Small scale hard rock mining and prospecting

[PickaxeCA]

I am starting a thread for anyone interested in hard rock gold. With a placer skillset, you can easily learn everything you need to find hard rock gold.

All it takes is 1 spec, and you'll be hooked.

[Geowizard]

PickAxe,

Excellent! There are many points of discussion that need to be addressed.

Gold recovered by hard rock methods represents a different "species" of GOLD.

This GOLD has not been subjected to the forces of erosion and "rumble tumble" of placer GOLD. Hard rock gold is recovered from a "fresh break" and has no organic coating or other environmental exposure.

It floats different! The forces of water acting on a shiny surface - called surface tension are greater!

This is gonna be fun!

- Geowizard

[PickaxeCA]

If you're like me, you might be a placer miner or hobbyist who was intrigued about the idea of finding gold straight from the actual source.

I set a goal last year of finding 1 speck of hard rock gold, and it didn't take long. Here's what to do.

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Hard Rock Prospecting: Your First Speck (For Beginners)

To get your first speck of hard rock gold, you'll need to grab some samples.

Here is what to look for:

1. Ugly Quartz
Color: broken, brown and gray (BBG) is better than pristine
Sulfides (e.g. iron pyrite, arsenopyrite - in nano specks or large blebs)
Faulting, shearing, folding (shattered and/or fractured wall rock = fluid pathway)
Deformed/contorted look
Banded, with multiple layers

2. Edge of quartz (worth testing)
3. Wall rock next to quartz (worth testing)

Avoid pristine white quartz, also known as 'bull quartz'. In the beginning you're better off going for the ugly stuff.

Now, crush, sieve and pan. Use eye protection, and a mask or respirator when crushing rock as the dust is toxic (silicosis). Yes, your eye protection will fog up, but that's a small price to pay.

Here are some ways crush rock on the cheap:

CONTAINED CRUSHING (all-in-one)
Pipe crusher: 1" steel pipe with a cap, inside a large steel pipe and cap (2") - available at hardware stores
Dolly pot
Mortar and pestle

HAMMER
Rock hammer
Sledge hammer
Regular hammer
Tow hitch ball

BASHING PLATE
Sledge hammer on ground sideways, as an anvil
Axe head on ground as an anvil
Cast iron pan
weight lifting plate
Steel plate (1/4" or thicker)

The basic idea is to place some type of thick, heavy metal on the ground, and bash rocks until they are crushed to 20 mesh (apprroximately window screen size). That is sufficient for test panning purposes.

You may have to do a few rounds of crushing - the first to ~1" or 1/2", and then to powder from there.

Here is the technique to use:

Smash and bash (down to 1/4" or so), then...
Turn, twist, drag back and forth, smearing and shearing
Dump often into a 20 or 30 mesh screen to sieve out the powder (to avoid overcrushing which can create slimes) - window screen works well, so do dollar store sieves, or your regular old classifiers.

MORE EXPENSIVE CRUSHERS
Jaw crusher
Hammer mill
Impact mill (e.g. angle grinder size, or Keene G-Force crusher)

OLD SCHOOL CRUSHERS
Stamp mill (scaled down to a portable version)

THE FERRARI OF CRUSHERS
Anything by Mount Baker Mining and Metals

---

Now, pan the powder.

PANNING THE POWDER

Panning hard rock gold is very different than placer, so you'll have to adjust your technique slightly.

Check out Hard Rock University's videos on how to pan micro fine gold. Use his technique, as it works really well (it's what I use).
Buy a 10X jeweller's loupe and use a light to spot gold not visible to the naked eye (fairly common)
Use a black pan, as you won't be able to see a lot of hard rock gold against Garrett green or other colors (note, I own and enjoy using Garrett pans for placer)

If all goes well, you might see 1 or more specks of fine gold in your pan.

If not, then keep crushing and panning rocks... until you find your first piece of hard rock gold!

[PickaxeCA]

I have found some pieces of hard rock gold hammered flat during crushing that tend to flutter more than other pieces. This is one reason to avoid overcrushing beyond 20 or 30 mesh, as the old timers running stamp mills found out the hard way when they had to deal with excessive slimes that stole gold by gumming up their water!

Also, I like to go for hard rock specimens of all sizes rather than crushing everything down small, so I will classify to various size factions, and run them separately from the powder first. Sometimes I'll even take the powder home in my backpack to keep the recircluating water cleaner for longer.

I run multiple sizes separately because I have test panned beautiful small pieces of crystalline wire gold in my area, and I'd like to keep them intact where possible (I do this for a hobby, not a living).

[PickaxeCA]

Loaming - The Australian Art of Panning Soils to find hard rock gold

I'd like to draw your attention to loaming. This is an effective technique for panning soil samples to find gold.

The basic idea is to pan soil samples along a line, or on a grid, noting values along the way.

Once you stop finding gold in the pan, you have likely passed the slope that the gold came from.

You then go back, and start doing pans halfway between specific intervals, smaller and smaller. At this point, you'll have a hand drawn map showing sample spots and specks per pan. You then start working up slope, doing pans in the same grid fashion.

At a certain point, you may locate the outcrop the gold came from.

Because soils are oxidized, they can contain free gold. You can literally pan gold out of soils if you're in a gold-bearing area.

This makes panning soil samples an effective mineral exploration technique for the hobbyist who doesn't want to pay for assays.

I pan soil samples all the time, and routinely find visible gold in the pan. It's not unusual to get 5 or 10 specks in a pan from a very small sample e.g. 1-2 cups of material if you're in a good area.

