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Detectorist Dan

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  • Gear Used:
    Fisher Gold Bug 2
    Minelab GPX 6000

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  1. Nice work Gerry!! Now where exactly where were you?? 😂 I would like to see that machine try out the hot rocks here sometime 😉
  2. That equation gives the same results as my approach. Just a different approach. Its nice to see that algebra works 😁 You could reduce my equation to Weight of Gold = 1.1589 * (Weight in Air) - 3.0712 * (Volume of Specimen) These values came from Gold at 19.32g/cm^3 and Quartz at 2.65g/cm^3. We would need to adjust those to get a better approximation, but then its just an approximation. haha I also realized my explanation of the volume was convoluted. If we set up a scale with a cup of water on it, tare the scale, and then suspend the specimen in the water, we get a measurement of the buoyancy force. This is the same as measuring the Volume of the Specimen directly. Then we dont have to set up a fancy rig to get the weight of the specimen itself in the water. Just tie a string around the speci and hold it in the water by hand and record the scale readings. You could take that Volume and subtract that from your Weight in Air and get your Weight in Water. Thanks Gerry for the way you've done it. Thats the same process that Doc uses in his video. I wish there was an explanation to where the numbers you multiply by come from. Thanks for the Thread mn90403. That thread gave the same conclusion that geof_junk has.
  3. I've been looking at how to estimate the amount of gold in a specimen. Chris Ralph has an article in the ICMJ about how to calculate this amount and Doc has a Youtube video showing how he calculates the amount of gold. Both of the methods go through the same steps of measuring the dry weight and the wet weight of the specimen but then after this the calculations differ and you get different results. Both equations use constant values that do not seem to have any description into where they come from. So I decided to sit down and use my thinking cap to derive the equations for determining this. This of course gave an even different result. IF anyone can tell me where the numbers from Chris Ralph or Docs equations come from I would be happy to know. Otherwise below is my algebraic proof for solving the weight of the gold. Chris Ralph article: https://www.icmj.com/magazine/article/determining-the-amount-of-gold-in-a-quartz-specimen-1189/ Doc Youtube: Let me start here with this equation Mass(total) = Density(Quartz) * Volume(Quartz) + Density(Gold) * Volume(Gold) To make it shorter I am going to abbreviate M = mass, D = Density, V = Volume, t = total, q = quartz, g = gold Mt = Dq * Vq + Dg * Vg If we can assume there are no voids in the specimen, the total volume of the specimen can be written as follows Vt = Vq + Vg We solve for the volume of the quartz as follows Vq = Vt - Vg Lets plug this into the first equation to get the following equation Mt = Dq * (Vt - Vg) + Dg * Vg We can solve the above equation for the volume of gold as Vg = (Mt - Dq * Vt) / (Dg - Dq) The mass of the gold can be solved by multiplying by the density Mg = Vg * Dg If we use 2.65g/cm^3 for quartz and 19.32g/cm^3 for gold, we can plug this into the equation from above to get the mass of gold in the specimen Mg = 19.32 * ( Mt - 2.65 * Vt) / ( 19.32 - 2.65 ) The mass Mass total (Mt) is the dry weight (Wt) of the specimen divided by acceleration due to gravity 9.81m/s^2. The volume can be measured by weighing a cup of water with the specimen suspended in the water. This is possible because water has a density extremely close to 1g/cm^3. The buoyancy force (Bf) is equal to the fluid density (1g/cm^3) * acceleration due to gravity (g) * the volume displaced (V). Therefore if we set up a scale with a cup of water on it, tare the scale, and then suspend the specimen in the water, we get a measurement of the buoyancy force. (Remember the scale measures force not mass) We can then divide by 1g/cm^3 and from this we are given the volume in cm^3 / 9.81m/s^2. Vt = Bf / ( 1 * 9.81) or just Bf / 9.81 We can also solve for the volume by finding the specific gravity as Chris and Doc do. Just subtract the Wet weight from the Dry weight. This gives the Buoyancy Force above. (It is because of buoyancy that we get these two different weights) The acceleration due to gravity can be removed from this equation as it is carried along with all of the other calculations as well. The values given from the scale is a force and not a mass. To convert from weight to mass we divide by 9.81m/s^2. To more correctly state the equations above the Weight of the gold (Wg) is as follows Wg = 9.81 * 19.32 * ( Wt / 9.81 - 2.65 * Bf / 9.81) / (19.32 - 2.65) If we multiply 9.81 through we end up with the following equation for the weight of the gold in the specimen Wg = 19.32 * ( Wt - 2.65 * Bf) / ( 19.32 - 2.65 )
  4. You cant have your cake and eat it too, if you dont like the delay, then plug in. I detect plugged in all the time with my GPX6000 unless I'm in real rough terrain. I'm more curious about how the Axiom's multi ground balancing works. We've got some areas with hot rocks up the wazoo and I would like to see it run on that ground. I havent even made it there with my 6 yet though so maybe that machine will handle them fine, I just know my GB2 didnt stand a chance on that ground. Also my friend's sdc had many issues on the ground too.
