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Jim Hemmingway

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Jim Hemmingway last won the day on July 18 2016

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About Jim Hemmingway

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    Copper Contributor

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    Male
  • Location:
    Canada
  • Interests:
    Fish & Wildlife Biologist (Retired), Prospecting, Mineralogy, Music, Reading, Fly Fishing, Camping.

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  1. Jim Hemmingway

    Odd Beach Find?

    Hi Kevin… I think that oldmancoyote and Jeff have probably nailed down the more likely alternatives for you, given the location. Its moderate depth in Florida sand leads me to suspect that it is probably a manmade ferrous object that may have reached that depth over some number of years with the ensuing obvious corrosion. As Steve mentions, it is difficult to assess just what types of corrosion products exist on your sample. Iron metal corrodes to rust and manmade rust is a form of iron oxide called maghemite, which frequently does react to metal detectors depending on its physical characteristics, the ground conditions, the type of metal detector, and how it is operated. I very much doubt that a chunk of magnetite would naturally occur in your area. As mentioned above, limonite is a generic term describing a number of hydrated (containing water) iron oxides that can present themselves in different ways and in vastly different environments. A good example is to recall driving along a highway that has been blasted / cut through pre-existing igneous rock that could be comprised of any one of several different types of rocks. Iron is a very abundant element and in all probability does exist within such rocks. Upon exposure to weathering, even trace amounts of ferrous material will oxidize to form a natural rust on the exposed surface of those rocks. This is a good example of why limonite is described in mineralogical texts as “Nature’s Rust”. It is typically the goethite constituent that produces generally brown soils in temperate regions around the globe. My limonite samples produce no effect on a PI metal detector and very little on a VLF detector. It exhibits relatively little magnetic susceptibility and incidentally can be characterized as having a fairly low magnetic loss angle, thus permitting it to occupy a somewhat similar area to magnetite on VLF ground phase readouts. But it simply has no ferromagnetic strength that is comparable to magnetite or maghemite. Hence, I rather do think something metallic within your sample has produced the signal. The photo below depicts another commonplace example of what is described as amorphous (without shape) limonite. The F75 GB45 compensation point should ensure that all iron oxides produce only a negative threshold signal and that is the case. This sample does not react to my TDI Pro at the sensitive 10 usec pulse delay, small mono coil, full gain, and with ground balance turned OFF.
  2. Jim Hemmingway

    My Last Three Detecting Outings

    Hi JW… marvelous post, always enjoy your field presentations!!! Thanks for the extra effort to take those nicely illustrative photos for our benefit. It’s the next best thing to being in the field with you. I think you enjoy a very good relationship with the local farmers, and I’m sure that in large part it is due to your diligence and consideration regarding their property and farm-related operations. I think you are very fortunate to have such widespread areas that produce gold nuggets, where the ferromagnetic soil minerals are apparently not a serious factor influencing metal detection depth / sensitivity to small low conductive targets. Additional moisture in that ground doubtless helps to create an ideal metal detecting scenario for you guys, and I think that a part of your consistent success is that you are proactive in taking advantage of such conditions. Quite pleased to see that the wife is getting out with you even if it doesn’t necessarily mean she’s into metal detecting on any given day. My wife is the same way JW, sometimes she’ll take a whack at detecting (and has done surprisingly well over the years) but just as frequently prefers to read a book or birdwatch with her identification guide and binoculars. Just a quick note to let you know that we appreciate and enjoy your contributions, and to congratulate you on your elusive gold nugget recoveries……………… Jim.
  3. Jim Hemmingway

