News — gpx 6000

* Some Awesome Aussie GPX 6000 Finds *

The Minelab GPX 6000 Pulse-Induction detector has now been available in Australia for about 2 years. In that time some awesome nuggets have been unearthed throughout Australia. Some of these significant finds have been publicised, and not surprisingly, many fantastic finds have not been publicised for various reasons.

Several big chunks of gold have been recently found in Western Australia.

Below are some of the Minelab GPX 6000 finds that have been shared online:

The big nugget shown in the two photos above reportedly weighs  about 13 Ounces  (about 0.4 kg).  My "guesstimation" is that the total weight of all of the above nuggets would be  at least 30 Ounces !

Below are some more finds using the GPX 6000:

“Here are two of the nicest bits for the season, biggest is 5.5 oz (171.2g) and the other is just over an ounce (35.5g). Both found with a 6000 while pushing. Interestingly the big bit was laying flat, in a crevice in a rock bar, about 60 cm down I suppose (from the bottom of the push) but it was not an inverted signal, and I have no idea why.

Every other solid bit I've got from a gram or so up has been an inverted signal. It started off as a normal up down signal, sounded very OK like a few gram specie 10 inches or so down, good but not outstanding. It just got louder and louder the deeper I got. By about 40-50 cm down I knew it was going to be a better bit, maybe an ounce or two even, and I was convinced that it had to be a specie as the signal wasn't inverted.

The pinpointer was going crazy over a red rock stuck in the crack and I couldn't see any gold yet so I was convinced it was under the rock, got the biggest shock when I got that rock out and felt the weight. It was flat and heavy and clearly a nugget but even after giving it a wash I still couldn't see any gold.

Took a couple of days in alibright for the red coating to dissolve. It has about 6 g of rock in it based on an SG test so it's technically a specie but I'm happy to call it a nugget. The smaller bit was in a different spot, in old wash, probably 70 cm or so down from the surface. I had pushed it though so I only had to dig a few inches. Before I dug it I tried detecting it from the surface level and got no response. Had to be down another 6 inches or so before any signal but it was inverted all the way. The bit was in a small crack but standing upright on it's side and it looked bright and shiny like it does now when it was still stuck in the hole.”

An old Aussie gold prospector (who has used all of Minelab’s other pulse-induction detectors over the past decade (e.g. SDC 2300, GPX 5000 & GPZ 7000) has also used the GPX 6000 in Western Australia for 118 days (about 1,000hrs of swinging) and on 100 of those days, his GPX 6000 detected 854 gold nuggets in highly mineralised ground. He mostly used the large Minelab GPX17x13” elliptical Mono coil for excellent ground coverage (“patch hunting”) and depth capability. In fact, the GPX17 coil easily detected two spherical-shaped nuggets (a 5-grammer, and a 6 grammer) at depths of between 40cm and 45cm in highly mineralised ground north of Kalgoorlie. The GPX17 coil also picks up the small bits too – using the proven “Low & Slow” technique. He also found the GPX14 DD coil excellent for use in salty/conductive ground (where it was almost impossible to run a Mono coil), as well as in areas within/nearby high electromagnetic interference (EMI).

Liz Pickthall spends her spare time detecting in the central goldfields of Victoria.

"I finally had seen and heard enough, and at the age of 28 I decided to go out and invest in my first detector. Only then did I realise my true love for it, and I’ve been addicted ever since. As the years went by and my love for detecting grew, I started to work less and detect more.

After upgrading my metal detector to the GPX 6000, I was keen to upgrade my coil as well. I waited for the release of all brands of coils, and was lucky enough to be able to try before I bought two different coils – one of which was the Coiltek 9” GOLDHAWK.

It didn’t take me long to see that it was the standout performer in all areas including weight and sensitivity – and it worked wonders on all ground types in the Victorian goldfields. I was so impressed by how quiet it ran for such a sensitive coil. The 9” coil has found gold in the most ‘flogged out’ areas, with the coil’s size making it so easy to get in tight areas under and around bushes and trees.”

