HARD ROCK MINING on a tight budget: (1)

[dwt]

and my favourite "oh these bloody things again, must mean were in some sh#t ground boys"

:lol:
Good thread dwt. I've mostly been around U/G coal so reading the hard rock perspective is great - similar but very different at the same time I s'pose. We bring in or have specialist support teams that do our bolting - probably what you do I guess.
They do work hard - had some lads putting up 8m strands with a Rambor last week cause they couldn't get an airtrack or LHD with a QDS bolter in to do it. They had to carry everything in then put the bolts in by hand with the Rambor. I take my hat off to them blokes - hard yakka in trying conditions.

Never had anything to do with coal mining mate, it seems like it would be a tough gig in itself, you should see the look on coal miners turned hard rock miners faces when they see you working underground smoking cigarettes, let alone a underground loader bouncing of the walls with sparks flying everywhere, i reckon you can see the moment their heart stops for a split second until they remember its not a coal mine.......my hat is off to the coal miners in Australia, tough gig

 

[HeadsUp]

i encountered black quartz on a tunnelling job in brisbane

It would wear out tungsten rock saw blades in 2 months that last 5 years on every other rock type imaginable

Diamond saws were getting as poor as 80 metres per set of diamonds @ $ 9000 per set until a supplier got some especially made for us and those gave around 900 metres in black quartz and 3000 metres cutting life in sandstone , concrete and volcanic ignimbrite.

black quartz i rate enemy number #1 , followed by some grades of granite and red jasper :/

 

[dwt]

Now we have been sinking our shaft and hit our required depth, we need to take our first drive cut because we are now on the ore.
Keeping the ore in the upper left/right section of our face(depending on which way your driving) is paramount for when it comes to stopeing which will be coverd later, it is also the best way to maximise the amount of ore we can recover in one cut.(corner to corner)
We have established our air/water services for our tools (drills ect) and our vent bag which is pumping air down our shaft via a fan from the surface,
and also we have a sump line at the base of our haulage section for pumping out of water, wether that be from drilling or hosing down, or simple ground water.Having an old tyre at the base of our haulage shaft just assists in reducing the damage to the base of our kibble bucket when sitting it on bottom.
At this stage the ore is quite rich in this section, and we dont want to drill it out into small cuttings on the floor and have it wash away with tailings so we simply move the burn (the centre of our cut wich incorporates our reamers and first initial shot holes) to one side of the ore.
By doing this we are not drilling directley into the ore, therefore saving on drill bits and avoiding the risk of blocking a drill steel, from the firing sequence you can see that we are creating a large void to then strip the backs (term used for the top part of our drive) walls and floor.
Later we will cover part facing so as not to dilute the ore.
Now that we are in gound that can handle explosives better than the more softer sandstone bedrocks, we will be using short plugs as our primers, and anfo/sanfo as our main explosive, the numbers are in sequence of our electronic detenators. By running the full perimeter in the same number helps with smashing the rock together on firing and making it more user friendly to bog. (dig)
This type of firing sequence is only a guide there are hundreds of ways to bore and fire a cut, i have seen some drill operators put their burn in upper left or right corners, and some almost at the bottom of the face, just depends on the ground, conditions and expierence of the operator as to where the burn is situated.
Having a deal inplace with a larger mining company can help out with access to explosives and a blackticket/shotfirer inplace, by this i mean having a deal set up as to sell some of your ore to help cover the costs of explosives and licensing these can be very expensive, also the access to mines rescue, if something should go terribley wrong its a good idea to have these guys know what your up to.
Alternatively, if you find that you are still in sandstone type of bedrock and you dont feel the need to employ explosives, than onto the jackhammers you go, plenty of small shows around that use drills and jackhammers to break the dirt without the need of explosives, it all depends on the ground your in.
Next we will look at where to situate your surface fan/s and water supply, and look at a few ways to set up ore retreval and processing areas, still rolling on our tight budget.

 

[dwt]

Lets take a quick gander at some of the equipment used to run holes for boring out a face.
These are referd to as knock on bits plenty of different sizes for whatever the job is your doing, Xcut bits and buttons

The one on the left is a reaming steel and bit and the one on the right is general boring, the reaming steel is used to create a void in the rock for first initial shot.

These are the air legs, 2 stage extendable pusher leg powerd by compressed air, these come in different lengths for different stages of mining.

Pictured here is the operating centre of the leg, the small button you can see is a retract button, expierenced operators can use this button to quickly retract the drill from the face , the rounded handle below it is called the pineapple, it operates like a motorbike throttle, the more you twist it back, the more air you send down the leg, and the faster and higher the leg pushes, below that is the minsup air fitting.

