[meteorite-list] "not the best place to hunt meteorites"

From: Lasse Lindh <3l_at_meteoritecentral.com>
Date: Thu, 21 Feb 2008 21:45:19 +0100
Message-ID: <47BDE2DF.6070906_at_comhem.se>

Hi Michael and all

We have had quite a lot of discussion about neodymium magnets for
hunting on Skyrock Cafe. Some of the members there have used that method
for some time. It does work quite well. In have a neo on a monopod stick
with 40 kg pull force. But I was not satisfied with this solution
because the chance to miss that little chondrite or iron is too big when
using just one small magnet, so I desided to make a rake like you have
done. This rake is bit larger and have wheels for easier pull and to
keep the magnets off ground so they won't wear down too much or the duck
tape that protects them.

This is a 3D drawing of my Neo Meteorite catcher... ;o) It's slightly
modified the wheeled rake by using five 4 inch neo magnets with 140 lbs
pull force. That allows me to cover just over 2 feet search area at the
same time.

http://www.swedbird.com/meteorite/met_mag.jpg

Regards

Lasse


Michael Murray skrev:
> Hi List,
>
> (This is somewhat of a rehash of information I have posted before)
>
> If the meteorite hunting bug has landed on your shoulder but you think
> the area you live in is not the best for finding meteorites, you
> should give my hunting method a try. You could be pleasantly
> surprised at what you come up with. I went to a local hardware store
> a few years back and purchased a shop magnet cane. It has a wooden
> handle about 40 inches long with a ring magnet on the bottom that is
> sandwiched in between two plates of steel. I also purchased a couple
> 2" x 2" x 7mm neodymium iron boron sugermagnets which I placed very
> carefully side by side on the trailing edge of the bottom steel
> plate. Please note: If you attempt this beware, strong magnets like
> that can injure your fingers quite easily. Use plenty of caution. I
> put the cane in a vise so it could not move before attempting to place
> the first magnet on. The second magnet was a bit harder to get into
> place until it got close enough to the first one.
>
> I have drug my magnet cane all over the place, mostly wherever there
> are gravels. I have not had any of my finds substantiated by
> experts. None-the-less I have come up with some very possible
> "suspect" stones. Some are what I believe are irons and some stonys.
> A couple suspect stonys I found in dirt not gravels. This is what
> leaves me to believe that even if you might not think hunting in your
> area would be very good, you may still find that the magnet will find
> them anyway. The smaller objects falling to earth most likely will not
> penetrate very deep into the soil when they hit. Some not at all if
> the surface is somewhat hard. Erosion can also expose them over
> time. I live in an area where a river cuts its way through the
> valley. I have found that the river gravels contain quite a few of
> what I term "suspect" stones. I suppose the reason for this is that
> in time, due to constant washing from snow runoff and forceful rains,
> a lot of small material finds its way into the river, including
> meteorites.
>
> It takes a little time spent looking close at local rocks to get to
> where you can pick the unusual out from the rest with any certainty.
> Of course, if you live in an area with very few rocks, anything you
> pick up might be worth investigating.
>
> After I have drug the magnets for a bit, I clean off anything that has
> stuck to them into a fine mesh (window) screen sitting down in a gold
> pan. I put water in the pan so it covers the material. I then wash
> the materials vigorously in order to get rid of the dirt and fines,
> which are usually magnetite. Then I screen the material again through
> a 1/4" mesh screen. That lets me look at similar sized pieces less
> than 1/4" by themselves, and then also those larger than 1/4" that
> have been separated by the screen by themselves. I will keep some
> water in the gold pan with the smaller material and do what is known
> in the gold panning world as a blueberry bounce. That moves the heavy
> material to the one side of the pan and lets me see any iron or metal
> fairly easily as otherwise those pieces might remain buried under
> other lighter weight stones. Then I can pass a strong refrigerator
> magnet barely above the rocks and pull out almost all the bigger
