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  1. I thought I was pretty damn good, but this technology has me beat. https://www.nbcnews.com/science/environment/mining-gap-companies-push-find-raw-materials-electric-vehicle-boom-rcna5077 Might be time to invest?
  2. Metal detectors often seem to have a 'Depth Gauge'. How is it calculated? Is it the strength (or inverse of it) of the amplitude of the return signal? So, for instance, everything else being equal, the 'deep' target would mean either a stronger target at greater depth or a weaker shallow target?
  3. While we're all abuzz with the announcement and advertised feature and performance characteristics of the XP Deus II, I'm wondering about tests that distinguish between detectors' target separation abilities. 'Word on the street' is that in trashy iron sites, the original Deus is still the best available. Presumably those reports are based upon in-field testing, which of course is the real proof. But the downside is, (AFAIK) these are qualitative observations, not quantitative. Subjectivity involved? Unfortunately, yes. We do have Monte's Nail Board Test for a special case -- iron nails near a single coin, all in the same plane and typically all on the surface of the ground. Add depth combined with some mineralization (burying the MNB) and you've included another real world dimension. But in the field, multiple nearby targets are seldom in the same plane. So you hopefully see the purpose of this post. Has anyone seen/tried other methods to better simulate actual in-field conditions to differentiate between competing detectors to best be able to handle trashy sites?
  4. I mostly hunt in lakes and the bottoms are mostly all sand. A test on a sandy beach with the Equinox 800 and Xp Orx, both hit hard on a 14k 3.7 gram gold ring buried at 14". For mild ground I don't see a need for multi frequency. I do like the multiple frequencies on the Orx. Is there an advantage to multi frequency in mild ground?
  5. We have the Deus 2 just announced, Nokta/Makro Multi on the way, possibly the next generation Equinox from Minelab, and maybe even another Garrett multifrequency model to follow Apex, all coming in 2022. I guess we should even toss First Texas in there, as they just officially discontinued the CZ-3D, with the possibility something new will replace it soon. If this does not mean we are moving past single frequency, I don’t know what does. Or are we? There will no doubt always be a place for a finely tuned single frequency detector. However, if you consider Deus as selectable frequency, and Equinox as selectable/multi, then very many of us have already moved past a simple single frequency detector as our primary detectors. This is the thread to speculate on what is coming, where we are, and where we are headed. 2022 is shaping up as the year SMF (simultaneous multifrequency) finally takes off for real. In some detectors, it’s just companies chasing the latest marketing catchword. Multifrequency is only as good as the way it is implemented, otherwise we’d all have been swinging White’s DFX ages ago. It’s not enough to make a SMF detector, it also has to have genuine performance advantages. About the only given is that any multifrequency machine will outperform a single frequency on a saltwater beach. The rest, however, is very much up in the air. For some detailed explanation of the technology, and a history of past selectable and simultaneous multifrequency detectors, see my write up on Selectable Frequency And Multiple Frequency Where it all started, Fisher CZ-6 and Minelab Sovereign, both released in 1991. I think Fisher wins claim to being first, since Minelab takes a swipe at them in their Sovereign introduction. Notice how the misdirection on transmitted versus received and processed started on day one. Fisher CZ-6 Quicksilver. The technology: Dual frequency Fourier Domain Signal Analysis. Patented state-of-the-art analog/digital electronics transmit two VLF signals (one 5 kHz, one at 15 kHz) deep into mineralized soil. The receiver circuitry had two ground compensated target signals to analyze, compare and identify. The result? Deeper targets, more accurate target identification. Wet sand is no problem for the CZ-6, it compensates for salt and ground mineralization simultaneously! Source Fisher CZ-6 Datasheet "The Sovereign" is the first of the latest generation of metal detectors from Minelab featuring Minelab's new technology called Broad Band Spectrum or BBS for short. This revolutionary new technology which is unique to Minelab has already been awarded patents in the USA, Canada and Australia and has several pending. Unlike other metal detectors which operate at just one frequency, or even the "newest" two frequency machines, "The Sovereign" actually transmits over a wide spectrum of frequencies. The resulting signal that is received from a target buried in the ground is processed by a microprocessor that removes interference caused by ground mineralization which limits the depth at which targets can be found, and often results in inaccurate target identification. The remaining signal can then be analysed to determine the actual composition of targets even if they are deeply buried, or if the ground is mineralized or salt water is present. Thus it is the only detector that can simultaneously reject both salt and mineralization while at the same time accurately discriminating the target, making it ideal for black sand beaches and many desert areas. In many areas that are highly mineralized and have been heavily searched in the past, "The Sovereign" will prove that many of the valuable targets are still there waiting for a Treasure Hunter with the proper detector to locate them. Source Minelab Sovereign Instruction Manual
