I would have to place trash, mineralization and hot rocks at the top of the list of challenges that every nugget hunter faces when he or she goes into the field. Learning how to deal with all three is an on-going process because each situation presents its own unique problems and every time you go out you learn something new which, hopefully, will come in handy at some future time in a similar situation.

Dealing with trash is pretty much straight forward: you dig everything. Some machines have an iron ID meter which can be of some use depending on the site. In some ground though, even nuggets will break up and ID as iron so some experimenting is called for before you can trust the instrument. Several detectors have discriminating circuitry built into them and as a last resort you can crank in some very low level discrimination (no more than 2 on the knob) and still find the odd larger nugget. I did this once along the top of a trench which had been scraped out with a bulldozer. For some reason the whole area was littered with large nails but I knew there was a chance of finding some gold there so I set the discriminator on my LST to just cancel out the nails and got lucky and found a nice ten grain piece. This is not a fun way to hunt but, if you are reasonably certain that there is some gold around, it is an option. Another method worth trying is to grid the area, maybe ten feet by ten feet, and dig everything. I don't generally have that kind of patience but perhaps you do. It does work and could pay off in a nice way.

Mineralization is not that big of a problem nowadays because all of the modern gold machines do a very good job of neutralizing the ground. The most important control on any detector is the ground balance. Some detectors are manually ground balanced and some, like the Lobo SuperTraq and Minelab SD2200 balance automatically. I have yet to find any area where my LST doesn't do an excellent job of controlling the ground minerals. Once your detector is balanced to the prevailing ground conditions it is usually a simple matter of tweaking your ground balance manually as needed if you are using a manual machine. Sometimes it has to be done every foot or so if you're in some nasty mineralization and sometimes you can run all day at your original setup.

After the ground balance control, the second most important control is your sensitivity. In very heavy mineralization, you are going to have to turn the sensitivity way down, maybe even to 2 or 3 on the knob. Don't be afraid to do this as today's machines have plenty of receiver gain built into them and you won't be giving up very much depth at all. The key to this control is to run it as high as you can without having to listen to a lot of ground chatter which can drive you crazy after awhile.

Hot rocks are something else again and are my biggest pain to deal with. Every detector likes some type of hot rock, some more that others. Even the vaunted PI machines, which are touted as ignoring ground minerals and most hot rocks, have their favorites. You have to deal with them because for some reason, the more hot rocks there are around, the better the chances that there is gold there also.

Basically, a hot rock is hot because it has a higher mineral content than the ground surrounding it and will therefore sound off as a good target. Then there are those rocks which have a lower mineral content than the surrounding matrix and your machine will null out over them and then return to normal threshold with a loud boing or overshoot. I subscribe to Larry Sallee's definition for this type of rock as "cold" stone.

There isn't a whole lot you can do about "hot" rocks except learn to identify them in the particular area that you are hunting in at that time and every time you get a target- like signal, check the ground and, if you see a suspected "hot" rock, kick it aside and re-check the area. Every once in a while, in a badly infested area, you are going to dig eagerly down as much as a foot or more and get all deflated when you see that big ol' rock staring you in the face. Can't be helped. Sometimes you can differentiate between "hot" rocks and good signals by the very slightly broader, fuzzier signal the rock makes as apposed to the shorter, sharper sound of a good target. This is a very subtle difference but it can be heard if you train you ear for it. Unfortunately, it doesn't seem to hold true in all cases.

I've experimented with my LST by flipping the mode switch into alkali position when I suspect that I'm over a hot rock and it will give me a "boing" sound when it really is a rock and not a target. Over a good target, the machine will give a good sharp response in either position.

I don't trust it 100% though, so I'll double check the signal anyway.

"Cold" stones are fairly easy to determine because of the characteristic overshoot so they don't usually give you too much trouble unless the ground is covered with them and they present a masking problem. In this case, a manually ground balanced machine can be slightly de-tuned toward a negative ground balance and sometimes cancel out the "cold" stone without being too far out of ground balance. If this is a viable option for that area, you can still hear any nuggets in amongst the "cold" stones. Give it a try sometime and see how it works.

Keep on walking and swinging. RD