Imagine how many tens-of-thousands of gold nuggets (& specimens) have been found throughout Australia over only the past 2 years using the mighty Minelab GPX 6000 detector.

Imagine how many more huge chunks of gold are still out there throughout Australia - that have never had a GPX 6000 scan over them !

To boot ..... there are now  SEVEN  (7)  different coils available for the GPX 6000.  Even better - four of these new coils are AUSSIE-MADE.

Coupled with a super-low 1.225 kHz operating frequency of the GPX 6000 - it's no wonder the GPX 6000 is a gold magnet !     (By comparison the GPX 5000 "is configured to operate at a fundamental operating frequency of 5 kHz", and the GPZ 7000 "is configured to operate at a fundamental operating frequency of 3.675 kHz”, whereas for the SDC 2300 "the transmit frequency is about 3 kHz")

With the gold price at a near all-time-ever record high (over AU$3,000 per Ounce in early September 2023) - you only need to find less than 3-ounces of gold to cover your investment cost of a new GPX 6000.

Aussie-made  Coiltek  GOLDHAWK  coils

The Minelab GPX 6000 detector has now been available for nearly 2 years. Many prospectors throughout Australia have re-visited goldfields, including their “fav” patches, that they considered “flogged” and then unleashed the GPX 6000 over such areas to find even more gold, including at depth.

The popularity of the GPX 6000 is not only due to its high performance, but also because it is of relatively light weight (50% lighter than the Minelab GPZ 7000), and it is very easy to use - even for “newbie” detectorists, and budding “prospectors”. It also costs approximately 20% less (a few thousand dollars less) than the Minelab GPZ 7000.

Now, there are even more coil options available for the GPX 6000 detector. In fact, there are currently more coil options available for the GPX 6000 than for the GPZ 7000.

With Minelab’s approval, long-time Aussie coil-maker ‘COILTEK’ recently released a range of 3 different sized Monoloop (“Mono”) coils for the GPX 6000. These are named the ‘Goldhawk’ series of coils.

The Coiltek Goldhawk coils (very pale tan coloured) are rated as waterproof to 1-metre depth, have a 2-Year Warranty, and include the following sizes/weights:

9 inches round - cost $609  (weighs 700 grams)
10x5 inches - cost $579  (weighs 575 grams)
14x9 inches – cost $639  (weighs 900 grams)

Feedback so far, including from many gold hunters throughout Australia, has been impressive as to how stable (smooth & quiet) the coils run, and how sensitive they are to all sizes of gold nuggets, with great depth capabilities.

Many people also prefer the elliptical shaped coils, for not only ease of use in confined areas/less-open ground/more vegetated ground, but also for better pinpointing capability than a round coil.

 Minelab GPZ 7000 - a Deep Gold Getter

The Minelab GPZ 7000 detector was released about 8 years ago in 2015. Costing nearly ten grand, this Minelab detector is suited for serious/deep gold hunting. Experienced users often refer to the GPZ 7000 detector as the "7"or "7,000" or "Zed".

Unique ZVT Technology
The GPZ 7000 is a unique detector as it features Minelab-Patented ‘Zero Voltage Transmission’ (ZVT) technology – which, technically, is different to both Pulse Induction (PI) technology and Very Low Frequency (VLF) technologies. The inventor of the patented Minelab ZVT technology, Dr Bruce Halcro Candy, explained the differences between VLF, and PI, and ZVT technologies as follows:

“Very Low Frequency (VLF) – VLF sinewave detectors have a major disadvantage in having to ground balance out, all of the soil signals simultaneously (all three soil components above).
Pulse Induction (PI) – PI metal detectors have a major advantage of not even detecting the major soil signal; the X component, but only the saline components, but this is mostly insignificant, and the VRM component, which is just a very small percentage of the X component.
This makes the capability of PI technology to ground balance far more accurate than VLF detectors.
A disadvantage of PI is its lesser ability to detect very small nuggets compared to VLF detectors.

