A Little Information About Gold
Where Do You Find Gold?
Gold is found in many locations around the world, from sea water to
solid rock. It can be found in specks smaller than a pin head, or in nuggets larger than a
softball. In most places, it's right under your feet!
Most commercial mining operations are called "hard rock" mines. This means that
shafts, or tunnels are carved out of solid rock and the gold found there is so tiny, that
the miners have to use chemicals to remove the gold.
The type of mining that most people do is called recreational mining, or
"placer" mining. This means that the gold is recovered from current, or old
river beds. Miners doing this type of mining use pans, sluices, or dredges to remove the
sand and gravel from the bottom of the river and seperate out the gold.
Where is the gold in the river?
When you find gold in a river, you will find it near the bed rock in pockets. Gold being 19 times heaver than water, sinks into these pockets and waits to be found.
Gold Mining
As gold mining developed, more elaborate methods were introduced and hydraulic mining was invented. The hydraulic method consists of directing a powerful stream of water against the gold-bearing gravel or sand. This operation breaks down the material and washes it away through specially constructed sluices in which the gold settles, while the lighter gravel is floated off. For mining on rivers, elevator dredges are generally used. The elevator dredge is a flat-bottomed boat that uses an endless chain of small buckets to scoop up the material from the river bottom and empty it on the dredge into a trommel (a container built of screening). The material is rotated in the trommel as water is played on it. The gold-bearing sand sinks through perforations in the trommel and drops onto shaking tables, on which it is further concentrated. Dredging can also be used in dry beds of ancient rivers if ample water is within a reasonable distance. A pit is dug, and the dredge is moved in and floated on water pumped from the adjacent source.
Extensive underground deposits of gold-bearing rocks are often discovered by a small outcrop on the surface. Shafts are sunk, as in coal mining, and the ore is brought to the surface. It is then crushed in special machines.
Gold is extracted from gravel or from crushed rock by dissolving it either in mercury (the amalgam process) or in cyanide solutions (the cyanide process). Some ores, especially those in which the gold is chemically combined with tellurium, must be roasted before extraction. The gold is recovered from the solution and melted into ingots. Gold-bearing rock with as little as 1 part of gold to 300,000 parts of worthless material can be worked at a profit.
The rarest form of gold is a nugget. The largest known nugget, the Welcome Stranger, weighing about 70.8 kg (about 156 lb), was turned up accidentally, just below the surface of the ground, by a wagon wheel in Victoria, Australia, in 1869.The western gold fields extend in the Cordilleran region from Alaska to Mexico. Gold was discovered first in this region in California on January 24, 1848, during excavation for a sawmill on land settled by the American pioneer John Sutter. During the next five years gold valued at more than $285 million, an amount 21 times greater than the value of the total previous production of the entire country, was produced in California. The gold rush took place at this time, when people from all parts of the world rushed to the new gold district. The discovery furnished the incentive for the exploration and development of the whole far-western section of the United States. The Comstock Lode, a famous discovery made in 1859, is situated on an eastern spur of the Sierras, extending into Nevada. Placers and veins similar to those of the Sierras are found also in Oregon and Washington.
