YES, we are willing to load any hauling vehicle or trailer that meets the required specifications for Michigan load limits.
YES, our Recycled Aggregate locations accept clean broken concrete for a small fee per axle.
Peak particle velocity refers to the maximum speed of a particular particle as it oscillates about a point of equilibrium that is moved by a passing wave. It is a term used to describe vibration, or elastic movement, resulting from excitation by seismic energy as it passes a particular point. We usually measure this speed in "inch or inches per second." The reason we use this measurement is that it has been shown in numerous studies over the years to be the best indicator of whether damage to a residential structure is possible or likely.
Scaled distance is a relationship used to relate similar blast effects from various explosive weights at various distances. Scaled distance gives a blaster an idea of expected vibration levels based upon prior blasts detonated at a project. It is calculated by taking the distance in feet from the blast (source) to the receiver and dividing it by the square root of the maximum pounds of explosives detonated per delay. It is for estimation and may supplement actual seismograph measurements.
The interior measurements represent "structure" motion and are not considered the same. In many cases the vibration levels measured within the home are less. Research on the effects of blast vibration upon structures has been conducted while recording the blast vibration on the ground, outside of the structure, and usually in the area of the closest portion of the structure to the blast. Vibration recording by the United States Bureau of Mines and many other individual researchers, over many years, with many structures, has allowed those researchers to observe, and predict with a very high degree of certainty, how typical residential-type structures respond to blast vibration. Further seismograph standards are based upon exterior ground vibration levels which take into account the structure's response to vibration. The measurements on the exterior also allow for consistency. The geophone or transducer (sensor of the seismograph) is attached and secured by spiking, burying or other physical attachment that cannot be accomplished within someone's home. The outside measurement is consistent and allows comparison of the measurements on a day by day basis.
Regulations that govern most quarries, mines and construction projects place limits on vibration to protect nearby structures whether that structure is ten feet or thousands of feet away from the blast. The blast is designed to meet these regulatory limits, and monitoring of every blast is done in order to ensure compliance to the limits. Maintaining levels below limits provides off-site vibration levels that will not cause new defects or aggravate existing defects.
The USBM recommended limits are published in Report of Investigations No. 8507. The "Z-curve or Siskind curve" is the information most often cited, which was published in 1980 as a result of an extensive study conducted in the late 1970s. The study was completed using numerous blasts, throughout several states, while monitoring at different types of structures. The graph shows recommended limits to reduce the damage potential for structures when comparing ground velocity with its associated frequency. The USBM curve is like a speed limit. If vibration levels do not exceed the curve, damage is not likely. For those cases over this limit it does not automatically mean vibration has caused damage; however, it does indicate a thorough evaluation should be made. The graph shows the limits recommended by the USBM to preclude cosmetic damage to plaster and drywall, the most fragile building materials.
It was determined by the evaluation that each of the structure types (single, 1 ½ and 2-story homes) have a varying natural frequency. Blast vibration matching the frequency of the structure of concern may amplify the shaking within the house. If the particle velocity is high enough, cracks can occur or may be extended. This cosmetic, threshold damage potential is alleviated when the limits are maintained. As the frequency of the ground motion changes from low to high (1-40 Hertz) the structure responds less and the limits increase. A safe level of 0.50 ips for plaster and 0.75 ips for drywall that exists for 4 - 15 Hertz increases as the frequency increases to a maximum velocity of 2.00 ips.
Building materials that are in your home did not necessarily come from your state either. The criteria in place are designed to protect building materials regardless of where those materials are located. Those materials don't change as they are designed to meet minimum ASTM published standards which are incorporated into City, State and Federal Building Codes. While building practices may change to some extent the materials and the types of construction are consistent and would apply.
ing pools next to an existing home, utilities next to roads and buildings, foundations, or a basement for a slab on grade home are typical. It is the level of vibration that creates damage within or to structures and not the distance. Blasting, pile driving, compaction or any other vibration source is reduced or l
People feel vibration and are very perceptive to a very small amount of ground motion. However, people cannot put a value on the amount of motion created, which is necessary to assess whether damage occurs. That is the key issue in determining damage potential. Was there sufficient vibration to create damage? There is no disagreement to feeling vibration, but homes take quite a lot of vibration before damage occurs. Homes are built to move and react to everyday activity and environmental motion. Door slamming, thunderstorm activity and wind all produce vibration that we feel and take for granted since they are "cultural" events. The level of vibration in these events equals or exceeds the vibration from blasting or other vibration activity. Building materials can withstand specific vibration levels before damage occurs.
