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A compendium of BT posts on prospecting with the X70.
Posted by: BarnacleBill
Date: March 17, 2007 10:23AM
G,day Dan. I virtually always use tracking when gold detecting as the ground I hunt is pretty variable in places. If the ground is super quiet though I now and then try Fixed but as yet I cant see any difference. Some say Fixed on most detectors give the greatest depth and Tracking can track out targets. I used Tracking in a place where I was recovering bits down to 1/40th of a gram and they stayed signals all the time. Perhaps waving the coil back and forward repeatedly over an iffy target may track it out or diminish the response but I don't do that and also don't recommend doing it either.
Try things out for yourself as the areas you hunt may be totally different to where I hunt and maybe what I do is no applicable to your areas, who knows. Now and then give the Tracking a reminder by giving the coil a pump here and there as you hit the track button twice. It'll become second nature in no time and improves it heaps in real bad ground. When the threshold drops for any length of time or rises in a similar , but opposite way, slow down and hit the track like I described. Don't swing of too far either when it drops out for a second or two. Stay put until it recovers proper threshold sound and then detect away like normal. During that recovery time it does become target blind until it recovers.
Good luck mate.

Some wonder about the depth the 70 can find gold at.
Here's a few examples I have experienced.
5 Grams at around 6 inches. Sounded good and I reckon it may have been able to be heard from another 2 perhaps. Medium ground mineralisation. Sens set at 25.
I always make it a rough but close guestimation as I dont carry a tape measure as a rule:lol:
.7 g at roughly 4 inches. Sens set at 30. Mild ground.
.5 g at about 3 inches in hot ground sens set at 26. Soft signal, probably at its limit of detection.
Different ground though makes it all different to what depths can be acheived.
Bad ground on a scale of 10 out of 10 can reduce depths by up to 50% from what you may expect in mild ground.
Real bad ground too will make the iron mask misclassify if set too high. 1 is a good setting though sometimes it will try really hard to blank in one direction if its real hot ground.
I have found though numerous species and little bits of gold up to 1 gram for the nuggets and sometimes several grams of gold in the species just sunbaking on the surface in some areas where you would swear there would be nothing left. Obviously other machines couldnt hear them such as PI's which can struggle badly on rich fine gold species and spongy gold. Sometimes too they dont seem to get the punch on crytalline gold like a good VLF will.
The 70 is the winner for those gold types.

Depth to me is not paramount. To me I want a machine that can see better through mineralisation. Two machine in quiet ground may very well be head to head for depth but when it gets mineralised you can find one blitzing the other. Sometimes by a substantial margin.
I dont want a new machine to come out and go 3 to 4 feet deep.
I want a machine that can simply see almost all that is there in just the first 12 to 18 inches max.
I have found too many rich gold species and strange hard to detect gold nuggets which for years has been passed over by other machine, even SDs and GPs and yet which the 70 gets easy to believe most of the gold in the first 12 inches is gone.
I have some which contain 7 grams which the 70 gets from just 4 inches deep and the others , SDs , GPs, cant even get from 1 inch away.
There must be loads of that type of gold still out there.
Everyone , mostly, has "big nugget" fever and never even think for one minute that there are other types of occurances which can still put a big smile on your dial when you find them.
I often couldnt care less when I am in one of those gold type areas and see a bloke wander over with a SD or GP because I know that he will never hear what Im hunting for.

Yep, it was 1/40th of a gram and I have found a few that size since.
Small gold I know but sometimes fun to find even though it wouldn't even buy me a beer.
The settings were 30 on the sens, auto tracking enabled from start to finish, tone 10, volume 20 and a super slow sweep speed.
It nearly drove me mad trying to find it and I nearly walked away from it twice. It was a small sound but defined, a little "zip".
The ground was super quiet with just a slight murmur here and there from some light mineralisation.
Some say why bother with stuff like that but for me the monetary value of the gold I find comes last. Ive had a good day as far as I am concerned if I find anything at all.

The main coil I use is the 18.75 elliptical DD.
Its dynamite on just about all gold types.
Crystalline, spongy, fine gold species, rough reef gold.
Even fine gold specks down to 1/40th of a gram.

Here's some species I found along with the others I posted the other week.
Pic 1 is of , on the left a bit with leaf gold in it containing about 2 to 2 1/2 gs. On the left is normal gold with about the same amount thereabouts.
Pic 2 Is of a crystalline gold/pyrite mix with the one on the left having around 3 gs inside it. You can see it has more going into it by the dark patch underneathe the quartz but after once damaging a similar specie I stopped at the point it is at now.
The one on the left is from the same chunk and has a bit less in it, about 2 gs.
The bit of pyrites below them has gold running right through it, about 1 1/2 gs worth. I would have liked the pictures here to have come out a bit better on the scan but after 30 mins of trying to get it right, im definately no computer genius as you will now know, I settled for what I had.
They were found at a place called Crystal Hills which is one of the most picturesque areas I have ever detected in.
Pine trees, huge wash piles, gully workings and reef works

G,day everyone.
The settings used were Prospecting mode, Iron mask on just 1 (ive had too many sus calls on the preset of 5 in mineralised ground, sens ranged at tha spot between 22 to 30, tone set at 10 (I love those lower tones) headphones used and volume set at 20. Auto tracking anabled but I give it a reminder now and then to keep up by hitting the tack button twice real fast whislt giving the coil a pump every few feet. Sweep speed a slowwww 7 seconds per meter.
Ill post up some more stuff (beautiful species) in the next day or so from the same place. Took me weeks to finish the spot and even though it wasnt big gold it sure was a buzz to find.
The 70 is "the best VLF I have ever used here in OZ".

