Before I go any further, I think it needs to be clarified exactly what the GOLD MONSTER 1000 (GM 1000) actually is and where it fits in the Minelab line up of gold-centric metal detectors. Before 1995 the only style of detector available for gold prospecting was a VLF-type detector of which there were several brands offering various detectors based around a common theme, namely single frequency machines ranging from 6kHz to up to 71kHz. Generally speaking, the higher the frequency the better the sensitivity to small gold, but proportionally the ground signal will also increase. Minelab were leaders in this field thanks to well-designed electronics but also lead the way with very well designed automatic ground balance systems which ‘ironed out’ ground signals significantly, allowing target signals to be readily heard.
VLF detectors are brilliant at sniffing out tiny nuggets in quieter soils and also have reasonable discrimination capabilities, but they are not good at handling highly mineralised soils like MPS, MPF or ZVT detectors. The GM 1000 will not be able to compete with an SDC 2300 in highly mineralised environments because the constant transmit nature of a VLF detector just does not allow for ground signals to dissipate. In essence, the GM 1000 is a replacement for the aging Eureka Gold detector which was discontinued in recent times.
So, what exactly is a GM 1000 good at? Well, now that we have come to terms with a VLF detector limitations we can now focus on the GOLD MONSTER strengths, and there are PLENTY of them I can assure you. As the Minelab bio states, it is an ultra-wide dynamic range 45-kHz machine (I actually initially thought it was a much higher frequency). The GM 1000 has zero threshold, “EASY-TRAK” Auto Ground Balance and interestingly a 2-stage Auto and Auto+ Sensitivity modes. Combine these features with modern 24-bit signal processing and you suddenly have a power-house VLF which in the right hands can kick some serious goals. The GOLD MONSTER is not a toy VLF, it is a ‘wolf in sheep’s clothing’, so be prepared to have an open mind to its many strengths compared to other VLF machines.
Getting the best from the GOLD MONSTER 1000:
There is going to be plenty of literature in coming weeks about this product so I intend to cut straight to maximising your knowledge of this detector to improve on your infield results.
There are three key principals to the GM 1000 which complement each other, namely they are the Zero threshold, Auto EASY-TRAK Ground Balance (Auto GB) and the totally new Auto and Auto+ Sensitivity controls. As most people know, VLF detectors react to ground signals very readily, even in quiet ground environments, therefore having an Auto GB is VERY useful. Because the GM 1000 has Zero threshold it tends to run reasonably quiet even in our hotter ground conditions here in Australia .This helps iron out variable ground signal assaults on the audio, allowing target signals to be more readily heard - in essence it acts as a filter.
You can read more about the basics of the Auto/Auto+ Sensitivity in Minelab’s blog Understanding the Sensitivity Control on the GOLD MONSTER 1000
The key to effective use of the GM 1000 is finding a happy equilibrium between Zero Threshold, Auto GB and the Auto+ Sensitivity.
Firstly, turn the detector on with the coil facing any potential EMI areas. Once this is done, using the left plus+/minus- control, bring the Sensitivity up to 6 segments then slowly ‘pump’ the coil over the ground until the unit is quiet. Then sweep the coil in a controlled fashion and you will hear a further quietening of the detector as the Auto GB averages the ground in your area. This averaging process is important because the next step is to take the Sensitivity control to the full position to take advantage of the Auto+ feature which is my favourite position for this detector.
Now, something I noticed when testing, is the auto-sensing operation of the detector is always active. Therefore, less experienced operators might struggle when the coil is lifted away from the ground suddenly or when the coil is placed on the ground for long periods during target retrieval. So while it’s very easy to follow Minelab’s 3-step start process in many instances, I offer the following advanced workflow to use with the GM 1000 for improved efficiency:
- Turn on the machine and let the Auto Noise Cancel complete.
- Change from the default Gold Mode to the Deep All Metal Mode (see diagram)
- Set the sensitivity to half way and bring the coil to the ground and ‘pump’ the coil until quiet.
- Swing the detector in the immediate area to further enhance the GB as it averages the ground, keeping in mind the detector is in Auto GB at all times.
- Increase the Sensitivity control until all segments are filled and the centre is also infilled (see diagram), you are now in Auto+.
- Be sure to keep the coil at ground height while making setting changes to avoid throwing the GB out.
- Sweep the coil until the audio goes quiet and stable and then continue to detect in your chosen area, taking full advantage of the Auto GB and Auto+ Sensitivity options.
- Get into the habit of carefully pumping the coil periodically to re-centre the Auto GB.
- When a target is heard check with the Gold Mode (Iron Reject) listening to the audio and looking at the Gold Chance Indicator.
- When you decide to dig, take the Sensitivity to Manual and set at approximately the same signal strength at which the target was originally heard.
- Dig and retrieve the target.
- When resuming detecting, leave the Sensitivity where it was, ‘pump’ the coil and then walk about until the audio becomes smooth and stable.
- Switch the detector back to Auto+ Sensitivity, listening to the audio as the detector ‘smooths out’ while the coil is swung. There will be a period of time as the Auto GB and Auto+ Sensitivity align themselves together. You can tell when they come into alignment because the GM 1000 will ‘smooth right out’.
- Be careful not to lift the coil away from the ground suddenly as the GM 1000 can sometimes lose its equilibrium quite easily, particularly in highly variable mineralised ground.
Savvy operators will be able to work the GM 1000 in surprisingly noisy ground once they come to terms with the methods I’ve described above. It takes practice but the effort is well worth it because these two Auto functions in combination with Zero threshold really does allow this detector to work in ground a VLF has no business working in - areas that I would consider to be MPS and MPF territory. In the quieter soils, Auto+ lifts the sensitivity to levels that surprised me, behaving like a much higher frequency machine Although not a ‘deep-punching’ machine like an SDC 2300, the GM 1000 still ‘holds its own’ on the shallow surface gold crumbs missed by the more powerful Minelab detectors.
I started my professional career with a 32-kHz machine in the form of the XT 17000. I’ve used numerous VLF detectors professionally over the years and find the GOLD MONSTER 1000 to be a much more serious detector than the name suggests!
Read more at Detector Prospector forum
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