The United States Bureau of Mines studied the repeated effects of vibration on structures. They concluded that as long as the vibration levels were below regulated limits, cumulative or repeated effects that produce fatigue were not seen. Their conclusions summarized that a home could withstand blasting twice per day at 0.50 inch per second for 28 years before the first crack would be expected to be extended, let alone a new crack created. In the same study, they found that there were forces acting on the structures that were greater than the levels from the blasting operation. These factors were changes in temperature and changes in humidity. These forces occur every day and are constantly putting strain on the structure in excess of the vibration. Since these occur over many years daily during the life of the structure, with greater effect there is little vibration will do within the regulatory limits.
Human perception is not a good measure of blast effects. Blasting and other vibration producing activities do not take place in the same location each time. The change in distance may affect the actual vibration levels and this would be supported by seismograph measurements. Whether or not the person is expecting the blast or whether they are inside or outside at the time of the blast may affect perception as well. In the case of construction blasting the actual blasts may change the explosives type or amount necessary to break rock being excavated. In addition, the size of the blast, orientation and direction of initiation may also affect perception. Also, the airblast may cause an additional effect. The ground vibration travels faster than the airblast (noise) associated with the detonation, and each affect the structure differently. As airblast is highly affected by environmental conditions, mainly wind, the effects change with each blast.
When a blast is detonated, there are two primary effects - one is ground vibration and the other is air overpressure, or airblast. The ground vibrations move very quickly, arriving at nearby structures within a few seconds typically. The airblast waves move comparatively slowly, at about 1,000 feet per second. This can be compared to seeing lightning and then hearing the thunder. The light travels extremely quickly compared to the sound wave. In the case of vibration, the ground motion is the faster of the two components. This creates two separate pulses as the vibration affects the structure and then the airblast.
There are two major areas to consider with wells and natural water supplies. One alleged cause of well problems commonly claimed is from rock fracturing. To cause fracturing or shifting of rock strata, blasting operations must be within close proximity to the well. Many people believe that if the energy can be felt then it is also fracturing the rock at that distance. This is not the case. Fracturing of the rock takes place within about 10 feet of the drilled borehole. Outside of that radius, the energy that remains is elastic in nature and is felt as ground vibration. For the overall blast the fracture zone is a bit bigger but not past a few hundred feet, depending also upon the size of the blast. This is the reason drillers put boreholes on a specific spacing pattern and use multiple holes in a blast. In other words, the fracturing of the rock only occurs within a very small area around the drilled blast hole.
For the vibration component of a blast, well studies dealing with ground vibration produced from surface mining provide solid research. Numerous studies were developed to analyze the relationship between ground vibrations, well components and the aquifer. These studies all concluded that vibration damage to wells and well components requires much higher velocities than the regulated levels currently set by state and local governments. Research shows that wells are resilient to vibration and levels at the surface are reduced at the depth of the well. This precludes damage to submerged pumps and plumbing and the well casing.
The decision to use commercial explosives for breaking rock requires careful consideration. Rock hardness and equipment ability are evaluated and blasting was determined to be the most effective option for the project. Blasting is an expensive option and requires permits, holes to be drilled, explosives to be purchased and blasting safeguards to be implemented to ensure safety. Blasting is conducted when other means cannot be completed. This is a costly program and is not undertaken lightly.
