Using The GMT To Find Black Sand Paystreaks

[Reno Chris]

8 minutes ago, Jim in Idaho said:

the only real use I can see for this feature is trying to locate pay streaks of flour gold.

When you give it a try, let us know how it works.

[Jim in Idaho]

You can count on that. I got tangled up on another project, and ran out of time on the black sand thing. Hoping to get back at it soon, assuming the weather doesn't get me.

Jim

[Steve Herschbach]

As near as I remember this was something Garrett started with the early marketing of detectors, BFO units in particular. Garrett's early books and marketing material always made a point of using detectors to trace black sands.

From the 1991 report on the Garrett Gold Stinger by Andy Sabisch:

"My wife, Rosanne, and I return to this stream planning to use the Scorpion to locate potential areas to bring our dredge in at a later date. Rather than using the detector to locate metal targets, I intended to use it to locate pockets of black sand which often contain gold.

With the 16-turn ground-balance control and the manual audio threshold tuning mode, the Gold Stinger was ideally suited for this application. I used my gold pan to sample a gravel bar located in the stream and determined that, while there was a little black sand present, it would be a good spot to "calibrate" the detector for my search.

Setting the Depth control to Preset, the operating mode toggle switch to All-Metal, and the tuning toggle switch to manual, I preceded to ground-balance the Scorpion. When searching for black sand deposits, I found it preferable to run the audio level slightly higher than normal in order to hear any change.

Slowly scanning likely looking spots, the audio threshold suddenly decreased noticeably, indicating the presence of an increased amount of ground mineralization which is usually caused by a concentration of black sand. Filling the gold pan with a sample from the area and panning it down showed that not only was there a fair amount of black sand present, but a number of small gold flakes as well.

I tried panning some of the material nearby, but saw that the gold was only in the small area pinpointed by the Gold Stinger. Over the next hour, we were able to locate several spots that deserved additional work with either a sluice or dredge based on the gold that was recovered.

On the way back to the car, I tried scanning the bank in an area where an old stream bed intersected the present stream. In one area the threshold disappeared completely, indicating a highly mineralized deposit. Carefully panning a shovel-full down, I found more gold in the pan than I had ever found by panning in this creek.

While there were no nuggets, there was enough color to justify bringing a dredge in and thoroughly working the area. The Scorpion had pinpointed several potentially profitable areas in much less time than it would have taken by sampling with a pan."