How to learn to evaluate structural integrity of an old mine?

[Ragnor]

"Don't go in there" is not how to learn.

There is a mine I would like to explore. I walked in about 50 feet once before. There was a giant hanging slab held up by a rotten timber. I turned around and left. I had no way of knowing if it was safe or not and I recognized that. A friend of mine told me that sill did actually colapse if I recall correctly.
I would like to learn how to know what is safe and what is not. To learn to identify stable and unstable configurations.
While we all have to face our fate one day and that is certain for a fact I have no desire to push the matter.
I know about bad air and have personal experince with what happens when some well meaning fool plugs up an air shaft. It involves allot of confusion and purple and blue floating spots in your vision. I understand all that.
None the less I would like to study up on the matter without having to become a certified mining engineer.

Can anyone suggest some good learning materials?
How can I learn if a mine is stable enough for exploration.

This particular mine entrance is big enough to drive a truck into. I just found some documents saying it has thousands of feet of tunnel over 5 levels. So it was pretty big for having no record of ore shipments.

 

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[diggingthe1]

Happy Hunting, I would find someone local who knows these things and take him or her in with you until you get comfortable. Or use your best judgment and be more carefull than that. I witnessed a cave in and that would be the end. Good Luck!!!

 

[hvacker]

Your talking about structural engineering. Old timers probably learned by what didn't work, which is what most engineering is.
I know many incidents happen while trying to stop things from happening.
I would probably start at the library. Finding photos of existing mines and study how they were reinforced. I saw a film on a silver mine that went into the engineering of the structure but it was a large shaft. They are probably the hardest. A lot of engineering is common sense but sometimes it doesn't occur at first.
The type of rock would also need studying as some would more solid than others.

A lot of mines are initially stabilized with support bracing then drilled for expansion anchors. The anchors are quite long and would require an air/water pneumatic drill. After anchoring, the bracing would usually be removed and used again.

I used to do a lot of caving and do know how unstable rocks can be even if they have been stable for a long time. If there are any tourist mines near you it might be worth a visit. Take a camera.

 

[Hitndahed]

This guy does this to preserve the past. I would watch his videos and probably contact him with these issues.
https://www.youtube.com/user/fhood

They KNOW when to NOT continue in these old mines.

 

[SoCalDesertFox]

First and foremost, know these three basic rules of safety in mines:

1. NEVER GO ALONE. TWENTY METERS MAXIMUM SEPARATION DISTANCE BETWEEN PERSONNEL.
2. MAINTAIN A CONSTANT CONTACT POTENTIAL - KNOW WHERE EVERYONE IS AT ALL TIMES (I suggest FRS/GPRS radios.)
3. WATCH YOUR ROCK - if you come across unexpected fractures or moisture while mining, GET THE HELL AWAY UNTIL YOU KNOW FOR SURE. GROUND PENETRATING RADAR AND NOTHING ELSE AT THIS POINT.

Yes, this seriously increases your costs. Your life is worth more than these costs, and if these costs are too much to bear, stick with surface mining or open pit mining.

I have a video I just made this past weekend, exploring an older abandoned mine with geolover. I'm still getting a bit of editing done, but you can tell where the original miners (and myself) stopped COLD because we knew the conditions at this area were way too dangerous to proceed.

Let me impart one tip to avoid unexpected flooding, thinking of that video:

If you see green life above where you're planning to dig an adit or shaft, find another spot without it. You're likely to run into an underground spring or aquifer and lose your life from a flood or unstable water-flooded collapse.

Also, watch out for dangerous gases. Standing water is a bad thing for unexpected gases. If you come across an old pool of standing water, do not disturb it. If disturbing it is unavoidable, put an outward-suction hose/vent next to it.

In general, exploring mines caries the same risks as exploring a cave. If you follow the same safety procedures, and use a little common sense, you can avoid being one of the roughly three dozen fatalities per year that occur during mining.

One final tip - stick along the hard rock. That's your most stable support. Don't leave it if possible, and don't get rid of it unless absolutely necessary to get to your desired target.

This comes from a guy (me) that did small-scale hard rock mining in the UK under license.

 

[dave wiseman]

It is sweet to dance to violins..it is delicate and rare..to dance to lutes and dance to flutes is way beyond compare...but it is not sweet with nimble feet to dance upon the air..from the ballad of Reading Gaol by Oscar Wilde...One might be one step away from death and the only sound you'll hear is your own scream as you tumble into eternity.

 

[Ragnor]

Hi Dave, Long time no see.

 

[Mad Machinist]

Ragnor,

I had to take some time to think of how I was going to respond to this as there are a lot of variables involved. Things like age of the shaft or adit, type of rock, seismic activity, fracture zones, water seepage, and a whole host of other variables come into play.

