Originally Posted by George Baker

Can one of our experienced limestone quarry aggregate producer type members advise ...WHAT IS THE SAFE DISTANCE to move your portable track crusher from the blast FACE area when moving out to do the blast?

I have a thought....but, others have other opinions. Any imput would be fantastic. Thanks.

George Baker

MODERATOR

Hello George,

There is no real safe distance george because flyrock is unpredictable due to the nature of the bench shot, hole pattern, explosive depth and lift depth/drill hole length.

We had a fellow killed in the quarry above the mine when he was buried and crushed by the rock wall face after he was scraping and cleaning away the shot muck with the loader. The bench face was loose becuase it was a vertical folded bed of limestone and it was cracked and broken after the shot.

if the quarry benches werre undercut it would require much less explosive and smaller blast hole diameter but I dont see anyone employing undercutters to do this either.

No george you cannot hide it safely behind a muck pile either.

George, when you have a free moment could you call me at your convenience?

Leon ■

George

The safest distance is 10' past the place that the farthest flying fly rock will land and stop moving. j/k

All kidding aside George the safe distance is typically regulated by State or Provincial authorities. The type of burden as well as the type and amount of explosives being used make a big difference in this distance.

It would be best to contact the local authorities for their input and advise. ■

Yes, we both have lived with that suprise of a 20 pound lump either landing by us or flying by have we not Gary HA.HA. ■

Yes Leon but I wish it was only a 20 lb lump. I had a fall of ground land within about 20 feet of me that crushed the handrail on the platform I was working on. Luckily it went down on the off platform side and not on the grating that I was standing on. It didn't take me long to get the H out of there. ■

Was it at one of the belt transfer points Gary or the old screen plant? ■

In Europe all persons must take shelter. Some quarries have igloos to reduce working delays: some don't. Sheltering applies throughout the workings, everywhere.

But::

When I used to deliver bitumen to asphalt works with adjacent quarries I was the only one who was allowed to take makeshift shelter at the blind side of my semitrailer. I had to be in complete control of the tanker internal pressure and the discharge valve. Looking back I can see that the management involved had decided that the driver would be OK because a flying rock would impinge from the face working side and so the contents of a punctured tank would spill away from the driver. Reasonably uncomfortable if the delivery had just started and there was 28tonnes of hot bitumen about and a rock was headed for the tank top nearside. My point is that if the management are clever enough, a complete non-starter if ever there was one, they ought to get those sub-pervisors to give adequate prior warning.

I have crossed swords many times with Health and Safety clowns in many lands and came to the conclusion that they are worthless, often bordering on dangerous, regardless of who's paying. ■

Originally Posted by johngateley

In Europe all persons must take shelter. Some quarries have igloos to reduce working delays: some don't. Sheltering applies throughout the workings, everywhere.

But::

When I used to deliver bitumen to asphalt works with adjacent quarries I was the only one who was allowed to take makeshift shelter at the blind side of my semitrailer. I had to be in complete control of the tanker internal pressure and the discharge valve. Looking back I can see that the management involved had decided that the driver would be OK because a flying rock would impinge from the face working side and so the contents of a punctured tank would spill away from the driver. Reasonably uncomfortable if the delivery had just started and there was 28tonnes of hot bitumen about and a rock was headed for the tank top nearside. My point is that if the management are clever enough, a complete non-starter if ever there was one, they ought to get those sub-pervisors to give adequate prior warning.

I have crossed swords many times with Health and Safety clowns in many lands and came to the conclusion that they are worthless, often bordering on dangerous, regardless of who's paying.

John, I raise a pint of Guinness to you in a toast my dear friend.

I was once blessed with working with fools that would not even bother

to tell me that they were shootiing down below when i was transferring fuels.

That was quite an evening where I had to stop refueling and escape as the

exhaust air path was right in the same tunnel where I was.

All the more reason to be wary of anothers claims of personal safety and

adequate distance from the flyrock zone at the quarry face.

lots of examples of this at the MSHA home page in the fatal grams/quarry deaths.

