Treasure Talk blog posts on the GPX 5000
How much deeper does the new Minelab detector go compared to the previous model? I hear that question a lot and to be honest get a bit stumped on it. Not because it’s hard to answer. It’s just more complex to explain properly without going to the major effort of demonstrating it to the uninitiated…
Whenever I hear the term ‘’every man and his dog has been there” I am always up for the challenge as to see what they have left behind for me. On a recent trip to the Goldfields I decided to spend my time working some old diggings located in a gully that over the years has been well known to many prospectors. Including myself as a 12 year old where I found my very first nugget operating the XT 17000.
Every detector operator approaches an area in their own unique and individual way. Whether that be deciding to venture off in a certain direction because something in the distance catches your eye. Things like a certain type of tree or shrub, quartz and ironstone, rabbit warrens presenting the deeper ground mineralisation or even something as simple as a web containing a big spider in the centre of it. Resulting in the prospector detecting in another direction as to what they normally would. As long as you are out moving that coil around you are in with a chance of finding something that has been missed by others.
One might think that within not too long a period a person could run his metal detector over every inch of ground inside a mine. However because the Original Sixteen to One is a combination of a number of old mines and the property has been worked on a more or less continuous basis for well over 100 years, there are literally miles of old underground workings to explore and one could spend a lot of time going over every bit of the vein that was exposed in the walls of the old workings.
The time had finally arrived! I was on the plane flying back to the Victorian Gold Fields all the way from far North Queensland, meeting up with my old man to spend some time hunting down that elusive yellow metal. I had spent a lot of time gold prospecting around the triangle with my father over the years with both of us uncovering many great finds, so I was very excited to be going back to my old stomping grounds. To add to the excitement I would be swinging a brand new GPX 5000 as I recently traded in my GP 3500. I was also very keen to try out the new Fine Gold Timings on the GPX 5000 after hearing so many great things about this new Timing.
All good adventures have a beginning and an end, and ‘The West Australian Adventure’ was no exception. Personal reflections made when you’ve had time to sit down and go over your experiences all over again is what truly makes a great adventure and to that end they put this trip right up there with my all-time favourites. As I write this I’ve just received word from Chris Ralph who is waiting for an early flight at an Airport in the US, he’s on his way back home from a whole new adventure with Steve Herschbach poles apart from our trip last year. I’m amazed to find it’s been close on a year since we parted, so I suppose WA was truly a great adventure as it’s taken nearly a year to tell the story!
When I look back on the latter part of trip with the benefit of hindsight’s 20-20 vision, I finally realise that what I was now noticing in Chris and Steve’s behaviour was mirrored closely to the freeing up of my own worries and concerns in trying to get them over gold each and every day. This phenomenon is a pretty common occurrence in the gold game, you at first manically try to find crumbs all day every day then towards the end of the trip tend to back off and relax, its then that things generally come into alignment. Chris and Steve now knew the drill; they had confidence in their detectors and felt more in tune with their surrounds which was then subsequently reflected in their gold finds.
Cement as the name suggests is very hard, requiring special methods and tools. In this blog post I wish to discuss the way I set up our GPX 5000s to get maximum performance in the location seen in the video.
Firstly the area was well known to me and as a consequence has seen a lot of attention with all previous models of Minelab detectors dating back to the SD 2000; as such it’s a very good litmus test to the effectiveness of any new Minelab design!
Being asked to have a play with the PRO-FIND 25 pinpoint probe lacked excitement for me based on past experiences with similar devices due to a number of factors. Firstly a lack of sensitivity to small nuggets especially in mineralised soils and secondly my GPX 5000 would pick up my previous pinpointer from a long way away even when the thing was turned off!
The GPX 5000 has quite an array of Timings and selecting the right Timing to get the most out of this detector requires a little understanding of the ground you are working. Certain Timings work better in certain environments, and understanding the gold bearing ground conditions is an advantage in choosing the best Timing. However sometimes using a pair of Timings can be even more powerful.