  6. I love coinshooting, and I'm often in my local parks or private permissions searching for clad and silver coins. But I noticed that when digging up shallow clad coins (3 inches or less), my AT Max with the stock coil would say the coin is 6 inches down. Sometimes, a surface coin would read at being 4 inches deep. I didn't think this was that big of a deal, b/c I could always pull out my F-Pulse and see if the assumed coin target was truly shallow or not. Also, the incorrect depth reading wasn't keeping me from digging a desired target. Tonight, I read: and http://www.fisherlab.com/hobby/davejohnson/SearchcoilfieldshapeApril2012.pdf Both of these mentioned anomolies or issues with DD coils and shallow targets. Is what I'm experiencing with my shallow coins and AT Max one of these anomolies? Or is there something else going on?
  7. speculation please. what does the future hold? what advancements might happen? keith southern are you out there?
  8. I got in a few hours of metal detecting yesteday with my AT Max, which included some time at a park and a few permissions (private homes). Nothing of note was found, although I continued to struggle with trying to find good targets in high-trash soil. Given how I'm using the Garrett AT Max, I know have two primary options for finding good targets (silver coins) in these types of conditions. First, get a smaller coil, like the 5x8. Second, start digging the trash targets to clear up the ground and reveal possible good targets that are being masked or otherwise "overshadowed" by all the bits of aluminum, nails and other garbage. The second approach is not a viable option for most places I hunt (parks and private permissions). Not only do I not have the time to implement that strategy, my body can't readily handle that much digging. Also, I'm pretty sure digging almost everything is bound to lead to the loss of any good graces I have with property owners and park maintenance crews. Ok, so that leaves the first option. But before I go that route, I have to concede the possibility of getting an Equinox. Based on my experience with my Vanquish, limited time on the Equinox 600 and experiences with my AT Max and Fisher F2, I'm confident that one of the advantages of getting an Equinox will be more stable VDIs and more accurate VDIs at depth. And right now, I think I can live with that. I understand that getting a solid signal (a good, repeatabe signal from both swings and in 2 directions) on a dime or quarter at 6+ inches in my mineralized soil isn't always realistic with the AT Max. But I know the AT Max is at least capable of getting a decent signal (a good, repeatable signal from at least 1 direction and in 1 swing). Put another way, I get how the AT Max may not get me the "dig me!" type of signal that an Equinox can, but I at least need it to get me the "take a closer look, please" signal. All of that to say that I'm thinking about how my AT Max's target separating ability and recovery speed limitations (using the stock coil) will compare to an Equinox 600 and a stock coil. I came to this realization when running the AT Max with only iron discrimination set at 35 resulted in information overload for me and notching out everything below 70 was likely leading me to completely miss "take a closer look, please" signals that might lead to silver coins, dimes or quarters. Therefore, I want to use Monte's Nail Board. I know it's not ideal, and I plan on using Steve's approach of using both the AT Max and Equinox 600 on real-world targets. But I think the Nail Board will offer quantitative data when comparing the AT Max and Equinox.I also plan on using it with my Fisher F2 and Vanquish 340 to help put things into perspective. So how do I go about doing this test? Here's my approach so far: Step 1: Create Monte's Nail Board and use it with a modern, clad dime and new nails. Step 2: For each of the 4 passes, I will give it a rating: Will Dig, Maybe Dig, Won't Dig. Step 3: I will set the sensitivities at either 50% or the highest possible given EMI Step 4: I will run each machine with zero discrimination and with enough notching so that it's only going to sound on dimes and quarters (and maybe copper pennies). Step 5: For the AT Max, I will also test it with iron discrimination set to 35. Step 6 (maybe): Run the test with the AT Max using both its stock and 5x8 coils. So here's my first real question: what changes or additions would you all make to my current approach? My second real question(s): what "base" setting should I use with the Equinox 600. I'm thinking Park 1 with recovery speed set at the highest setting (3?) and a small or moderate amount of iron bias. Should I also run some tests with the Equinox 600 in 4KHz mode? My third real question: would it be benefitical to modify Monte's Nail Board so that the nails are replaced by either clumps of aluminum or maybe pulltabs? A lot of my hunting is in parks and yards that are often littered with more aluminum trash than iron trash. Any insight is appreciated. Thanks!
