So you think you have some hard digging?

[Deas Plant]

Hi, Folks.
So you think you have some hard digging/ Wanna try this marble on for size? This photo was taken in a central Queensland coal mine which chooses not to be indentified. Do not kid yourself that you know where it comes from from analysis of the markings on the digger.

There has been no photo 'doctoring' - it's straight out of the camera except for re-sizing on my computer to get it down from about 2Mb file size.

The surveyors on site calculated that this 'marble' weighed around 700 tons. The digger is a Hitachi EX5500 of around 570 tons.

The flat spot on top is where a Cat D11R dozer tried to rip it out. An optimist, maybe? The rock was found in the overburden, two levels up from the coal - about 25 feet up - and was excavated around until it was fully exposed. Even then, the excavator could not move it. Further excavation - carefully - removing some of the coal from under one side of it, eventually allowed 2 Cat D11R's to push it into the hole left by the removal of the coal where it still rests today, 8 weeks later.

 

[Deas Plant]

Hey, Squizzy, Wanna Have A Go?

Hi, Squizzy.
Do you wanna bring your li'l jigger along and have a go at this one? LOL.

 

[Tigerotor77W]

Oh, no -- I'll take that rock with my pickaxe and toothpick any day!

 

[Squizzy246B]

Hi, Squizzy.
Do you wanna bring your li'l jigger along and have a go at this one? LOL.

AaaaawwwwWWWWW...might have to get the rock breaker out I think!

 

[Deas Plant]

Getting the rock breaker out??????????????

Hi, Squizzy.
Would I be too impertinent in suggesting that you bring your lunch too?

 

[Squizzy246B]

Deas I think that job would require two lunches, a lot of coffee...and a quantity of Gelignite

I'm impressed that two 11's could roll it, undermined or not. Did they consider the some of that fancy new cold cracking low frag platic fantastic explosive?? ..or maybe...you know, that expanding bait stuff we used to use up in the Timor Sea.

 

[Deas Plant]

Fracture to be applied later.

Hi. Squizzy.
From what I can gather from the gentleman who gave me the lowdown on it, they plan to poke a few crackers into it when they blast the next floor behind it. I think they want the 'worms' to chew a few holes in it before they do that to give the 'penny bungers' the best shot at it. Don't know that I'd want to be standing in its shade when that happens. Could be a little noisy for a moment or three, not to mention the sudden increase in the atmosheric particle count.

 

[rino1494]

That would make a good landscaping rock. Well, it would, if it wasn't bigger than a house.

 

[Squizzy246B]

Yup, building walls out of resident stone takes on a whole new meaning

 

[Deas Plant]

Landscaping??????????????

Hi, Folks.
I guess that 'marble' would make a halfway noticeable feature in some front gardens.

It appears that they are stemming the top 15 -20 feet of the blast holes to reduce noise and fly rock. The result is this sort of thing. This is an extreme example but I'm told that the digging in the overburden is pretty rugged most of the time with a LOT of oversize that is very hard to handle.

And then they complain about lack of production. And they want to blame the workers instead of the methods. Yeah. Right.

 

[Construct'O]

A road construction company that i use to work for that stripped rock quarrys in the winter to keep busy got into a bunch of big rocks,that covered the the whole bottom of the floor just above the last 7 to 8 ft of cut before hitting rock.

They was almost perfect round rock and so close that you couldn't hardly get them pryed apart.They was really nice bouncing over and hooking the corner of the 627 scraper bowls on.

They would have made great landscape rock.All different size,colors,but almost every one were perfectly round.I thought that unusual.Thats been several years back,so lots of thing was unusual then :usa

 

[surfer-joe]

Well, blasting overburden off coal isn't an exact science, so you get stuff like this once in a while. The trick is to shoot all the rock down close to, but not into the vein of coal. It's considered bad form to blast the coal into pulverized tiny bits impregnated with rock and dirt. The tipple boys will be quick to let you know that you messed your drawers when they get a few dirty loads in for processing.

