Note the strange geology of the region: basalt on sedimentary rock. Unlike the Red Rock Canyon area to the left, the El Paso Mountains sedimentary rock is in layers of fine clay, rounded rocks, more clay, etc. in what appears to be the result of a series of flash floods. Which brought the most gold is anyone's guess, but the old timers tended to favor a yellow clay layer. Still, they had to process the entire layer. There is no bedrock or other geology that could concentrate the gold.
A larger panorama further west on this road exposes more of the strange geology. The sign shows says "To Hwy 14 -->"