  9. From what I can gather, higher frequency VLF detectors are more suited for smaller gold but ground mineralisation may be something to factor in. Would there be a “better” frequency for nuggets 1 gram and above in heavy ground? I’m not too concerned if I miss sub gram nuggets if there is a better suited frequency. The old Garrett Groundhog circuitry was legendary in this country…..I think it was around the 15 kHz mark. Is this frequency range a good starting point or do I need to consider other things such as better ground balancing capabilities or Garrett’s extra coil voltage. My Minelab PI units will be mainstay detectors but as mentioned in another post, I have ground littered in man made iron junk and the ground mineralisation is severe. There are plenty of nuggets in the 1 gram to 5 gram range (maybe bigger) but the iron signals are as dense as 5 per square metre 🤬 Thanks for any ideas.
  10. After the good new I realized when tested a few days ago my machine after It drowned and I've succesfully reanimated It.... Now the horrible gasket Is fighting to stay out of the housing against any kind of attempt😒. So I'm in the middle of a headache manutention session with scarce results. That's the Mood guys😑
  11. See NASA-Tom’s comments https://www.dankowskidetectors.com/discussions/read.php?2,181189
  12. Don’t know any other better subforum to place this. When manufacturers design make sure platform can allow at least 2 software versions or at the very least allow what I call both newer version update (whole) and a older subset (portion of older version) to be used. Why? Makes testing easier if and when a newer version is designed and requires pre release testing in the field for validation. Would allow users after version release to use different versions and gain first hand feedback of the benefits or lack thereof of different versions or version subset(s). Case in point. Notice Minelab left old iron bias to be user selected when they released newer version with iron bias F2 option. So in a nutshell this allows the detector versions ( or version subset) to be compared to the themselves in the field by the user. Xp should have done this too. They should have designed Deus imo where at least 2 complete version allowed to be uploaded to unit. Notice the later released Ace Apex. Garrett should have allowed on it too. Don’t know what added production cost this would cause. Hopefully not much.
  13. This was mentioned by geof_junk in another thread and had a little Google. Found this https://www.phys.k-state.edu/reu2011/nnorvell/Metal_Detector_Research.html I don’t really understand the technical side of metal detectors. Does this have any application to current day detectors? Will it help cancel out ground noise more? Will the current crossing/not crossing the ‘bridge’ tell you something about what is under one of the receive coils. Although I don’t understand it, I am amazed and a little in awe of those that do 👍
  14. This is a topic relevant to every(?) form of detecting -- ground coverage. I'll list several questions concerns I've had but any replies of course aren't limited to these, nor do they need to address any of them. Just tossing out some ideas to prompt further discussion. 1) What methods and efforts do you apply to ensure full ground coverage in the cases where that is one of your goals? 2) Is your sweep a straight line path or an arc? 3) How long is your sweep? 4) How much do you overlap consecutive sweeps in the direction you walk? 5) How much do you overlap side-to-side swings when following parallel paths (e.g. when walking two side-by-side swaths in the same direction how much does the left end of one path overlap the right end of the next path or vice-versa)? 6) Have you ever measured your coverage? How well do detectors with GPS (e.g. Minelab GPZ-7000 and Minelab CTX-3030) monitor ground coverage to this detail? Have you used other devices to measure ground coverage. E.g. I can imagine a drone with camera could provide useful data. Are there smartphones app that would help quantify coverage?
  15. Just dreaming... What'dya think? Minelab technology going on the next moon mission? X6 must be space-worthy.
  16. If this question has been addressed elsewhere, I apologize in advance and hope someone can give me a link for it. I have noticed that other companies besides Minelab are coming out with PI detectors for less than $3K. How do these detectors compare to the best Minelab detectors for Gold and also relic hunting?
