Mining BMPs Could Help Reduce Toxicity of Floodwaters
This is the sixth in a series on Sand Mining Best Management Practices (BMPs) proposed by the Texas Commission on Environmental Quality (TCEQ). BMPs help reduce erosion and prevent pollution, but these don’t address some important issues.
Strengthening them could reduce both the magnitude and toxicity of future floods. By reducing the amount of excess sediment that enters the river, we can help reduce blockages that contribute to flooding. And by better managing fuels, we can help reduce the toxicity of stormwater runoff.
Public comments are due by August 19, 2021.
Sixth in Series
The five previous posts have talked about:
- Scope and Need for Proposed BMPs
- Setbacks from Rivers
- Vegetative Controls
- Structural Controls
- Pre-Mining Planning
This post will focus on the actual mining phase. For brevity, I will summarize the BMPs. But here is a link to the exact proposed text. I will also provide suggestions for improvement at the end of this post for those committed individuals still with me.
Large parts of this section describe the mining process. Some have no BMPs. I have summarized the process and tried to condense the BMPs for readability.
As we saw in the post about setbacks, simply having the setback requirement is no guarantee operators will observe it. Likewise with some of these BMPs.
I never really thought about fuel storage at a sand mine until I read these BMPs. Then I reviewed by pictures and found that few mines would comply with these proposed rules.
4.1 Dredging Activities
After stripping away overburden, dredging begins. Suction and pumping send sand and other materials to a wash plant where they are separated using a sizing screen. Water generated during the pumping process can flow back into the pit. Sand is separated from gravel and stockpiled or sent to the pit via a sand flume. Sized aggregate is stockpiled onsite until sale.
4.2 Aggregate Wash Plant Area (Wet Processing)
Process wastewater results from the production, clean-up, or use of any raw material, intermediate product, finished product, byproduct, or waste product. Treatment of wastewater before discharge to alter its characteristics is often required to achieve compliance. Examples of treatment include pH adjustment and removal of solids through either physical or chemical means prior to discharge to surface water.
BMPs required during this portion of the mining process include proper berming and/or ditching of pump water from the dredge to the wash plant and back into the open pit.
Pump water flows back into the pit to avoid unpermitted process water from escaping.
Runoff from the stockpiles must be routed to the open pit. Rainfall runoff from stockpiles must also go to the pit.
Other BMPs include silt fencing, berms, and vegetated buffers to ensure runoff from stockpiles is controlled.
4.3 Aggregate Processing Plant Area (Dry Processing)
Some sand used for fill, bedding, etc. does not require processing, but most does. Processing for specific markets involves the use of different combinations of washers, screens, and classifiers to segregate particle sizes.
After transport to the processing plant, the wet sand (raw feed) is transported to fixed or vibrating scalping screens that separate particle sizes. Oversize material may be directed to a crusher for size reduction to produce manufactured sand. Following crushing, material returns to the screening operation for additional sizing.
Alternatively, oversize material (greater than two inches) may be used for erosion control, reclamation, or other uses.
During screening, water sprayed onto material removes clays and other deleterious material.
After classification, sand is dewatered, then conveyed to storage bins or stockpiles.
4.4 Maintenance Area(s)
Controlling contamination of stormwater is critical. Stormwater quickly picks up pollutants from improperly stored materials or spills.
Train employees to cover toxic materials, channel stormwater, and perform preventative maintenance to reduce pollutant-laden stormwater.
A Spill Prevention Control & Countermeasures (SPCC) Plan must be in place to implement spill prevention and response. Ongoing inspection assures that site management is having the desired effect.
Locate fuel/oil storage/handling facilities away from the main sediment and wash-water retention facility.
Equip all such facilities with approved containment, monitoring, and collection systems.
Store fuel above ground.
Route runoff from adjacent surfaces to a retention pond that can be cleaned after a spill.
4.5 Petroleum Product Storage and Handling Area
1. Regulatory Requirements
Operators must comply with all local, state, and federal requirements for petroleum storage tanks.
TCEQ requires registration of petroleum storage tanks.
EPA requires a written Spill Prevention, Control, and Countermeasure Plan for any facility that stores more than 1,320 gallons in containers 55 gallons or greater.