G,day Bob. The 70 is a wild thing on gold for a VLF. On the 18.75 khz DD it will pick up gold down to 1/40th of a gram. I have found a number of "specks" that size with mine.
Gotta be carefull with target Id,ing though as the ground gets more mineralised the readout for gold can range from 6 like you said up to 22 on the scale. This happened just a few days ago when a piece read 18 which I detected. I was a specie which was sitting on the surface with about 2 gs in it.
Iron mask has to be watched too. The hotter the ground the lower you set it or the iron in the ground, which we have heaps of here in Oz, will make the detector think its iron and try to blank it out. I leave mine on just 1 for the iron mask and check out anything which doesnt completly blank. Had a half g be early this week which tried to blank on just 1 and which did blnak on 5.

This gold was found using the X Terra 70 fitted out with the 18.75khz DD coil.

I use the X Terra 70 over here in Oz for chasing gold and coins on the goldfields of the Victorian Golden Triangle. We have the worst ground conditions I am told in the world. Mostly I use the elliptical 18.75khz coil when hunting gold and find it works no probs anywhere.
I rarely have to turn it down, the sens, below 18. It will find gold down to a mere 1/40th of a gram, specks, in quiet ground when wound up to 30 on the sens scale. The cocentric coil which is the standard, 7.5khz, is great for the coins but struggles too much in hot ground and creates too many ground noises when used in Prospecting mode. It can handle hot ground in the coin/relic modes though but rarely does the sens get to be set higher than 18. The 7.5khz 10" DD is great for those dog areas where the ground is real mineralised and does not pick up as many hot rocks as the 18.75 does. Sensitivity differences are marked. The 18.75 will pick up gold in specimen form which the 7.5 will not even register on.
These can be bits containing a couple of grams in small to fine form gold. The concentric coils do have more sensitivity than the DDs and if your hunting in super quiet ground the 18.75 concentric should outperform the same khz in the DDs. But mineralisation is their cryptonite and thats where the DDs rule. The 7.5khz DD can seem, next to the 18.75, pretty insesnitive but begins to catch up when the gold reaches around the 7 gram or 1/4 oz range then begins to overtake it as the gold increases in size. It will outperform the 18.75 on gold in the 1 to 2 ounce range and upwards by roughly 2 to 3 inches.

Re: Thanks for a great post - Question about black sand streaks
Posted by: GoldinOhio
Date: March 17, 2007 02:15PM
Thanks for the great post on gold prospecting with the X70. I am a newbie in Cincinnati and have had my X70 out on a local creek that the GPAA says is about the best place in Ohio for fine placer gold. Panned and sluiced there all last summer and did OK for fine gold.

But now I have an X70 and I understand that it can be used to read black sand streaks and deposits (where the gold could be hiding) like the MXT can. Would you explain to me how that works or send me the link to a previous post that can teach me how to do that? Since this area is almost all fine gold and has alot of metal trash, I know that the X70 could find me the small pickers, but I never got anything larger than a flake all last year.

Thanks for your willingness to share your knowledge and expertise with us in this great forum.

Edited 1 time(s). Last edit at 03/17/2007 02:40PM by GoldinOhio.

Re: Thanks for a great post - Question about black sand streaks
Posted by: BarnacleBill
Date: March 17, 2007 03:01PM
Hi Pat,

I want to make clear that I am not "BT". The great finds and content of that post are all from BT. I simply took the liberty of gathering them all together in one post so that I could include a single link in a post titled "FAQ". BT is a prospector and I am not, so he deserves all the credit for what is in the post.

If you want to know about prospecting it is obvious that he is someone you can ask with confidence. So if you want know how to find gold in black sand, BT's the guy to ask, if you want to find pulltabs in black sand, I'm the guy to ask.:rofl:


Re: Thanks for a great post - Question about black sand streaks
Posted by: B.T
Date: March 17, 2007 08:38PM
I use the meter on the screen now and then to check out how much the ground is changing or what it reads in places where I find gold but am a stranger to hunting black sands with it. You might find someone on a whites site using a GMT doing that. I have heard of mixed success stories doing so.

Re: Thanks for a great post - Question about black sand streaks
Posted by: GoldinOhio
Date: March 17, 2007 09:46PM
Hi, BT.