  17. On the Anfibio Multi (and I think Kruzer & others) there is a definite step in sensitivity between 39&40 Gain and again between 69&70 Gain. Is this a change in the Internal Threshold? In a way this would be the inverse of the way the F75 adjusts sensitivity according to Mike Hillis. Regardless, it is a very good set up in difficult sites. Most NM users know about the difference in response speed between 89 & 90 Gain on 3DI. This is different. I had read about these steps in a forum post that quoted Alper of NM. I can't seem to find that post now that I want to re read it.
  18. https://patents.google.com/patent/WO2021016649A1/en?assignee=minelab&scholar&oq=minelab&sort=new This is the most out of this world Minelab detector patent I've ever read. There is so much here, some very sci-fi like, I don't even know where to start. My takeaway is they seem to be positioning themselves for a drone based detector eventually (main details in this patent could be easily transferred to a drone based platform - IMU, GPS, magnetometer, heads up display, FPV, remote control, robotic/vehicle mount, etc) . That is 100% a guess. But in the meantime, there is some interesting, novel items in the pipeline that we might actually see on a machine in closer future? No clue if this is a coin machine or gold machine or if it's something they are actually working on right now or just trying to get control patents on such things for the future which may or may not arrive. One thing is for certain, Minelab is BUSY in the engineering department. A few of the highlights: Heads up display over glasses/head mounted display (aka augmented reality). Settings, target visualization, shading of detected/not detected areas (I asked for this specifically 5 or 6 years ago here, awesome to see it in a patent now). Plus a camera showing the coil (why would you need that if not operating remotely as from a drone?) The detector has a camera, IMU (accelerometer) and magnetometer to determine position with accuracy. The IMU tracks the position of the coil in real time in relation to both the ground and the target, and combined with the camera video feed will provide a "visual" of the target in the ground through the glasses/head display, as in form of a heat map which increases accuracy with each pass of a coil over the target. A GPS tracks the machine position to properly map the IMU/coil visual target data on the ground and let's a user see the mapping as they detect. This data is recorded for future historical use and can be shared. Centimeter accuracy with the visual target heat mapping. Potential operators/users include entities other than humans such as "robots" and "an AI (artificial intelligence) using a metal detector" and this line: "The metal detector may be handheld, mounted on a robotic arm of a vehicle or a robot." Wireless connectivity to computers and phones, transfer of files containing settings configurations from instructors or expert users Remote control of the metal detector through apps on laptops or phones Ability to upload maps, including detecting data, historic human activity, buildings, or other items that seem to indicate custom mapping capability Internet connectivity, potential control through the internet (again, why if not for a drone type device?) "Teamspeak" to other detecting members in the area wirelessly Visual/spatial discrimination Accurate depth measurement Synthesized audio mode, eliminating noise completely and allowing the detector to "recreate" a synthetic audio stream based on data from prior swings Delayed audio processing (enhanced audio) mode or real time audio mode, ability to seperate multiple close targets, reason for this I venture a guess why below ---> This patent actually seems to be describing a completely new method of RX in a detector. Which is actually similar in some ways to the wacky idea I had years ago of reducing EMI/ground noise by emulating a radio telescope array. But in this case they appear to be describing a fairly ingenuous method of doing something similar with only one coil by monitoring RX of the same target at different points in the swing (with the IMU tracking these points) and combining all those RX signals. In this way (and this is my guess, the patent doesn't explain this), you can form a sort of comparator, gradiometer, or interferometer to seperate the wheat from the chaff, so to speak. If that's what they are doing, then I find it to be brilliant. If not, then I just gave them one hell of an idea to patent for the future. That probably sounds like jibberish to non-engineers. But I want people to understand the brilliance in simple terms. Consider this: EMI is random. At any given point in your swing you'll get noise here, but not there. So if you compare two points in the same swing, you will hear noise one point but not the other point because the "zap" already ended. But you might hear a good target at both points in the swing since it's not random like EMI, it's always there in the ground. So, you can effectively eliminate EMI by comparing what signal is not there at two very close points in the swing, and keep the target since it's always there. Similarly, with ground, the ground changes as the alluvium changes since soil is inhomogeneous. But a target is still the target. So, a similar method can be applied to the ground. In theory, you could use ideas like this to essentially get rid of the Difficult type timings and keep your gains boosted high, and deal with EMI/ground in this way instead which does not require reducing sensitivity. A totally new, novel approach to RX in a metal detector. The audio processing is very slightly delayed because they are using that time to compare measurements at a few different coil positions before letting the audio processor signal that there is a target present. That's my guess. If that isn't what they are doing, then someone else should patent that and thank me for it later when Minelab buys it. Either way, they have something totally new in the RX department here. And the future of detecting looks bright and interesting to me still.
