A Great Question about Blasting

Bill Hamlin, Vice President-Aggregate Operations

We recently received a great question about the potential effects of repetitious blasting over a long period of time to nearby structures. The U.S. Bureau of Mines, Minerals and Safety has studied this issue extensively. Studies have shown that normal environmental stresses far exceed the effects from brief, repetitious blast vibration sources at safe levels. These studies were conducted under extreme conditions far exceeding what occurs in a quarry operation. (see my entry on blasting from September). Typically, blasts are conducted once every 7 to 10 days and last seconds. To compare, below is an excerpt from the report that Sauls Seismic prepared for Boxley addressing the questions and concerns about this topic:.

REPETITIOUS BLASTING AND DAMAGE POTENTIAL

The effects of repetitious blasting are another common concern, and have also been studied. In one case, a house was constructed in the path of an advancing surface coalmine. The structure was subjected to more than 600 blasts over a period of 2 years, with ground vibration levels as high as 6.94 IPS (RI-8896). This study also measured strain levels in the structure due to normal environmental factors (temperature & humidity changes, wind, etc.) and human activity.

These normal factors were found to result in strains and movements equivalent to those produced by ground vibrations of 1.2 IPS, or more (as high as 3 IPS where a strain gage bridged a crack). Structures in other climates or other soil conditions can experience even greater normal, environmental strains. It was found that house superstructures are continuously subjected to environmental stresses comparable to blast effects up to about 0.5 IPS. Other studies have found human activity or environmental stress to result in local stresses equivalents to vibration of 8.0 IPS, or more.

After the study, the structure was mechanically shaken to induce fatigue cracking in the sheetrock walls. The first fatigue crack occurred appeared after 56,000 cycles, and was equal to blast generated vibrations of 0.5 IPS, twice per day, for 28 years. The obvious conclusion is that normal environmental stresses far exceed effects from brief, repetitious blast vibrations sources at safe levels.

In another study, a test structure with sheet rock walls was subjected to typical quarry blast vibration simulations levels of 0.10 IPS, 0.5 IPS, 1.0 IPS, 2.0 IPS, 4.0 IPS, 8.0 IPS, and 16.0 IPS. Each simulation level was run once, then 5 times, 10 times, 50 times, 100 times, and 500 times, inspected after each run, and then progressed to the next higher vibration level. No damage (sheet rock cracks) occurred until the 6th run at 4.0 IPS (5 simulations at 4.0 IPS, and 2664 simulations below 4.0 IPs preceded this.)

 

 

 

 

 

Ballfields or Nature Park?

Jeff Perkins, Vice President-Aggregates

During the application process, I heard lots of comments from neighbors that Boxley needed to give back to the local Evington community. One idea we had was to offer Campbell County a lease agreement on the 135 acre residentially zoned land located on the eastern side of our property to build a multi-use park. This is just one idea!

Boxley is seeking other ideas on the use of this 135 acre tract. To help facilitate this communication process, Boxley would like to work with the Evington Community Association to determine what the neighbors of Evington would like us to do with this land. Could it be left in a low impact, natural state? Sure. Could we put some walking and biking trails on this property? A good topic for discussion. Does the community want a multi-use facility? I don’t know.

Boxley intends on working with the Evington Community Association and Campbell County to determine what is the most appropriate use for this land. We will meet with the leaders of the Evington Community Association early next year to discuss all options.

Boxley will listen to the desires of the community and determine what is the best mutually agreeable solution for the community, the County, and Boxley on the future of this land.

Communicating the Next Steps

Jeff Perkins, Executive Vice President-Aggregates

 

The Flat Creek Quarry is scheduled to begin operation in about 15 years. We plan to use this site to communicate any activity that will occur with the Flat Creek quarry.  Today, we want to keep you informed of our plans and the fulfillment of our commitments.

 

Here’s an overview of what to expect:

 

Next Steps:

Groundwater Protection Plan

We have established the Independent Escrow Fund for the Groundwater Protection Plan and placed the first $50,000 in the fund. In 15 years this fund will have $150,000 to be used in the unlikely event the operation were to affect a neighbor’s well. See Groundwater Protection Plan under Pages section for complete details.

 

Develop minimum 15’ Screening Berms

This work will be done in 2009 to allow time for the landscaping to mature.

 

Install Monitoring Wells

These will be installed on the Flat Creek property in 2009 with monitoring to begin immediately.

 

Identify Evington Community Leader

This person will serve as part of the Independent Hydrology Team and will participate in the recording of the Monitoring Well data.  We will seek guidance from the Evington Community Association and Campbell County on the selection of this individual.

 

Develop Park and Nature Area

Campbell County Parks & Recreation will take the lead in the development of this project. Boxley has committed to funding the Master Plan and the site development so that the park would be open within 5 years. Community Involvement will be a key component in the development of the park plan.  See Park and Nature Area Proposal under Pages section for complete details.