Another disadvantage of PI is its capability at detecting very large nuggets compared to CW metal detectors, such as ZVT. CW means Continuous Wave and includes all technologies that do not have zero transmit periods (almost all technologies other than PI).

Zero Voltage Transmission (ZVT) – ZVT has the same major advantage as PI for ground balancing in not detecting the major soil component X, but has the same advantage of CW metal detector technologies compared to PI for detecting very large nuggets because ZVT is CW (unlike PI that is not CW), and also the same advantage as PI for being relatively insensitive to saline soils compared to VLF.”

So, in simple terms - you get the best of both worlds - ZVT technology has the same excellent ground balancing properties of Pulse Induction (PI) technology while retaining Continuous Wave (i.e VLF) technology's ability to detect very small nuggets - so you can find more gold of all sizes, including deeper, even in highly mineralised soils.

Advantages of the GPZ 7000 Super-D coils - compared to Monoloop coils for PI detectors
Conventional configuration Monoloop (“Mono”) coils, and Double D coils, would both not operate effectively with ZVT technology. Hence, Minelab invented the ‘Super-D’ configuration coils (sometimes referred to as a “DOD” configuration coil).

The Minelab Super-D coils consists of two symmetric D shaped receive windings (one on the left and one on the right), with a central, oval-shaped transmit winding. This Super D coils winding geometry provides a double audio response for shallow targets, and a single audio response for deeper targets.

The Minelab Super-D coils have also been designed to have minimal response to the impacts of scraping and knocks to the coil housing - which can cause annoying false signals during detecting e.g. some PI detector coils suffer from this.
The Minelab GPZ14 Super-D coil (which is actually 14’x13’ in size), and the bigger GPZ19 Super-D coil (actually 19’x18’ in size, and weighs 1.83kg), are also both waterproof to a rated depth of 1 metre. The GPZ 7000 detector control box & control panel are NOT rated as waterproof.

Other Features of the GPZ 7000
Unlike the GPX 5000 and GPX 6000 (and most other Minelab detectors), the GPZ 7000 features a concealed coil cable whereby the coil cable (and plug) is housed (internally routed) within the removable lower shaft.

Unlike the GPX 6000, the GPZ 7000 does not have a built-in speaker. However, the GPZ 7000 is supplied with a wireless ‘Audio Module’ speaker (WM12).

With 256 Noise Cancel channels, the GPZ 7000 has enhanced immunity against Electromagnetic Interference (EMI), and hence picks up less atmospheric noise, including from power lines, electrical equipment, and also other metal detectors operating nearby. There are two options to Noise Cancel - either via Auto Noise Cancel function (Default), or manually. Auto is the recommended setting, and may take up to about one minute.

Most people immediately notice the weight difference between the 7000 (3.22kg) and the younger Minelab sibling GPX 6000 (2.1kg) - with the 7000 being about 50% heavier than the 6000.
The use of a quality Bunji/Bungee/Bungy cord can effectively reduce the "swing arm-carried" weight of a detector by at least one-half (50%) e.g. so that the GPZ 7000's "felt weight" is comparable to the full weight of the GPX 6000.

Recommended Techniques for Achieving Optimal Performance
Like other Minelab detectors, good ground balancing techniques are crucial to getting the optimal performance capabilities out of the detector. The initial ground balancing technique for the GPZ 7000 IS DIFFERENT to the technique you should use for a Minelab Pulse Induction (P.I.) detector like the GPX series of detectors. Minelab recommend the following ground balancing technique for the GPZ 7000:

“Ground Balancing   VERY IMPORTANT
The best way to ground balance initially after switch on with the Quick Trak trigger depressed, is to sweep the coil in a typical side to side search mode at the expected operating height above the soil surface, e.g. 2–3 cm or whatever the soil saturation or terrain will allow, but at the same time move forward at slightly faster than normal walking speed, so as to cover as much different ground as possible in the first 10 to 12 seconds. The idea during this initial period after turn on, is to expose the detector to as much different soil data as reasonably possible to improve the
initial calibration.
IMPORTANT!   DO NOT ground balance using a coil up and down motion (like one would do using a PI detector) initially after turn-on with the Quick Trak trigger depressed. This does not give the initial calibration enough different soil information to calibrate optimally. If ground balance is required again sometime later (but without turning the detector off), ONLY THEN is the usual (PI type of) ground balancing up and down coil motion OK.”

