Tag Archives: gold mining

A Short History Of Gold Mining

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Since the second century many people have been gold mining in one way or another. Some experts believe that mining was started in India. It is almost impossible to prove were it all began though. As the years have gone by various different methods have been used to varying degrees of success.

During the gold rush in California which happened between eighteen forty eight and eighteen fifty five many new methods were discovered and quickly caught on with the rest of the world.

Before all the different methods were introduced, many people used a method called panning. This included the use of a large, wide and shallow pan which would be filled with the materials from the sea bed. When the pan was submerged in water and shaken the golden metal would sink to the bottom. Of course this method is not very useful for getting large amounts of the metal.

An advance on the panning method is known as dredging. Dredging adopts the use of a small machine with a hose attached to it. One person operates the machine and another guides the hose which picks up materials from the sea bed into a sluice box which can then separate the metal. This technique is not very widely used anymore as better techniques have taken over.

In years gone by the majority of people would look for gold by wading through riverbeds and using different techniques such as those already mentioned. This is mainly done by people as a hobby now because most of the worlds gold now comes from beneath the earth. To get to it large corporations spend a lot of money on technology and experts to help locate the areas to be mined.

These companies employ the use of geologist to help find the ideal areas for digging. They then expertly drill many hundreds of meters below the earths surface through hard rock. Gold mining through this hard rock produces the majority of our worlds supply of the precious metal.

As well as having a huge financial value, this unique metal has a wide variety of uses. During the medieval times they thought the metal was so beautiful that it must have healing properties, so they used it as medicine to help cure a number of different illnesses. Dentists today use it for fillings in our teeth and it can even be found in some of the foods and beverages that we consume.

It is a very common material used in the making of jewelry and in some Asian countries it has huge significance in their religious ceremonies. As well as all that, this remarkable metal is vital to the production of some electrical devices. Because of its very high electrical conductivity it is used in things such as computers and televisions.

The worlds supply of the most amazing metal seems to be endless but it has become less easy to find. New inventive ways of finding it will no doubt always be developed as technology advances. Mining is big business these days and the gold is more valuable than ever before.

Placer Mining: Three Methods Used To Mine Placer Gold

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The word placer, as will be found throughout here, is derived from the same Spanish word which means “sandbank”. It specifically refers to an alluvial deposit of detrital material, such as gravel, which contains particles of precious chemical elements.

The term “placer gold”, therefore, refers to gold that has formed in rocks moved and placed on stream beds by some geological forces and by the action of water. Lode gold tends to erode from its source, distributing itself naturally among other rocks that have been subjected to similar geological forces. This results to the formation of a secondary deposit.

Thus the mining of alluvial deposits for gold and other precious metal deposits is called “placer mining”. Placer mining may be done through a number of tunneling procedures into riverbeds. There also are the open-cast mining and hydraulic mining. In the former, placer mining is done by open-pit; in the latter, water pressure is used for excavation.

There are three placer mining methods used to mine placer gold:

Gold Panning:

This method, which involves the use of a pan, is the oldest and simplest way to extract gold from a placer deposit. In this method, mined ore is placed in a large pan (made either of plastic or metal) and poured with a liberal amount of water; it is then agitated. The gold particles, having higher density than the other materials (examples, mud, sand and gravel; also, gold is about nineteen times heavier than water), settle to the bottom of the pan, while the lighter materials are washed over the side.

Sluice Box:

This method uses the same principle as that in gold panning, only on a larger scale. In this method, a short sluice box is used. The box is constructed with barriers along its bottom, so that the gold particles are trapped as all materials are washed by water. The sluice box method is best suited for excavation in which certain implements, such as shovels, are used to feed ore into the box.

Trommel:

This method involves the use of a screened cylinder to separate materials by size (trommel is Dutch word for “drum”). A trommel specifically consists of a rotating metal tube that is slightly tilted, with a screen at the discharge end. Attached to the inside part of the metal tube are lifter bars. Ore is fed into the trommel through its elevated end. Pressurized water is supplied to the tube and the screen sections. Valuable minerals from the ore are separated by the combination of water and mechanical action. The small pieces of ore bearing the valuable minerals pass through the screen and are concentrated further in sluices. The larger ones (those that do not pass through the screen) are moved to a waste stack using a conveyor.

Today, placer mining goes on in many parts of the world as a source of gems and industrial metals and minerals. This is true in countries like Sri Lanka and Myanmar. Placer mining for placer gold continues in British Columbia, the Yukon, and especially in Alaska.