  19. Hello, now here’s an opener that might just get me banned on my first post! Bear with me, my intentions are pure :) Does anyone know if it would be possible to jam an MD signal? The reason I ask is to combat the evident problem we have in the UK with “nighthawks”, illegal detectorists. Over here, any landowner can grant permission for detecting on their land (with caveats, known historic sites are protected by law). What often happens is that such a permission is granted and a detectorist innocently sets about his / her business. Someone less scrupulous spots this person and assumes there may be something important there, so shows up at night with a couple of friends and the landowner awakens to a field / lawn full of holes, then bans metal detecting. Historic sites are also looted. Just an off the wall question, how tricky would it be to build a device to block this on a piece of land? Anyone any ideas?
  20. 99% of my detecting is done on central Florida beaches. Since it’s impossible to establish a well stocked test garden at a public beach, I sorta brought the beach home with me and developed my own private beach garden! I cut slots in two large empty chlorine tablet buckets at various depths as shown from 2 -16 inches. I then filled one with New Smyrna Beach sand and the other with soil...for the few times I land hunt around here. I embedded numerous examples of ferrous and non ferrous targets into paint stirring sticks. I also have several blank sticks I use for gold and silver jewelry as well as artifacts that I don’t want permanently attached to a stick. I then insert the target(s) in the slots, each at its desired depth, and start scanning. This allows me to rapidly change the targets, depth and relative position of each. I can now test for sensitivity at depth as well as separation of ferrous and non-ferrous targets in a variety of scenarios using actual beach sand where I do my detecting. If I want to test in wet salt sand, I just soak the bucket sand with authentic sea water that I also brought home from New Smyrna Beach...and the Atlantic Ocean never even missed it. 😉 Works for me.....
  21. Found this patent that Whites filed and got a patent on in 2014 on a hybrid IB/PI machine. https://patents.google.com/patent/US20110316541A1/en Curious if anyone heard anything about this. Maybe Garrett will take it on?
  22. I know we have had some great advancements in VLF metal detector's over the recent past, but I am hoping that we can keep some of the older design features that seemed to work well. My favorite new technological features being offered in VLF's are Multi-IQ and single frequencies options, fully programmable settings, waterproof, noise cancel, USB chargers, li-ion batteries, Bluetooth headphones, prospecting & coin/relic options, and lightweight. Really a great job by the inventors of these detectors. IMHO I hope we do not lose some of the past designs that worked well, such as the ergonomics of the balanced s rod that would separate in three places for backpacking, the hip mountable brain box, the detectors that would not fall over when put on a little bit of an uneven surface, the 6.5 inch elliptical concentric or double DD coils for great access in rocky areas, the 1/4 inch headphone jack, the spare interchangeable battery pack that takes regular batteries to serve as a back-up for the li-ion battery pack, and higher frequencies options. I would like to see what else had worked well with other detector user, seems like we are always buying aftermarket parts to retain some of these older features where possible.
