This area down out of Uvalde, Texas is unique in that there is mining of asphalt, ready to pave a road as it is dug from the ground. Limestone gravel coated with an asphaltic bitumen content similar to that produced in operating asphalt plants.

Many roads in south Texas have been paved with this product. I’m not certain that it meets TxDot specifications to pave state highways without farther processing, but it looks and acts like a hot mix/cold lay material produced in just about any asphalt plant and used mostly on private roads and temporary patches.

On a personal note, in the mid 1970’s we had a contract to replace water and wastewater lines all around Crystal City, Texas and used this product to repair all the city streets we disrupted.

The first 2 links below give more detail about this mining operation.

https://tshaonline.org/handbook/online/articles/gpu01

https://tshaonline.org/handbook/online/articles/hnd01

The 3rd link is one I put on the Texas Railroad History Group about a railroad built to service the mines.

https://en.m.wikipedia.org/wiki/Wikipedia:WikiProject_Trains/ICC_valuations/Asphalt_Belt_Railway