    Skunk Breaker

    Hi Simon… a thoroughly enjoyable read, and thanks a lot for the nicely illustrative photos!!! The cave photos were particularly interesting to me because I enjoy exploring them for possible minerals. That aside, you guys have access to incredibly scenic and potentially productive gold areas to ply your prospecting skills, clearly a win-win scenario. Digging an expanded VDI range will obviously translate into digging more junk, but will increase finding occasional gold items as you know. I found it hard to stick with digging low conductives over the years and eventually returned to exclusively digging only high conductive items. The old tokens and silver coins lurking in the older town parks and picnic groves were the main targets of interest. At about that time, I decided to get involved with water hunting to compensate in the gold department. The photo below depicts two finds from a nighthunt at a local freshwater beach in waist deep water using a Fisher 1280X Aquanaut equipped with a 10” round concentric coil and using small iron discrimination where ferrous trash is a bit overwhelming in close to shore. That said, I usually get away from the shoreline unless there are plenty of rocks in the shallows immediately in front of the main beach bathing area. Such conditions facilitate ring slippage and do tend to retain gold rings from all but determined detectorists. I recommend that you do the same thing with your Nox or whatever suitable unit, to bolster your gold finds regardless of the VDI range coinage and jewelry that you continue to hunt on land. Moreover, you may be pleasantly surprised at the quantity of older (silver) coins found in the water too. Congratulations to both of you on your gold recoveries. I doubt that a little healthy competitiveness in the field results in anything consequential other than an increased sense of camaraderie. I feel that you and your bike-riding colleague are both winners in so many important ways that do matter………….. Jim.
  4. Hi Cal_Cobra… well I suppose you might call it a bust, but frankly I enjoyed reading your post and viewing your relic finds. I find that my interest in relic hunting has increased a good deal because of the contributions to the forum from you and others. On occasion some remarkable coins and artifacts are recovered, and that is exciting. But I think what attracts me most to relic hunting is the historical significance of the artifacts and how they were used by North America’s native residents, our colonial forefathers, and the following generations who lived each phase of our history. Then too, pursuing the identification of relic finds is a challenge, not to mention the accrued knowledge about these artifacts and related activities from so long ago. All this is to let you know that your contributions are much appreciated by us. Incidentally, I’ve found a few of the old Chinese coins over the years as depicted below. It’s all quite interesting to me, please keep up the good work, and thankyou for the just excellent illustrative photos………………..Jim.
  5. Jim Hemmingway

