Triple PG Sand Mine Turns Blue-Green

Aerial photos of the Triple PG sand mine in Porter taken on April 21, 2020, showed several of the ponds turning a bright blue/green (cyan).

Expert Believes Color Not Due to Cyanobacteria

A retired water-quality expert, who used to work for the City of Houston and who wishes to remain anonymous, reviewed the photos. He felt cyanobacteria, similar to the type reported in February on the West Fork San Jacinto, did NOT create the color . “You don’t see the subtle layering common with cyanobacteria,” he said.

Bright blue/green pond in foreground is part of Triple PG’s wastewater pit.

Likely Cause is Chloride Buildup

What is it then? “When you wash sand and gravel,” he said, “you often get very blue water. Most times it is high in chlorides. The chlorides discourage bacterial growth, or for that matter any life. The water is just too salty.”

Sand going to a big “washing machine.” The wastewater is then channeled to…
…a pond where silt settles out of the chloride-laden wastewater. Over time, the chloride concentration builds up and causes water to change color.

“Once a mine’s ponds get super saturated, they are no use to miners. That’s because they can’t wash the sand and gravel clean any more and they have to get rid of the water.”

Water-quality expert

“If it’s not chloride free,” he continued, “they can’t sell the sand because the chlorides will attack steel, such as rebar and girders, used to reinforce concrete. They also have to wash the sand used for pipeline bedding. If it’s not chloride free, the chlorides will attack the steel in the pipe over time.”

A construction manager for a major Houston refinery confirmed that chloride pitting and chloride cracking are indeed major concerns for pipelines. Not even stainless steels are immune.

Another part of the main wastewater pond at Triple PG mine

Saltwater Once Covered Entire Area

Where did the chlorides come from? The water-quality expert said, “This was a marine environment at one time, covered by saltwater. Over time, evaporation concentrated the chlorides and they were trapped by a confining layer…probably clay. Now that they are mining and washing material, the chlorides are the only thing left,” he continued.

“We used to see mines create dikes that were designed to fail in the event of a flood or heavy rain. If the chloride concentration got too high before a rain event, they would simply pump the salty water over the dike at night. Then they would replace it with fresh water and start the washing process over again. Dilution is the solution to pollution.”

Rapidly Changing Color Could Reveal Unauthorized Discharge

“If you continue to monitor this mine and the color disappears overnight, it’s a problem,” said the water-quality expert. That’s what I used to see often. The pond would become saturated and no longer usable. Then they would flush it out and it was usable again.”

The Triple PG mine currently operates under a temporary injunction and heightened scrutiny.

Triple PG Plagued by Legal Troubles

The State Attorney General is suing the Triple PG mine for unauthorized discharges of process water and dikes that remained open for months.

The mine sits near the confluence of White Oak and Caney Creeks. A TCEQ investigation found that two breaches in the mine’s dikes – one facing each creek – allowed the water from one creek to wash through the pit and into the other creek.

A Travis County judge set the trial date for June 22, 2020.

Flimsy Fixes to Other Dikes Remain

While the mine waits for trial, it has sealed those two breaches. But other prior breaches sport flimsy fixes that could wash out in the next large rain and discharge this water into the surrounding creeks. The mine has also been photographed pumping wastewater onto neighboring properties.

On 12/3/2019, I photographed the mine discharging waste water from what is now the blue pond onto neighboring properties.
Site of repeated breach into Caney Creek from Triple PG mine (background), photographed on March 3, 2020.
Site of another repeated breach into Caney Creek (left) from Triple PG mine, also photographed on March 3, 2020.

Potential Trouble Regardless of Cause of Color Change

Whether the color is due to high chloride content or cyanobacteria, it still poses a threat to drinking water. Chlorides would still need to be filtered out of drinking water pulled from Lake Houston. Cyanobacteria are worse. They often create toxins.

A World Health Organization (WHO) book called “Toxic Cyanobacteria in Water: A guide to their public health consequences, monitoring and management” claims WHO has found no documented cases of human deaths due to cyanotoxins. However, there have found many documented cases of animal poisonings. The most likely result of human exposure: dermatitis, “swimmer’s itch,” and severe oral and gastrointestinal inflammation. They also say cyanotoxins promote tumors in mice.

The Triple PG mine underscores the danger of allowing sand mines to operate in floodways and flush their wastewater downstream into the drinking water of 2 million people.

I will continue to monitor the color of the water to see if it changes rapidly.

Posted by Bob Rehak on 5/9/2020

984 Days since Hurricane Harvey and 233 since Imelda

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.