Probably. If blasting is occurring near your home, you can expect to feel some vibration and hear some noise. However, the vibration levels are normally lower than those caused by a slamming door, thunder during a storm or children running and jumping around the house. While you may feel or hear the blast effects, they are not dangerous to your family or your home. In fact, research and experience has shown that vibration readings taken within a home will usually be at a higher level from normal indoor activities than from local blasting operations. These occurrences normally go
unnoticed throughout the day.
Understandably, however, you still may be concerned about the blasting. If you fail to hear a warning signal, you may be startled by the vibration and noise. Because the human body feels very low levels of motion, you may feel vibrations in the floor if you are standing or sitting indoors as opposed to being involved in an outdoor activity. On occasion, the airblast may rattle windows and doors.
People are more sensitive to blasting vibrations than their homes. Even though you may hear or feel a blast, its suddenness, coupled with your sensitivity to vibrating floors, walls and windows will make the blast seem worse than it really is.
Federal, State and/or Local Governments often impose strict limits on the level of vibration and noise that can be produced by blasting. Most blasters prefer to “shoot” or blast so that the resulting vibrations are well below these limits. Blasters know that keeping ground vibrations and noise to a minimum will reduce neighborhood concerns.
From a cost perspective, it is also preferable to keep vibration effects to a minimum. It takes a large amount of energy to break rock. Energy in a blast that fails to contribute to rock breakage is dissipated in the form of vibrations. This represents wasted energy. Given the high cost of explosives, it is to the blaster’s advantage to utilize as much of the energy as possible in breaking the rock, thereby keeping vibrations at the lowest possible levels.
Seismographs produce data that can be used to evaluate the performance of the blast. Of course, of primary interest to the blaster is that the measured vibration and airblast levels fall within safe and legal limits. In addition, these recordings often contain data that can be used by a blaster in the design of future blasts so their blast effects can be further minimized.
The seismograph recordings may also be forwarded to an independent consulting firm, comprised of geologists, seismologists, physicists and/or mining engineers. These independent consultants can verify the blaster’s interpretation of the readings while confirming the measured levels of ground motion and airblast.
Yes, considerable research has been done on the effects of blasting on structures. Numerous factors have been studied, including blast design variables and structure type. Historically, research agencies, such as the U.S. Bureau of Mines, produced the majority of this country’s technical data on blasting. Today, institutions, corporations and individual investigators, both here and abroad, continue to contribute to blasting research. Current legal and recommended vibration and airblast limits are based on this research. By adhering to these limits and following safe blasting procedures, the blaster minimizes or eliminates the risk to structures located in the surrounding area.
Specialists, such as seismologists, who measure and evaluate ground vibrations are often employed as independent consultants. Their experience and training, coupled with the blaster’s knowledge, help to produce the desired results with minimum vibration and noise.
Blasting seismographs are specialized instruments that are often used by explosives users, consultants and seismologists to measure and record data from each blast. These instruments, which have been specially designed to measure man-made vibrations, measure both ground motion and airblast.
The results of these measurements are stored electronically and/or printed on-site.
Blasting is a specialized occupation that requires extensive training in the storage, transportation and field application of explosives and detonating devices. In many states, blasters are required to be licensed, a process that requires classroom instruction, written exams and an apprenticeship. It is during this training period that blasters learn how to design blasts that will maximize rock breakage, properly distribute the fragmented rock and minimize the resulting ground vibration and airblast effects.
Vibration and noise levels are influenced by a number of factors, many of which are under the control of the blaster. These include the size and depth of the holes and the type of explosives utilized. However, blasters must also contend with factors outside of their control. These include the weather, slope of the land and certain geologic conditions.
Before a seismograph is approved for use in the field, it is thoroughly tested and its accuracy verified by the manufacturer. Seismographs are carefully calibrated on specially designed shake tables. This procedure, which is generally repeated on an annual basis, is done using laboratory test equipment calibrated to national standards. The seismograph operator also has the option of performing a simple test, on-site, which will verify that the instrument is in proper working order. Manufacturers have also decided upon a set of standards for all instruments to measure blasting accurately and with the same methodology. This makes sure data is uniform and correct.