The day I found the 17 gram nugget turned out to be very exciting, we all had our eyes well and truly opened to the power of the GPX 5000, especially the new Enhance and Fine Gold Timings.
The day started crisp, clear and cool. Chris and Steve were now well and truly immersed in the adventure, having perfected their Australian detecting techniques over the previous few weeks to the point they were now naturally targeting productive areas with their GPX 5000s.
The day previously, Steve, Chris and I were working an old scrape taking turns to detect the richest sections of ground where cap rock was exposed (cemented wash with gold enclosed), assisting each other with hammer and chisel to remove the nuggets. Due to the
Our third week was inter-mixed with confused emotions about the trip; we were on the home stretch with the days now being measured by how long before hopping a flight home. Both Steve and Chris were feeling the effects of the time away, both from a comfort point of view due to their mattresses being too thin for the hard Aussie ground, but also due to the effects of being away from loved ones and familiar surrounds...
When the GPX 5000 metal detector was released, some existing GPX-4500 users questioned whether it was a GPX-4500 with a new Timing for very small gold, and a make-over in the colour department. While these were true, the GPX 5000 has a few extra tricks up its sleeve!
Detecting a Gully/Wash
Our first week ‘Out Bush’ was an eye opener for everyone, for me because I was seeing my homeland through the eyes of others and for Chris and Steve because even though metal detecting is a familiar pastime the world over, Australia’s particular brand of geology is pretty unique due to the sheer age of our rocks and more particularly the oxidisation of those rocks through eons of weathering.
‘Did I just say that out loud?’ I asked myself replacing the receiver of the telephone after talking long distance to Reno, Nevada where Chris Ralph, aka ‘Reno Chris’, the author of ‘Fists Full of Gold’ lives. Chris and I go back a reasonable distance after having met each other on a couple occasions when I was in Arizona doing lectures for ‘Arizona Outback’ and I instantly took a liking to the big friendly American with the ready smile and loud booming voice.
When the GPX 4800 and GPX 5000 metal detectors found their way onto the red clay fields of Virginia the results were outstanding in the way the detectors ignored some of the worst soils in the United States. We have seen targets come out of the ground at impressive depths and more importantly we have seen targets that were just below the surface in areas that were undetectable in the past.
There is however, one observation I made while hunting the area that I would like to pass along to those detecting in these soils...
Historically, discrimination when gold prospecting has never been encouraged due to the danger of a very impure nugget or one encrusted in ironstone being miss-read as being ferrous. For this reason, it is usually best to recover all targets, especially when you are working a known gold producing patch. However, in real trashy areas, it can take days to dig out every bit of metal present, and it’s these spots that many operators walk away from. When used correctly, discrimination can allow you to detect these high-trash areas successfully.
The GPX 5000 metal detector has a Search Mode switch that is located on the front control panel at the top, just below the Threshold adjusting knob. The markings are: Deep, General and Custom. These are the names that Minelab decided to label them. The Search Modes could have been called 1,2 and 3, or any other sequence, but the function these Modes have are the important part. The factory presets for these are set so that Deep Mode can be utilised for...
We hitched up the caravan to our truck and headed across the Nullarbor plains on another gold seeking adventure. This time round I was asked by Minelab Electronics to do some field-testing on the upcoming GPX 5000 especially the new timings that would be incorporated in the design.
In recent years Frieda and I have discovered life is much simpler to pick a good area to camp and stay put rather than packing up and moving camp every few weeks...
On page 63 in the GPX 5000 Instruction Manual, Gain is described as being:
“…..a function that allows the GPX Series to be optimised for differing conditions; controlling the sensitivity of the detector to its environment and targets.”
Basically speaking this means you can use the Gain control to lift or brighten the response from a signal, a little like increasing the volume of your detector but in a more dynamic way.
