Gold Fever Leads to Metal Mining in Garbage Dumps and Sewage Sludge


Photo tao_zhyn @ flickr.

The shaky economy has caused gold prices to shoot up to over $900 per ounce - even though 85 percent of gold mined these days goes to jewelry, and there's no "gold standard" backing currencies, gold is considered a valued commodity in economic downturns. Gold mining is an industry fraught with environmental peril, however - tainting of water resources, and the use of cyanide and mercury to extract gold from crushed ore are two of the worst offenses. Fair Trade groups are trying to get certification for gold from artisanal mining in place this year. In the meantime, the Japanese are industriously embracing urban mining - finding unique ways to turn waste management into gold and other precious metals. Read on.Mining from sludge a golden opportunity
The sewage plant located in the town of Suwa in Nagano Prefecture has begun to process sewage for its relatively high gold content - coming from waste emissions from the precision machine, plating, and electronics facilities that are located in the region. Approximately four pounds of gold can be retrieved from each ton of molten fly ash generated when sludge is incinerated. That is better than the 20 to 40 grams of golden metal retrieved from each ton of ore at Japan's Hishikare mine, according to Reuters. The plant has known for a couple of years about the high gold concentrations but didn't think it economically worthwhile to mine it until the price of gold crept up, and they have now begun to sell the ash to a smelting company, expecting to get about $167,000 in profits for the first quarter of this year. The facility treats 100,000 tons of wastewater daily, generating about 3 tons of ash.

Urban mining another way to say scavenging at the garbage dump
Japan's relatively low density of natural resources makes recycling of precious metals attractive. Urban mining, as it has come to be known, should really just be called proper waste management and recycling! Japanese company Yokohama Metal calculates a ton of cell phones can yield 150 grams of gold, 220 pounds of copper, and 7 pounds of silver. Via: Pink Tentacle and Reuters
Read more about gold
Spinning Garbage Into Gold: An Alternative to Mining?
There's Gold in Them Thar Smelly Hills
No Dirty Gold: Jewelry Retailers Urge End to "Dirty" Mining
and at Planet Green
How to Go Green: Fashion Accessories

Tags: Accessories | Japan | Jewelry | Waste

Best of TreeHugger