...[Much] of the gold left to be mined...is being wrung from the earth at enormous environmental cost, often in some of the poorest corners of the world... "The biggest challenge we face is the absence of a set of clearly defined, broadly accepted standards for environmentally and socially responsible mining," said Tiffany's chairman, Michael Kowalski... This month a Philippine province sued...Placer Dome, charging that it had ruined a river, bay and coral reef by dumping...waste... Placer Dome...answered by saying that it had "contained the problem" and already spent $70 million in remediation and another $1.5 million in compensation... [The] largest sellers of gold are not luxury outlets like [Tiffany], but rather Wal-Mart stores... [Masses] of disturbed rock...are...the source of mining's multibillion-dollar environmental time bomb. Sulfides in that rock will react with oxygen, making sulfuric acid. That acid pollutes and it also frees heavy metals like cadmium, lead and mercury, which are harmful to people and fish even at low concentrations. The chain reaction can go on for centuries... [A] new mine built by Glamis Gold [in Guatemala]...was chosen by the World Bank last year as a new model for how gold mining could help poor people. But the mine has faced protest at every turn... Six [illegal] miners have died in the last several years [near an AngloGold Ashanti mine in Ghana], most of them overcome by fumes when waste from the mine gushed into the pit, said Hannah Owusu-Koranteng, an advocate for the illegal miners. The mine tried to keep the men out. [also refers to BHP Billiton, Pegasus Gold, Newmont]