Industrial Metal Detectors
While most people think of industrial metal detectors as those used in the food and garment industries to detect potential contamination, metal finders have a lot more uses than just that. Many people use metal detectors for fossicking and prospecting throughout Australia, both above and below the water. Not only does it get you outside, but it also gets you moving around so you can actually get some exercise when following the hobby. Give it a try; it can be both fascinating and rewarding.
How Do Metal Detectors Work?
All metal detectors work on the same basic principle. Because metal is conductive it responds to electromagnetic fields, and that causes a corresponding change in the field. There are three main kinds of metal detector, each of which works in a slightly different fashion:
- Beat Frequency Oscillation: These detectors have two coils, one in the head and one in the handle, with an oscillator connected to both. When the search coil encounters metal its field changes and the other one doesn't. These are the simplest and least expensive detectors.
- Very Low Frequency: With two coils in the search head, these detectors are more powerful and expensive than BFO models.
- Phase Induction: Most sensitive of all, a phase induction design uses only one coil. It works very well in mineralised soil like beaches and makes an excellent gold detector.
Using Metal Detectors in Australia
Metal detectors are legal for use in most of Australia, but each state has its own specific requirements. Some states require a fossicking license, while Victoria requires that you obtain a Miner's Right. In most cases you don't need one just to look for lost items on your own property, but you do for fossicking on public land. There are also fossicking clubs you can join; some of them have licenses of their own that you can use rather than having to get one yourself.
Different Types of Metal Detector
The most common type of metal detector is the handheld metal detector; this is the kind of detector you're most likely to see when you're out and about. Most use either BPO or VLF technology, and are used for work above the ground. Phase Induction detectors often work as secondary devices by serious fossickers. These detectors have the best chance of finding deeply buried gold due to their improved discrimination. You can also get waterproof metal detectors for use on the beach and to find treasure below the surface. Underwater metal detectors are also available, so SCUBA divers can extend the search into a whole new dimension.