The miners then drill a series of precision holes into the rock face, pack in explosives, clear everyone out, and blast. After checking for gas leaks, workers reinforce the walls and ceiling to prevent cave-ins and then hoist the ore out of the mine through the vertical shafts. Gold, a pure element identified with the chemical symbol Au, exists in nature. Tiny gold particles are encased in tons of rock, so the ore first goes to a mill where it is crushed very fine. The larger particles separate from the ground rock on a vibrating table that works on the same principle as panning, in which substances of different densities separate from each other.
Some bacteria chew up the cyanide in wastewater.
Others chemically alter stubborn rocks so that the cyanide treatment can be more effective. This is called bioleaching. Mining can have significant environmental effects, particularly in developing countries without strict environmental monitoring. For example, cyanide and acid wastes from mines contaminate streams. We use gold not only for jewelry, money, and high-tech products but also as a part of our language.