The Complete Guide to Gold Detecting Machines
One of the most common requests we get from the metal detecting community is for tips on the best way to detect for gold, information on the different types of gold detecting technologies and our recommended gold detectors. To get answers to these questions, we turned to our resident gold expert, Don Newell.
Don, who lives in Arizona, has been gold detecting for more than 12 years. The purpose of this guide is to help you figure out which gold detector you should buy based on your prospecting area, the type of gold you want to find and your budget.
The most important question you need to ask when deciding on a metal detector for gold nuggets is what type of gold you have in your prospecting area. Everyone wants to find large gold and strike it rich, but in reality, about 95 percent of gold fields have small nuggets.
Choosing the right gold detector will help you find these smaller nuggets, which all add up in the end. We’ll let Don take it from here.
One Gold Detector Won’t Get It All
When I first started detecting early in my mining career, I had the opportunity to detect a 100-year-old underground gold mine that had never been detected.
Those old-timers that built the mine tunnels didn’t have metal detectors!
I started out with a Minelab GPX series detector and found clusters of gold nuggets scattered all over the mine. There was one area in particular that had bedrock loaded with gold nuggets. I cleaned this area out… or so I thought.
About five years later, I acquired a Minelab SDC-2300 detector and found a few more ounces of gold that the GPX detector had missed in the same exact spot. This was a wakeup call for me as I thought the GPX was getting 98% of the gold and only leaving a few crumbs of gold too small to be worth recovering. I never expected there to be so much chunky gold left behind by my main detector.
About a year later, I detected the same area with a high-end VLF gold detector and found a little over an ounce the SDC detector had missed. Currently, there isn’t one detector that detects every size and type of gold.
There is always some gold left behind when metal detecting. This gives the electronic prospector armed with new technology hope to find more gold in areas already detected by others. There are many different types of gold out there: from large to small hammered solid nuggets, wire gold, prickly & porous gold pieces, foil gold, specimen quartz float with fine gold inside, and more.
There is always more to be found and new technologies will light up these different types of gold.
The Basics of Gold Detector Technology
There are two main types of gold detector technologies: Very Low Frequency (VLF) and Pulse Induction (PI).
The VLF machines are usually focused on finding small shallow nuggets. For VLF, your coil needs to be within a few inches of a tiny nugget to hear a signal. They do not handle hot rocks or highly mineralized ground very well.
You need to work slowly to hear the whisper-small nugget signals among all the ground noise of the gold field. Occasionally, you will find a medium or larger nugget in addition to all the small stuff. These detectors work best when scanning bedrock with the overburden (ground) removed or only a few inches deep. VLF will usually miss deeply buried, larger gold.
On the other hand, a PI machine will go deep on both medium and large gold. But, if that size of gold is not there, you won’t find it.
They handle highly mineralized ground very well. With a pulse induction machine, you can cruise through a mineralized area quickly to find the deeper medium and large “sitting duck” nuggets and move on.
Remember, about 95-percent of gold is small. Spend your time chasing the gold that exists where you detect. The bigger stuff might be long gone or may never even have existed in your location. This is why many people opt for a VLF gold detector. In addition, a VLF detector is a much smaller financial investment, especially when first starting out gold prospecting.
New Technology: Minelab GPZ 7000
Minelab’s latest flagship detector is based on new Zero Voltage Transmission (ZVT) technology, which is a hybrid between VLF and PI. The 14” coil uses 3-winding (1 transmit, 2 receive) and is called a Super-D coil. While I won’t go into details about the technology inside, the end result is a machine that will see a variety of gold types at great depth. I mention this machine separately because it’s the first of its kind and does not fit into the VLF or PI category. The GPZ 7000 is incredible for both large and small gold. If Minelab comes out with a smaller coil, it will really be a vacuum cleaner on the gold fields, getting most of the gold!
VLF vs. PI on High Mineralization
Most gold is formed in highly mineralized, iron-stained ground. Detector engineers designed the VLF and PI gold machines to handle noisy mineralized ground so that you can hear the faint nugget signals in the mix. On a PI detector, most hot rock signals are either ignored or minimized so that you can work quickly, not wasting time chasing “ghost signals” from ground noise.
This is where PI detectors shine and VLF detectors struggle. A VLF detector is best on bedrock or in mild to medium ground. If using a VLF in high mineralization, work slowly to minimize the ground noise and hot rocks.
Unfortunately, some gold prospecting areas are loaded with trash. If your area has this common problem, use a VLF detector to try and weed out some of the iron junk targets like nails, rusty tin cans, and old wire. But be careful, as mineralized ground wreaks havoc on target IDs, and some deep gold nuggets can read as iron. When in doubt, dig it out!
Unlike VLF, most pulse induction units do not discriminate trash well, even though some manufacturers make claims about it. Treat your PI detector as a “beep & dig” detector. And use some time-saving strategies — for trashy areas, if the target is in the top 2 inches of dirt, it’s probably junk. Don’t waste your time!
