Question About Mineralization

[Blink]

I know this topic has been discussed a number of times but I can't find it. As I remember it, when ground balancing and you GB to a low number the mineralization for that area would be moderate to high and a double D coil should be used. If the GB is a high number the mineralization would be lower and a concentric coil should be used. About where on the GB scale would determine which coil to use. If your a site and getting low GB readings in one area and your using a DD and in another area of the same site you get high GB readings would you switch to a concentric coil?

Thanks Blink

 

[BarnacleBill]

Both of these posts are in the FAQ but I pasted them here for your convenience.

http://www.findmall.com/read.php?55,566150,567211#msg-567211

If you have an X70 read this.

http://www.findmall.com/read.php?55,574329,574329#msg-574329

Don't worry about swapping coils unless you are able or have to change the sensitivity either up or down dramatically from one area to another. Dramatic being 25-30%.

HH
BarnacleBill

 

[Digger]

BarnacleBill has shared some excellent information about mineralization and how it effects the way a detector responds. I recommend you read those posts and understand the principles behind mineralization and GB settings, so you can apply it to your detecting techniques.

My preferences are more "seat of the pants' and are simply based on what works best for me in the places I hunt. My soil (for the most part) is considered to be moderately mineralized. And I can generally GB a 9-inch concentric with settings between 35 - 50. As such, I prefer to use the 9-inch concentric coils, as compared to the 10.5-inch DD's. The concentrics are lighter weight and provide me with as much (or more) depth as the DD coils. In addition, Minelab doesn't offer a 3 kHz coil in DD. And I really like the 3 kHz for hunting old homesites.

With that said, I occassionally get into a site that is more heaviliy mineralized and my concentric coils just don't handle the conditions well. (lack of depth, unstable operation) When that happens, my GB settings will almost always be lower than 28 on my X-70. So, instead of fighting the noise, I switch to a DD coil and the X-70 stabilizes. So I guess my "magic number" for around here is 28. If I run into a spot where I have to set the GB at a setting of less than 28 with my concentrics, I switch to the DD. If it remains higher than 28, I keep swinging the concentric and figure I am getting the most out of my detector.

Now don't misinterpret what I am saying. You could probably use a DD coil all the time and get along just fine. In fact, many detectors, including my Minelab Advantage, only have DD coils available. The reason I use the 9-inch concentric coil for most of my open field hunting is because I like the audio response provided by the 3 kHz for various targets. I have convinced myself I can hear ferrous targets better with 3 kHz than the other two frequencies. And, 3 kHz is a silver and copper killer! The concentrics are also lighter weight and are more comfortable for me to swing for extended periods of time. And when set up correctly, I can get as much or more depth out of my concentrics than I can the larger DD. JMHO HH Randy

 

[Blink]

Thanks guys, I was hoping I would hear from you, I appreciate your info. I know if anyone could set me straight you could.

Blink

 

[Jackpine Savage]

Low numbers (0-11) can result in areas with VERY low mineralization. All it takes is what little mineralization is there to be Fe based. Thats a fact! The numbers are an indication of the overall phase of the ground just like the detectors use to determine the ID of targets and we all know that TID numbers can be the same for a wide range of sizes and alloys of non-ferrous targets. Phase is a measure of a materials (ground or targets) relation (proportions) of magnetic and conductive properties. So, low conductive, low Fe soils can read a low phase number on the Xterras. On most other detectors such as the T2 they read high numbers. ML just does some things differently.

When I put the 70 in beach mode on my fresh water beaches the Phase numbers went from 10-11 down to 0 and it tried to go lower! Autotrack in beach mode resulted in GB readings of 27-30 which is probably a "preset" GB the engineers put in to handle extreme low mineralization areas where the auto track circuit gets confused.

my 2 crappy zincs

Tom