 

Other than the action steps listed above, activity on the site will be minimal.  Over the next 10–15 years, we will be working on further developing the site design, establishing the buffer around the property, and going through the permitting process with our oversight agencies. I look forward to working with the Evington Community Association in the future to ensure our site incorporates our neighbors’ input to provide for the best possible solution for everyone. 

Putting Your Concerns to Rest about Asbestos Form Minerals

Tom Roller, Professional Geologist-Boxley

 

Finding a quality deposit for construction grade materials is not an easy process.  Boxley researched 18 different locations before finding the greenstone deposit at Flat Creek.  For the past 3 years, Boxley has conducted extensive testing and performed numerous studies to determine if this deposit met the criteria for a long term aggregate supply for a replacement to our Lawyers Road quarry.  As part of our extensive analysis for any deposit exploration, Boxley tests all core samples for asbestos form minerals. 

 

ATS International, an independent geologic firm, drilled and collected over 2700’ of core samples.   The drilling was done to provide an accurate cross section of the deposit. There were 3 professional geologists that examined the core and no asbestos form minerals were found.   As part of our standard procedure to ensure detailed analysis for this type of mineral, representative samples were sent to DCM Science Laboratory, one of leading geological analysis firms in the country, for microscopic analysis and testing.  This petrographic analysis accurately determines the mineralogy of each sample and the core samples that were analyzed were free of any asbestos form minerals.  Based on this detailed and microscopic analysis, the greenstone deposit at Flat Creek is considered a quality deposit suitable to construction aggregate applications. 

 

We appreciate the opportunity to address this concern.

 

Solutions for Our Community

By Ab Boxley, President and CEO

 

The July Campbell County Planning Commission hearing was a wake-up call for us. That night it was obvious we hadn’t addressed your concerns effectively. Rest assured, we listened hard and will continue to listen to your constructive input. We appreciate your concerns for our community and have a shared goal of ensuring our community maintains a high quality of life.

 

To that end, we have revised our site plan and put binding commitments in place that give you the peace of mind that you and your family, your property, your water, and the rural character of the community will be protected. 

 

We feel it is important that you are aware of the changes we have made in advance of the Board of Supervisors meeting so that you can make decisions based on the new plan.

 

Boxley’s New Plan

We have amended our current application submittal and are now requesting the following:    

• We have reduced the number of acres we are requesting for rezoning from 488 to 353 by removing the 135 acre parcel zoned Residential on the east side of the property.
• Our mining and processing operations will be on only 243 acres, leaving 547 of the 900 acre Flat Creek property as natural buffer
• We have proffered a minimum 300-foot natural buffer around the entire site (110 acres total) which includes 55 acres of the Flat Creek Riparian Preserve along Flat Creek on the western boundary (see attached site plan)
• We have proffered to have no Asphalt or Concrete Plant on site
• We have proffered no commercial entrances on Blackwater Road  

Our site plan incorporates tremendous buffer areas to preserve the area’s natural setting. We are committed to making this land an amenity to the community. To that end, we have offered to underwrite the cost to design and develop a park and natural area in the eastern 135 acre buffer. The design and use of the park and natural area would be dictated by what Campbell County Parks & Recreation and area citizens desire for this site.

 

We heard your concerns regarding water.  Although it is unlikely that the operation would affect neighboring wells, we have developed an independent plan to provide you with assurances that well issues will be resolved at Boxley’s expense.  A summary of the plan is attached and the highlights are as follows:

·     An independent team will be established to include a independent Hydrologist, Evington Community Leader and Boxley Team member

·     An independent fund will be established that will have $150,000 in the account when the quarry opens in 15 years, $200,000 in 20 years and will increase an additional $50,000 every 5 years after 20 years to pay for any water repair/issue

·     Boxley will drill you a new well, or hook you up to County water

·     Details of the complete plan are attached for your review       

 

Boxley has a long heritage of working with neighbors and being an integral part of local communities, and we look forward to building this relationship with you in the near future.

 

Debunking Myths About Blasting

Bill Hamlin-Boxley’s Vice President-Aggregate Operations

 

We find that many of our neighbors’ concerns come from misconceptions about modern blasting. They have notions that we light sticks of dynamite and drop them down the hole. None of our pay ranges come close to what it would take to pay someone to do that!

 

These days quarry blasting is a precise and highly engineered activity that uses a series of smaller blasts which actually work against the following blast to significantly reduce noise and vibration. It is stringently regulated and should be. All of our quarry blasts are designed, loaded and overseen by a professional blaster, certified by the State of Virginia.

 

So how are shots measured and monitored to ensure compliance? The energy released from a blast generates ground vibration and air overpressure. Ground vibration is measured in inches per second. This is the speed at which the vibrations move through the ground not displacement of the ground. Overpressure is measured in decibels which can also be converted to pounds per square inch. Seismographs are placed at the nearest off site occupied dwelling per state law to measure the vibration and overpressure generated by each of our blasts to ensure compliance.

 

If you live within a half mile or sometimes even a little further from a quarry shot you will know when the blast is initiated. The fact that you can feel or are aware of the shot does not mean that your house has been or will be damaged.

