Dykon Blasting has received hundreds of emails asking various questions about the demolition and/or blasting industry. In an effort to make information easier to obtain, we shall post the most frequent questions that have been asked with the best answers that we can provide.

We at Dykon wish to thank everyone for the phone calls and emails we have received.

We try to answer each of them personally but as always, time does not often permit us to do so.

Where do you receive formal training for demolition blasting?

To our knowledge, there is no formal training available for demolition blasting. Experience can only be obtained by employment directly with a firm which specializes in demolition blasting. Demolition blasting companies usually train their employees in-house.

The explosive industry has a very large presence in world economy and has many different facets that influence things to differing degrees. Explosive demolition accounts for a tiny percentage of the whole picture. In comparison to drilling blasting contractors who specialize in rock removal, explosive demolition contractors are few and far between. It’s not feasible for a university to prepare a study course and train people on a full scale basis to fill such a tiny niche in the market place.

On the other hand, there is formal training available for those who wish to gain knowledge of explosives in general. A good working knowledge of explosives, safety, and the laws regarding their storage and use is a perfect place to begin a career in their use. A list of links to some of these schools is published directly below.

Training on explosive use and safety can also be obtained from Bradley Safety Consultants. The president of BSC is Mickey Bradley and his school handles explosive training and licensing for the states of Arkansas and Oklahoma.

Mickey Bradley can be reached at 918-465-3405 or you can email him at bsc@cwis.net

How does an implosion work?

Not all demolition blast (s) are implosions. The industry often refers to them as implosions because it is a popular expression. A true implosion is a case when a structure has been caused to fall inwards on itself. Smokestacks, towers, bridges and most buildings are not imploded. They are simply knocked over.

Implosion is used when there is limited area on all sides of a structure making it impossible to lay them out.

The principles used on an implosion are basically the same whether it is a true implosion, or if the structure is simply going to be laid out. The principle tool in an implosion is gravity. The explosives are used to weaken and cause the supporting members of the structure to fail, thus allowing gravity to pull the structure down or over. If you have a four-legged table and you remove two legs from one side, the table will fall over.

You can control the direction of fall by choosing which two legs to remove. A large building generally has many legs, or columns, that support it. In an implosion, you remove the columns from within the building first, thus causing the initial collapse to start from that point. The resulting collapse of the inner columns first, help drag the structure down towards the center.

Why do you have to blast rock?

Blasting is usually the most cost effective way to break rock. This helps to reduce your costs for coal, building materials, utilities, or any other product which comes from rocks or minerals.

Lower costs encourage more expansion and more jobs. The tax dollars that you spend go towards roads, civil improvements, utilities all of which are usually funded by government money.

Our lives as we know them today would not be possible without the use of explosives.

When blasting is done near my property, what keeps my home or my well from being damaged from ground vibration?

Federal, state, and sometimes, local governments impose limits on the level of vibration and noise produced from blasting.
It takes a lot of energy to break rock. Energy in a blast which is not used for rock breakage is wasted in the form of ground vibration and airblast. The use of explosives is the use of energy. Energy is not cheap in any form. Look at the price of a gallon of energy on any gas pump. It takes about 2 tons of natural gas to manufacture 1 ton of ammonium nitrate blasting agent.

Ground vibration is controlled by limiting the amount of energy released into the rock at a time. The energy is distributed through the rock to be blasted in the form of holes drilled into the rock. The holes are detonated in a progressive sequence that resembles slices of bread being removed from a loaf. One slice is removed to make room for the next slice, and so on. By controlling the number of holes detonated at one time, you control the amount of energy released as well. This energy decays with distance from the shot.

By knowing the distance to the closest structure you wish to protect, you can calculate the amount of energy that can be released into the ground at any one delay period without causing any damage due to ground vibration.

It would be an exhaustive process to describe in detail, all the steps that are taken to protect the property of people surrounding a blast site. When blasting near people’s homes and property, the entire blast is designed to protect that property from excessive ground vibration and flyrock. There are volumes of books dealing with this topic and the legal limits as well. Interested parties can find these publishings, for sale, at the web site of the International Society of Explosive Engineers.