Since the release of the GPX 5000, one of the lesser talked about new features is the Salt-Gold timing. This replaces the Salt-Coarse timing found on the GPX 4800 and previous GPX and GP series models, so what is different about it?
For my fourth blog on Treasure Talk I want to pass on some of my experiences about achieving a good Ground Balance (GB) when using Smooth, Enhance or Fine Gold. As most of you will know by now the 'Smooth Class of timings' were developed for the GPX Series to allow the use of a Monoloop coil in highly mineralised soils. The timings do this by removing a lot of the ground signal, however in doing so they also remove a small amount of the target signal too, dependent on Ground Balance position, target orientation and more particularly size and shape of target.
The reason it’s suggested a Monoloop coil is better for performance is they provide better...
The first thing new comers to detecting will learn is, detectors are all about noise; they can seem like a talkative child who rambles on incessantly with the poor listener not being able to make head or tail of what it is they are trying to say. Noise or the lack of it is one of the main reasons why Minelab have what is considered to be the “World’s Best Metal Detection Technologies”. In my first blog as a guest writer for Treasure Talk I want to talk about noise and why I feel the lack of it makes the GPX 5000 so unique.
The GPX-4000 metal detector first introduced a special ground balance mode called Specific Ground Balance which is still used in newer GPX detectors. This ground balance mode may allow the detector to ground balance in areas that otherwise would have too much ground noise. The Specific mode uses a special second-order ground balance algorithm that can deal with more complicated ground responses than the normal first order ground model.
If you ground balance in the normal way and the detector still displays ground noise then this may be a situation for Specific ground balance mode.
I have heard from some users that have tied themselves into knots when trying to find the best settings for their detector. This can happen because there are some combinations of settings that don’t work well together and there are some lesser used settings that you may have set and then forgotten to check.
In these cases please remember to perform a Factory Preset. This will return your detector to the settings that it contained from the factory.
By now you have probably seen the GPX 4800 and GPX 5000 brochures and seen the term ‘Improved electronics’. This post will enlarge on this feature a little and demonstrate an effect of the changes that will enhance performance in the field.
I love testing new detectors, but having had so much success with the GPX-4500, I wondered, could we improve on it?
Well after many hours of product development, lots of fine tuning, countless hours of testing by internal and external testers, at locations all over the world, the GPX 5000 was perfected. I started testing simply by carefully burying a range of gold nuggets of different sizes at varying depths, and comparing the signal response of the GPX 5000 to the GPX-4500. So far so good, the GPX 5000 got everything the GPX-4500 did, and certain targets gave a much clearer signal in the new Fine Gold timing compared to Enhance on the GPX-4500.
In this post I will try to explain the GPX audio controls in a different way to that described in the user manual. There are tools available on a web page that can't be used in a printed manual. I'd like to try and visualize the way that the audio controls affect the sound that the operator hears
In my travels, talking to Minelab GPX users I have encountered few people who make much use of the mode switch. When we first designed the GPX-4000, after much discussion we put a 'Mode' switch on the front panel. Our intent with this switch was to try and let operators do one of three things with this new switch.
1. New users could easily change the character of the detector before learning the finer points of the settings in the menus on the LCD. This is a bit like using the dial on the top of your digital camera to change between Sports, Portrait and Night modes...
Metal detectors are sensitive instruments designed to detect small changes in magnetic field. Nearby metal changes the field as intended but so do far off thunderstorms, electric motors, electric fences, RF transmitters, power lines and nearly everything that a modern society plugs into an electrical outlet.
Many of Minelab’s metal detectors have a function that allows them to locate and avoid these interfering signals. In some detectors we use the term ‘Noise Cancel’ while in others we use the term ‘Tune’, ‘Auto Tune’ or ‘Manual Tune’. These terms all refer to the same thing, that is the process where the metal detector or the operator searches through the available tuning range, looking for the quietest point at which to operate...