Search found 241 matches

by ncoord
Sat Apr 09, 2016 7:35 am
Forum: Near Surface Geophysics
Topic: Terrain Conductivity Meter
Replies: 2
Views: 549

Re: Terrain Conductivity Meter

If you can build one much cheaper, I will buy it. :D
by ncoord
Tue Aug 25, 2015 11:26 am
Forum: Mineral Prospecting
Topic: metal detecting
Replies: 11
Views: 1933

Re: metal detecting

Bayoubill wrote:Not familiar with the term EM.
Electromagnetic
by ncoord
Mon Aug 24, 2015 8:04 pm
Forum: Mineral Prospecting
Topic: metal detecting
Replies: 11
Views: 1933

Re: metal detecting

If you have access to a helicopter, airborne metal detecting would be the best way to do it. However, since it's not a ferrous metal, you should use an EM instrument instead of a magnetometer.
by ncoord
Mon Aug 24, 2015 7:03 pm
Forum: Mineral Prospecting
Topic: metal detecting
Replies: 11
Views: 1933

Re: metal detecting

It is a big area. You can use a cart-mounted metal detector such as EM61 with GPS and pull it with a ATV. You should be able to finish it within one week. This is assuming the ground surface is relatively flat and favorable for driving. If you have to walk with the metal detector, it's going to take...
by ncoord
Sun Aug 23, 2015 8:56 pm
Forum: Mineral Prospecting
Topic: metal detecting
Replies: 11
Views: 1933

Re: metal detecting

How large is the metal and how deep is it?
by ncoord
Tue Aug 18, 2015 5:00 pm
Forum: General Geophysics
Topic: Radiometric method
Replies: 2
Views: 844

Re: Radiometric method

I would also like the info if someone has it. I suspect it to be very simple like a magnetic survey. But more info on instrumentation and logistics would certainly be more helpful.
by ncoord
Tue Aug 18, 2015 4:56 pm
Forum: Near Surface Geophysics
Topic: EM61 malfunctioning
Replies: 4
Views: 730

Re: EM61 malfunctioning

Thanks for the feedback! Do you know how old your unit is?
by ncoord
Tue Aug 18, 2015 7:16 am
Forum: Near Surface Geophysics
Topic: EM61 malfunctioning
Replies: 4
Views: 730

Re: EM61 malfunctioning

Do you have a new battery to try? Sometime even it seems to have enough voltage but may not have enough current if it's bad. I would make sure it's definitely not a battery problem and then send it to Geonics for repair.
by ncoord
Mon Jul 13, 2015 9:01 am
Forum: Near Surface Geophysics
Topic: Ohm Mapper
Replies: 8
Views: 1347

Re: Ohm Mapper

Ohmmapper is not meant for locating underground utilities. As in normal electrical resistivity imaging (ERI), the resolution is not good enough for small targets such as pipes and cables. Unless you are looking for large diameter pipes (for example 6 feet in diameter), you should not use ERI for und...
by ncoord
Fri Jul 10, 2015 6:57 am
Forum: General Geophysics
Topic: Creating 3D ERT from 2D ERT
Replies: 10
Views: 1825

Re: Creating 3D ERT from 2D ERT

It's better that you do a true 3D inversion with a 3D inversion software such as res3inv or Earthimage 3D. You need to combine your 2D data to form a 3D data set first. Otherwise you can do 2D inversion and interpolate between lines. However, the results are often not ideal doing it this way.
by ncoord
Wed May 06, 2015 6:35 pm
Forum: General Geophysics
Topic: Resistivity Contouring HELP
Replies: 4
Views: 954

Re: Resistivity Contouring HELP

Here is a free program for inverting the data:
http://www.es.lancs.ac.uk/people/amb/Fr ... eeware.htm
Also you can try
http://resistivity.net
by ncoord
Tue May 05, 2015 8:20 pm
Forum: General Geophysics
Topic: Resistivity Contouring HELP
Replies: 4
Views: 954

