Old idea. I worked for Magma Copper for many Years. My Dad worked there for 40+ Years. About 70% of the employers were Mexican American and many were trucked in from Nacozari de García, Sonora, Mexico and the nearby mine at Pilares during WWII. Others including a relative of mine walked across the line at Naco years earlier. Why? The mine was dangerous and very hot (rock temp up to 145 degrees and working faces had to be cooled (Mine had first underground refrigeration system).
These people and their descendants are very good people and good Americans, most serving in the military. It is a shame the mine was closed but it may be reopening as there is a huge but hard to get at ore body. It is worth noting that the reason the mine was closed in the first place was its purchase by BHP who could make higher profits at its Southeast Asian mines.