Magnetometer For Tracking Black Sands

[Gene-Yo]

There is a lot of experience on this website and hopefully someone can give me some advice on a magnetometer.

I have finally saved up enough to purchase a single sensor Proton Magnetometer or basic Proton based Gradiometer. My plan is to use this along with a deepseeking PI and White's MXT detector for hunting paydirt (gold containing black sands) in the Rocky Mountain areas such as Colorado or Wyoming.

Is anyone out there been successful using this approach. Or are there too many hidden problems such as iron containing rocks, hot rocks, and related geological junk that would make a magnetometer difficult to use.

I'm hoping someone can give me some sound advice before I put down a big chunk of change on one of these units.

[Willy Bayot]

A single sensor PPM would surely detect any of those objects (and even most probably any metallic meteorite), more specially if they are magnetized.
I have no personal experience in searching for black sands but I guess that the field gradient generated by individual objects like those would be localized in a small region around them while a larger region of black sand would generate a much wider gradient region.
Another

Willy

[Unregistered]

blacksands and magnetometers

If the blacksands have magnetite in them (they usually do), then a magnetometer will work beautifully on detecting them.
Geo Jim

[Unregistered]

mag resolution

then the question will resolve around sensitivity/resolution
I started with a Dalton dual sensor fluxgate - worthless
got a Geometrics 856 proton mag (very useful as a diurnal base station),
then a G-858 cesium mag (which I still have and is for sale)
- think gradiometer for near surface anomalies

will magnetite (sand) give a response - sure
will you be able to distinguish such from everything else the sensor is also responding to ??

I like seismic refraction.

[Larry Hough]

Where can i find a proton magnetometer kit i can build ?



Thanks
Larry

[Unregistered]

Would this $700 earth magnetometer work at mapping out black sand?
http://www.trifield.com/edcm.htm


Jerry

[Gene-Yo]

Black Sand

I looked at that model because it was around $700 or $800 versus several thousand of dollars. I went with a higher end model and here's why:

1. How do you connect a computer to that model which will actually read the inputs into a software program with useful results. No idea... Everything turns into a hack program.
2. If you read the fine print this magnetometer must be within 1/3 degree for accurate measurements. Ouch!
3. You must reset this mag between readings, so if you wanted to manually write down or type in the results for each point then you could map with this instrument. However, it appears to be a very long process.

Versus getting a proton mag with RS232 outs that only needs to be pointed within about 30 degrees and that's easy to do while walking.

Believe me I would have loved to save a few thousand dollars and purchased that model but I couldn't figure out how to make it really work. Iin short, you get what you pay for.

[davey]

What is meant by 1/3 degrees? I would guess it means that it must stay pointed at the same direction but what does 1/3 means in degrees.
Am I seeing partof this right?

[allgold]

There is a lot of experience on this website and hopefully someone can give me some advice on a magnetometer.

Hope this helps
http://bb.bbboy.net/alaskagoldforum-...m=2&thread=758

[BillA]

all threads may include words presented as fact

the guy promoting fluxgates in that thread also sells them
the 80nT he cites as a minimum "black sand anomaly" response is tripe
he apparently has no personal experience with proton or cesium mags
all his "software" is his personal script

a proton mag will work, but one must stop while taking a reading
a gradiometer will be much better for near surface anomalies

a cesium mag with integrated DGPS will take readings with coordinates while walking
also for the cesium mag, a gradiometer will be much better
big $, and not user friendly

Bill

[Willy Bayot]

the guy promoting fluxgates in that thread also sells them
the 80nT he cites as a minimum "black sand anomaly" response is tripe
he apparently has no personal experience with proton or cesium mags
all his "software" is his personal script

a proton mag will work, but one must stop while taking a reading
a gradiometer will be much better for near surface anomalies

a cesium mag with integrated DGPS will take readings with coordinates while walking
also for the cesium mag, a gradiometer will be much better
big $, and not user friendly

Bill

Just my pennywise data to this post:
A proton mag does not require the operator to stop while making a reading. I do that all the time while walking without any problem.
The near surface anomalies will be detected very well with a simple mag with its single sensor, it does not require a gradiometer but a gradiometer will also certainly detect them. The main purpose of a gradiometer of differential instrument although being more expensive than a simple mag is to cancel the daily field variations in order to detect weak field gradients. When the seeked targets are made of magnetic material, the field gradients generated by the successive readings on a survey line are more than enough to locate them with precision.

Taking readings with coordinates has nothing to do with ceasium mag. A GPS does that but it is true that most ceasium mag instrument integrate a GPS as option.
I have integrated a GPS device to my PPM and it works very well without DGPS provided it is an up-to-date GPS and there are a large number of satellites in view (9 or 10) which is very usual in open countryside.

Willy

[BillA]

Thanks for the corrections Willy, I should have qualified my comments.

Other than the Dalton, all my mag experience is with Geometrics.
For the 856 they recommend pausing for reading, today they still sell - but for base stations which is how I eventually used mine.
I always stopped when taking a reading with a proton mag - thought that was the norm.
The 858 (cesium) Geometrics promoted as a "walking mag" - and a seller called it such on eBay, w/o bidders and I bought it for $1300

I think the GPS solution depends on the situation, in AK satellite acquisition is a problem, in S. America its the canopy and no WAAS. Again, Geometrics for Bolivia recommended DGPS with a Trimble Ag132 specially modified/demagnetized ($13k as I recall); I used an Ag114 as it is already nonmagnetic ($800). Used a regular Ag132 as the base station.

Willy, which GPS units are nonmagnetic ?
I could not find a mfgr specing such, and I asked (8 yrs ago, the problem ?).

Bill

[Willy Bayot]

Bill,

Since the PPM I curently use is my own making, I use an OEM-type GPS chip (GLOBALSAT ET-318 SIRFIII) which do not have any spec of magnetic material. Besides, it is located inside the electronic box far from the sensor which is at the end of a long stick.

I have also used a GPS mouse like the HAICOM HI-204 III (SIRFIII based). That is working well also.

Note that the SIRFIII-based GPS are VERY sensitive for use in covered places like forests. I can even get a 3D location from inside my house.

Willy

[Willy Bayot]

Bill,

By the way, buying a working ceasium mag for $1300 is a miracle that I would like to reproduce one day!!

[Unregistered]

G-858 cesium mag (which I still have and is for sale)

then the question will resolve around sensitivity/resolution
I started with a Dalton dual sensor fluxgate - worthless
got a Geometrics 856 proton mag (very useful as a diurnal base station),
then a G-858 cesium mag (which I still have and is for sale)
- think gradiometer for near surface anomalies

will magnetite (sand) give a response - sure
will you be able to distinguish such from everything else the sensor is also responding to ??

I like seismic refraction.

How much are you asking for it? contact me at [email protected]

thanks