Many BMPs address proper storage, handling, and transfer of petroleum products. Some of the more important BMPs include:
- Signs must be posted instructing drivers to remain with their vehicles at all times to prevent overfill spillage.
- Fuel delivery drivers must be chock wheels or lock brakes prior to offloading fuel, and ensure all hoses are disconnected prior to departure.
- All fuel transfer areas must have secondary containment large enough to handle the largest single compartment of any tank truck in the facility. Alternatively, discharged material must be directed to a containment pond through the use of berms and swales.
- Use drip pans or buckets at disconnection points of hoses and/or piping to collect drippage of oil.
- Inspect all storage tanks once per month for signs of fatigue or failure that could lead to the spillage. Document these inspections. Promptly repair any leaking, corroded, or deteriorated tanks that could discharge oil.
- Examine all pollution prevention equipment once per month to ensure it is in good operating condition. Fill out and keep onsite the monthly report.
- Build secondary containment structures around all bulk oil and lubricant storage tanks. They must have sufficient capacity to contain any spills caused by rupture of the tank.
- All secondary containment structures must have 110 percent of the capacity of the largest storage tank and must be constructed of material impervious to tank contents.
- Containment structures must have manually operated gate valves to drain rainwater. Alternatively, keep a portable pump available to drain the containment area. All manually operated valves must be locked closed when not in use.
- Inspect accumulated rainwater prior to discharge to ensure that there is no petroleum sheen on it. Water with a sheen must never be discharged. It may be pumped for disposal, allowed to evaporate, or removed by some other appropriate method. TCEQ requires documentation the visual inspection.
Oil Discharge Response and Cleanup
When an oil discharge happens within the plant area, all manpower and equipment available must be utilized to prevent the discharge from reaching a navigable waterway. Stop the discharge. Control its impact to the environment.
Procedure after a discharge:
- The first person to notice the discharge must immediately notify the plant superintendent; the superintendent, in turn, must simultaneously implement best management practices to capture the discharge.
- Depending on the volume of the spill, the operator is required to notify TCEQ immediately, or at least within 24 hours. Operators must refer to 30 TAC Chapter 327 for complete rules and regulations regarding spills.
- If possible, prevent further leakage by plug sources and/or closing valves.
- A front-end loader must be immediately available to build a berm or dike with dry sand to absorb the discharge if the secondary containment should fail.
- In the event of a discharge on the concrete in the shop or other hard surface, the following procedure must be used:
- Absorbents must be used to keep the discharge from leaving the hard surface.
- Identify the source of the discharge and fix the leak by whatever means necessary.
- Place used absorbent in a drum (labeled with USED ABSORBENT, NON-HAZARDOUS). The drum must have a lid, which is kept on at all times when not in use. The drum must have the first date the used absorbent was placed in the drum. Keep drums under a roofed structure to prevent stormwater contamination.
- If any discharged material has left the impervious surface, the media contaminated from the discharge must be properly removed and disposed of in accordance with all applicable local, state, and federal environmental regulations.
- If the discharge is too large for plant personnel to contain, employ a contractor.
After the leak is repaired, the discharged product must be recovered from the secondary containment and appropriately managed in accordance with current state and federal regulations. If sand or surface soils are contaminated, dispose of them in accordance with current state and federal regulations.
These BMPs address fuel management more than mining. In my opinion, both sections are good as far as they go. But I would like to see at least some BMPs added based on observations of actual practices.
Operators should not dredge a vertical wall at the edge of buffer zones. This can lead to cave ins at the edges that decrease the width of the buffer zones.
Under fuel management:
Fuel depots and fuel storage tanks must be located outside of the floodway, on the highest ground possible and as far from rivers as possible. Make sure the location meets Atlas-14 requirements.
And two more:
Remove all fuel storage equipment and tanks before abandoning a mine.
Finally, do not store excavation equipment underwater.
To Submit Public Comments
Please submit your thoughts on Mining and other BMPs to the TCEQ. Email Macayla.Coleman@Tceq.Texas.gov with the subject line “BMPs Guidance Document” before August 19, 2021.
Posted by Bob Rehak on 8/15/2021
1447 Days since Hurricane Harvey
The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.