Minelab Software Updates
There have been two software updates released by Minelab for the GPZ 7000.
The first update (released in 2015) related to a new auto ground tracking algorithm, and improved auto ground balance function.
The second update (released in 2017) featured an all-new ‘Ground Smoothing’ function as a primary enhancement. This function provided selectable noise filters that help deal with difficult ground, especially salty soils. A ‘Semi-Auto’ setting was also added to the ‘Ground Balance Mode’ to provide improved ground balance stability.

Yellow Ferrite Ring Ground Balancing
Minelab also recommended the use of their Yellow Ferrite Ring for optimal ground balancing.
Minelab stated:
“It’s very important to Ground Balance the GPZ 7000 using the yellow ferrite at the start of your detecting session. By doing this, any ferrite-like components encountered in the soil will not cause any false signal audio responses. The updated software shows the use of the yellow ferrite as part of the animated guide sequence when you follow the Quick Start/Quick-Trak process. (This is also a way to determine if a GPZ 7000 detector has the new software installed.)”

Accessories included with the Minelab GPZ 7000 detector
Accessories included in the Minelab GPZ 7000 box (in addition to the detector + Minelab GPZ14 coil) are:
Quick-Detachable Control (Guide) Arm + WM12 Wireless Audio Module + KOSS headphones + Pro-Swing 45 Harness + battery charger & charging cables.

Optional Coils
The Australian company ‘Nugget Finder’ (NF) recently released the Minelab-approved ‘Z-Search’ range of non-spoked coils, namely a 17x13" elliptical coil, and also a 12" round coil. These coils have a DOD configuration, a 3year Warranty, and are rated as water resistant to 1metre. These NF coils also include a Minelab lower shaft.

Several incredible gold nuggets have been discovered in Australia over the past 8 years using the GPZ 7000, including down to depths of about 1 metre, and no doubt yet more big nuggets will continue to be unearthed.

TIPS  FOR  GOLD  HUNTING  IN  WESTERN  AUSTRALIA  –  Part 3

DETECTING TECHNIQUES
Gold Detecting Tips:
1.    Upon commencing detecting each day, consider doing a “Factory Preset” (on the GPX 6000) or “Reset Audio & Detection Settings” (on the GPZ 7000) – in order to optimise the operational performance of your highly-sensitive, Minelab pulse-induction detector.

2.    Be patient, the gold is not going anywhere – if the GPX 6000/GPZ 7000 becomes a bit noisy or “chattery”, then do a noise cancel followed by manual ground balancing using the “Quick Track” button. Some days I do this often throughout the day. This will optimise the performance of your GPX/GPZ so that you are not wasting time and possibly missing those quieter/faint target signal noises often associated with deeper gold.

3.    Swinging technique is also VERY CRITICAL to how much gold you are likely to detect. The “Low and Slow” rule is VERY IMPORTANT to find more gold. On soily ground (without too many sharp rocks) I would lightly and slowly rub my coil upon the ground, with overlapping sweeps from side to side, in order for the detectors pulse induction to energize gold nuggets as long as possible, and so as to increase the chance of the nugget being detected. I found that the coil skid plates lasted longer than I expected, and they are a small expense to pay for the benefit of finding more gold. (The gold price recently hit an-all-time record high of about AU$3,000 per ounce – nearly $100 per gram).

4.    After finding a gold nugget, and then re-checking the back-filled hole, I would always do a Noise Cancel, and a manual Ground Balance, to optimise the operation of my detector to find further nuggets.

5.    Whenever possible, and about half-way during a day of prospecting (during my midday lunch break), I would replace my detector's Lithium-ion battery with a fully charged battery.

