The standard low-tech approach for gold mining: 1) mix crushed ore with mercury; 2) let sit for a while; 3) boil off mercury over a fire; 4) sell gold. Maybe you try to condense some of the mercury. But mercury is cheap compared to gold, so why bother?<p>Also, we burn lots of coal. And coal contains mercury.<p>Anyway see this cool EPA page: <a href="http:&#x2F;&#x2F;www2.epa.gov&#x2F;international-cooperation&#x2F;mercury-emissions-global-context" rel="nofollow">http:&#x2F;&#x2F;www2.epa.gov&#x2F;international-cooperation&#x2F;mercury-emissi...</a>