On a personal note I read with much satisfaction about the Justice Department and

and the State of West Virginia seeking additional charges against the previous managers of

Massey Energy the other day in the New York Times. Too late for the 29 men who died

and thier families, but the federal legal and the state justice system in West Virginia

is still in hot pursuit of Massey Coal and Don Blankenship its former chief manager. ■

As I said George it has to do with the type / amount of material being blasted, how many holes, how deep the holes are, diameter of the holes and the amount of charge being used. The distance is going to vary greatly depending on those factors. So without knowing all those factors it is impossible to give you a reasonable answer. It comes down to the company procedures, blasting technique being used and experience as well as the laws governing the local. Fly rock during a blast is very unpredictable.

Leon - it was in the old underground screen mill that was replaced in the mid 2000's. I was up on one of the floor levels of the mill when it happened probably 30 feet above the rock floor and the FOG was maybe 20 feet above that level. ■

Originally Posted by George Baker

Can one of our experienced limestone quarry aggregate producer type members advise ...WHAT IS THE SAFE DISTANCE to move your portable track crusher from the blast FACE area when moving out to do the blast?

I have a thought....but, others have other opinions. Any imput would be fantastic. Thanks.

George Baker

MODERATOR

Originally Posted by lzaharis

Hello George,

There is no real safe distance george because flyrock is unpredictable due to the nature of the bench shot, hole pattern, explosive depth and lift depth/drill hole length.

We had a fellow killed in the quarry above the mine when he was buried and crushed by the rock wall face after he was scraping and cleaning away the shot muck with the loader. The bench face was loose becuase it was a vertical folded bed of limestone and it was cracked and broken after the shot.

if the quarry benches werre undercut it would require much less explosive and smaller blast hole diameter but I dont see anyone employing undercutters to do this either.

No george you cannot hide it safely behind a muck pile either.

George, when you have a free moment could you call me at your convenience?

Leon

Originally Posted by Gary Blenkhorn

George

The safest distance is 10' past the place that the farthest flying fly rock will land and stop moving. j/k

All kidding aside George the safe distance is typically regulated by State or Provincial authorities. The type of burden as well as the type and amount of explosives being used make a big difference in this distance.

It would be best to contact the local authorities for their input and advise.

Originally Posted by lzaharis

Yes, we both have lived with that suprise of a 20 pound lump either landing by us or flying by have we not Gary HA.HA.

Originally Posted by Gary Blenkhorn

Yes Leon but I wish it was only a 20 lb lump. I had a fall of ground land within about 20 feet of me that crushed the handrail on the platform I was working on. Luckily it went down on the off platform side and not on the grating that I was standing on. It didn't take me long to get the H out of there.

Originally Posted by lzaharis

Was it at one of the belt transfer points Gary or the old screen plant?

Originally Posted by johngateley

In Europe all persons must take shelter. Some quarries have igloos to reduce working delays: some don't. Sheltering applies throughout the workings, everywhere.

But::

When I used to deliver bitumen to asphalt works with adjacent quarries I was the only one who was allowed to take makeshift shelter at the blind side of my semitrailer. I had to be in complete control of the tanker internal pressure and the discharge valve. Looking back I can see that the management involved had decided that the driver would be OK because a flying rock would impinge from the face working side and so the contents of a punctured tank would spill away from the driver. Reasonably uncomfortable if the delivery had just started and there was 28tonnes of hot bitumen about and a rock was headed for the tank top nearside. My point is that if the management are clever enough, a complete non-starter if ever there was one, they ought to get those sub-pervisors to give adequate prior warning.

I have crossed swords many times with Health and Safety clowns in many lands and came to the conclusion that they are worthless, often bordering on dangerous, regardless of who's paying.

Originally Posted by lzaharis

John, I raise a pint of Guinness to you in a toast my dear friend.

I was once blessed with working with fools that would not even bother

to tell me that they were shootiing down below when i was transferring fuels.

That was quite an evening where I had to stop refueling and escape as the

exhaust air path was right in the same tunnel where I was.

All the more reason to be wary of anothers claims of personal safety and

adequate distance from the flyrock zone at the quarry face.

lots of examples of this at the MSHA home page in the fatal grams/quarry deaths.

On a personal note I read with much satisfaction about the Justice Department and

and the State of West Virginia seeking additional charges against the previous managers of

Massey Energy the other day in the New York Times. Too late for the 29 men who died

and thier families, but the federal legal and the state justice system in West Virginia

is still in hot pursuit of Massey Coal and Don Blankenship its former chief manager.

Originally Posted by George Baker

Gentlemen: your absolute range of experiences was fascinating to read....not a standard answer in any of them...wow.

