You ever use soil samples to aid in placer prospecting?

@slatcoau - Haven't used a soil sample grid for placer, but I have used panned soil samples on my hard rock gold claim (10 x 1 lb weighed samples, visible gold in every sample revealed by careful panning).

A grid pattern works well, that's what the big guys do when doing placer drilling.

A soil grid is used when doing 'loaming' - an Australian method where one samples up a drainage to identify placer and/or hard rock deposits.

When sampling for placer at a micro scale I normally do test pans in areas that are the most likely to have the best gold. Once the highest gold grain count location is identified, I do test holes around it to outline a possible pay streak, or more broadly, a deposit over an entire bar or bend.

When I do placer work its always the creek first ... I do samples/pans every 10 m or so up the creek testing for gold concentrations , once that is done i take the best result and work my way into the bench to do a one yard test at least highbanking and go from there...

As for Hard rock / mineral , I like to do rock samples first and test all the outcrops i can find , checking every sample with a hand lense for mineralization , lithologies and look for any silicification/ Cal- Carb hoping the fluids braught up some goodies ..

Once I get results back then we tend to do a soil grid in the area to see what comes up ... from those results we usually go back and focus on the high zones to see if we can locate the source of the anomoly and check for more outcrop .

Assays are really the only way to know what is good and what is not ( other then seeing VG which is rare) ... Ive seen rocks loaded with sulphides that ran nothing and boring seeminly garbage rocks that have run good ( too small to see ) Alteration is also a good tool , especially with Skans !!

Cant wait to get out there this year <best of luck out there !!!

Solid info Sebo, thanks!

I can't speak much to placer, but for hard rock, my approach depends on a few factors:

1. Are there already known showings/mineralization?
2. How big is the area of interest?
3. Can I use historical data to narrow down the search?
4. How much is known about the deposit type and chemistry/alteration?

My first step is always to look at what data is available. In BC we have a ton of great public data like geophysical surveys, stream geochemistry, etc. which makes for a great starting point. I'll start with an idea, and ask myself "What would this deposit look like in the public data?" If I'm staring from scratch and/or working a big area, I usually like to do steam sediment samples with trace element geochem, since that can focus you on a specific drainage and narrow down the search fast. If you're looking around known showings under cover, soil grids can be a great tool to test the potential size of an occurrence or find new hidden ones. Keep in mind that in steep/wet areas, the soil anomaly is often downhill of the showing.

At the end of the day though, nothing sells a property like juicy in-situ samples, so mapping and general prospecting is always the majority of the work once I have a reasonably manageable area, following the structure and alteration to (hopefully) find the main deposit. As Sebo said, the truth is in the assays - I've seen samples with VG assay almost nil due to dilution, and plain looking diorite run 10g/t.

@lindsayrichards - excellent info, thank you.