Before I purchased my X70 a couple of weeks ago, I was considering a White's MXT, and even downloaded part of the manual that dealt with using ground numbers to find flour gold at one end of a black sand streak. Since I live in an area that was glaciated from gold bearing areas in Canada, we have some decent fine gold, but not many pickers and even fewer nuggets. According to White's, higher ground phase numbers mean predominately ferrous black sands while lower numbers mean less of it. And a change in those numbers from low to high and back can indicate a potential black sand streak. So if I can find more areas of black sand in my creek, I'm thinking I'll be finding more fine gold (and maybe even a picker or two).

BarnacleBill sent me a message outlining an undocumented feature in the X70 that allows the user to make a reasonably accurate assessment of ground conditions including the iron black sand content. I'm excited about it and am anxious to try it out this next week. Thanks again, Bill!

A big thank you to you too, BT, for posting your prospecting tips, tricks, and finds in this forum. I'll be taking my X70 to Georgia next month and to Arizona in the fall to do some prospecting with this wonderful piece of equipment. And armed with the information from the posters in this forum, I'm looking forward to many successful hunts.

Re: A compendium of BT posts on prospecting with the X70.
Posted by: auldrider
Date: January 08, 2010 03:12PM
Any further progress or updated observations on prospecting with the X-70 or now X-705?

Re: A compendium of BT posts on prospecting with the X70.
Posted by: Mick in Dubbo
Date: January 08, 2010 07:05PM
I don't think that there is anybody on this forum that regularly hunts for gold with the X-Terra's at the moment. BT is involved with selling Whites machines these days, so his efforts are spent there.
Mick Evans.

Re: A compendium of BT posts on prospecting with the X70.
Posted by: Furious T
Date: January 09, 2010 10:42PM
BT has, over the years, written many many articles in the Australian magazine, Gold Gem and Treasure; His articles on the X Terra 70 cover gold prospecting and relic (+ coins) hunting. His experience on the goldfields is considerable and his opinions were usually well-founded. Whilst I didn't always agree with everything he wrote, I found his articles (on a range of detectors and topics) interesting and informative. That he now works for Whites is their gain I guess, as his experience and knowledge would be an asset to any detecting business. I have BT to thank for making me aware of the potential of the X Terra, and I can say that his articles were instrumental in my making the decision to purchase one.

Re: A compendium of BT posts on prospecting with the X70.
Posted by: JasonBkn
Date: January 19, 2010 09:35PM
HI guys i am just starting out in prospecting would a x Terra 50 be worth while getting to look for gold in the gold triangle of Victoria.

Jason Blackburn

Re: A compendium of BT posts on prospecting with the X70.
Posted by: Terra1959
Date: January 19, 2010 10:22PM
Hi Jason,

You can use one if thats all you have ( you will need a DD coil) but the Goldfields of Victoria have heavy mineralisation, some areas are worse than Dunnolly
In Vic. the Xterra's are very chirpy on the more mineralised ground, I reduce the sensitivity to a level where you can bear all the chirp noises...and keep checking what a real target sounds like (take along a little test piece)...and swing slowly.
They can be so noisy chirping away on hotrocks and general mineralisation that it's hard to concentrate and one may miss a real signal.
They dont get anywhere near the depth that a Minelab SD or GP series would but are useful for fine gold.
I use one at present in Vic. ( heading over this weekend) but am saving for a specialised gold detector which will handle heavy mineralisation and give me more depth ( I am hoping to start with SD 2000 , SD 2200 or 3000 extreme)

As much as I love my Xterra as an allrounder, I have to admit it cant handle the mineralised Golden triangle soil too well.
Hope this helps.


downunder ... South Australia.

X-Terra70, E-Trac, Excalibur II, CTX3030, Equinox 800

Fisher F-Pulse, Garrett Pro pointer., SITO scoop

Re: A compendium of BT posts on prospecting with the X70.
Posted by: Gold Digger
Date: January 25, 2010 06:53AM
thanks for the tips taking xterra 70 to AZ this yr hope to find some color Gary

Re: A compendium of BT posts on prospecting with the X70.
Posted by: candp
Date: November 12, 2010 02:02PM
We just bought a 705 gold pack along with a 6 inch DD coil. No gold yet but we've been looking in California and Nevada. We hope to post some finds by Monday!

Re: A compendium of BT posts on prospecting with the X70.
Posted by: Corsairian
Date: December 23, 2010 01:50AM
Howdy all,
I've been dredging on my claims here in Washington State for about 4 years now. Plan on taking my -70's (I have 2, one for me and one for the wife/son) down to shoot for nuggets this coming summer (dredging season is August - November). Have the 10x5" and 6" 16.75 coils. We've gotten quite a few large pickers and lots of fine gold these past few years, and I'm still learning to "read" the stream. The area I'm in has massive amounts black sand, hematite and magnetite. I'm hoping it won't be too bad for the -70 to be able to work... I guess we'll see, aye? Lots of exposed bedrock and nice areas to hopefully find nugglets with the -70's. I'm also looking forward to trying to locate pay streaks too, or large sections of blk sands. There may be so much already it'll drive the detector nuts! Going to have to just give it a try and see. Plan on taking the 6" into the shallows, and definitely keep the 5x10" on the bank and outta the water. I'll advise what I come up with, and hopefully it'll help someone down the road. :thumbup:



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