Target In Dry Creek Rock Wall: Chisel/Hammer, Or Rotary Hammer Drill/Feathers & Wedges?

[Caliche]

Never planned on doing any hard rock prospecting, but it's found me.  Got a nice tone with PI in a granitic gneiss wall in a dry creek in a known gold bearing area, at the very bottom of the side wall.  TRX pinpointer also picks up target (after ground balancing on nearby hot rocks), so it can't be in too deep.  (Copper has also been found about five miles away, btw.)  Was able to break out about 2" of the horizontal rock on the bed with pick, but the vertical rock is too solid to get any further.

Besides PPE, what should I bring when I go back?  Thinking DeWalt Rotary Hammer (on sale on Amazon) with ten 3/8" feathers & wedges, and insert in a "V" to pop out a wedge, then repeat as necessary.  I'm thinking if it's a vein, I could chase it deeper with the rotary hammer and wedges than if I only have a chisel and hammer.

Thanks for any tips.  I'll be pissed if it's a bullet that somehow penetrated the rock without leaving a noticeable hole, lol.

[GotAU?]

Feathers work very well- buddy of mine takes on huge boulders in his hole with those. Just don’t drop anything on your feet or get slabbed, side walls can be deadly. Post a photo of your progress (closeups are good).

[Caliche]

^ Thanks.  I'm thinking just pop out a little section, maybe 12" x 12".

Are 3/8" wedges enough (easier to drill), or is 1/2" better?

[GotAU?]

My buddy is using 9/16” wedge and feather shims for splitting his boulders and is using a Harbor Freight Bauer hammer drill with 9/16” Bosch bulldog bits (the included bit type in the Amazon link does not fit the hammer). He also said the 5/8” sized wedges are good to use also.

I’m not sure about those you mentioned though, maybe someone here with more experience can help.

[Redz]

3/8 work fine but you need to place them 4-5 inch apart. I use these because I get more battery life in my drill. I am not sure about the wedge shape. Typically I just do straight lines

[Caliche]

The wedges would be in two vertical lines on the wall, but if you looked straight down from directly above, they'd be angled in a V to pop a chunk out of the face.  Might help to drill some holes in horizontal lines at the top and bottom of the pattern to help the top and bottom of the chunk fracture so it can eject.  Hopefully the chunk would go deep enough to get the target in the first go.

If it's a vein that needs chasing, it'll get more complicated.

[jasong]

I use 5/8" for stuff like that and 3/4" to break boulders in half, depends on how competent your rock is. You don't want your tools to get stuck in the rock without it fracturing. So I like having plenty of length on the wedges personally. 

If you are trying to basically pop off a chunk, drill your holes at angles so that the force of the wedge presses both back against the rock wall and out into open air so the rock has somewhere to flake off/move into. Try to find the natural foliation of the rock and use that to your advantage. Gneisses will have some you can use as long as they aren't too strongly folded/deformed. 

[jasong]

Here is an example of what happens when you use too small of wedges and go perpindicular to the foliation of the rock, so to speak rather than along the natural grain/fracture planes (with this rock it may not be exactly the right term).

My first time trying it with 1/2" wedges. This was with jade though, notoriously tough rock. Wedges get stuck and just small pressure flaking on the surface.

It's possible to get them back out once they bottom out, but I just kept it as a reminder to myself of what not to do. 😄

[Zephyr]

In my opinion If 12”x12” is substantially beyond the metal detectors signal boundary, it would be just enough margin, however if that is not the case it sure would be a shame to knock out a small section and in the process break a potentially beautiful specimen into chunks.
 

 I made this mistake a few weeks ago, got lazy removing rock and ended up breaking a multi ounce chunk of crystalline gold into several sections.