Re: Resistivity Contouring HELP

You need a gridding and contouring software: http://surfit.sourceforge.net/index.html
by ncoord
Thu Apr 09, 2015 3:29 pm
Forum: Mineral Prospecting
Topic: Joint inversion of time domain electromagnetic and resistivity imaging data
Replies: 3
Views: 1140

Re: Joint inversion of time domain electromagnetic and resistivity imaging data

Nice demonstration. What's the typical instrument you use for time domain EM?
by ncoord
Tue Feb 24, 2015 6:41 pm
Forum: Near Surface Geophysics
Topic: GSSI EMP400
Replies: 11
Views: 1380

Re: GSSI EMP400

Are there any sources that I can read that will give me a good working knowledge of processing steps and techniques for EM data? most of the papers that I've read provide little information on how to go about processing such data. I am guessing that most people must learn it through working with so...
by ncoord
Tue Feb 24, 2015 6:53 am
Forum: Near Surface Geophysics
Topic: GSSI EMP400
Replies: 11
Views: 1380

Re: GSSI EMP400

lostmytrowel wrote: I should just say that it was too badly collected.
Unfortunately, yes. No data processing including inversion could help it.
by ncoord
Mon Feb 23, 2015 9:48 pm
Forum: General Geophysics
Topic: Idea League MSc Applied Geophyiscs
Replies: 1
Views: 540

Re: Idea League MSc Applied Geophyiscs

Automation is very close to what test engineers do, I don't think you will have much difficulty finding jobs outside oil and gas industry.
by ncoord
Mon Feb 23, 2015 7:19 pm
Forum: Near Surface Geophysics
Topic: GSSI EMP400
Replies: 11
Views: 1380

Re: GSSI EMP400

How big are the well heads supposed to be? It seems to me that your line spacing is too big. Anyway, as rfadams13 pointed out, if you are lucky to go directly over the wells head , you should see negative readings, in both quadrature and and inphase data.
by ncoord
Sat Feb 21, 2015 9:49 am
Forum: Near Surface Geophysics
Topic: GSSI EMP400
Replies: 11
Views: 1380

Re: GSSI EMP400

Have you displayed the contour after gridding the data?
by ncoord
Sat Feb 21, 2015 8:35 am
Forum: Near Surface Geophysics
Topic: GSSI EMP400
Replies: 11
Views: 1380

Re: GSSI EMP400

What are you looking for with the data? The main step is to grid the data to see what the data look like and check whether you can see what you are looking for. You can do clip to block out unwanted portions in Surfer as well. I don't know what ZMT is. Despiking may not be necessary depending the qu...
by ncoord
Tue Feb 10, 2015 10:12 am
Forum: Near Surface Geophysics
Topic: Interesting blimp -- imagine using it with GPR and EM for UXO scanning
Replies: 2
Views: 491

Re: Interesting blimp -- imagine using it with GPR and EM for UXO scanning

geophix wrote:The blimp is probably good at high altitudes, but it needs extensive flying trainings. For relatively small survey areas, UAV like this one may be better: http://mgt-geo.com/
Good one, but I don't how much weight it can carry. The blimp is better for heavy equipments.
by ncoord
Wed Sep 24, 2014 8:22 pm
Forum: Near Surface Geophysics
Topic: Geonics training website (EM61, EM31, EM34 and EM38)
Replies: 3
Views: 1110

Re: Geonics training website (EM61, EM31, EM34 and EM38)

The way it's presented makes it appear that it is an official Geonics offering, but, though I don't know for sure, I suspect that Geonics has no connection with this site. The owners of the site should make it clear whether they represent Geonics or not as it will affect how the information is perc...
by ncoord
Fri Sep 12, 2014 9:55 am
Forum: General Geophysics
Topic: Resistivity and EarthImaging
Replies: 3
Views: 675

Re: Resistivity and EarthImaging

Questions are welcome. ;) I guess the instrument you have is from AGI?