'Copper is found in igneous rock at an average of about 55 ppm, ppm standing for this'
parts per million
COP ROCK: Copper is found in igneous rock at an average of about 55 ppm, ppm standing for this
Copper is found in igneous rock at an average of about 55 ppm, ppm standing for this
Copper is found in igneous rock at an average of about 55 ppm, ppm standing for this
COP ROCK
parts per million
COP ROCK