Progress on Pipeline Repairs at Sand Mines

In the last month, workers made progress on pipeline bed repairs to two area sand mines. But repairs at one sand mine look substantial. At another, they look superficial. Triple PG in Porter is still edging into the danger zone.

Exposed by Erosion When Mining Came Too Close

In December and January, I posted about pipelines exposed when sand miners mined too close to them. Floodwaters then swept through the mines and undercut the pipelines, creating safety hazards.

Pipelines exposed by erosion at Liberty Materials Mine in Conroe. Photo taken January 20, 2020.

Several HVL (highly volatile liquid) pipelines (above) and one natural gas pipeline (below) were affected at mines in Conroe and Porter.

Exposed natural gas pipeline at Triple PG mine near Caney Creek in Porter. Photo taken December 3, 2019.

Here’s where things stand on repairs at both mines as of last week..

Triple PG Mine in Porter: Another Big Cover Up

The Triple PG Mine in Porter has covered up the exposed natural gas pipeline with sand. As of 2/13/2020, Triple PG had made no other visible attempts to stabilize the area, which is subject to repeated erosion. Harvey first exposed the pipeline, which Triple PG subsequently covered. Then Imelda re-exposed it. And Triple PG re-covered it.

Fresh sand covers exposed natural gas pipeline. Will it be washed away a third time in the next big storm?

Readers may remember that after Harvey, Kinder Morgan tunneled 75 feet under the mine and spliced in a replacement for the section that had been exposed. They then filled the cutoff section with inert gas. So the exposed section was not active.

Still, without further stabilization, the pipeline will likely be exposed again and again by future storms.

Triple PG still has made no attempt to stabilize erosion creeping toward the HVL pipelines that cross the mine in a utility corridor. The same erosion that exposed the natural gas pipeline will threaten those in future storms.

Five pipelines carry highly volatile liquids through this utility corridor. Triple PG mines sand from either side of them. During floods, Caney Creek runs through this mine creating the erosion you see here.

Liberty Materials Mine in Conroe: Fix Nearing Completion

At a Liberty Materials Mine in Conroe, a much more substantial fix is underway by the pipelines. The mine spanned both sides of the utility corridor. Water from one side, trying to get to the river on the other, washed under several HVL pipelines, exposing them.

Repairs began in January and were well under way in February. Crews first expanded the washed out area under the pipelines. Then they placed two giant culverts under the pipelines to allow water to move from one side to the other. They also cemented the culverts in place and drove vertical steel reinforcements in the ground to prevent re-exposure of the pipelines.

Two giant culverts will now carry water under the pipelines. Shown above: the outfall.
Steel reinforcements rise above the level of the pipelines to help retard erosion. Photo taken 2/13/2020.
Rip rap and other reinforcements will also help retard erosion.
Inlets for the culverts. Photo taken 2/13/2020.
Looking west toward The Woodlands. San Jacinto West Fork is at far end of sand mine. Note all the sand and sediment that has washed under this area to the far side of the steel reinforcements.

As of 2/13/2020, crews were filling dirt in under, around and over the pipelines.

The repairs here appear much more substantial than in the Triple PG mine. I just hope the volume of sand washing from one section of the mine to the other does not clog the culverts. The steel reinforcements will protect the pipelines in this location, but water has a habit of flowing around obstacles.

Posted by Bob Rehak on 2/23/2020

908 Days after Hurricane Harvey 157 since Imelda