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Originally Posted by Seden
I've been looking at using one of those non-contact Digital Infrared Thermometers for detecting ore bodies and was wondering if anyone has ever used one? The 30:1 units are in the low $100USD range so much cheaper than a Thermal Imaging Camera and might even be useful for treasure hunting in the fall or spring when there's a larger temperature variation between day and evenings which would be the time to take readings.
What say ye?
Randy
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Hi Randy,
I tried one of them and posted my test results here:
http://www.geotech1.com/forums/showthread.php?p=52102
I only tested during the late spring at the beach. What I didn't post is my testing inland, where I found that wet or damp soil gives much colder readings than average, and shaded areas are much colder than sunlit areas of the soil. All this surface heating by the sun seems to cause the most significant temperature variations that can be read from an infrared thermometer. The idea of using one of these thermometers to locate buried metals seems a very poor idea to me, after a day of experimenting. In order to be successful, I would expect you need to search a flat area with no noticeable shadows shortly after sunrise or sunset. Then the problem becomes one of range. a 30:1 thermometer does not have a very good range because it is averaging a lot of noise within that cone that I would expect to miss all but the largest treasures that are in close range, and buried near the surface of a place that does not have any significant shadows.
In theory, this method seems like it would work, but after trying it, I figured I could cover more area with a metal detector, which has greater depth, similar range (6-ft), and does not get false signals from shadows.
About these thermometers.... They work good for taking the temperature of something that you do not want to disturb, such as rotating machinery, the side of a building at close range, the surface of a wall, etc. I use one of these as a preliminary indicator to tell if there are signs of moisture behind a wall. I never use it to search for where moisture is in a wall, I only use it to check the places where I suspect moisture before taking out the thermal imaging cameras. What the thermal imaging cameras show is vastly superior to the readings you can get with these thermometers. You see a picture that looks like a photograph of the temperatures. The difference between using a thermal imaging camera and an infrared thermometer to search for buried treasure is similar to the difference between using a camera and a light-meter to search for a treasure on the surface of the ground (where the light meter is equivalent to a calibrated one pixel camera with a 30:1 cone of view). Think about it.... If you had to wear blinders that prevent you from seeing the ground, which would you rather use to find a treasure on the surface? ... The screen of a camera, or the face of a light meter? This is basically what you are doing with infrared huntting during the best conditions.
If you wanted to find treasure from infrared, a digital imaging camera would be your only hope, in my opinion. And that hope would depend on how deep the treasure is buried, as well as the composition of the soil and quality of sunshine. Moisture in the soil will play a very large part in this.
Best wishes,
J_P