Starting the "ballroom" of a sapphire mine - how is it done?

[Lefty]

While I have little desire to go down a shaft, one thing has got me wondering about the small underground mines on the CQ gemfields(and elsewhere). The drilled shaft looks just big enough to accomodate a human body going up and down a ladder. Once the shaft is drilled, how does digging sideways at the bottom then commence in such a tiny space? Is a small jackhammer lowered down on a rope or something?

[The Rock Hunter]

pick and shovel if its in soft rock if not then drill and power tools and chinese people to fit down the shaft

[Lefty]

Must be pretty squeezy at first!

A job for the seven dwarfs

[Sioux]

Yep, I'm glad that we bought our mine already in operation. All the hard work was done for us. We are 35' down.

[Lefty]

Yep, I'm glad that we bought our mine already in operation. All the hard work was done for us. We are 35' down.

Are you in the Rubyvale/Sapphire are Sioux?

I remember when I was a kid, the people on the ridge above us at Russian gully were down about that depth. I remember them talking about an underground feature not visible from the surface that they called "the wall". An old lava dike perhaps?

[Bluey Zarzoff]

Hey Lefty.
After the shaft is dug, normally the shaft is belled, that is it is dug in about a metre all round.

Normally, a small area is dug first to allow the person below to get out of the way as the dirt is lifted. The dirt from this small area is dropped onto the floor of the shaft and gradually recovered later.

It all then depends upon how you get the dirt to the surface, whether you fill a few buckets, leave them at the bottom and go up top and go fishing, whether you have someone hoisting them for you, whether you use an up and over, or even a vacuum system (called a blower in the opal fields I believe).

A ballroom as you referred to is a large area dug out in the drive, much bigger than the shaft. Can be a bit risky building a ballroom without proper propping.

[Sioux]

Our mines (two linked) are just above Russian Gully. The original shaft was dug by hand by two brothers. It is rectangular and big enough to lower wheel barrows etc down. The other round shaft is too small for this.

I haven't heard about "The wall" before. I'll be out there this weekend so I'll ask my "other mother" who lives on the claim next to us, if she knows about it. It was her brothers who dug the first shaft.

[shaker]

A ballroom is started when all of the rooms and pillars have been cut.
Rooms or 'drives' are normally 2.4 mtrs wide x 1.8 mtrs tall. Pillars are 2.4x2.4 x1.8 mtrs of natural ground, and are the 'props' of the mine. A ballroom occurs when all of these props are cut away leaving an empty space.
It's a job that has it's dangers. As every underground miner knows it is almost impossible to stick to the measurements above but they are a guideline. A lot depends upon the stability of the roof and my advice is to prop' prop'prop and keep a very good eye out for lose ends.................

[Lefty]

Thanks for your replies everyone..

I've often thought that it seems a shame to abandon a claim once the shallow wash has been worked out when there is often a secondary layer deeper down.

It'd be a bit disconcerting to be in a tiny space, knowing that there's hundreds of tonnes of earth and rock hanging over your head, but I guess if it's done properly, the risk is minimised. I don't recall having ever heard of a fatal mine cave-in on the field.

I'd never attempt it without plenty of first hand advice from an experienced underground miner.

[Aussie Sapphire]

I don't recall having ever heard of a fatal mine cave-in on the field.

Just from a quick scan of the data from the International Mining Fatality Review, there have been probably 12-15 fatalities in Australia in small underground (eg. opal) mines.
Not a lot of room for error in these situations - once the rock falls, you dont have much chance to escape.  PLEASE get expert advice to prevent a disaster.

Some may be interested to see this:
http://www.resources.nsw.gov.au/safety/publications/statistical-publications/international-mining-fatality-review

A very good reminder to everyone in the industry to be as careful as they possibly can be.  Accidents can happen but the consequences are very severe.

Leah

[Bluey Zarzoff]

So right Leah.

The last 2 fatalities I read about were on the opal fields, where someone was digging in old workings and, as the ceiling had been previously disturbed, it was unstable and collapsed.

It all comes down to what type of soil you have over your head.

There is an area in Rubyvale where there is Sapphire at about 40ft but it is all loose packed soil above it. Too deep to open cut, too dangerous to tunnel, and machinery mining is not allowed.