This the guts of the set up your rock drill, this one is a SIG29, the "go baby go" lever is one the right, all the way forward is boring, and all the way back is to flushn your hole out with air only, no water.There are plenty of different types of drills on the market, personally i prefer the SIG brand these babies hit like an out of control frieght train, making quick work of hard ground, its the heaviest of the rock drills coming in at about 30 kg, just for the drill alone then add the weight of the leg, steel, bit and hoses it makes for hard work, some people dont like them because of the weight...............grow stronger!!!

The SIG29 with steel in the bridle.

All steels are hollow up the centre for water, keeps the dust down, and lubricates the drill bit to prevent excessive wear, also if your doing rehab work and someone has'nt checked for misfires ( left over explosives) you dont want to hit this stuff at all, letalone with a dry red hot bit rotating with a s##tload of percussion up behind it, makes for a short career in mining!!

 

[Metamorphic]

Yeh thats a given for sure DWT.

I was an open-cut lad myself, but I do remember one particular occasion digging out a freshly fired shot on the Hitachi EX5500 and striking a 'booster' from a misfire.

It took 2 teeth of the bucket and they ain't small teeth.

Shut down production for a few hours also while the guru's investigated......... I got a few pats on the back when we all got to the crib room for extended smoko!

 

[HeadsUp]

Yeh thats a given for sure DWT.

I was an open-cut lad myself, but I do remember one particular occasion digging out a freshly fired shot on the Hitachi EX5500 and striking a 'booster' from a misfire.

It took 2 teeth of the bucket and they ain't small teeth.

Shut down production for a few hours also while the guru's investigated......... I got a few pats on the back when we all got to the crib room for extended smoko!

ouch !

bucket teeth would have to be 60 kg each ?

thats not something you want coming through the windscreen for a lapdance 8)

 

[dwt]

The video below shows face boring, the white lines are face mark up, no matter how good you think you are it allways pays to paint the mark up on the face, the 2 yellow circles represent "butt" this terminoligy basically means non-exploded explosives left in the face and or the depression left from an exploded shot that has had to much ground on the hole for the explosive to be effective. The diameter of the yellow circles is representation of how far one should drill away from the butt Just as i had dropped the drill for the next hole the drill steel knocked some rocks down and the unexploded ANFO was clearly visible, sometimes you can do all the washing down and scaling in the world and it wont allways show up the butt.
Unfortunately this type off butt is from a lazy cross shift who believes that shooting detenators instead of using a small plug of power gel as a primer is acceptable, ITS NOT, its actually illegal, and it cost him his job, better his job than rock drill and steel sitting in my face where my nose used be.
ps language warning!

[video=480,360]https://www.youtube.com/watch?v=uuHiw-1GGzQ[/video]

 

[Metamorphic]

ouch !

bucket teeth would have to be 60 kg each ?

thats not something you want coming through the windscreen for a lapdance 8)

Yeh scared the life out of me at the time......not sure on teeth dimensions but they were a lot heavier than that HeadsUp.

The Buckets for this machine alone weigh around 30,000 Kg

I remember the fly-rock from the blast peppering the digger.....how the glass survived is beyond me, the cab sits about 15m high off the tracks which might have been its, and my, only savior!

Cheers

 

[HeadsUp]

that hidden ANFO wasnt far away from where you were drilling either :|

not a place for untrained heads

 

[Metamorphic]

Great informative post DWT. I learnt a lot!

I tilt my hat to you underground moles......It doesn't get any more dangerous on a work site anywhere else!

I know they take safety extremely seriously and virtually shove it down your throat with a broomstick, but you hit the nail when you said that the greatest danger is complacency and inexperience.

The pearly gates are only one monumental f***up away.

Our Drill & Blast crew had written on the back of their shirts......."If you see me running, try and keep up"

Good stuff mate!

 

[Metamorphic]

I still cant get my head around what a 'stope' is?

Im shaft illiterate.

Does it mean your taking ore from the ground - up horizontally filling the void?

Is it a form of ore development via a more economical extraction sense?

 

[dwt]

I still cant get my head around what a 'stope' is?

Im shaft illiterate.

Does it mean your taking ore from the ground - up horizontally filling the void?

Is it a form of ore development via a more economical extraction sense?

If I had my normal computer (scotch induced dilemma) I would draw you a pic mate, but in a nut shell,
You put your drive levels with a certain amount of spacing in between them, this is usually governed by geo techs and engineers, let's say for arguments sake that '1' level is at Sea level, or referred to in some mines as 5000 level, then 2 level would be at 4900 level, if you had mined a hundred meters below one level and ran your drive in there, the drives are not directly above each other but are on a angle that follows the ore body you are chasing, so if you were standing at the 4900 level looking directly North, the 5000 level would be NNW at 100 meters above you, when you 'stope' you drill in the ore body up to the next level, keeping your drill pattern nice and tight as to avoid over break and diluting your ore, stope shots are taken in panels (anywhere from 5-15plus meters in length) once you have 'bogged' the stope shot ore dirt out you then come in from the 5000 level and tip waste dirt or CRF (cement reinforcing) down to the 4900 level then continue the process until the level close out shot is taken

 

[Metamorphic]

Ah yes, the fog is clearing....thanks mate!

