Answers to questions regarding the community’s concern with dust
Updated January 20, 2022
Fermilab has continued to take measures to mitigate the dust emanating from the open cut. We have maintained direct visual observation of the conveyor at all times when operational, and have stopped transporting rock when dust has been observed at the fence line and/or when the wind exceeded 15 mph.
In addition, we installed the replacement chute on December 30, which extends to near the top of the main pile. We are continuing to apply the tackifier to all new material conveyed into the open cut.
We have not yet flown a drone into the open cut; however, we are engaged with the drone company to schedule this as soon as possible.
The dust observed during high wind speeds when the conveyor is stopped is coming from the finer material that has settled above the main pile prior to the chute and tackifier system installations. In other words, the dust is not emanating from the tackifier-treated material being deposited into the open cut.
Additional dust mitigation measures planned include testing a new snow fence that will be installed north of the existing fence to slow air speed inside the existing fence perimeter which will allow material to settle prior to leaving the open cut. Also, we will be testing the use of a tarp along the fence to help block the material from leaving the open cut. These measures should be in place by January 17.
See response above.
As described above, the dust observed appears to be originating from the untreated material above the main pile. The tackifier has been controlling dust where the treated materials cover the pile. The capping compound has not yet been applied using the drone; however, we are working with a contractor to do this work as soon as possible.
The conveyor has operated 17 days for approximately 80 hours since December 16. We have stopped operations due to observed dust 11 times and have not operated the conveyor on three separate days due to high winds.
The excavation and construction remain on schedule.
We look forward to keeping our South Dakota neighbors informed and have scheduled our next informational meeting on January 25 at 6:00 pm at the Homestake Opera House. We will provide an update on the overall project including dust mitigation efforts and respond to resident questions. Residents who would like to submit questions prior to the meeting can do so by sending to email@example.com.
We understand air quality safety is a key concern of the community. Fermilab investigated the rock’s composition during the design phase and investigated the historical facility operations in processing this same rock. The rock does not change chemically through processing or mechanical fracture. The only materials added are water and tackifier, neither of which modify it chemically. Both materials are safe and are used to help bind small particles together.
We are following the national ambient air quality standards established by the EPA for acceptable dust exposure. We monitor dust levels on both sides of the conveyor at the edge of the open cut. Regarding silica exposure, the dust escaping from the open cut contains trace amounts of silica. The concentrations of silica that citizens would be exposed to from dust emanating from the open cut are below the level recognized as safe for human exposure as determined by the American Conference of Governmental Industrial Hygienists (ACGIH).
The question below was updated December 17, 2021
Normal conveyor operating hours will be restricted to 7:00 AM to 5:00 PM MT Monday through Friday. The conveyor may run during these same hours on the weekend when needed. No rock will be discharged outside the 7:00 AM to 5:00 PM operating window.
The questions below were last updated December 10, 2021
Fermilab takes the concern with dust from the LBNF-DUNE project very seriously, and we agree that the levels of dust the community has experienced are unacceptable. We understand there are many questions from neighbors and apologize for the frustration and inconvenience this is causing. Because the dust situation is aggravated by high wind conditions, we have voluntarily shut down movement of rock into the open cut while we are working with the mayor on a plan for limited operations that better accounts for wind conditions. Additionally, as part of a series of dust-mitigation steps, we are working on new measures that include an upgraded chute which should reduce equipment-related dust release. We will continue to provide updates as these measures are put in place. Fermilab remains committed to being a good neighbor, and we thank the community members for their ongoing feedback as we work to resolve this as quickly as possible.
Fermilab has voluntarily stopped depositing rock into the Open Cut while we work with the Mayor of Lead on a plan for dust abatement. We do not expect to resume until a consensus with the Mayor has been met, and then would resume with limited operations.
We have implemented a number of dust-mitigation measures since the start of the project and will continue to pursue additional measures as necessary to resolve the dust concerns. Our efforts to date, which have involved consultation with experts in the field of dust mitigation solutions, include professional water sprays, a fogging machine, sprinklers, adding the tackifier product application and chute modification. Additionally, we will be applying a capping compound to the existing material in the Open Cut. If the extended chute and capping agent do not fully resolve the issues, additional measures will be pursued. Fermilab is committed being a good community neighbor and resolving the dust to satisfactory levels.