Safety of course is omni important and becoming even more so in the aggregate industry in Canada and worldwide. Why then, does this important weekly occurence not have a standard footage, meter or yardage to move away as a result?

Appreciate all of your responses. Thanks again.

George Baker MODERATOR

Originally Posted by Gary Blenkhorn

As I said George it has to do with the type / amount of material being blasted, how many holes, how deep the holes are, diameter of the holes and the amount of charge being used. The distance is going to vary greatly depending on those factors. So without knowing all those factors it is impossible to give you a reasonable answer. It comes down to the company procedures, blasting technique being used and experience as well as the laws governing the local. Fly rock during a blast is very unpredictable.

Leon - it was in the old underground screen mill that was replaced in the mid 2000's. I was up on one of the floor levels of the mill when it happened probably 30 feet above the rock floor and the FOG was maybe 20 feet above that level.

==================================================================================================== ==================================================================================================== ================================================================

Adding to what gary has detailed so well is the fact that many quarries either shovel rock cuttings

into the bore holes for stemming/packing the tops of the holes or some are using the rubber hole plugs

to help contain the blast force to some extent when shooting.

The stemming works and it does not work sometimes as the blast force also has a habit fo exiting the hole straight up at times losing much explosive force.

Many operators do not bother with stemming consisting of drill dust fines, wooden plugs or compression fit rubber discs for the holes and the hole requires more explosive energy because the hole is open to the bench top and they fill it completely with AMFO or a slurry explosive..

Depending on the blast hole size the hole will have very large blasting caps and detonation cord as well as wooden

discs that separate the charges. Then comes the AMFO and sausages of tovex or slurry explosives and detonators

tied together with the detonation cord as it is lowered into the hole to the bottom and then either amfo or water gel

explosives and or the sausages of dynamite or tovex are used. I have been away from it for too long so i do not know

whats used of late except water gel stick sausage and amfor slurry explosives and "primadets", zap cord and either a air shock detonators or conventional burning fuses or electric caps from my past experience- our shots were easier as the blasting caps were covered with bubble gum boosters to get the amfo to start easier in our case. using the detonated ing cord tied to the blasting cap lines in the bottom of the holes filled with amfo and then connected witht he fuse and fuse cap. our fuse ignitors were a timed fuse ignitor that had to be hand tied to the detonation cord prior to pulling the ignitor string to create a spark to start the burn for the fuse which was 6 minutes if I remember correctly before the fuse cord burned down to the fuse cap and initiated the detonation cord and then the blasting cap fuses the varied from zero milliseconds to 6 milliseconds. They are using electric blasing caps where I used to work and they create thier own set of challenges as the equipment used at the mine face is all radio controlled using FM.

OH By the way george an explosion is actually a high speed fire that travels beyond supersonic in speed to create a fire and explosion from the fuel, air and heat and explosive force is created by restriction of the diameter of the blast hole or blast holes in unison holding the explosive force until it overcomes the restriction of the bore hole in all directions.

There are many methods employed in controlled HAHA!!!!, explosions or what we think are controlled explosions and they do make a mess when they go bad with too much energy. the fly rock issue is well covered in the MSHA fatal grams George and worth the read in the canadian accident reports as well.

Several of the coal mines in Wyoming use explosives to simply uncover the WYODAK COAL SEAM in the hard rock sediment covered portion of the basin they are mining and simply drill angled drill holes to throw the rock to the other side of the excavation that has already been mined to expose the coal seam.

The other issue is weather and shooting in inclement weather if you are using electric caps and thats a big no no with lightning/bad weather in the area.

Its best not to leave anything in the pit when shooting and avoid playing with the devil simply because methane also can be huge unfriendly consequence when drilling or having cracked the rock and creating a gas seep with pressure that will find its way out and as its odorless it kills.

A few years ago we had a well driller using an air rig, sigh!! in the county ina shallow rock drill hole for a client and it did not take long to start and gas fire and torch the drill mast oif the rig as he hit a pocket of shallow methane gas with his air operated drill rig using button bits rather than a roller cone bit with water NOT Healthy as they had no way to monitor the gas potential with either a flame safety lamp or a methane/hydrogen sulfide monitor sniffer from MSA-Mine Safety Appliances.

Leon

Please call or e-mail me if you have minute george ■