  5. So you can detect for 16 hours instead of 12 now? The thing is already super light! 😄 I wouldn't mind getting one myself but I got a house to build first so no toys for me. 😐 Glad to see you finding some gold Gerry!
  6. A lot of good points in this thread Gerry! (and everyone else of course!) Funny story on this. After I got my 10" coil from you for my GB2, I went up to a new location to try it out. I also took my GPX-6000 with me. Ground was frozen and I did not want to dig a bunch of iron so I started off with the GB2. First target was a .25g piece maybe an inch down. I detected another hour and only a few pieces of trash. I switched to the GPX and went back over the same areas and pulled out 3 more pieces(0.23, 0.06, and 0.04g). I flagged each spot and went back over them with the GB2 to see if it was me or the machine. The smallest two I could hear with both as they were practically on the surface but the GPX was a more reliable signal. The larger one was out of the reach of the GB2 at roughly 4". I know I'm no expert on the GB2 but I had the settings "maxed out" and not even a whisper. Im certain with the 6" on the GB2 it would have been a different story, but this does show to me at least the insanity of the GPX-6000.
  7. Thats how mine is too. Just figured it would be worth looking in to so i dont have to do that every time i switch my coil around. I guess I Brake For Bedrock comment got deleted from above. He was giving me a bad time, telling me to worry about gold and not worry about shortening the cable.
  8. Been doing that! But ground still froze and snow storm moving in. Two weeks ago take
  9. My thought was to take it out and shoot from a ways away while standing behind my old pickup. Dont want anyone to know where my nuggets are at! Lol. I think there are more as i had other loud targets near this one
  10. Found this little fella my last trip out. Just glad it didnt go BOOM! on me while I was digging it up! How unsafe is it to keep it around?? lol Also would anyone have an idea as to the time frame?
  11. Is it me or does it seem like the cable for the GB2 is about twice as long as it needs to be? I guess I understand that you are supposed to be able to mount the control box to yourself. Has anyone shortened theirs? Would this cause any issues with the detector?
  12. I mean I always figured some if not most of the finds were staged just because you cant have the camera rolling 24/7 but its still something to watch. Ill have to check out some of the other shows suggested on here 🙂
  13. Feeling bored in the cold. Anyone know when Aussie Gold Hunters season 7 starts??
  14. Oh ya Gerry, I know my goose egg days are coming (There's been a couple, I may have exaggerated slightly 🤫). 17" coil would be cool but I gotta get that house built first! I do need to get that 10" for my GB2 for some dredge tailings and some coil covers from you sometime here when you're back from vacation.
  15. I have come to the conclusion that Minelab has discovered alchemy with the GPX6000. It is the only logical conclusion as to why I find gold everytime I go out with it. It must have something to do with all the calculations of the onboard computers and the frequencies of the the pulses into the soil. Maybe a modified flux capacitor is hiding in there. 😆 Maybe Steve Herschbach has some info on this?? 🤔
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