6.    A Guide Arm (or Control Arm) attachment to the shaft of your detector can also be very useful. The end-grip of the guide arm is held by your non-detecting hand, so as to provide precisely controlled swinging of the coil within both the horizontal and vertical planes. The guide arm is also great for distributing some of the detector weight to the strength of your non-detector arm. I found that a guide arm greatly increased my prospecting comfort, especially on long, consecutive days of swinging.

7.    A Bungee cord (also often called a Bunji or Bungey cord) is often worn by many prospectors using the heavier GPZ 7000, especially if it is being swung for sessions of longer than a few hours. I also used a bungee cord on my GPX 6000 (attached from the shaft of my detector to the “D” ring on my harness) to minimise fatigue since I would mostly swing my 6000 for about 8 hours a day (equivalent to the running time of a fully charged battery). Some weeks I would swing for 7 consecutive days (that was about 56 hours of swinging a week). I found using a bungee made a huge difference to my muscle fatigue, and it provided me with greater swinging endurance time per day. More swinging = more ground coverage = more gold.

8.    If you find a gold patch, then use all the suitable coils you have on the patch, and also then thoroughly over the patch – that is, not only sweep-swinging on a grid-like pattern in both perpendicular directions, but also at angles across the patch. It never ceased to surprise me how much more gold I picked up with the GPX 6000 by detecting in many different directions on a patch. I would firstly exhaust the patch of gold using the GPX17” mono coil. When I was finding little more gold on a patch, I would then run the GPX11” mono coil over the patch and find more gold. Finally, I would then put the GPX14” DD coil and often find some more gold.


UNFILLED HOLES
One of my pet hates .... unfilled holes dug by lazy detectorists/prospectors - it ain’t rocket science.
Besides, it is generally much quicker to fill in a hole than dig it.
Who would like strangers coming into their yard and digging holes? let alone leaving them unfilled?
To me, leaving their holes unfilled is a reflection of, not only someone’s personality, but also their professionalism as a prospector.

During my several years of prospecting in W.A., I reckon I encountered tens-of-thousands of holes, some up to about 2-feet deep, left unfilled by other people using detectors. Most poachers do not backfill their holes - for various reasons.

I would often run my detector over many of these unfilled holes and find trash left in them, or in the adjacent spoil.

Fortunately, on about half a dozen occasions, I found small gold nuggets either still remaining in the hole, or in the spoil beside the hole - that were missed. On two occasions I found two nuggets within a hole after digging out the holes deeper.

Always re-check your holes & the spoil, and then check again after you have back-filled them. You might just get a nice surprise, like I did on a few occasions.


THEY NEVER GET ALL THE GOLD
One day I encountered two old "blow-in" (from interstate) prospectors near Kalgoorlie detecting some recent scrapes using a GPZ 7000 with a Minelab GPZ 19" 'Super-D' coil and a "modified" GPX 4500 with a Coiltek 18" Elite Mono coil.
 
I also had written permission to be on that lease to detect gold using my Minelab GPX 5000 with my new Nugget Finder 15" Evolution mono coil.
I got yarning to these blokes as they were packing up to leave. They loudly boasted that I "would be absolutely wasting my time" detecting the scrapes with my "stock 5000" as they "had completely flogged the ground" with both of their "high performance" detectors.

After they left, I fired up my trusty & proven workhorse GPX 5000, and I unleashed it upon that ground with enthusiasm. The first thing I did was walk upon the top of the many windrows (soil bunds created via machinery pushing/scraping operations), and I detected their tops, and both side batters.

Over the next few days, I pulled out over several ounces of gold (40+ nuggets) including a stunning half-ouncer at a depth of 1.5 feet. Most of the bigger nuggets were within the windrows. Other blokes who had recently pushed this ground with a loader not only failed to detect the nuggets in the windrows, but so too had these two "mature"-aged interstate prospectors missed all these nuggets. I had found more-than-enough "missed gold" to buy a brand spankin' new Minelab GPZ 7000. I had a few quiet chuckles to myself.