In our experience, the degree to which property owners are affected by blasting is dependent upon their understanding of blasting and blasting safety procedures, as well as their ability to anticipate the blast itself. Therefore, we recommend that you consider the following:
- Learn what you can about blasting from factual and recognized sources.
- Inform yourself about the scope of the local blasting activities by questioning those involved with the project. Generally, they will be glad to answer any questions that you may have.
- Avoid being startled by the blasts by inquiring about the blasting schedule and by learning about what warning whistles or sirens will be used.
In some instances, homeowners living near a new mine, construction project or quarry will be given an opportunity to have their homes inspected before blasting starts or approaches their property. We recommend you take advantage of this service. The company doing the blasting often offers these inspections as a courtesy.
In most cases, the inspections will be performed by an independent company. The inspection reports will consist of detailed descriptions of conditions observed by the inspector. This documentation may include written or sketched descriptions, photographs or videotape. If you are contacted by an inspector, we strongly recommend that you take advantage of this service. We suggest, however, that you ask for some form of identification before giving an inspector access to your home.
One final point, just as you expect cooperation from the blaster, he is entitled to a cooperative attitude in return. To ensure the safety of you and your family, please adhere to any instructions posted on signs around the project, mine or quarry.
Most of the energy from a blast is used to break rock, but some energy will travel from the blast site in the form of ground and air waves. Each of these can cause your house to vibrate or shake. Human beings are very sensitive to all vibrations. It is possible that you will feel or hear your house shake from the blasting, even at very low levels.
How a blast feels depends on ground or air waves that reach your house. These are influenced by the type of blast, the distance from the blast and the amount of explosives.
Your location on the property also affects your perception of the blast. If you are outside a house, you will tend to feel the ground vibrations in your feet and legs. Inside a house you sense the structure and objects responding to the vibrations. You may also hear things rattle.
This is why you and your neighbors may feel or describe blast vibrations differently.
Typically, blasters are licensed professionals who are required by regulation or by their employers to continually obtain training. They are trained to plan, design, implement and monitor blasts. This training stresses safety in all aspects including protection of your property.
Prior to blasting, pre-blast inspections may be offered to nearby property owners to document the existing condition of buildings and identify any sensitive structures, building components or contents. The site conditions and the inspection information are employed to design the blast to minimize effects to your property.
To ensure that the blasts are working as planned, the resulting ground and air waves can be measured with a blasting seismograph.
A blasting seismograph measures and records the ground and air waves from a blast. The information is reported as waveforms, also known as time history records. Time histories show how the strength (amplitude) of the waves varies over time. Amplitudes are reported as particle velocity (inches per second) for ground waves and pressure (pounds per square inch) or decibels for air waves.
Another important characteristic of the time history is frequency. Frequency is the number of complete waves that pass by in one second. It is reported in cycles per second or Hertz. Both amplitude and frequency are needed to describe the motion from ground and air waves.
The blasting seismograph information is used to show compliance with regulations or specified limits and to evaluate blast design performance. Most importantly, it verifies that the ground and air vibrations are within standards set to protect structures.
In North America, safe vibration standards are based on scientific studies conducted by the U.S. Bureau of Mines (USBM). These studies recommend ground and air vibration limits based on scaled distance, peak particle velocity, air pressure and frequency. Meeting these standards will prevent even cosmetic cracking in structures. On the other hand, slightly exceeding these conservative standards will not necessarily harm a structure.
For ground vibrations, the standard is a function of frequency and peak particle velocity. At low frequencies the limit is 0.5 inches per second (in./sec.). At high frequencies the limit is up to 2.0 in./sec. For air vibrations, the standard is a function of pressure that is most often reported as decibels with a common limit of 133 decibels (dB).
A blasting seismograph is one tool that can be used to document compliance with these standards. Another method sometimes used is a minimum scaled distance which is a relationship of explosive quantities and distance.
No, blasting seismograph data is stored digitally and coded internally to prevent tampering. The data is printed with proprietary software from the manufacturer.