  23. Not sure where this belongs on the forum, (or if it even belongs here), but this seemed to be the best category to discuss this. Ever since information on the GPX 6000 started to trickle out, I had this nagging feeling something in detecting has changed for those of us who like the thrill of getting to know a new detector. I never would have envisioned the GPX line morphing into a simplified detector. After having the GPX 5000 for a bunch of years now, and using it for relic and beach hunting, I could not imagine relying on a machine that adjust everything for you. I get it that money talks, and when you are a publicly traded company, you go for profit first, and then deny it 😄 And now that there market has switched to an area that probably has very little experience with detectors, the GPX 5000 must have been daunting for them. So they cater to that market. But I was hoping that a new GPX would fix some of the issues that the 5000 had. I was naive. Minelab has never kept the good parts of their previous machines and just added the the things that needed improvements. On the E trac, the best part of it was the depth it had in finding deep silver, in long tones, multi. Also the bouncy numbers helped ID deep Indians. When the CTX came out, it lost some of that fluety tone and they tried to straighten out the numbers to a number 12 line. So a two dimensional screen that worked well was transformed into a 2 dimensional screen that bunched most targets on one line. The The EQ comes out and squashes out the numbers even further. So why I thought the 6000 would not do the same is beyond me. I guess I'm disappointing that the "trend" is to make machines where the manufacturer decides on how your machine is going to be set. I hope someone in my area gets a 6000 and is willing to bring it to the beach to compare settings on deep silver. If it wins, then I will eat my words. I know I will get some slack with people saying it's a gold machine, not a relic or beach machine, but to them I would say.... you should be worried when a company controls your ability to fine tune your machine. Thoughts?
  24. I'm looking for a Compass metal detector catalog that includes the Compass Gold Scanner, and Compass Gold Scanner Pro models. The full line catalog, and this would be about 1990-1992 or thereabouts. I'm adding a few key older metal detector catalogs to the Downloads Area to provide basic info on older models. I do not need a ton of catalogs, just key years where major model changes occur, as things moved slower back then. If the catalog was in pdf format that even better, but Googling only turns up a couple older catalogs, nothing I can find covering the Gold Scanner era. I am more than happy to pay for a print version if need be, so I can scan into pdf and put up for people to download. Thanks in advance for any help. Me and my Compass Gold Scanner, back around 1990:
  25. XRF's hold sort a mysterious place on the shelf of semi-unobtainable prospecting equipment. 99% of prospectors don't need one. Maybe this post will help clear up some of mystery around these devices, and show where they can actually be worth the outlay of capital. And why for almost all recreational/hobby prospectors, they are not worth the money. What does an XRF do? In very simple terms you point it at an object and it will tell you what elements are in that object. More on this, and why it isn't this simple, momentarily... After sometime over 5 years of searching, I was finally able to find a used XRF I could afford to finance recently. These are not tools for recreation. They are expensive and require understanding how they work, what tasks you need to accomplish, and understanding the limits of XRF. The trick with these units is to find one with the proper calibrations already installed as they can be many thousands of dollars to send to the manufacturer to get configured correctly for mining/prospecting uses and to add/subtract elements or to calibrate for certain matrixes (silicates/iron/etc). X ray tubes and X ray detectors are about $6k each to replace, and recalibrations are about $1500 a pop, so even maintenance is crazy expensive. It's a tool you need be certain you need or can put to good use before buying one. And buying used, it's probably best to find one with as few hours use as possible to delay the inevitable tube replacement, as well as with a recent calibration certificate. My unit is an XMET 7500 made by Oxford (now Hitachi). The more common units people generally see are the Olympus and Niton guns. This unit has basically every mining calibration Oxford offered on it in addition to soil and other specialized mining related modes, which is very valuable and very useful for prospecting. It also detects down to magnesium without any fancy helium purge techniques. The guns sold on ebay with only alloy calibrations are pretty useless for prospecting without spending a lot of $$$ on additional calibrations. Some other things to consider are the machines themselves vary greatly between model numbers and some models may be unsuitable for specific uses in prospecting. A few things to educate yourself on are: Beam energy and detector type (determines if certain elements can be detected at all, and how accurately) Electrode composition (Gold electrodes have lower sensitivity to gold in ores, for instance) Calibration to light elements, or ability to detect certain elements I don't think an XRF is particularly useful for people who are only looking for gold. Due to the electrode limitations, the PPM minimum to detect gold in ores can often be above what would be an economic (and thus desirable) concentration in gold ores. But, looking for tracer elements (stuff like Pb, Cu, As, Zn, etc) can be quite useful. It can also help outline buried ore bodies which can then be explored mechanically via drilling or other methods. For