Residual, Elovial &
Bajada Placers

Residual placers
Residual placers take place when the gold is free from its initial place and the material that covers it breaks down. This comes about when there is repeated surface weathering. Breakdown takes place when there are steady and strong geologic conditions that cause the mechanical break down of the rock and the chemical decay of the minerals. The top of the ore that bears gold is increased while the rock falls apart, due to the fact that some of the softer and more soluble parts of the rocks get taken and carried away as a result of wearing away.

Elovial deposits
After the gold becomes freed from the bedrock encasement and rock decay as a result of the weather, it begins to journey down the hillside and from time to time washed down to the rivulets and gullies and afterwards into the stream beds. Even as it is travelling down the gold every so often concentrates itself in an amount that merits mining. These types of deposits are what are known as elovial deposits.

Bajada placers
Bajadas consist of a confluent alluvial fan that is located on the base of a mountain range. The quantity of gold that is formed from bajada placers is not much in comparison to other placer workings because of the lack of efficient dry washing methods utilized in the past. The structure of a bajada placer is pretty much the same as a stream placer except that it is conditioned by the climate and topography of the dry region it occurs in. The amount of the gold that has been released from its environment as it works down from the lode outcrop to the bajada is then placed on the slope close to the mountain range. The gold falls down the line, which is the contact of the mid fill with the bedrock. Even though the greatest amount of concentration of gold will be on the bedrock, bulk concentration does not take place the way it does in a stream deposit. Because of the fact that some amount of the gold is still imbedded in its matrix, it is probable that a smaller amount of gold will get to the bedrock and more of it may be spread all the way through the deposit than in the case of the stream gravels.

Beach placers
A lot of beach placers have been found alongside the Pacific Coast and a lot of them have been worked on. Beach placers also take place because of shore currents and the action of the waves on the materials that are then broken down from the sea cliffs and washed into the sea by the streams. There are a couple types of beach placers; these include ancient beaches and the current ones. A great amount of the beaches that have gold can be found in California but they have not produced a great deal of gold. For the most part the gold comes about from the rocks that are being worn out by the waves.