Over the next few years I was often amused hearing others claim they had "flogged" areas. This always presented a challenge to me - to try and prove them wrong. In the vast majority of cases I always found multiple nuggets from such so-called "flogged" ground.

It would seem to me that it was highly likely that all of those hundreds of nuggets I found on such so-called "flogged" grounds was due to poor detecting techniques used by others (including lack of patience and thoroughness).


TERRAIN/GEOLOGICAL INDICATORS
The vast majority (90%+) of gold nuggets I found in W.A. were detected with a distance of about 0.5km to 1km of a hill or hill/s. Many nuggets I detected were on the sides of hills or near the toes of hills too. A salt lake/s was often nearby too, within about 1 to 2 km's.

Most of the biggest nuggets I found in W.A. were at depth, often nearby large/old trees, and they were either within gold patches containing numerous nuggets, or nearby at least a few other smaller nuggets.

I also detected many nuggets buried under tree logs & branches that I carefully moved (watch out for snakes). Sometimes I would find unfilled holes scattered nearby/beside big logs that, surprisingly, had not been moved. I would then move these potential "nugget covers" and sometimes detect gold nuggets below. Many part-time/hobby detectorists are not absolutely thorough in their physical quest for gold. Full-time prospectors mostly think-outside-the-norm, and also take those extra, hard-yards steps to find more gold - probably because for many of them, their (and their family's) livelihood/s depends on it.

Saltbush vegetation was often nearby where I found gold too. I found several great nuggets beside the roots of saltbushes.

Often where I found gold (and other long-time local prospectors told me the same too) nearby was any/many of the following geological indicators:
Quartz + ironstone (often called “salt & pepper” ground)
Laterite ground
Banded Iron Formations (BIF's)
Greenstone belts
Jasper
Fault lines and contact zones (sometimes they can be naturally marked by way of obviously contrasting/sudden changes in vegetation types)

Many long-time, local prospectors in W.A. enjoy going out prospecting after heavy rains (when unsealed roads are not closed and not boggy) - since good gold is often eroded out of the ground and exposed, to be possibly spotted by a sharp-eye, or become within the range of detection of a detector coil.

REFERENCE BOOKS

There are many good books (and atlases) available for information on gold prospecting in Australia. I particularly like reference books that contain good maps, including locations of historical gold workings & mines. For decades in Australia, aussie prospector Doug Stone has authored several such prospecting books & atlases, including for Western Australia.


SIMPLE AIR-DEPTH CALIBRATION TEST:
At the start of every prospecting session, after turning my detector on and then doing the Noise Cancel, and Ground Balancing procedures, to get the detector running quiet & smooth, I would ALWAYS do an air-depth detection calibration test - to ensure my detector was running at near optimum performance for depth.
For this test I used a new/clean Aussie 5 cent coin (that I would always carry in my pocket), and I would confirm the maximum height (above the coin-on-the-ground) that the coil could just detect the coin.
Around Kalgoorlie, I generally obtained the following air-depth testing/calibration results (on an unburied 5 cent coin) for the respective Minelab detector & coil/s that I was using:

GPX6000 with 11" round Minelab Mono coil = 14" depth
GPZ 7000 with 14×13" Minelab Super-D coil = 16" to 18" depth
GPX 5000 with 19" round Nugget Finder Evolution Mono coil = 16" to 18"depth
GPX 5000 with 25" round Nugget Finder DD X-Search coil = about 20" depth

The above air-depths were the absolute maximum detection depths I generally achieved, and less than the detection depth of the same metal target buried in the ground, especially in highly mineralised ground.

Pulse-induction detectors will generally lose depth performance to some degree in highly to extremely mineralised ground, particularly when using highly-sensitive, flat-wound Monoloop coils, and especially as the ground surface temperature increases.
In "difficult ground" (highly mineralised and/or conductive), and sun-heated ground, a DD coil of at least the same diameter (albeit heavier than a Monoloop coil of the same diameter) may be more of an advantage.