The tackifier (NALCO EG2600) is a non-toxic product derived from glycerol, which is an FDA- approved compound that is commonly used as a sweetener and thickening agent in many foods and medicines. The product poses no threat to human or aquatic life, as outlined in section two of the Safety Data Sheet (SDS) which classifies the product as “Not a hazardous substance or mixture.” The tackifier also meets effluent-based water quality standards governing Class II Cold Water Fisheries for discharge to Whitewood Creek (class 2 cold water fishery and class 8 recreational use). NALCO representatives along with the Fermilab team examined three products that had the potential to mitigate fugitive dust related to discharging rock. TRE Labs performed another toxicity test on NALCO EG2600 at the same concentration being used to treat the rock in the Open Cut showing no toxicity. The product has also recently been used in the State of Colorado in high country applications due to its safety.
We understand air quality safety is a key concern of the community. The dust escaping from the Open Cut contains trace amounts of silica. The concentrations of silica that citizens would be exposed to from dust emanating from the Open Cut are below the level recognized as safe for human exposure as determined by the American Conference of Governmental Industrial Hygienists (ACGIH). This is based on dust sampling performed in the underground environment by trained personnel using properly calibrated air dust samplers with results determined by an accredited laboratory (SGS Galson). This sample comes from the same rock and dust being deposited in the Open Cut. We will continue to address questions on this, along with all other resident concerns, through open community meetings.
Dust emissions at the Open Cut discharge are regulated under Federal 40 CFR 60.670 Subpart 000, which stipulates an opacity limit between the discharge point and the first stockpile below. Opacity is a visual assessment of dust or smoke in the air based on how much of the background is blocked by that dust or smoke. That Subpart 000 limit is set at 7%. Thyssen Mining (TMI) personnel perform daily opacity observations at the discharge point to ensure compliance, and both TMI and Fermilab personnel also perform quarterly opacity observations per permitted requirements. The personnel performing these observations are trained and accredited to perform the observations.
The dust concentrations from the Open Cut are monitored using two methods. First, daily visual observations, called Method 22 Daily Opacity Readings, are performed by personnel who are trained and accredited to perform these observations. Second, before conveying operations commenced, two dust monitoring stations were installed on the rim of the Open Cut, on either side of the conveyor. These stations continuously collect air samples and deliver the dust from those samples onto a very accurate Managed by Fermi Research Alliance, LLC for the U.S. Department of Energy Office of Science micro-balance scale. A calculation is made hourly of the concentration of dust in the volume of air sampled. These calculations are recorded by the system and monitored regularly to help guide our decisions on operation of the conveyor. It is not possible to monitor the total amount of dust that has escaped the Open Cut due to numerous variable factors involved. These factors include wind speed, direction, duration and the complex geometry of the landscape both inside and outside the Open Cut.
Several firms were involved in the engineering and design. Extensive testing was included as part of these efforts which involved analyses for dust particle distribution and control.
Fermilab has been monitoring the dust since we first began running the conveyor in early summer (2021) and recognized the dust as a potential concern. Therefore, we implemented a number of controls to help limit the dust which, over the past three weeks, has been aggravated by high wind conditions.
The current project schedule for drilling and excavation runs through late 2023.
Fermilab takes the concern with dust from the LBNF-DUNE project very seriously, and we agree that the levels of dust the community has experienced are unacceptable. To listen and better understand community member concerns, we engaged with all the individuals who have contacted us with concerns and are working with the mayor on a plan for limited operations that better takes into account wind conditions. As of Dec 9, 2021, four individuals have contacted either SDSTA or Fermilab with dust concerns. Fermilab has reached out to and engaged with all of these individuals to gather their feedback and discuss activities underway to address the dust and will continue to address residents’ feedback through open community meetings and updated FAQs. Fermilab remains committed to being a good neighbor. If residents have additional concerns, they should contact Fermilab at firstname.lastname@example.org.