Not exactly just exploiting minorities. My grandpa died because he mined Uranium post-war, but he was white and afaik so was everyone he worked with.
They didn't say "just" or "only" minorities. However, most of the mines were located on or near, Navajo land and over 4 million tons of ore came for that land. The workers were disproportionately Navajo and the land is now poisoned with radioactive waste from the mining, with cancer rates doubling from the 1970s to the 1990s. Land the Navajo were forced onto. Recognizing the damage this has done to an already persecuted minority population does not negate damage done to individuals of other races or ethnicities.
https://www.npr.org/sections/health-shots/2016/04/10/4735472...