milliseconds. A millisecond is one 1000th of a second. While this seems like a very short time, separating the charges this way can dramatically reduce the vibration produced from the blast. One of the key things we learned in those days was the importance of controlling the timing of each detonation in a blast. If the timing is selected properly, the vibration from one charge can reduce the vibration from other charges in the blast. If the wrong timing is chosen, the vibration can actually increase. This realization spurred the development of electronic detonators with extremely accurate timing. At the same time, software was developed that could predict the ground vibration produced from a blast by using information from single small charges. Vibration results began to improve dramatically. It is now possible in many cases to accurately predict the effect of different timing before a blast goes off. This technology is now routinely used to design blasts in urban and other sensitive areas.
Another factor that affects ground vibration is the actual shape of the rock mass to be blasted. In the late 1980s, a new technology emerged that allowed the actual shape of the blast to be measured. Using an industrial laser and specialized software, the geometry (shape) of the area to be blasted could be measured and the intended hole positions described. With this information, the amount of rock that each charge would break could be determined. I was privileged to introduce this technology in the United States and ultimately started my own business with the inventor to exploit this new development. Dramatic improvements in the control of blasting resulted from this invention. Vibration results continued to improve.
The industry has come a long way since my first day on the job when I didn't even know that fertilizer was an explosive. Every explosives company and mine operator is committed to living in harmony with neighboring businesses and residents. In the 35 years that I've been privileged to work in this industry, I've seen many changes. In 1977, the public was much less demanding and more forgiving. The explosives industry was much less technical and in many ways more relaxed. As a technical junkie, I'm pleased to see the strides that have been made in my industry and I'm proud to have played a small part in helping my industry become a much better neighbor. I know my colleagues will continue to strive to better understand and control the effects of our operations. I'm confident that new techniques and technology will make blasting operations even safer and less bothersome to the public. I look forward to the years ahead and all the things that we will learn.
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 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.
One common misconception is that a blast consists of a single charge of explosive. In reality, each hole in the blast has a separate charge and is set to detonate at a unique time. Typically, the time between individual detonations is between ten and 100 milliseconds. A millisecond is one 1000th of a second. While this seems like a very short time, separating the charges this way can dramatically reduce the vibration produced from the blast. One of the key things we learned in those days was the importance of controlling the timing of each detonation in a blast. If the timing is selected properly, the vibration from one charge can reduce the vibration from other charges in the blast. If the wrong timing is chosen, the vibration can actually increase. This realization spurred the development of electronic detonators with extremely accurate timing. At the same time, software was developed that could predict the ground vibration produced from a blast by using information from single small charges. Vibration results began to improve dramatically. It is now possible in many cases to accurately predict the effect of different timing before a blast goes off. This technology is now routinely used to design blasts in urban and other sensitive areas.
Another factor that affects ground vibration is the actual shape of the rock mass to be blasted. In the late 1980s, a new technology emerged that allowed the actual shape of the blast to be measured. Using an industrial laser and specialized software, the geometry (shape) of the area to be blasted could be measured and the intended hole positions described. With this information, the amount of rock that each charge would break could be determined. I was privileged to introduce this technology in the United States and ultimately started my own business with the inventor to exploit this new development. Dramatic improvements in the control of blasting resulted from this invention. Vibration results continued to improve.
The industry has come a long way since my first day on the job when I didn't even know that fertilizer was an explosive. Every explosives company and mine operator is committed to living in harmony with neighboring businesses and residents. In the 35 years that I've been privileged to work in this industry, I've seen many changes. In 1977, the public was much less demanding and more forgiving. The explosives industry was much less technical and in many ways more relaxed. As a technical junkie, I'm pleased to see the strides that have been made in my industry and I'm proud to have played a small part in helping my industry become a much better neighbor. I know my colleagues will continue to strive to better understand and control the effects of our operations. I'm confident that new techniques and technology will make blasting operations even safer and less bothersome to the public. I look forward to the years ahead and all the things that we will learn.
Jay Heck, Sr. is the owner and Chief Technical Officer of
Firmatek companies which specialize in seismic blast monitoring and the
use of the latest mobile lidar technology to accurately map
topographies. His story explains his arrival at what might be considered
two very different occupations. You can learn about Firmatek companies
at http://www.firmatek.com.
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