Mini Gold concentrator - Creswell Engineering

[jeffu]

Hi People.
Has anyone used the mini gold concentrator made by Cresswell Engineering?
Is it a worthwhile piece of equipment to have in my prospecting arsenal?
Good Prospecting everyone.
Jeff

[gidayray]

Hi Jeff,

I've used one of the concentrators and find it quite useful. It can process a fair bit of dirt once you get used to it. I take it with me every trip although I don't always use it.

Pros
Using a large tub you can keep reusing the same water.
Definitely quicker than a normal pan, at least for me.

Cons
You process a lot of dirt before you see the colour. It makes tracing the colour just that little bit harder. A pan at a time helps show the leads. Once you've found the colour though.....

You might also want to consider a turbo pan. This gets through a lot of dirt as well. I always take both nowadays.

Ray

[pol]

I was speaking to a boiler maker I work with about these the other day and he tells me that he used to work for Cresswell and made these, I am in the process of making something similar to this to try out.
I don't have access to presses etc so will be made from large steel pipe, screen from an airfilter (earthmoving) and a couple of old plough discs.

[hitchhiking]

When in the an area where it is suited to I love to use it and mine has been very sucessful. Great bit of kit!

[onegrm]

Hi Jeff, just came across your query and thought it worthwhile to offer a few belated comments.........

I got myself a Cresswell concentrator, sometimes known as a "Rotapan", about 5 years ago and have used it frequently ever since when the situation was suitable, it is much faster than using a pan alone. In practice, for me, the system that works best is something like the following -
(1) do test pans until an area is found where bulk processing of gravels seems worthwhile
(2) set up the Rotapan
(3) process about 5-7 shovels taken from just one specific area in the "patch" through the Rotapan, pan down the resulting concentrate and make a mental note of how much gold this sample has yielded up
(4) process another 5-7 shovels from a different part of the same patch and compare with what was found with the first batch of 5-7 shovels.
Doing it this way, you soon get an impression of which direction is best followed.

I usually find that the bucket fills up with discarded debris after 17-22 shovels depending on the amount of silt/sand in the paydirt

It is usually helpful to have a reasonable amount of extra water available over and above what is needed to fill the 20L bucket. Rotating the sieve unavoidably causes some spillage of water which needs to be replaced periodically since the Rotapan works best when the sieve part is fairly full of water

With a little practice the device is very easy to use efficiently, if uncertain, pan down some of the discarded material. If significant gold is being lost, review your technique!

It is not particularly good with clay but still better than in a pan

Despite claims to the contrary, it is not practicable to use only 20L or so of water for the day. In practice the recycled water gets so thick and mucky with fine silt and suspended clay that you will need to refresh it periodically.

cheers,

onegrm