Who determines the safe levels of ground vibrations for blasters to follow?

There has been an extensive amount of research done to determine the safe levels of vibrations.  The purpose being to establish a level for blasters to operate under that will eliminate the risk to properties surrounding a blast site.  The United States Bureau of Mines has contributed a major part of the technical data on blast design and vibration control.  Other agencies and institutions have provided a great deal of research that has contributed to the accumulated knowledge in this field.  You can visit the website of the Office of Surface Mining, (OSM) in the website of the department of the interior for more information.

Current legal and recommended vibration limits have resulted from this research.  By staying below these limits and following safe blasting procedures, the risk to property around the blast site can be minimized or eliminated.

The Office of Surface Mining, (OSM), publishes their findings on this subject in reports called “Reports of Information.”  Abstracts from some of the reports that deal directly with ground vibration and airblast are as follows:

This information is made available by the International Society of Explosive Engineers and is publicly available from their website at www.isee.org.  Point your browsers towards their technical information database.

How do you measure the ground vibration and airblast?

By using a device called a seismograph.  These instruments are capable of recording the amplitude of ground vibrations produced from a blast.  The readings can be sent to an independent firm who specialize in analysis of seismograph data.

Before a seismograph is approved for field work, it is tested and calibrated by the manufacturer/supplier.   After that, the seismograph is re-tested & re-calibrated once a year to assure that is is operating within specs.  Also, the seismograph is capable of a self diagnostic which the blaster can use each time the seismograph is deployed.  This self test tells the blaster that the unit is functioning.

How do you know the amount of explosive that can be used without causing any damage due to ground vibration?

Explosives are energy in a different form than others.  Electricians know how to calculate the amount of energy it would require to start and run motors and lights and other electrical components.  Car manufacturers can calculate the mileage one should expect, or hope, to get from a vehicle before it is purchased.  After you purchase a car, you then gain historical knowledge based on how much mileage your car actually gets.  So after a while, you know how much gas you better have in your gas tank before you set off on a trip.  And after a few months of utility bills, you know how much it will take to run the electrical appliances around you.

Gasoline, natural gas, propane and electricity are the most common forms of energy made available to everybody for everyday use.  People who manufacture products that consume this energy also know how to calculate it’s efficiency.

Blasters know how to calculate the efficiency of the energy they use.  By using only the amount of energy it takes to perform the job at hand, one can be assured that there isn’t enough left over to cause any ground vibration damage to property outside the blast site.

It would be unreasonable to think that a single gallon of gasoline could propel your car across several counties and back again, without running out.  It would be unreasonable to think that you could run your home with a single kilowatt of electrical energy for a month.

Each individual electrical appliance in your home uses a different quantity of power.  This is based on it’s size and workload.  Your air conditioner or heater is going to require more electricity than a light bulb in a lamp would need.  A big truck will use more fuel per mile than compact car if everything is running efficiently.

Different kinds of rock require different amounts of energy in the fracturing process.  Blaster’s must take all the properties of the geology into consideration when designing a blast round.

The United States Bureau of Mines adopted a mathematical formula that blasters can use when designing a blast, that when followed, will assure the blaster that there is not enough energy being released at any one time to cause damage to the closest structure.  A blaster who is not using a seismograph is required to use this mathematical formula in designing what we call the “Maximum Pounds per Delay” of explosives used.  The mathematical formula used, is known as the “Scaled Distance Formula.”  This formula, when used, is conservative to the point that it assures there will not be enough energy released into the rock at any one delay period to cause ground vibration damage to a well or structure.

A blasting operator who does not routinely use seismographs to record the actual ground vibration must adhere to the “Scaled Distance Formula” to design the “Maximum Pounds Per Delay” for his blast.

Do you have a question for us? Email it to questions@dykon-blasting.com