Cyanide dissolves gold, but not gold sealed inside crystals, so the industry either boils ore in acid with oxygen at about 230 degrees Celsius in an autoclave or burns it in a roaster. The residue is the other half: Nevada's gold industry cut mercury air emissions sharply, a genuine environmental success, while mine pit lakes will fill and concentrate dissolved material permanently.
Who's who
- Glenn MillerUniversity of Nevada, Reno scientist who surveyed byproduct mercury
- E. M. MurrayUSGS author of the 2026 federal mercury inventory report
Where it happens
- Goldstrike, NevadaSite of an autoclave and a roaster
- Gold Quarry, NevadaSite of a roaster and a pit lake
- Rye Patch Reservoir, Nevada+1 more episodeFish consumption advisories still posted
- Cortez, NevadaMill trucking refractory ore to the Carlin roasters
Timeline
- June 2002Gold companies begin a voluntary mercury reduction program with state and federal regulators.
- March 8, 2006Nevada adopts a binding mercury control program.
- 2005Participating companies had cut mercury air emissions by more than 80 percent.
- 2001-2023Nevada mercury stack emissions fall 96 percent, from 12,817 pounds to 501.
- May 14, 2026USGS publishes an inventory of the corridor's existing and future pit lakes.
Still debated
Autoclave and roaster operating figures come from industry bands and trade press, not agency sources. Wet mercury deposition showed no significant trend from 2003 to 2013, since atmospheric mercury is also a global pool.