South Texas Ballast

Does anyone have a source for an ho/s ballast marketed under the label So. Texas Ballast? The logo is printed on a flag with a single star.

I bought a few bags at a train show and found its pretty good stuff. Try as I might - I can’t find a source.

Any sources/ideas?

Thanks

Dibble’s Hobbies in San Antonio, TX was selling some bags of it at their store when I was there a couple weeks ago. They might be a good place to start.