how gold is produced
Spinning Gold: From Ore to Bullion
Since the California Gold Rush over 150 years ago, the prospect of finding
gold has driven men to great lengths. For the hardscrabble 49ers, the search
for gold meant wading in riverbeds to sift gold from the rushing water.
Today, gold is mined from the earth, since most of the surface gold - known
as alluvial gold - has been found. The gold-mining process is intricate and
multi-faceted, tying cutting-edge technologies with old-fashioned
Finding Gold: Eureka!
While gold exploration used to be a matter mostly of "boot and hammer"
prospecting, gold mining today is largely a matter of technology. First,
geologists use geology maps to look for favourable areas to explore. Ore
deposits are not easy to find and many of the ones exposed on surface have
already been found. Geologists use the physical and chemical characteristics
of the rocks they are looking for to zero in on prospective areas. Once
favourable geology is established, remote sensing, airborne and ground
geophysics and geochemistry are used to outline targets for drill testing.
Explorer IV Surface Gold Mining Plant
Drilling and Engineering: Taking stock
Drilling at these sites brings up rock samples from various locations. These
samples are analyzed to determine if any gold exists there, the size of the
deposit, and the quality of the gold. Using this information, mining
engineers determine if enough gold is under the surface to make the mining
worthwhile; the type of mine needed; the physical obstacles to getting to the
gold; and what impact a mine would have on the area's wildlife and
environment. If the gold is close to the surface, the engineers will design
an open-pit mine; if the gold is buried deeply, an underground mine will be
planned. Many gold mines in North America are open-pit mines, while those in
South Africa are underground.
Building a Mine: Be prepared
Before the gold can be mined, an infrastructure must be created. Even if the
gold is close to the surface, the simplest open-pit mine can take up to a
year to build. In fact, the time between discovering gold and actually
bringing it out of the earth can be up to five years. Since mines are often
in remote locations, an entire infrastructure-roads, administrative offices,
equipment storage areas, even towns, schools and medical facilities --must be
built. The plans for the mines must be given the green light by a number of
authorities at the local, provincial and national levels. Also, the mining
company must put aside money for reclaiming the land once the gold is mined.
In all, the preparation process can end up costing hundreds of millions of
dollars - before a single ounce of gold is mined.
How Gold Is Used
Mining and Processing of Gold