Rock fractures funny sometimes, with natural cracks or veins of soft rock or sandstone. Shots also go off funny if they aren't set right or someone was lazy and didn't load the holes right. You get the occasional bad blasting cap, or the shot lines aren't fixed up proper. Then there are the lazy or drunk drillers that don't go to proper depth with the blastholes, or sometimes way too deep.

I can remember using two 84A D10's to move some boulders out of the loaders way, or two 992C's trying to do the same thing. Using two or three D9L's was common in Kentucky, we had bad shots there all the time. Last resort was having a blasthole drill advance to the offending boulder and drill another hole or two or three, which were then loaded and set off to try to pop the thing into smaller more manageble pieces.

I can remember the coal seams would sometimes screw you up too. The driller would set the depth on one corner of the shot, and the damn seam would either roll up or down so that all the other holes were off by several feet. Ya never knew for sure what you'd find.

When we started to try casting shots that's when the fun really began. It took a while for the drillers and blasters to figure out the ropes on that, which caused a lot of extra work for the excavating crews.

You always took cover when a shot went off within a mile of your position. I was looking at a truck mounted drill one time when a shot was set off on the other side of a tall hill from us. A few moments later rocks rained down around us like hail, big rocks! we threw ourselves under the drill and listened to them rattle for a minute of more. The drill operator caught one in the leg which broke it, his leg was exposed between the frame rails and that's exactly where the rock sailed through. We had him hauled off to the hospital.

Another time we finished a shift and as was my habit, I was driving from one mine site to another to make sure everything was locked up when a shot went off very close. Cracked my windshield and put many a dent in the sheet metal of my trusty Chev pickup. Seems the boys hadn't set it off. They had only set the caps and stemmed the holes, and were going to set it off first thing in the morning. Apparantly a streak of lightening had hit close by and lit her up. This happened one more time a little later though no one was around that one. We switched to a percussion cap system shortly after that. There was too much lightning around that area for safety.

Blasting in some of the old coal areas in Kentucky is interesting. We set off a shot one time and the whole area settled about 60 feet. Come to find out there was an old underground mine right under us that no one knew about and the blast settled everything right down into the mine. No coal from that shot. I watched another shot one time sitting with Homer, the General Superintendent in his pickup. Boom, the shot went off, and as we watched, a double length of drill stem sailed up out of the dust and smoke like a rocket. It landed a few hundred feet away, and Homer calmly remarked that there was the string one of the drillers lost the night before. Homer said they had tried for a couple of hours to recover it, then moved on. Unfortunately, the blast bent the stems and we couldn't reuse them.

 

[Keith Bowman]

Big Rock !

 

[Lashlander]

Good stories Surfer-Joe. Thanks for sharing!:usa

 

[dirtwhore]

A couple years ago I was working Kiewit on a highway job in Idaho that was some of the nastiest rock I've ever seen. The powder foreman had a new shooting plan he called "step shooting". Our big joke around the the job was he missed the most important step of all, loading the holes! Any way some of rocks were so big that the 5130 shovel couldn't pick em up so they brought the 992D (which was backup for the shovel when it went down, which was a daily occurrence!) down to help out. They would get the shovel and the loader under those big boulders, pick em up then back the 777's under and try to set them in nice and easy. Usually just one rock per load. The drivers, after the first time of getting bounced all over the cabs started getting out and waiting till they were loaded. Cant say that I blamed em! I was running a D 10 on the fill and had one hell of a time trying to hide those boulders. I ended up shoving them all out the slope and building around them. I lasted a month and went and got a job running a scraper! Easier on the back!!
Jason

 

[980cCrusher]

Now that is one monster of a nugget. We get some in our gravel pit whenever we get close to the legde but never that size. The biggest we had took my 980c and the 980g to move and we were both still light on the rear sneakers.