> magnetite and iron pieces. I place the stuff that that small magnet
> collects onto a small paper plate and examine them for possible
> suspect stones before tossing them. (kind of like gold panning, you
> don't want to throw out a nugget) Then I will drain and let all the
> stones in the gold pan dry completely. Once dry, I once again do the
> blueberry bounce technique and look over the material closely again
> using my low-power m-scope. A hand lens, field microscope, or
> illuminated magnifier all work but the low-power microscope has been
> the easiest on my vision when used for any length of time. I also
> spend time closely examining the rest of the material in the pan
> because stonys don't always move with the heavier materials. Once I
> find a suspect stone, I pull it out of the pan with plastic tweezers
> and place it on a small magnet and put it under my scope for a good
> look. Some I recognize to be unique and put them in vials for study
> later on, and some I keep for examples of good meteorwrongs. Usually
> 99.999% are simply earth rocks, although even some of those are quite
> interesting.
>
> Not all the suspect stones are small but most I have found are 1/2" or
> less. A waste of time you say? Well possibly, but it has been a good
> way for me to learn about meteorites. This hobby has helped me also
> get interested in learning about other solar bodies as well as the
> earth. I have a lot of folks on the Met-List to thank for most of
> that type information. As far as meteorites go, I'm not so much into
> buying, selling and collecting. I just really enjoy finding them
> myself and seeing them up close.
>
> So again, I hope some of you who live in the "not the best place to
> hunt meteorites" give this a try. But be extremely careful how you
> handle strong magnets. I wouldn't want to see anyone smash a finger
> doing this. If you are one of the young enthusiasts in this hobby, I
> would have to recommend you don't attempt to add any magnets to the
> cane. Use it just like it comes from the store. I did for a while
> and still I found some very interesting stones with it.
>
> I have a picture here that shows both my cane and my latest attempt at
> a magnet rake. The rake has three 80 mm square x 10 mm thick NDIB
> supermagnets on it. If you look at it and wonder why I spaced the
> magnets so far apart on this apparatus, suffice it to say I was too
> chicken to get them any closer. I may move the two outside ones in
> about an inch each at some point. I can tell you, I had a enough fun
> trying to separate them when getting ready to put them on this rake.
> I wouldn't want to get a body part in between two of them.
>
> Everything was muddy when I last used both these things. It's cold
> and freezing here still so I haven't tried washing them off. I
> apologize, the picture is not the best. I think if you can zoom in
> on the cane by the wheel of the air compressor, you can still make out
> the 2 - 2" magnets there side by side on the front edge. Don't look
> too close at the rake, its my first attempt.
>
> I must explain too that my hunting method and the use of water are not
> highly recommended by others in the world of meteorites. The
> magnetism might affect testing the stone later on, and tap water may
> cause rust prone stones to rust.
>
> Anyway, best of luck with your hunting, If you find something, share
> a picture or two
>
> Mike in CO
>
> BTW, the last four pictures are of my first finds using my home-made
> magnet rake. I have used it twice now on some short distance walks.
> I believe the "suspect" iron is a match to 5 other pieces I had
> previously found with the cane. Most likely a piece separated out of
> an octahedrite, as I suspect the others like it that I have are. I
> can't wait for warmer weather so I can take it out to more areas.
> Pictures of the stones aren't too good as they are taken with a camera
> on the m-scope.
>
> <http://i127.photobucket.com/albums/p124/mmurray_02/IMG_0579.jpg>
>
> <http://i127.photobucket.com/albums/p124/mmurray_02/2008_i2.jpg>
>
> <http://i127.photobucket.com/albums/p124/mmurray_02/2008_i1.jpg>
>
> <http://i127.photobucket.com/albums/p124/mmurray_02/2008_s1.jpg>
>
> <http://i127.photobucket.com/albums/p124/mmurray_02/2008_s2.jpg>
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Received on Thu 21 Feb 2008 03:45:19 PM PST