Riffles: Why They're Made & Benefits of Incremental Lengths

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In summary: The riffles are designed to catch the heavier particles, while allowing the lighter ones to pass over them. This results in the separation of different weights of tailings, with the heavier copper particles being collected and the lighter non-copper particles being discarded. This is the advantage of making the riffles in this particular way. Additionally, the constant shaking of the table helps to further separate the particles based on weight.
  • #1
gracy
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why these riffles are made ?and These riffles increased in length incrementally from the top of the table down to the bottom.why these are made in this way? what's the advantage of making in this particular way?why this table constantly shakes?
table-post-2.jpg
 
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  • #3
jedishrfu said:
Here's an article on the table

http://www.coppercountryexplorer.com/2007/09/mill-machines-the-wilfley-table/

I think the riffles are there to separate out different weights of tailings as the lighter weight stuff would move more with the shaking than the heavier stuff.
I am still confused (even after reading the link you gave )can you please clear all my questions/doubts given in my first post.
 
  • #4
This quote from the article sums up its operation:
The Wilfley Table is simply a large wooden table, on top of which are a series of parallel “riffles”. These riffles increased in length incrementally from the top of the table down to the bottom. The entire table is set at an angle, and the slime is poured onto it from the top corner. The heavier particles (copper) would be held up along the riffles, while the lighter particles (the non-copper) would roll over them. The whole table is oscillated back and forth over 200 times a minute, which works the copper particles down the riffles and towards the opposite end of the table. From there they are removed. The rest of the slime simply floors off the table at the opposite end and is carried away in a waste launder.
 
  • #5
jedishrfu said:
This quote from the article sums up its operation:
I didn't understand the following point:
The heavier particles (copper) would be held up along the riffles, while the lighter particles (the non-copper) would roll over them.can you please explain .
 
  • #6
Simple physics, lighter particles bounce higher and travel further.
 

Related to Riffles: Why They're Made & Benefits of Incremental Lengths

1. What are riffles and why are they made?

Riffles are shallow sections of a stream or riverbed that are characterized by a series of small, shallow ridges or bars. They are made by natural processes such as erosion and sediment deposition, or by human activities such as dredging. Riffles serve important ecological and hydrological functions, including improving water quality, providing habitat for aquatic life, and preventing erosion.

2. How do riffles benefit the length of a stream or river?

Riffles can help to improve the overall quality and health of a stream or river by creating a diverse range of habitats for aquatic plants and animals. They also help to maintain a stable channel shape and prevent excessive erosion along the stream or riverbank. Riffles also play a crucial role in the transport of sediment and nutrients downstream, contributing to the overall health of the ecosystem.

3. What factors influence the length of riffles?

The length of riffles can vary depending on several factors, including the type and size of sediment present in the stream or river, the gradient of the channel, and the flow velocity of the water. Human activities such as construction or dredging can also impact the length of riffles.

4. Are there any negative effects of altering the length of riffles?

Yes, altering the length of riffles can have negative impacts on the overall health of the stream or river. Removing or altering riffles can disrupt the natural flow of water and sediment, leading to erosion and loss of habitat for aquatic life. It can also impact the water quality and the overall stability of the ecosystem.

5. How can we use riffles to improve stream or river health?

Riffles can be used as a natural and cost-effective way to improve the health of streams and rivers. By creating or restoring riffle habitats, we can improve water quality, enhance aquatic biodiversity, and prevent erosion. Additionally, proper management and maintenance of riffles can help to maintain a healthy and sustainable ecosystem for both humans and wildlife.

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