    T2 & F75 Electrical Interference

    Hi William… here in northeastern Ontario, we do most of our prospecting for native silver in the motion all-metal mode. There are occasional exceptions where excessive trash is encountered as described further below. Let’s take a look at how we operate this unit up here. The motion all-metal mode, that conveniently features a target ID, is deeperseeking and more sensitive to ground conditions and to small nuggets than are the discrimination modes. This mode is particularly effective for searching over rough, variable terrain where ‘low and slow’ scanning is necessarily dictated by such conditions, for example, poking the coil between and around boulders. We also prefer its comparatively unimpeded target-sizing ability to better assess what is happening beneath the searchcoil. When searching in the motion all-metal mode, use as much sensitivity as the ground conditions will permit while maintaining stable detector operation with a reasonably smooth threshold hum. Adjust the threshold as low as possible but still able to hear a faint mosquito-like hum. Many senior hobbyists have experienced hearing loss, therefore it is even more important to adjust the audio pitch to a level where you can most easily hear faint target signals. Set it appropriately and leave it alone. I use NuggetBuster headphones to help me hear weak target signals. The original F75 provides two features to ground balance the detector. The manual GB effectively does it all, including slight GB adjustments to offset neutral GB settings to perhaps enhance depth / sens to small nuggets or possibly to subdue various ground / hotrock effects. The ground balance procedures are described in the manual so we won’t go over it here. (a) The important thing to remember at all times, particularly when searching over tough ferromagnetic ground, is to ground balance to the same elevation above the ground that you will be scanning the coil. Otherwise over tough ground you will undoubtedly experience false signals. (b) If the ground mineralization prevents you from obtaining a ground balance, you must either switch to a smaller coil (DD coils are more effective at reducing the effect of tough ground) and / or reduce sensitivity. For nugget hunting you will likely be using a small sniper coil anyway, so reducing the sensitivity is the only remaining alternative to achieve a good ground balance. The alternative ground balance procedure is to use the autograb feature by pressing and holding the “trigger” forwards while bobbing the coil a few inches as described in the manual. It’s convenient, fast, and accurate. The autograb GB feature can also be used to supply additional information about a suspect target, but the technique described below benefits from using a concentric coil rather than a DD coil. Prior to disturbing the soil, pinpoint the target and do an autograb GB over it. Pump the coil four or five times but no more, and allow the software to function as designed. Note any movement on the ground balance scale readout. We find that positive signals from rusty iron, cobaltite, niccolite, and pyrrhotite generate significant GB reductions frequently shifting from typical search mode GB86 readouts right down into the GB40s. Positive diabase “hotrock” signals produce a relatively small GB reduction. But fortunately native silver samples free from either cobalt or nickeline contaminants will generate little or no downward movement to more conductive GB values. You will experience some questionable responses at times that will require some interpretation based on your knowledge about local minerals and field conditions. The GB information provided by this technique can be ignored if in doubt, or it can be used in conjunction with target ID and target-sizing to evaluate suspect signals. We practice this procedure to eliminate unnecessary digging in difficult rocky substrates. In a prospecting context, we utilize iron discrimination in areas where hotrocks or ferrous targets are excessive to the point where effective detecting is either inefficient or no longer enjoyable in the motion all-metal mode. We all encounter areas that are so inundated with blaring signals from small bits of iron trash such as tiny nails and tacks, non-descript shards, and interminable wire scraps that effective detecting in the motion all-metal mode is frustrating or next to impossible. In such conditions we use smaller coils to help with separating target signals, and we make good use of small iron discrimination or iron tones. Try adjusting to small iron discrimination levels initially as suggested above by Steve, give it a go and make any further adjustments according to what you can tolerate. This will depend on the amount of trash you’re willing to dig. Using iron tones or iron discrimination will result in overlooking deep non-ferrous targets that occasionally do target ID as iron. But it is a necessary compromise to at least enable us to enjoyably detect excessively trashy sites. Hotrock discrimination is somewhat different from small iron discrimination in northeastern Ontario. By and large we deal with non-conductive mafic hotrocks, diabase is usually the culprit that can produce either positive or negative signals just depending on circumstances, while conductive pyrrhotite hotrocks are mostly responsible for producing positive signals. There are other minor conductive nuisances, for example infrequent bornite and even more rare graphitic rocks. Pyrrhotite signal elimination is straightforward. Large samples may target ID into the low foil range, but most of it is eliminated with mid-to-upper iron range discrimination. This material in abundance renders entire sites unsuitable for detecting with either VLF or PI units. Discrimination settings do vary according to how each discrimination mode processes our non-conductive diabase “hotrock” signals. For example, all discrimination modes eliminate signals from negative diabase hotrocks at a zero discrimination setting. However while both the DE and PF modes require a discrimination setting of “1” to eliminate positive diabase signals, the higher gain JE discrimination mode requires a full iron discrimination setting of “15” to achieve the same result here. Hotrocks in your area may vary considerably from our experience. The only other suggestion that occurs to me at the moment is to equip your F75 with a small coil for gold nugget hunting. Small coils are far more sensitive to small nuggets than is the stock DD coil. There really is no comparison. The 6½-inch elliptical sniper concentric coil is superior in my estimate, although the 5” round DD is a very close performer over my ground. A further advantage to these small coils is that they permit using higher sensitivity settings in prospecting country because they obviously see much less ferromagnetic ground mineral than do the larger coils. I hope the foregoing will be of some use to you. There undoubtedly will be differences in the ground conditions, the hotrocks, and the trash levels in your areas. Good luck with everything William, and welcome to the forum!!! Jim.
  6. Jim Hemmingway

    Indicators

    Hi Norm… both these minerals are fairly common in the areas that I explore, but there is normally no gold associated with them. That aside, I did like viewing your photo layout, particularly the doubly-terminated, stubby little quartz crystal located at the bottom edge. Commonplace quartz in its various color schemes is my overall favorite mineral, in part because specimen grade samples are fairly easy to find and quite durable. The cubes presumably are iron pyrite. Iron pyrite abundantly occurs in quite a variety of environments because it forms under a wide range of conditions from high temperature ore veins to coldwater sediments. Interesting to see that a couple of your examples are transitioning to an iron oxide, nature's rust generically called limonite but that possibly may include maghemite. I’d like to find something similar for my mineral collection. As mentioned above Norm, that little yellow nugget in the middle of your display is the best indicator of where to search for gold. Hobbyists should look for gold where gold has previously been found, preferably in quantity and detectable size. I consider that to be the first principle of metal detecting for precious metals and put it into practice to search for native silver in northeastern Ontario. Jim.
  7. Jim Hemmingway

