If you want to work in the oilfield

Caliche for building the pads, or maybe cuttings. But cuttings can also go in end-dumps, roll-off boxes, or vacuum tankers.

Frac sand usually goes in sandboxes or those trailers that look like a modified grain hopper. I don't know what they're called, but they're built specifically for hauling frac sand. A few years ago it mostly traveled in pneumatics.