This is the art of loaming, or panning soil samples for gold, and it's well worth adapting to your area.

[Geowizard]

The tools are different:


All good points. One of the adjustments for anyone new to hard rock mining is learning to use tools that are designed to apply force to break and crush rock. If they can crush rock, they require a high level of care.

Not only is the GOLD different, the tools are different. In placer mining we use tools like pans, sluice boxes, dredges! The hard rock domain has a mix of hand tools and mechanized tools. Companies like MBMM, LLC demonstrate most of these tools in action!

Small scale hard rock mining gets into mechanized tools like breakers, muckers, crawlers, loaders, excavators and mine cars on a "small scale". Miners can scale up operations from pick and shovel to the use of "mini" machines that beat the heck out of a #2 shovel!

Bobcat loaders are frequent visitors to small mining operations.

Note: The use of trade-names is meant only in a generic form and not as a solicitation to buy or sell. Exposure to manufacturers though just as in placer mining can be beneficial in pointing miners to sources of the tools.

Many of the tools, found today come from off-shore sources. That's just the reality of global markets. Sources from countries like South Korea and China are prevalent. Russian Republics are entering the stage too.

Our challenge is to find the right tools at an acceptable price from a worthy source!

Can it be done?

Stick around and find out!

- Geowizard

[Geowizard]

Prospecting or mining?

Prospecting begins way before a shovel hits the dirt.

Research needs to be done on areas known to have GOLD mineralization, Study of maps that show GOLD mining districts will be a guide. Not all mining districts are GOLD mining districts.

The other option is "Wild cat" prospecting! GOLD is found in .004 parts per million in the crust of the earth. That's FOUR parts per billion!

Do you feel lucky?

Prospecting without deliberate consideration and overabundance of research beforehand should be expected to be a matter of almost impossible odds. Life is short and GOLD is "rare". Prospectors today have a great advantage over our predecessors. We are in the "information age". Cyberspace with all of the search bots and search engines combined with "artificial intelligence" provide prospectors with a wealth of resources that form vectors or pointers that point in the direction of GOLD deposits. Not a "speck", a "deposit"!

Working "in the field" represents a task with all of the inherent challenges associated with being outdoors, exposed to environmental conditions that work against our ambition to find GOLD. Every effort should be made in advance to make that time rewarding. The reality is that it is rarely rewarding even with having done the homework and the sampling. It is discouraging! The successful prospector reaches within and continues until a discovery is made.

That's where a decision to mine or not to mine is made. Are you a prudent man? Is it practical? Is it feasible to mine?

The chase is on!

- Geowizard

[Geowizard]

The chase is on;

Where do we begin the chase? The short answer is; "with a discovery". The statement has been made that "every creek and river in Alaska has GOLD in it". Just for the sake of argument, let's assume it's true.

From casual observation and listening to all of the discoveries gone bad and untold fortunes spent on gopher holes, one must analyze their own sanity. I call it a "sanity check". I first joined this forum at a time when Fortymile was "hot" for GOLD prospecting! The reason was all of the excitement to do with something called "placer mining".

The question in my mind at the time was... Where are the LODE deposits?

There-in lies the reality that placer deposits are formed from lodes and the "lode prospector" must look for placer deposits! Simple logic. Right? The challenge with the region around Fortymile is "glaciation" and the fact that the surface is covered by overburden. You cannot see those rusty, crusty, quartzy gold riddled rocks!

Well, so much for theory! What to do? one might ask.

The Canadians found an answer!

- Geowizard

[Geowizard]

Canadian Shield;

The Canadian shield covering 8,000,000 square kilometers contains what is becoming the largest source of precious metals and diamonds on the planet!

https://en.wikipedia.org/wiki/Canadian_ ... %20rebound.

There's a problem!

Momma won't let you see it! Yep! It's all covered up and buried! Mother nature decided millions of years ago to cover it all up.

Stick around and find out!

- Geowizard

[Geowizard]

Anomalous GOLD;

Prospectors are faced with an awesome challenge to find GOLD. That's because we are looking for a needle in a hay stack even in areas with anomalous amounts of GOLD. Consider a prospective area to have one part per million - an amount 250 times more than the "relative abundance" of GOLD in the crust of the earth. There would be one gram in one metric tonne. With even distribution there would be one microgram per gram or one milligram per kilogram.

That amount of GOLD requires any prospector to crush, mill, screen and pan one kilogram (roughly 2.2 pounds) of hard rock to "successfully" recover one milligram of GOLD. If you want the rest of the gram, you must repeat that sequence one thousand times in total. Noting GOLD spot, that's a take-home of around USD $70.00. Moving the decimal place 3 places to the left, to put that in better perspective is USD $0.07 pay for working your way through each kilogram.

This is the point where a prospector has to push his hat back on his head and do some introspection. That's the sanity check I mentioned earlier. The reality of GOLD prospecting involves human toil combined with recovery of nuggets of GOLD. Consider the scenario at hand with equally distributed one gram nuggets. There will be one pan with one nugget.

This is what separates the placer miners from the hard rock miners! Momma helped out the placer miners by doing all or most of the work - crushing, milling, concentrating to create those rare and elusive placer deposits.

In summary, the term "small miner" is an oxymoron. A prospector - wannabe hard rock miner must by the exercise demonstrated above defy common sense and scale a mining operation to a level that makes sense.

Can it be done?

Stick around and find out!

- Geowizard