Great explanation, thread is very informative and should be made a sticky!

Thanks again.

 

[Metamorphic]

Makes sense that drives on other levels are not directly above or below each other, as its the reef 'dip' that regulates the drives bearing over distance berween levels. Yes?

More questions my friend.

(1) we have completed removing the ore from the stope between levels and we fill the stope with waste from the level above as you state.
Are we doing this because its more economical than raising the waste to the surface?
Or is it mainly to enhance structual integrity for further stoping from lower drive levels?

Does the waste used for filling this void come from cutting the drive to the reef?

(2) We know the reef runs (lets say) in a North/South direction and the dip is 55 degrees from strike.

Where is the best spot to sink the shaft?

Do we sink 'inline' with reef direction cutting through the reef and then driving in at different levels after we pass it to pick it up again or is there a better way knowing we want to avoid as much overburden as possible?

Is it best to sink where the loam test results show the most color in pan directly above the deposit Even though the reef does not outcrop?

Hope these questions make sense mate.

Thanks in advance.

Meta

 

[Dug]

Dwt ,These posts are a top read ,a great insight .

 

[dwt]

Meta's questions,
1: Both mate, by backfilling stopes with waste we kill a few birds with one stone, firstly, cost cutting on the transport of waste to the surface, secondly, minimises the wear and tear on our haulage gear, thirdly, we can support the 'open stope' to take our next 'panel' or round and for general ground support.
Allow me to elaborate a wee bit before I continue, we are still talking small scale here, by this I'm talking drives that are roughly 1.8meters wide, by 2.8meters high, the norm for stopes is anywhere between 4-6 meters (plus) depending on your ground integrity, and the type of equipment being run.
You can run smaller drives and minimise your waste from around your ore, in this case you would most likely be using a little dingo or toro digga to bog your dirt, or maybe even a wheel barrow.
There are a few things to be aware of when tipping waste back down stope, make sure it's waste, there is such a thing as secondary enrichments, scattered minerals outside of the main ore body, gold, tin, lead, copper, whatever, this is not visible to the human eye, for small scalers, or water processors, anything we can't see is waste, that very well may not be the fact, biox processing mines extract dirt as little as 4grams to the tonne, with chemicals they can leach gold so fine we cannot see it, your waste from around the ore body, might actually be running from 2-20 grams to the tonne, but if we can't see it, it's waste, strike a deal up with a larger mining company that can process mineralised gold, you could very well find yourself selling what you would assume to be waste, for a substantial amount per tonne, that amount could quite easily cover costs, and see everything else as pure fat on top
And for the safety side, before tipping waste down an open stope, a bund wall needs to be installed before you can even attempt to backfill, this wall needs to be 3/4 the height of the tyres on whatever machine you are operating, I've heard quite a few stories of loaders going over into open stopes simply because they forgot to install a two to three bucket wall, and if your wheel barrowing or bucketing, I would suggest a harness and lanyard, 3 meters might'nt sound far but it is in the dark landing on jagged rocks!
Right back on track
I think I can answer the rest of your questions combining them all together, for sinking your shaft, honestly you would want to pick the best ground, so in saying this, the face of your non gold bearing rock heads down and joins with the lower edge of your reef, this is referred to as the 'footwall', opposite that on the other side of the reef is called the hanging wall, rule of thumb, sink your shaft in the 'footwall' and waste, steer clear of the 'hanging wall' and ore body, ordinarily I would sink quite a few meters away from the ore body, ensuring that I was placing my shaft in good ground, but, in the case of working a tight budget and we can only afford to break pay dirt, then I would sink directly on top of the gold bearing reef, keep in mind though, if you do sink directly on top of your ore body, you have just destroyed your chances of mining whatever gold may be sitting out in that ore body within 5-6 meters of your shaft the whole way down.
Also good to keep in mind is where your going to sink your second shaft for return airway and secondary means of egress.
"Does the waste come from cutting in a drive to the reef"
Yes and no, your first initial waste dirt will be on the surface till you hit pay, and I wouldn't be contemplating stopeing till you have a good number of drives in, or the ground is suitable to take a stope, you don't want to go throwing crapy muddy ground in a stope when your taking panels, good hard rock, a mix of large and small, will see a nice tight fill.
all of the above is not really relevant if your 'Lead' mining, then you'll choose good solid ground, and sink until you hit the lead.
I do realise I missed quite a bit in this post, but I hope I've answerd most of your questions mate

Just realised I missed on of your questions mate, in reference to direction, by sinking in the footwall we can drive in to the ore body, once we hit the ore body we would put in a turn out cut, and start driving North and South, thus leading us to Development Ore Drives, so after we have sunk our shaft to its required depth, we would drive off to the East till we hit the ore body
Pheeeew, almost as long winded as a chapter of the 'Play'

 

[Metamorphic]

Mate i owe you a bottle of single malt Springbank 100% proof from the highlands.