A general guideline to follow is if there is debris on the floor then the shaft or adit should be treated as unstable. The only way to fix this is to bolt the back and possibly install chain link under the roof bolts to help with smaller rack falls. In really unstable areas, shotcrete is often sprayed over the chain link to further control smaller rock falls. Keep in mind though, that there is no guarantee that bolting the back or the ribs will stop all rock falls. Funny things happen underground and the deeper you go the odder they get.

I recently spent a few days in the field here evaluating an adit for just what you are asking. Right now were are looking at just opening up the adit by another 6 -8 feet overall to eliminate as much hazard as possible. BUT rehabbing an old mine takes a lot of money and there is no amount of gold in the world worth living with getting someone hurt or killed. Hence the reason I am evaluating and trying to build some smaller equipment.

If I was you, I would ask around to see if there are any of the old miners who would be willing to give you some on site advice. Get opinions from as many as you can and go from there.

 

[Mad Machinist]

This should give a start. Not exactly a perfect set up but it will give you an idea. They have other videos concerning these things too.

 

[Ragnor]

Shotcrete was the first solution that crossed my mind when I started thinking real hard about it. But like you say, that would cost a whole lot of money.
Thanks for the reply. I recon for now I will only just be thinking about it.

Ragnor,

I had to take some time to think of how I was going to respond to this as there are a lot of variables involved. Things like age of the shaft or adit, type of rock, seismic activity, fracture zones, water seepage, and a whole host of other variables come into play.

A general guideline to follow is if there is debris on the floor then the shaft or adit should be treated as unstable. The only way to fix this is to bolt the back and possibly install chain link under the roof bolts to help with smaller rack falls. In really unstable areas, shotcrete is often sprayed over the chain link to further control smaller rock falls. Keep in mind though, that there is no guarantee that bolting the back or the ribs will stop all rock falls. Funny things happen underground and the deeper you go the odder they get.

I recently spent a few days in the field here evaluating an adit for just what you are asking. Right now were are looking at just opening up the adit by another 6 -8 feet overall to eliminate as much hazard as possible. BUT rehabbing an old mine takes a lot of money and there is no amount of gold in the world worth living with getting someone hurt or killed. Hence the reason I am evaluating and trying to build some smaller equipment.

If I was you, I would ask around to see if there are any of the old miners who would be willing to give you some on site advice. Get opinions from as many as you can and go from there.

 

[Joanne]

It all depends on what your ultimate goal is. Do you want this specific mine inspected? Do you want to learn more about how to safely explore mines? In the first instance, you could contract with a company such as Burgex Mining Consultants who specialize in inspecting and documenting old mines. Underground explorers might undertake it as well. If you are looking to gain more personal knowledge, then teaming up with someone from the mine exploring community would make sense. Most of us are more than willing to share our experience with someone. I have a complete extra set of exploring gear for when friends want to go along. (I have a lot of photos up at Abandoned Mines of the Southwest)

When it comes to book reading, my "go to" place is Google Books and search for "mine engineering", "mine timbering", and similar search strings. Some book references are recent, and due to copyright laws aren't available online. But they also have some very interesting books from the late 1800s and early 1900s. Before you shun the old books, the information is still very valuable and often lets you better understand what you are seeing when you go underground.

Here's an interesting facebook page about a book on mine timbering: Timbering For Small Underground Mines

Out of curiosity, where are you located?

Joanne

"Don't go in there" is not how to learn.

There is a mine I would like to explore. I walked in about 50 feet once before. There was a giant hanging slab held up by a rotten timber. I turned around and left. I had no way of knowing if it was safe or not and I recognized that. A friend of mine told me that sill did actually colapse if I recall correctly.
I would like to learn how to know what is safe and what is not. To learn to identify stable and unstable configurations.
While we all have to face our fate one day and that is certain for a fact I have no desire to push the matter.
I know about bad air and have personal experince with what happens when some well meaning fool plugs up an air shaft. It involves allot of confusion and purple and blue floating spots in your vision. I understand all that.
None the less I would like to study up on the matter without having to become a certified mining engineer.

Can anyone suggest some good learning materials?
How can I learn if a mine is stable enough for exploration.

This particular mine entrance is big enough to drive a truck into. I just found some documents saying it has thousands of feet of tunnel over 5 levels. So it was pretty big for having no record of ore shipments.

 

[mofugly13]

Here's that book, for free:

http://www.google.com/url?sa=t&rct=...xH9rhp_H87wc0LBhg&sig2=4BzjgiVOLITP1MiXHsrqIQ

 

[OwenT]

Maybe get in contact with Northwest Underground Explorations. They may have been in your mine and written about it in one of the Exploring Washington's Historic Mines books.