PICKS
For extra grip for my big hands, and also for increased shock-absorbing capacity, I fitted a rubberised tennis handle wrap to my pick handle.

I always had a super-strong, round/flat, rare earth magnet mounted upon the top middle of the head of my pick. It was great for pulling out iron-based trash e.g. wire etc. It also often grabbed hot rocks. Don't just assume that all such hot rocks consist totally of iron and don't contain any gold. Over the years I found several hot rocks on my magnet that when broken up contained gold.


RECORD & SECURE YOUR NUGGETS .... & 4WD KEY
Most gold prospectors I have met (hundreds of them) use a plastic container (i.e. a used medication-type bottle) in the field to store their smaller, found gold, and most carry that container in either their shirt pocket or trouser pocket.

Over the years I was told by several local W.A. prospectors that they had found small plastic pill-type containers apparently dropped in the bush by other prospectors. Most contained gold nuggets. One bloke told me the container he found had 19 nuggets in it, totaling about an ounce. It was found on 'Pending' ground.

I store my freshly found nuggets within a plastic container, either secured:
(A) inside a zippered, deep compartment inside my backpack (together with the keys for my 4WD); or
(B) inside my trouser pocket - with a lanyard made from strong, pink coloured string that is securely connected from the bottle thread to a belt loop on my trousers.

I also use compact (pocket) digital scales to weigh, and I also photograph my significant gold nuggets in the field immediately after finding them.
That way if you then lose such a valuable nugget/s (either by accident, or it being stolen), at least you have a digital record (with a date & time stamp) of you having then had possession/ownership of it prior to it being lost or stolen.


LOOKING AFTER THE BUSINESS END OF YOUR DETECTOR
I regularly inspect my detector coils for any damage, and very carefully/gently remove the coil skid plate to clean out any dust and soil that may possibly congregate over time. In Western Australia where highly to extremely mineralised soils are common, such very fine mineralised dust can eventually find it’s way into between the coil and the skid plate.

This is even more likely to occur for large diameter spoked coils, compared to small round solid coils – mainly due to the significantly more total length of the contact faces between the coil and the skid plate.
If enough such material gets in, and also moves around whilst swinging, then this can affect the performance of highly sensitive, pulse-induction detectors.

I also wrap the circumference of all my coils with a quality adhesive tape. This acts as both a seal against any possible ingress of moisture and/or dust, and also as a protective layer on the outer vertical edge of the coil which nudges/rubs on soil, rocks, etc. I prefer Scotch heavy-duty grade ‘SUPER 88’ vinyl tape. It usually lasts me several months of swinging.

Talking about dust - which can find its way into almost all small gaps - it can pay to make sure that all the pin connections for all cables (like the coil cable plug, and also any battery cable plugs) are fully inserted, with the screw rings also done up firm.

Given the tens-of-thousands of dollars I spent buying pulse-induction metal detectors over the years, I always protected these investments from the dust, heat, and potential damage (e.g. caused by impact/scratching etc), by way of fitting quality, Aussie-made, padded canvas protective covers over the control box of each detector. Such protective covers can also protect the manufacturer’s labels of serial number/security codes – which may be useful down the track.
Furthermore, for concealment and ease of transportation of my detectors and accessories, I also use quality, Aussie-made, padded canvas carry bags for all my detectors.

When I was gold prospecting full-time in W.A. I soon learned the benefit of dusting down my detector & coil/s at the end of each day (with a soft cotton rag), prior to placing my detector & coil/s into the padded carry bag. This end-of-day ritual sure helped minimise the amount of fine dust that got caught inside the canvas carry bag. After every week of prospecting I would empty my carry bag of it's contents, and then turn it inside out to thoroughly shake out any dust that had congregated. I also kept all electrical-related accessories (like spare cables, and batteries and headphones, etc), within separate plastic clip-seal bags to minimise any dust entering the plugs or connections. This held me in good stead for years without any issues.

[Nugget image source - Facebook page of Finders Keepers Gold Prospecting - Kalgoorlie, W.A.]