    Whites Spectra V3i Ground Test

    Hi EL NINO77… thankyou very much for producing this excellent video that illustrates your multi-frequency metal detector’s responses to a wide variety of targets in your test garden. I found it particularly interesting because I’ve always enjoyed using White’s coin hunters, although I’ve no firsthand experience with the White’s V3i. I won’t discuss the pros and cons of test gardens other than to mention to you that obtaining stable, correct target ID on deeper targets, say beyond four or five inches (depending on target size and shape) in my highly iron-mineralized magnetic susceptible test bed is not possible. Thus I recognize the potential value of your multi-frequency pinpoint bar graph to assist with target signal analysis. That feature strikes me as a quite valuable tool to help with the decision of whether “to dig or not to dig” depending on just what type of targets one wishes to recover from a site. I do think that relative side-by-side test plot depth comparisons are viable, despite that we realize that those depths may or not reflect depths obtained in real world scenarios where targets naturally settle into undisturbed ground. In natural undisturbed ground, the electrical continuity of the soil and the naturally occurring magnetic susceptible iron mineral fraction of the soil remain intact. These conditions should provide a depth advantage over disturbed test plots generally. I mention this because my ten-year-old disturbed ground test plot targets still do not generate depths or target ID reliability that can be had on similar undisturbed ground targets recovered in this same area. The foregoing comments are not intended as a criticism but rather are just some observations from my test plot and general area. I do think test plots are a valuable aid to learn more about one’s detector within the constraints as described above. And incidentally, our observations from disturbed ground test plots can be directly applied to detecting other real world scenarios where the ground is disturbed, for example urban renewal projects. We learn not to trust target ID on penny-to-quarter size targets beyond shallow depths in such conditions. Thanks again for the effort required for you to produce this instructive video. It takes a lot of work just to get to the point of producing a coherent video. I found the video easy to listen to because there was no background wind noise, and your voice came across pleasantly clear and your thoughts were perfectly understandable at all times. We look forward to the next one!!! Jim.
  8. Hi Simon... you've presented a very understandable step-by-step set of instructions to modify this unit. And the modification is necessary to eliminate inconvenient fiddling with controls. So nicely illustrated with the detailed photos that show exactly what you've done. Incidentally this is one of the reasons I didn't purchase this unit. I viewed this aspect of the design as unnecessary inconvenience in the field. Otherwise I felt it was a satisfactory design at the time, not too shabby on shallow small stuff, but better depth on deeper stuff than the higher frequency Goldbug2. Thanks for the instructions Simon, some of us have no electronic background, so it's nice to get some information along these lines. I do think you'd make a very good teacher!!! Jim.
  9. Jim Hemmingway

    (6 Inch Coil) Beginner's Luck?

    Hi GB_Amateur… thanks for sharing your recent coin hunt with us. I thoroughly enjoyed reading this presentation and particularly appreciated that you provided a detailed description of your observations and thoughts at the time, and the settings utilized with operating your detector. It was such an informative and interesting read, thankyou. Congratulations on your coin recoveries, the silver coins are always a welcome addition to our collections, and especially that handsome Barber dime. It appears to be in remarkable shape, not bad for a coin that is 106 years old and has likely spent most of those years in the ground. I would think the war nickel ought to clean up nicely too. I’ve found a few over the years, and have been quite pleased with how easily the stains were removed using a brief (mild solution) electrolysis followed by a very light finger application of a silver cleaner (Goddard's Long Shine Silver Foam) / water paste followed by a warm water rinse. Of course I’m not at all concerned about any associated value when employing such methods, but just want the coin to look nice. Below is a photo of a very ordinary but fairly representative dug example that I've cleaned using the described technique. Thanks again for putting together this excellent post, including the nicely illustrative photo of your coin finds………………………Jim.
  10. Jim Hemmingway

    Lord Of The Rings!

