Good morning all.
Having used one of these (Thermo Niton) extensively in a mining environment
I can add a few thoughts to those already made. The point regarding the
limited are of examination is most important. In say a hand specimen left
behind by the 'old men', it is quite possible to have an indication of both
a barren and conversely a rich mineral content particularly when examining
for cassiterite. The comment by Geoff regarding the vanning shovel is the
significant point.
The reported 'elmental' composition is just that, an indication of the
elements present not the presence of an ore mineral i.e. tin will be
reported but not whether that tin is present as an oxide, sulphide or
silicate even if it is within, for example, a garnet matrix.
All of these things the portable instrument will not tell you. In short,
there is no substitute for experience.
Best wishes
Bruce
-----Original Message-----
From: Geoff Treseder
Sent: Saturday, August 19, 2017 7:00 AM
To: [log in to unmask]
Subject: Re: XRF and XRD hand held
Hi Phil,
Ian Hodkinson seems to have confirmed what I suspected about these devices.
What I would say however is that a sample should be a sample, there
shouldn't be any prior knowledge of its content to say that it is worth
analysing. The sampling method should be undertaken in a way that gives you
something representative of the material that you wish to know more about.
The pan and the vanning shovel are much better tools for for looking at tin,
they are cheap and give more meaningful results and much more useful
information.
Regards
Geoff
-----Original Message-----
From: Ian Hodkinson
Sent: Saturday, August 19, 2017 2:28 AM
To: [log in to unmask]
Subject: Re: XRF and XRD hand held
I use them regularly at work (mineral exploration). Hand-held XRF
analysers are great at what they do but the effectiveness is limited by
a couple of factors. They have a very small field of view, only a few
square millimetres, which means they work well on a homogenised powdered
sample but wouldn't be good on something like a grainy alluvial
material. You can get round that to some degree by pattern testing but
that increases the time. They are notoriously bad at detecting nuggetty
material like gold and thus presumably cassiterite grains in a rock or
alluvium sample. Experience suggests to me that the Olympus ones are
asomewhat more user friendly than the Thermo Fisher Niton ones.
WIth XRDs I only have experience of using them to identify discrete
mineral species. Once the sample gets beyond a handful of mineral
species the identfication of the contained minerals can get very
complicated although there is software for that these days.
You can certainly rent them in Australia - in the UK though ? Then
there's all the X-ray user licence/possession licence bureaucracy to
wade through.
Hope that helps a bit
Cheers
Ian
On 19/08/2017 1:33 AM, Phil Newman wrote:
> Hi,
>
> Does anyone have any practical experience of XRF and XRD hand-held
> analysers?
> Can they be used to detect all types of ferrous and NF metals and do
> they give instant results on site?
> I'm looking at detecting unprocessed alluvial tin stone and dressing
> waste in a clay context within an area of post-med tinworks. It would be
> easier to have some idea of what we put in the sample bags before
> shipping them off to a lab for full analysis.
>
> Also, is it possible to hire this kit?
>
> Thanks for any help.
>
> Phil
If you need to leave the list, send the following message to
[log in to unmask] -
leave mining-history
---------
If you need to leave the list, send the following message to
[log in to unmask] -
leave mining-history
---------
If you need to leave the list, send the following message to [log in to unmask] -
leave mining-history
---------
|