prospectors branching out beyond just gold however, an XRF can be even more useful. And that's when one needs to understand the elemental limitations and what your application specific uses are. Any affordable XRF today will not detect lighter elements than magnesium. Some will detect to magnesium, but then do not contain calibrations to allow it (extra $$) and some require helium purging to measure light elements. Elements like hydrogen, carbon, oxygen, and sodium are very common "rock building" elements. But XRF readings will lack these measurements. So, when a looking at a rock your readings will often give fractional (less than 100%) results. This is why - the missing mass is tied up in atoms lighter than magnesium. Fortuantely, a lot of common rock types have unique fingerprints still in elements such as Mg, Al, Si, P, S, Cl, K, Ca, and Fe. But some don't. This is why it's important to understand what you are looking for first in the field, and then find a tool that is going to match your needs. Further, a lot of minerals in certain locations but not other locations will also have further fingerprints in other elements such as Cr, Co, Mo, Nb, certain compositions of rare earths, etc. To make it more complex (this part took me a while to wrap my head around), each calibration within the machine may or may not be configured for some of these elements - even if they are within the range of detection of the machine! Like, an alloy calibration will have little use for silicon or calcium. Conversely, a mining calibration without magnesium or calcium may be next to useless depending what you are looking for. Of course, it costs extra money to add elements and even if you have for instance a precious metals calibration that includes platinum, the mining mode may not itself include platinum and that's more $. That is why the matrix matters, each mode can be calibrated to a specific matrix. Like mining modes are generally going to assume that the sample is mostly silicon, whereas precious metals mode might assume the only things that exist in the universe are metals. So if you analyze solid metal with mining mode it may misidentify elements thinking they have to be metals when they aren't, same as if you analyzed a piece of gold ore in precious metals mode where it will try to assign certain non-metallic spectra in the ore to something like gold or platinum, giving you false positives. This is why calibrations available and elements assigned to that calibration is so very important when it comes to XRF and accurate results. Why else is XRF bad for gold-specific uses? (I emphasized this because this is primarily a gold prospecting site, even though I prospect for many other things myself). First one needs to understand how XRF works - simply put it kicks a few electrons out of a few different orbitals around an atom at discrete energy intervals (these are spectral "lines"). When another electron falls into the empty orbital to replace the vacancy, another X Ray is emitted at this discreet energy. Unfortunately, some elements have some very close to identical spectral lines. Look here at some lighter elements and see the overlaps on this visible spectra chart that we use to ID elements in stars? Some might be familiar with these from astronomy or high school. Well, the same happens in the X Ray realm. This is coincidentally why ionized gases look a certain color to us and how "neon" signs can be different colors (different elements inside the tubes). The same thing happens in the X ray spectrum, just not visible to our eyes. Except when the X ray spectra is reaaaaaaally crowded around the gold lines. Making it hard for specific ID's when other elements with similar lines are also present in ore, and unfortunately some of the elements are also commonly found with and around gold mineralization. Combine this with the anodes on many affordable XRF's being gold which itself interferes with really precise Au measurements, and you can see why an XRF isn't the best tool for specifically gold prospecting. Here is an actual XRF spectrum. You can see how very common accessory gold ore elements populate and crowd the gold spectral lines at various orbitals. And also how you might be missing critical lines if your X ray tube only goes to say 15kEV instead of 40kEV (EV stands for electron-volts), you might miss some Ag, Ru, Cd, or Zr fingerprints in this specific case. Now notice how iron stands all alone? That's why some elements (iron) are easier for an XRF to ID than others like gold. So for some such tracer elements in soils and ore, and identifying certain minerals which really can only be accurately identified via spectroscopy or thin sections as for some gems, an XRF can save months of time and thousands of dollars for in field qualitative assays to do first stage determinations, ie, wether a resource is simply present or not, ignoring actual concentrations. This is why it's so important for anyone considering one of these units to know exactly what they are looking for first, to know the limitations of XRF, and to know if a unit will meet their application specific needs. Almost every company I spoke with had a story about a prospector, or even a few cases some junior mining companies, who purchased an expensive unit only to find it wouldn't work at all for what they needed to do. So hopefully this clears up a little mystery about XRF's and maybe saves someone from making an expensive $15k mistake. I am by no means an XRF expert and everything I know is just self taught. So if I've included an inaccuracy then please correct me. This is not intended to be definitive, but just to share what I've learned over the years in a few pages of simpler to understand jargon for those prospectors interested in these devices. More later with some actual measurements...
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