Most serious prospectors/miners own both a PI and VLF detector. Just like tools in a toolbox, there are detecting tools to match each situation. If you want to get all the gold, you need several detectors. If you are hitting a mining claim known for large whopper nuggets, use a PI detector. If you are on bedrock with tiny cracks known to hold little gold “pickers” or tiny nuggets, use a VLF detector. Take the detector to match your spot or bring both!
Remember: If you’re looking for small, shallow gold, use VLF. If you’re looking for large gold in medium deep locations, use pulse induction. PI detectors will usually signal well on any nugget more than .3 grams. VLF detectors will find that size and smaller.
All About Detector Coils
Selecting the right collection of coils will improve your chances of success. Match your coil to the terrain and remember, low & slow is the best way to detect for gold. Keep your coil scrubbing on the ground (low) or slightly above it to maximize detection depth. Detect slowly or at a moderate coil sweep speed. Rushing through an area will miss faint signals that just might have been that big nugget!
Round vs. Elliptical Coils
Round coils usually go deeper than the equivalent elliptical-shaped coils. Use round coils whenever possible. However, elliptical coils can get down in between rocks and scrubby terrain better, or cover more ground per coil sweep. Use the coil size that makes sense for your area that will get the coil as close to the ground as possible.
DD vs. Mono Coils
DD coils have two D-shaped windings inside the coil. One is a transmit coil and one is a receiver. The mono coils have one winding inside that acts as both transmit and receive.
Most VLF detectors for gold will use DD coils to deal with the mineralization. Mono is described as a concentric coil in the VLF world.
On the PI side, DD coils are known to handle mineralization a little better than mono coils, but the cost is about 20-percent less in detection depth compared to a similar size mono coil. When possible, use mono coils to maximize your detection depth. The mono coil also has edge sensitivity all around the coil’s edge, while the DD only detects down the center strip of the coil. This edge sensitivity will score nuggets in tight spots like mine tunnels or under rocks.
Large vs. Small Coils
The larger the coil, the deeper it will detect, but at a cost. The large coils will lose sensitivity to small gold. Use large round coils for maximum depth when hunting medium and large nuggets. Use the small coils for maximum depth on small nuggets or in rough terrain.
It’s very difficult to use a big round coil on rocky or brushy ground, while the small coil will get in between rocks and brush. Match the coil to your terrain. Also, larger coils pick up more electromagnetic interference. This EMI will cause noise and cost detection depth.
Don’s Gold Detector Picks
If you are on a budget, just starting out, or an experienced prospecting/miner wanting a VLF gold detector in your toolbox, I recommend the Minelab Gold Monster 1000 as the top choice. I would also recommend the Whites Goldmaster 24k as a good second choice for nugget detecting. And lastly, the Minelab Equinox 800 wins as a great multi-purpose (coin, jewelry, relic, gold nugget) machine. It will hunt gold nuggets and you can use it at the park and beach, as well.
Serious Prospectors & Miners
If you aren’t limited by budget and want a serious detector for deep gold. I recommend the Minelab GPZ 7000 as the best choice and the Minelab GPX-5000 as a less expensive alternative to the 7000. Both of these machines are incredible gold detectors that will find a pile of gold nuggets.
For a middle of the road detector, I also recommend the Minelab SDC-2300 for small gold only. It’s a super-fast PI machine, so it will ignore all those pesky hot rocks. It will also hit some types of gold that no other PI detectors will find. This makes it a special-purpose machine and a joy to use. But for deep large gold, go with the 5000 or 7000 mentioned above. The SDC was designed to be hot on small gold that’s not too deep. Plus, the SDC is waterproof up to 10 feet!
Here are some other great gold detectors that are worth considering.
Nokta AU Gold Finder: A great sleeper machine, works very well on nuggets. Uses VLF technology.
Whites TDI SL: Excellent inexpensive alternative to the PI machines mentioned above. Uses PI technology.
Garrett ATX: Use the solid coils for best performance. Uses PI technology.
Pro Tip: Gold Detecting On a Budget —the “Scrape and Detect” Method
Are you stuck with a VLF detector due to budget constraints? Then use the “scrape and detect” method. Use this method when you are on a nugget patch. This is either an old nugget patch or a new patch you have stumbled upon while out prospecting a new area. Choose an area maybe 20’x20′ or smaller to focus your detecting efforts.
- Detect the top layer of ground, remove all target signals with your VLF detector and put them into a 5 gallon bucket.
- Remove and discard 3-4 inches of the ground in the same area.
- Re-detect the freshly uncovered ground and remove all new target signals into the bucket.
- Repeat steps 1 through 3 until you reach bedrock or go past the gold bearing layers.
- Make sure to thoroughly detect the bedrock. This is where most of the best gold will be hiding.
- Gold pan out your bucket of dirt containing all the targets; some will be gold nuggets and some will be trash.
This method will allow you to get all the gold without using multiple expensive detectors. You can always buy a more expensive PI detector later with all the gold you will find using this method!
In some locations, 99 percent of the gold will be on bedrock. In these cases, remove the top overburden completely and just focus on detecting the bedrock targets.
Work smarter, not harder!
Have a gold detecting question for Don? You can reach him directly at firstname.lastname@example.org, or call Kellyco Metal Detectors at (855) 216-3771 and ask for Don.