As Camden County Planning and Zoning commissioners weigh a proposed rezoning request to expand a rock quarry, a blast during a visit to the current site by a couple of the commissioners has sparked more debate between opposing sides in the case.
Magruder Companies is seeking industrial zoning of a 30-acre tract at Highway 5 and Tree Lane adjacent to another 30-acre tract where mining has been done for more than a decade. The existing quarry operation is located within the Village of Sunrise Beach. The proposed addition is under Camden County jurisdiction.
At the public hearing for the rezoning in November, several residents in the vicinity of both properties attended in opposition to the expansion citing concerns about blasting and noise in addition to reduced property values.
Keith Henderson, a blast technician who does contract work at Magruder’s Sunrise Beach quarry, citied studies from the U.S. Bureau of Mines related to the impact of different levels of blasting and subsequent vibration levels on structures. These studies along with his reporting of blast levels at the quarry indicated that the level of blasting they are doing would not damage houses in the area.
Planning Commissioners Tom Spradling and Jacob Neusche requested a visit to the site to experience what a blast felt like.
Magruder representative Clark Bollinger complied with the request and welcome the commissioners to a site visit Nov. 22.
That blast has now sparked more controversy about if the quarry set off a reduced charge to make the blasting not seem so bad.
Sunrise Beach Police Chief David Slavens issued a letter to Ron Yarbrough with the Citizens Against the Rock Quarry in Sunrise Beach.
According to the letter, Slavens has attended many blasts prior to this incident. He states as his opinion that “this blast was considerably less than a normal blast.
“As police Chief (sic) of Sunrise Beach Village, MO. I am notified of all blasts in advance per Missouri Regulations and have witnessed many previous blasts. I don’t have any special equipment to measure the blast but this one was considerably less than any other I have witnessed.”
While some, including Slavens, have termed it a “test blast,” Bollinger called it a production blast, with the design and amount of shot set at the level needed to meet their commercial production needs - with no other factors.
He sat down with the Lake Sun and went over some of the site’s blasting logs from Buckley Powder Company and seismic records from Saul’s Seismic, LLC to show the complexity of blasting. The records included the blast from Nov. 22.
While the record of every blast was not available, the records made available showed a variety of recent dates going back to October. Because neighbors have not allowed seismographs on their properties, Bollinger said all of the seismic readings are not taken on the site of the existing quarry.
A blast on Oct. 30 included 13 holes for 1,890 tons in shot, while the Nov. 22 blast included 22 holes for more than 3,000 tons in shot. There were also records of shot from Nov. 2 and Dec. 5, which had 59 holes and 24 holes respectively.
According to Bollinger, the records show that there is much more to blasting than the amount of shot - or holes, as it described in industry terms.
Location in relation to the highway or homes, depth, overburden, geology, the stemming or timing of shot are just some of the factors.
Bollinger acknowledged that, yes, people feel the blasts, but says that does not mean damage is occurring to structures or wells from the blasts.
What is felt may more often be a result of the acoustic part of a blast, also referred to as the air blast, rather than actual vibration in the ground.
The Missouri Division of Fire Safety oversees compliance with the Missouri Blasting Safety Act. The Lake Sun independently called this division and the mining division of the Missouri Department of Natural Resources (MDNR) for information about blasting and quarrying at this site and in general.
Regional Chief Scott Stoneberger explained that the state has placed limits on blasting, but that sites keep their own log books with three years of records required to be maintained. If a complaint if filed, the state can require the company to provide these logs for review within 24 hours.
Stoneberger does not recall any complaints against this quarry in the last six months.
He confirmed that just because someone feels a blast does not mean damage has been done to any structures or wells, but that doesn’t mean that damage can’t happen.
Typically, he says when someone feels something, it’s the acoustic part of the blast, not the blast itself. Windows shaking is a typical symptom of the air blast.
There are scientific formulas for determining the size of shots, how many, even how they’re designed or laid out, said Stoneberger, which is why most quarries contract blasting out.
“Most of the blasters today are very well educated and understand that it’s in their best interest to follow guidelines, but I can’t promise there won’t be damage either,” said Stoneberger.
About 95 percent of the time when complaints are filed, there is no violation of state regulations though, he said.
“Some people aren’t happy with that, but we have to fall under the legal limits. There’s not a whole lot we can do as long as blasters are within legal limits,” Stoneberger commented.
Bill Zeaman is Chief of the Industrial and Metallic Minerals Mining Unit of the MDNR. This department oversees the mining aspects of quarries, mainly regulating where overburden (the earthen material on top of the mineral being mined) is removed from and where it is placed afterwards.
DNR has not received a mining permit request from Magruder for the proposed expansion area, but Zeaman noted that it is not unusual for a company to wait until zoning is in place before moving forward with an application for a land reclamation permit.
The water table and water wells have been a main area of concern in relation to the quarry and its depth.
There is no state regulation that limits how deep a quarry can go; however, the state does have a water protection program and has many monitoring wells, including five in the vicinity of the Sunrise Beach quarry.
Zeaman said that a permit is issued based on mining for a certain type of mineral. In this case, it would likely be limestone. The geographic horizon of the earth is such that there are strata of earth and rock formations. Limestone is a really hard rock and doesn’t hold water, he explained, so the water table is generally around two geographic strata below limestone.
According to Zeaman, intercepting an aquifer during limestone quarrying is rare in Missouri - the only site he was aware of in Missouri was near the Mississippi River where they were mining below the surface level of the river behind a bluff. The water can be pumped and mining continued, but it does drive up the cost of doing business, he said.
According to Bollinger, he has been in the quarry business a long time, and said that they are capable of going far deeper than the site is now. He indicated the extra cost of pumping water or whatever it may be would simply be added to the cost of their product, and thereby also potentially driving up the cost of development in the area.
Zeaman also explained that in-ground structures such as a foundation or well can take much more force from a blast than, say, glass above ground. The earth acts as an insulator and concrete is a far more durable material so, despite the vibrations of the air blast which is what people typically feel, there is likely no damage to structures or wells.
He also noted that structures do not retain memory - unlike for example fishing line unwound from the reel. When a blast occurs whatever is going to happen as a result of the force of a blast occurs then and there is cumulative effect, he said. Whatever the point of impact, the structure absorbs and deals with it in that moment. If there’s no damage at that moment, there will be no damage from that particular blast and multiple blasts over time will not add up to something greater than each individual incident.
Back at the quarry with Bollinger, he stated that the science of blasting is complicated. To try to simply show the commissioners the relative safety of blasting done at the quarry, they did a little science test during the blast. They placed two uncooked eggs and a lightbulb in separate holes located 125 feet behind the shot. All of them came through unbroken.
The Camden County Planning Commission is scheduled to consider the case again at its Dec. 20. If it makes a recommendation on the rezoning case then, which is likely, the case will go to the Camden County Commission for another public hearing and final decision.
The Sunrise Beach Board of Trustees have previously voted to officially oppose the rezoning to industrial mainly based on its comprehensive master plan to make this vicinity a commercial area, not industrial.