Its hard to find blokes of your calibre willing to share what you do and take the time.

Thank you so much big fella as you have taught me lots.

Much appreciated.

Your mate....meta!

 

[Heatho]

Excellent thread! Gives someone like me with no mining experience a decent idea of what happens underground.

 

[Metamorphic]

strike a deal up with a larger mining company that can process mineralised gold, you could very well find yourself selling what you would assume to be waste, for a substantial amount per tonne, that amount could quite easily cover costs, and see everything else as pure fat on top

I would never have thought of that mate......Thats a very valuable point in economic mining for the smaller scale lads such as myself.

And for the safety side, before tipping waste down an open stope, a bund wall needs to be installed before you can even attempt to backfill, this wall needs to be 3/4 the height of the tyres on whatever machine you are operating, I've heard quite a few stories of loaders going over into open stopes simply because they forgot to install a two to three bucket wall, and if your wheel barrowing or bucketing, I would suggest a harness and lanyard, 3 meters might'nt sound far but it is in the dark landing on jagged rocks!

Copy that.....yeh we had very strict rules on 'bunding' in our open cuts to avoid this exact scenerio.

When i was with Boral down the open-cut quarry in the Cat 998, I was busy bunding the exposed bench after a new shot with the haul trucks lined up waiting for me to load them.
The toss of a supervisor we had at the time got on the UHF and gave me a burn for holding up the loads to the crusher????

Go figure?......they tell you one thing in the class room, but sometimes its a different thing on the ground when the pressure is on!

ordinarily I would sink quite a few meters away from the ore body, ensuring that I was placing my shaft in good ground, but, in the case of working a tight budget and we can only afford to break pay dirt, then I would sink directly on top of the gold bearing reef, keep in mind though, if you do sink directly on top of your ore body, you have just destroyed your chances of mining whatever gold may be sitting out in that ore body within 5-6 meters of your shaft the whole way down.

This is where it gets tricky for me to get my head around as I have only ever seen diagrams and never been involved with it in a real 3D situation!

Not sure i know what you mean exactly here mate.

Also good to keep in mind is where your going to sink your second shaft for return airway and secondary means of egress.

For the return airway, both of your shafts should be joined in the drive? yes?? or is there a better way?

I wouldn't be contemplating stopeing till you have a good number of drives in, or the ground is suitable to take a stope, you don't want to go throwing crapy muddy ground in a stope when your taking panels, good hard rock, a mix of large and small, will see a nice tight fill.

Makes good sense, thanks mate......ground integrity would be important.

all of the above is not really relevant if your 'Lead' mining, then you'll choose good solid ground, and sink until you hit the lead.

I know it all depends on the depth of the 'lead', but i always thought open-cut best for lead mining. I know shafting is preferred if really deep, for waste minimization, but it scares the crap out of me!

Just realised I missed on of your questions mate, in reference to direction, by sinking in the footwall we can drive in to the ore body, once we hit the ore body we would put in a turn out cut, and start driving North and South, thus leading us to Development Ore Drives, so after we have sunk our shaft to its required depth, we would drive off to the East till we hit the ore body
Pheeeew, almost as long winded as a chapter of the 'Play'

Can you find me any pic's mate to illustrate this theory...It will help to communicate the advice to my small area of 'grey matter' as the beer is clouding my thinking on this!

Thanks again mate.

Great advice

 

[dwt]

Sorry mate, been caught up watching the Aussie movie ROUGE (for the 10th time :lol: )
I think the easiest way might be for us to catch up for a meet & greet 'chin wag' for a few hours one day when your floating around the area,
Quickly though, (cos I'm at the part where the croc rips that dudes arm off )
Sinking directly on top of the ore ruins your chances of recovering the ore around your shaft,
Let's say 'theoretically' the ore body is running North South, if you sink directly on top of the ore body, (for reasons of expences) and your shaft is 2.4meters length ways (North South) and 1.5 meters width ways East West, the ore that is outside of your shaft up to the first (roughly 6meters) will be inaccessible due to the fact that your shaft is smack in the middle of it.
Wall integrity will be easily compromised if you start digging out into it.
I hope that's a bit clearer for you mate on that one
Ok, quickly before I go, in reference to your comment on the shaft scares the crap out of you................................. :|

MAN UP YOU BLOODY FAIRY

Anyways, (I was just kidding )
Gotta go Metta, movies a waiting, I shall endeavour to have a dip at it later (soonish) and see what I can do about drawing pics