Gold removed from west Texas mine shafts has been almost exclusively in combination with other ores, making it impractical for a casual prospector to harvest. Millions of tons of copper ore were mined in west Texas in the 1800s and early 1900s, and some of this contained very small amounts of silver and gold. The Hazel Mine was one of the top copper and silver mines in Texas during the 1880s. This mine is located north of Van Horn on Highway 54, and west of the roadway. It is sealed to prevent entry. Entering an old Texas mine in the hopes of finding any significant gold today is very likely a waste of time anyway, but the area around it might be an interesting place to look. Searching downslope where old ores may have washed away from the mine entrance or machinery area is best.
Texas gold is more likely to be found in streambeds. This is called placer gold as opposed to the type dug out of big veins, which is called "lode" gold. Placer gold flakes off exposed ground formations and falls into small creeks and dry washes. Since gold is heavy, it accumulates along rifts in the creek bed or at bends in the waterway. The gold is removed by carefully sifting through the gravelly streambed material in a water-filled pan. The gold settles to the bottom--when you do this properly, you can separate gold flakes if any are present.
A prospector wishing to search in the Van Horn area should get permission from landowners before exploring, as most land is privately owned. Creek beds located downstream from higher elevations are best. Wild Horse Creek runs just east of Van Horn; head upstream (southward) and you may find some places worth exploring. Travel east on I-10 a few miles to Plateau, Texas, and you will find several dry washes south of the Interstate that come down from the mountains. These present more exploration spots.
Trace amounts of gold exist today in the mountains around Van Horn, so it's possible to stumble upon some. It's likely to be more of a fun adventure than a "get rich" scheme. However, at today's gold prices, even a few tenths of an ounce will make for some nice pocket money.