Hi Tony,
I don't have an answer to your question, but have heard that due to the severe mineralization in the areas of interest you listed, a machine that can handle such would be required. If small gold is what you want, use a smaller coil. Frequency of operation is a key to success- high F will resolve small gold. Machines that can find small gold run from 45 to 70 khz. A larger nugget will show of course, if it is within the range of your coil. For depth and large targets, use a large coil- for smaller nuggets, use a small coil. Most machines made to find gold in the lower 48 run from 19 to 70 khz. That is because there are few big (1/2 oz) or bigger finds. You will find more small match head size (and half that) in the areas of interest. Here is another point of interest: you get better depth for gigantic nuggets with a low freq. machine. Those same machines may not even 'see' a small target. They are transparent because of the resolution of a low F. So it depends where you are, the likelihood of what it is you will find that determines the machine of choice. The GMT is capable of finding remakably small gold, you will give up some of the resolution for those tiny specks for improved depth over the stock coil, employing the hotshot. That's what you want, depth and resolution. Mineralization can shut you down, the pulse machines can get you around that - but also the manual GB like Gold bug works well. Hope this helps you some.