    Thanks for sharing your highly diverse, recreational family vacation with us Simon. Great narrative as usual, unbelievably beautiful photos… the lovely scenery seems to be the status quo for New Zealand because it’s always so breathtaking, and an inordinate quantity of coins that obviously pleased your daughter a great deal!!! A new tablet is a wonderful way to end a family trip, I think everyone would agree!!! We are so pleased for you to find such a valuable treasure as that 14K / 15-gram (that’s huge) engraved gold ring. I can’t think of a more deserving hobbyist!!! If there are recreational beaches in the area, it might be interesting to do some regular water hunting, that’s where you’ll find much better jewelry pickings… particularly in knee to shoulder deep water. And finally please say howdy to JW. He’s quite a character, the boating video was fun, we just can’t believe how much energy he puts into his hobbies / interests!!! And how successful he is at everything he tries, you two are both very capable, energetic individuals. Thanks again for sharing your various activities, and for the effort required to put this post together. WTG Simon!!! Jim & Joanne
  11. Jim Hemmingway

    Fools Gold?

    Granite is not a metaconglomerate. Rather, it is an intrusive (plutonic) igneous rock normally comprised of quartz, orthoclase feldspar and another dark material, for example biotite (black) mica............ Jim.
  12. Hi Simon… I realize that your T2 is somewhat different from the F75. But let me describe how I operate the original F75 to deal with issues related to EMI. The original F75 version is very much subject to erratic behavior in areas where EMI is present. Hunting urban areas in zero discrimination with the stock 11” DD coil is frequently impossible. I avoid using this coil in urban environs because it is quite vulnerable to EMI issues (extra windings / antennae effect) compared to the 10” elliptical concentric coil, and this is especially true when compared to any of the smaller coils. So don’t hesitate to switch to a smaller coil, preferably a concentric coil if the ground conditions permit. An added benefit if hunting micro jewelry, is that the smaller coils, particularly the 6” elliptical concentric coil, is quite sensitive to small stuff compared to the stock 11” DD coil. In fact I put it to good use for hunting naturally occurring native silver in rocky environs. It’s not unusual to find sub-grain material with this coil. If using a discriminate mode, avoid JE mode in EMI areas. It is extremely high gain, and therefore much more sensitive to EMI than are the DE or PF search modes. Another very useful technique, if necessary, is to increase the iron discrimination level until erratic behavior settles down to an acceptable level. Do this while moving / holding the coil on the ground, and not while waving it around in the air. Keeping the coil to the ground much reduces EMI instability because it reduces the coil’s antennae effect. Adjusting the sensitivity control is not necessarily the final step in stabilizing how the machine behaves in EMI environments. Do as you please with it. Keep in mind that you may wish to limit iron discrimination to about 6 or 7 and no more as Steve describes, depending on your preference. At that point, if necessary, you may wish to experiment with decreasing the sensitivity control to achieve stability. Of course for prospecting applications, and low trash urban areas, the first choice is to search in the motion all-metal mode. It is much less vulnerable to EMI than are any of the discriminate modes. It makes a huge difference. In closing, I should add that in remote prospecting areas, my original F75 is normally as quiet as a churchmouse regardless which search mode, settings employed, or the type / size of coil that is used. On rare occasion we do experience an intermittent EMI induced instability from what I suspect is the local microwave tower. These occasions are always temporary, rarely lasting more than a half-hour…………….. Jim.
  13. Jim Hemmingway

    Congratulations Phrunt - Minelab Winner Of The Month!

    Congratulations Simon for earning this outstanding recognition in the hobby!!! I doubt anyone is the least bit surprised that you wanted no reward for doing this good deed as a matter of principle. We would be remiss in not acknowledging how pleased we are to have you on this forum, and how much we enjoy reading your thoughtful, articulate contributions. WTG!!! Jim.
  14. Jim Hemmingway

    My First Equinox 6" Coin Hunt

    There can be a silver lining to every metal detecting "cloud", and your optimism and determination turned a skunk into a real productive outing.That's a recipe for success in this hobby!!! Congratulations Simon, and an especial well done on the 50% silver coin. WTG Jim.
  15. Jim Hemmingway

    Gerry's Tips & Tricks Video - White's Goldmaster 24K

    Thanks Steve for posting this instructive video from Gerry, his presentation was kept simple and straightforward, very easy for casual hobbyists to understand and retain. I enjoy his contributions to this forum because they’re knowledgeable and frequently creative. His technical information is always top-shelf. Jim.
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