LMI Materials dike at Moorhead mine. Photo taken 4/21/2020.

Are Sand Mine Dikes Designed to Fail? State Sets No Standards

More than one engineer has told me that sand mine dikes appear as though they are designed to fail. Part of the problem is that the State sets no standards for their construction; the State simply says they must be “effective.” But there are only minor penalties if they prove ineffective.

How Sand Mines Use Water

Mines use water to separate sand from silt by spinning the mixture through a centrifuge. The large sand particles go to a stockpile. The smaller silt particles return to a settling pond. If left long enough, the water clarifies and can safely be released.

Water and silt go one way, sand the other.

The constant inflow of silty water in the settling pond creates a delta that raises the water level.

Constant Battle Against Silt and Water

The problem, however, is the buildup of silt and water over time.

The fine sediment often does not have enough time to drop out of suspension before water in the settling pond begins to overflow. That’s when dikes often break and sediment laden water is released into the river.

Last November, the Texas Commission on Environmental Quality cited the LMI Moorhead mine for the unauthorized discharge of 56 million gallons of white goop into the San Jacinto West Fork. It had 25X more suspended solids than water from upstream.

Sadly, this is not an isolated problem. I have documented breaches in most San Jacinto River mines.

Road Disappears as Dike Gets Higher

Since then, aerial photos show that LMI is building dikes higher to prevent future releases. But as the thin dikes made out of sand/silt get higher, they also get narrower. They seem designed to fail at some point.

Process waste water leaks through them into surrounding wetlands and the West Fork. To keep the dikes from failing, the mine even appears to be pumping water out of its pit into the wetlands.

A large rain could easily overwhelm these dikes and cause another failure. As a starting point, review the satellite photo below from Google Earth. It was taken about a month after a major breach from another part of the mine. Note the perimeter road around the entire pond. It disappears in aerial photos taken a few months later.

Satellite photo from 12/1/2019 shows a drivable road around the entire eastern perimeter (right) of the LMI Moorhead mine.

Now compare that to this series of helicopter photos taken on 4/21/2020. The series starts in the upper right of the satellite photo and heads south (toward the bottom of the satellite image). This area of the mine is far from public view, except from a helicopter..

Note the difference in elevation between the pond in the mine and the pond outside of it.
Note the partially buried pipe between the two ponds. A siphon?
Looking south along the eastern perimeter. you can see how the road now disappears and the wall of the dike gets thinner.
Zooming out, you can see how the far this condition exists and why I ask the question, “Are these dikes designed to fail?”
Tracking south to the next grove of trees, you can see water leaking through the narrow dike as it approaches the top. Comparing the dike to nearby tree trunks, I estimate the dike is no more than 2-3 feet wide.

Where 56 Million Gallons Allegedly Entered River

The same condition exists on another pit at the same mine. The dike shown in the foreground is the one that the TCEQ says failed last year. Note water ponding on the narrow road. See photo below.

Note the difference in the color of the water in the pond and in the river in the photo below. The pond color has not changed during the eight months I have been documenting these sand mining operations from the air.

Same dike, photographed from a different angle, looking north. West Fork is in foreground.
A new Artavia drainage ditch in the background now funnels water from more than 2000 acres straight toward mine. The mine blames Artavia for the November discharge.

No Texas Regulations Govern Dike Construction

Unfortunately, the State of Texas has no regulations that address construction of dikes.

No standards exist for height, width, composition, compaction, or reinforcement.

I asked Ramiro Garcia, head of enforcement for the TCEQ, this question. Does Texas have regulations for sand mines that affect the width, height, slope, compaction, and materials used in perimeter dikes or barriers?

His reply: “The Industrial Stormwater Multi-Sector General Permit requires the use of pollution prevention practices that can effectively protect the water quality in receiving waters, or that are necessary for remaining in compliance with the general permit. The GP states that “the permittee shall evaluate and use appropriate measures and controls to reduce soil erosion and sedimentation in areas of the facility with demonstrated or potential soil erosion and sedimentation” (Part III.A.4(c)). There are no specific requirements for width, height, slope, compaction, or materials for dikes or barriers.

So the permittee gets to determine what’s “appropriate”!

Designed to Fail?

The lack of regulation is how we get strips of sand a couple feet wide holding back hundreds of millions of gallons of waste water. One big rain, a flood, and the wastewater buildup is gone. Conveniently!

If the TCEQ discovers an unauthorized discharge, the mine pays a “slap on the wrist” fine. They average about $800. That’s why I ask, “Are sand mine dikes designed to fail?” It seems cheaper and easier to pay the fine than build earthworks that protect the source of drinking water for 2 million people.

State Rep. Dan Huberty tried to implement effective sand mining regulations during the last legislative session. Unfortunately, most of the mining bills he sponsored died in committee. I’m using the time before the next session to document mining practices on the San Jacinto. Hopefully, we’ll be able to make a better case next year.

Posted by Bob Rehak on 5/4/2020

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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.