 

The United States Bureau of Mines has issued guidelines to ensure homes are not damaged by quarry blasting. These guidelines are based on 50 years of data from scientific studies to determine exactly what levels of vibration or air overpressure can cause damage to residential structures. These standards are based on science, physics and engineering and have been proven to be factual and have never been successfully challenged in a court of law. Vibrations and decibel levels from Boxley’s blasting operations are well below the allowable limits dictated by Virginia law.

 

Virginia law allows vibrations up to one (1.0) inch per second which is twice as stringent as the U.S. Bureau of Mines guidelines. Virginia laws are based on the U.S. Bureau of Mines extensive testing on what level of vibration or overpressure can cause even cosmetic damage to residential structures.  Vibration levels from blasts at Boxley’s operations are 70%- 80% below the state allowable levels.  

 

The U.S. Bureau of Mines has also completed several studies on wells and underground pipelines to determine if blasting will cause damage to these underground structures. Virginia’s vibration limit of 1.0 inch per second is 4% of what these underground structures can safely tolerate.

 

Most people are surprised to learn that common household activities exert many times the stress and strain on a home than a quarry blast. Slamming a door produces 25% more stress on a residential structure than Virginia’s vibration limits allow.

 

While normal human activities in a home produce a lot of stress on a house, the real culprit in routine cosmetic cracking and minor damage in residential structures is weather. Changes in temperature and humidity and wind have been proven to cause the overwhelming amount of normal and routine cosmetic damage that occur in residential structures. An outside change in temperature of 27 degrees causes stress on a home 8 times what the state laws allow from a quarry shot. A change in humidity of 35% is equivalent of a quarry blast over 5 times allowable state limits. Winds of 23 miles per hour stress a home more than two times what the state allows a quarry blast to produce. 

 

To give further perspective to the amount of disturbance a typical blast causes, here is a chart with information provided by Sauls Seismic and the US Bureau of Mines:

 

 

 

Facts about blasting at Boxley:

• Blast records are open to state regulatory inspection.
• Each shot is designed and overseen by a professional licensed blaster.
• No explosives are stored on site.
• The bulk explosives are delivered to the quarry in a safe and inert form. Only after their arrival are the explosives activated prior to being placed in the rock formation.  
• Blasting would occur about once a week at the Flat Creek operation.
• A blast last about 1-2 seconds.
• Dust from a blast settles in a couple minutes.
• Unprecedented large buffer (distance from neighbors) at the Flat Creek site will allow dust from the shots to settle on site.

Safety is the paramount concern of our blasting program. Your safety, your home’s safety and the safety of our people are the highest priority when each and every shot is designed and detonated.

A Picture is Worth A Thousand Words

Jeff Perkins, Boxley’s Executive Vice President-Aggregates

 

There is an old quote from Thomas Cooper that says “Fraud and falsehood only dread examination.  Truth invites it”.  Not long ago a quarry operation could hide behind a gate.   There was no such thing as local zoning ordinances. State and federal agencies such as the DMME, DEQ, MSHA, and EPA did not exist. The truth about how a company operated was behind the gate. Not so today.

 

Today a quarry is one of the most heavily regulated industries. The above mentioned government agencies are some of the regulators. It is not uncommon for the surrounding neighbors to play an active role by supplying feedback, positive or negative.

 

Additionally, several of our operations are located directly on major roads where drivers of more than 16,000 vehicles a day can view and judge our sites. The Blue Ridge and Fieldale operations are examples. The truth about how we operate at both Fieldale and Blue Ridge is not hidden behind a gate.

 

Are we perfect?  No. The truth of the matter is that we aren’t perfect 100% of the time. However, we invite examination and welcome neighbors to tour our facilities and join in constructive dialogues to help make us better and to make the community a better place to live.

 

No one is perfect.   For instance: Tiger Woods may hit a 300 yard drive 99/100 times.   To take a video of the drive where he doesn’t reach 300 yards and label that as typical is falsehood. This type of falsehood deserves examination. A branch of an environmental activist group in Fieldale would have you believe that Boxley is not a good neighbor. We urge you to get the facts for yourself. We respect our neighbors and invite this type of examination.

 

A picture is worth a thousand words. The following are typical shots of our Fieldale quarry. We invite anyone to conduct further examination and would welcome the opportunity to give you a tour of any of our quarries.

 

Boxley is committed to having attractive and well maintained properties. This is a view as you approach the entrance to our Fieldale Quarry.

A view of the playground across from the Fieldale Quarry

A view of Jordan Creek as it runs through the Fieldale Quarry site. The Fieldale Quarry returns more water to Jordan Creek than is withdrawn. Over the past five years, the operation returned anywhere from 20 to 57 million gallons more each year than it withdrew. This helps keep Jordan Creek and its aquatic life healthy.

View of Route 220 from the Fieldale Quarry Site

Boxley designs its sites with forest, berms and additional land to provide substantial buffer between our operations and our neighbors. The proposed Flat Creek quarry will utilize 100 acres on a 488-acre site.