Explosions and Water (Again)

OK, first thing is I am in no way saying I know anything about the cause / effect - I remember your last discussion on this.

But let me chime in that where I live, we have the largest open-faced granite quarry in the WORLD - it's huge & only 1/2 mile from what we call downtown - shoot, there's even houses across the road lining up on the backside of the quarry. They have been open blasting for 100 years - you can hear it from anywhere around when they fire-off - these guys can release a slab the size of a football field & then process it - even determining the depth of the slabs!

All I can say is I feel for you - if it was me & someone got hurt that was mine, or close to me - My first thought is they could have my guns after I ran out of bullets.

best of Luck getting root-cause & sending them packing

Missed your previous posts - can you give us a link?

http://cr4.globalspec.com/thread/32950

Take photos of the damage and other evidence: write up accounts with time and date. That's the kind of documentation that's good for court, so everybody knows you mean business.

Flying rocks are dangerous! Put them front and center in your complaint. Tell them to put a stop to it before someone is hurt.

I don't know about dolomitic sink holes? What are they? The creek is your drainage, for runoff in hard rains. If it's not designed to take industrial water you could have floods - if it rains much. In South Africa, do you have any problem with mosquitoes? If the mine water doesn't flow away quickly or becomes a breeding ground, it could be a health issue down the road.

With some people it's more effective to make your complaint as small as possible and stick to the actual damage and present danger. If they're just ordinary business people who could be happy as good citizens, try to find them an economical, good engineering solution to handle their waste water and control their blasting. Hope it is all settled soon.

"Please can I have my rocks back?" Dump them on the Managing Director's desk!

Hi Hendrik

Where are you? Is this the Centurion bunch up to their tricks again? I know how pathetic our bunch of so called Gov Officials are! Find out who the blasting company is and who their supplier is. Then get hold of their opposition..... they will give the best advice on who to bring in to help. The "Mines Inspector" used to be the guy but if they are effective any more is doubtfull. That is unless you give him a house in your neibourhood! I'll try to call some of my old buddies in environmental control. Hope they can help.

I work at several large mining facilities in Pennsylvania USA. We are governed by several different agencies concerning blasting. MSHA (Mine Safety & Health Agency) and PADEP and the two main agency. Every time we blast we notify every residence and business in a two mile circle around our facility. We have several seismographs set-up around the site. One of our facility has been active in the US since the 1600's it's the oldest active mine and industry in the country it is located in the Philadelphia area, so we have a whole boat load of homes around. We have yet to receive one complaint about blasting or flying shot rock. If the holes and explosives are done correctly you shouldn't be able to feel the shot go off let a lone have shot go flying. I personally live with-in 1 mile of three separate mines for the past 10 years I have yet to feel a shot go off.

This seems to be a problem poor hole placement and either too much explosives or the wrong kind. You need to find out what regulations this mining facility has to follow and what agency is in-charge.

Concerning the water again you'll need to find out what regulations they most follow, if any and who is in-charge of the regulations. Our facilities have to follow very strict laws and regulations in-order to release water from our sites. Every site must have a permit, and keep record of when releases occur, how long pumps are running, if treatment to the water is required, the water must be analyzed before releasing, etc.

It sounds like the environmental policies in South Africa are very lax or non existent.

Hendrik,

Have they considered the possibility that heat/energy from the dynamite/ANFO/Ammonium Nitrate blast is superheating trapped water in the fissures creating instant steam that is expanding rapidly to project smaller rock to a further distance? The energy from the primary blast should be absorbed by the dolomite and in moving it from the face. However, expansion of any steam produced is another matter.

How large or wide is the actual shot area? Can you place heavy poles + say, an EPDM sheet over the actual blast area to intercept any flying rock? What is the actual explosive charge used? Brissance? Shattering or pushing force generated? Dolomite hardness is typically 3.5 to 4 (Mohs), while granite is typically 5.5 to 7. I would suggest that your blasting crew is using a more powerful explosive or larger charge than required to do the job w/o throwing stone the distances you suggest!

When surface protection against fly-rock is needed, blasting mats are used. They consist of either a mass of woven wire rope that looks like a heavy blanket or a combination of old tires that are laced together with wire rope. These are heavy, cumbersome units and are costly and time-consuming to retrieve after a blast and then place on the next blast area.

They're also only good for blasting small areas. They really are not needed, if the blasting is done correctly. Our mining permits allows us within a 100 yards of a dwelling 25 yards from a property line. If the shot is design right you should not feel hardly anything maybe a little rumble.

I only have rumours and guesses to work on but have applied for official information.

In the meantime I would like somebody tell me what the charge and circumstances would have a double brick size of rock (as part of about a wheelbarrows load of rubble) travel about 10m up and 900m horizontally.

You may assume a crack in the rock-face at any angle to produce a natural ramp and water or saturated rubble at the back.

This is not homework.