Research has shown that it is more consistent to measure the ground waves entering the structure. Therefore, the seismograph sensor is attached to the ground outside your house. By installing the sensors outside, the measured vibration levels can be compared with known safe limits, existing regulations, or industry standards.
The two scales are not related and cannot be interchanged.
A blasting seismograph simply reports how much the ground vibrates in one particular location. It measures the intensity of ground motion. This measured intensity will be stronger if the seismograph is close to a blast, and lower if the seismograph is far away. In blasting, the unit of measurement we use to describe this motion is peak particle velocity.
The Richter Scale reports the power of an earthquake, or its magnitude. It's an estimation of the energy released at the source. In blasting, it would equate roughly to the total weight of explosives used in a blast.
Earthquake scientists do use seismographs to measure the intensity of the ground waves at different locations, and then calculate a Richter Scale magnitude. This value is based on two things - how far the seismograph was from the earthquake, and the intensity of the ground waves at numerous seismograph locations.
Ground waves change as they pass through different kinds of materials, and in general, the strength (amplitude) decreases rapidly as it moves farther from a blast. This happens regardless of whether they follow the same rock layer or whether that layer changes. As these waves reach your property, your house will be protected if the strength of the vibrations are within allowable limits. These limits are conservatively set to protect surrounding houses regardless of the underlying material.
The foundation is the strongest part of a house. Vibration standards are designed to protect the weakest parts of the house, such as plaster and drywall. Ground vibrations strong enough to crack foundations consisting of concrete and masonry would far exceed the limits set by typical standards.
Below-ground structures are confined in the ground and can only move as much as the ground itself moves. They respond less to the ground waves than a house or other buildings above ground. Therefore standards that protect houses will also protect below-ground structures.
Only unusual soils like very loose, saturated sands are susceptible to settlement from ground vibrations. Even where these soils are present, typical blasts do not create conditions which cause settlement due to the short duration and relatively low amplitude of the ground waves.
Vibration energy is not stored in the house and has no potential to be cumulative. Each blast affects your home as a single event and rarely lasts for more than a few seconds. As ground and air waves pass, the house will begin to vibrate. When the ground and air waves end, the house will stop vibrating and there will be no further effect from the blast.
This question has been studied by the USBM. In one study a house was intentionally shaken hundreds of thousands of times. Over 50,000 cycles of intense motion (PPV ~ 0.5 ips) were needed to cause a cosmetic crack. For most blasting projects, the total number of ground wave cycles of this intensity reaching a house is fewer than 100. Vibration limits have been set to prevent cracking from repeated blasting.
The pre-blast inspection protects both the homeowner and the blaster by documenting the condition of the home before blasting. After blasting has started, any suspected changes that are found can be compared to the initial condition.
An undocumented crack isn't necessarily the result of blasting. There are other factors to consider in determining whether blasting caused any crack. For example, environmental effects such as temperature, humidity and wind, as well as homeowner activity may contribute to cracking. On rare occasions, a crack may be the result of blasting if ground or air vibrations exceed recommended standards.
A blasting specialist needs to look at the blast and seismograph records to determine the intensity levels of ground and air vibrations at your home. Based on the estimated or recorded vibration levels at your house, as well as other factors, it can be determined whether blasting could have been responsible.
There are many possible causes. Every day, construction elements of your house shrink and swell from environmental changes, and movement occurs from human activities such as opening & closing doors and windows, hanging pictures on a wall or simply walking through the house.
Continued research has shown that changes in temperature, humidity and soil moisture can yield greater changes to a structure than ground and air vibrations from a blast that are within recommended standards.
Pets, like humans, are sometimes startled by the sound of a blast or warning signals, just as they might be startled from thunder. Like humans, animals are subjected to a variety of vibration sources and events each day, with no long term effect.
A CO monitor represents an appropriate safety precaution for all parties. For nearly all blasts the CO vents to the atmosphere and rapidly dissipates. In rare situations, however, some CO may travel underground through voids and along utility lines into nearby homes.