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First Impressions Of New Nokta Impact In Victoria's Golden Triangle


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Got delivery of a Nokta Impact detector early June after it was unpacked by Nokta at the shipping point and the latest software version installed and then repacked.Two week delay but worth it.First impression of the unit on the first day of use was one of amazement on how stable it was on our very heavily mineralised ground on our goldfields.I had reservations before that it would be tough going for the Impact but happily these did come to reality.The auto GB was very easy to do and the unit only needed to re balanced every 15 minutes just to make sure.I would recommend this procedure in very heavily mineralised soil. On the second day I was mostly using the GEN mode and on the fourth day I got sick of digging up all the hot rocks and turned up discrimination in GEN mode to its minimum setting of 01.That way I got normal tones when sweeping at normal speed on hot rocks but when checking out the signal and sweeping slowly I got the iron low tone.As a novice user I did not have to change the settings except to increase the frequency to 20 Khz more suited for gold,as the settings are optimized for each mode.Isat setting was left at default of 06 and gain at 70.In the discrimination modes the extreme patches of mineralisation which were 2 feet in diameter gave a target response,but in GEN mode these came up as a broad patch and not a spiked signal so were clearly not genuine targets.It may be possible to eliminate this target response in the disc. modes by altering the settings so I would appreciate getting any feedback from other prospectors on this subject.This VLF detector is clearly marketed by Nokta as a coin and relic hunting detector for use in parks and on beaches but can also be used on goldfields for hunting nuggets.Fitting the larger 16 inch Im40 coil will give more faster coverage of terrain but in heavily mineralised ground it would not necessarily give greater depth although from previous experience adding a 16 inch coil on an old Whites detector turned it into a mean nugget hunter in the days when larger nuggets were still plentiful..Further I would like to point out that higher frequency machines are better for finding sub gram nuggets but in heavily mineralised ground are more unstable.Fitting large coils on these machines may incur penalties such as higher instability in these conditions.I did encounter a huge patch of extreme ground on top of a hill only once in 30 odd hours of detecting but switched the unit to COG mode.Unfortunately I could not continue in COG mode as we spent 2 hours on top of this hill and my wife got cold and wanted to leave.I had found a 1/4 and 1/2 oz. nuggets on top of this small hill previously with an old Whites detector so must investigate this patch further with the COG mode.This hill produced lots of surface nuggets during the goldrush and the west side has been surfaced down to bedrock on the top and to pipeclay on the side of the hill,so basalt lying on top of pipeclay.Further south towards a small town called Dunolly there are numerous shallow gullies which produced lots of large nuggets and also dozens of gold reefs.Even further south just north of a large town called Maryborough there are diggings at Simons where diggers had to penetrate  a layer of basalt  to get to the numerous nuggets which were lying on top of pipeclay.A large nugget was found near Dunolly 2 months ago by a prospector which was about 4 kilograms in weight.At Maryborough there is a main street full of shops built over the main lead which is estimated to still contain lots of gold.At Wedderburn a town at the northern tip of the Golden Triangle residents ripped up the main street in the 1950,s looking for gold.Such is gold fever.

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  • The title was changed to First Impressions Of New Nokta Impact In Victoria's Golden Triangle

Thanks Mike - it's good to hear the Impact handles tough Australian ground conditions so readily.

It is always a battle, trying to get more sensitivity on small gold while struggling not to make ground conditions worse. The ability to change frequencies when using a VLF can certainly aid in dealing with tough ground and is a plus in favor of the Impact.

Here is my Impact with the small elliptical coil mounted...

nokta-impact-with-small-coil.jpg

 

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Steve I have not yet found I needed to lower the 20Khz frequency just to make the Impact more stable operating in the heart of the Golden Triangle so far after only 30 hours of detecting, and I was using the default settings in GEN mode except for the 14 Khz frequency.But I usually get a quick feel for a machine and after 2-3 days use and will know if it will be a goer.There is nothing to put you off with the Impact,its superb good looks and balance,lack of unsightly wrap around coil,the easy to use selection menu,all these things build up your confidence.Oh and I discarded the armband.as the optimum balance makes it superfluous.If it can live with me it must be good as believe you me I get very irate about bad design and performance as I am a professional mechanical engineer.After 20 hours use the batteries were only half flat.The good stability on our goldfields is an added bonus which I had not really expected to tell the truth.The Impact did overload when it encountered extreme patches of mineralisation but so did the  PI detector next to me about 300 feet away and it was NOISY .But these patches were more prevalent in only one gully.Slipping it in COG mode may have fixed that and any shallow nuggets may be found in these patches. Recently I tested the Impact in my back yard on a one gram gold specimen and found the VLX2 mode reacted to it very differently than the GEN mode.Whilst the GEN mode signal became more broader as the distance in air was increased and eventually resembled ground noise,in the VLX2 mode the signal remained spiked even at distance and did not change.

I cut my teeth on a Whites 5000D many years ago  and found the addition of a 16 inch coil enabled me to find many more larger nuggets ( up to 3 oz.) than I had found with the standard 8 inch coil.It may have become a little more unstable but it certainly went deeper also.I feel I need to buy the 15.5 inch Impact coil to gain that extra advantage.I can just smell that half oz. nugget coming.After reading your comments about devoting 50% of the time detecting virgin ground I feel it makes sense to add the large coil for faster ground coverage and also not to miss any deeper larger nuggets.

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Steve,you said you have only used the Impact in a park so far,but you will see how good it really is when or if  you use it on your Nevada goldfields,I went out yesterday detecting South of Ballarat to a small place called Durham Lead.All farmland but I headed into the forest and found a small patch of diggings.Low min. level on the meter.The Impact gave a loud growl straight away indicating I had found iron or a hotrock..Please confirm it dear and my wife dug as far as a large rock,ok dear don,t worry. Next I got a good signal in GEN indicating non ferrous.I dug down 4 inches and eventually found a small sliver of black metal without rust which was probably high grade steel and flaked off something like a crowbar.It was 3/8 inch long and 1/16 inch wide at most and may have weighed about 0.1 gram.All this took me 30 minutes of sifting with the plastic scoop and intense concentration.Do I really want to detect objects so small?.Really even with the 11 inch coil the Impact is finding really tiny metal flakes that takes so much time and patience to locate with the naked eye.I really need those head mounted magnifying scopes that surgeons use.

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