Front-to-back dozing?

[diggerop]

Good point on leaving a little on top. Where I work there a quite a few operators that think they need to get every bit in the hole and they end up throttling down a little or about fall into the v. If you leave a little on top you can just raise your blade a little throw it into reverse full throttle like th ey are designed to do and be half way back for your next push before the guy next to you starts backing up.

I've seen guys "including me" that about 3 in the morning on a night shift where that little pile keeps a dozer from going for a 150 foot ride to the bottom.

+1:thumbsup That's pretty much the rule where I work whenever we're working the stockpile, pushing over the highwall or any other dropoff. It can save you a lot of embarrassment or injury and time. We refer to it as the double push method.

 

[Telkwa]

... throw it into reverse full throttle like they are designed to do ...

I gotta go back to this comment. Several years ago we were talking about some of the little things that operators can do to get the work done without breaking the equipment. The heavy equipment shop foreman specifically mentioned stepping on the decelerator for a second before changing direction. All our dozers are fairly modern D10 or D11-R's.

It made sense to me, just because of all the horsepower and weight involved. Is there any consensus on this? Full-throttle change of direction is OK?

On a different subject, the term "production pushing" has come up several times here. Do you just mean when the main job is to move as much material as possible, versus other projects such as filling or sloping or etc.?

 

[mntman552]

Cat mechanics out here tell us that its fine to change direction at full throttle. There are some dozers in our fleet that must not be set up quite right because some are smoother shifting directions than others. When I refer to production pushin i'm talking about back hoe dozer spreads in the coal mine I work at. If you search 13 D11's pushing side by side you can see what i'm talking about. The second set of pictures was taken at the mine I work at. I used to be in the production push but now I am a groundsman/oiler for one of our draglines. Well not at the moment been off work since thanksgiving gettin treated for leukemia but hope to get that taken care of and back to work.

 

[tripper_174]

Best wishes and all the luck in the world to ya mntman!

 

[Telkwa]

Found the old "13 dozers pushing" thread. That's pretty impressive.

https://www.heavyequipmentforums.com/Forum/showthread.php?t=1385

 

[Telkwa]

OK, here are a couple of sketches. I'm not sure how this forum handles attachments, but I scanned this as a .pdf. If anyone wants to, I'm pretty sure they can "save" the .pdf to their own PC, print it out, doodle on it, and submit as an attachment to a new post.

Of course, the sketches are nowhere near to scale - the highest the piles get over the reclaims is about 80', and the push can be over 500' long. But it gives you an idea.

The upper scenario is similar to what I tried to describe early in this thread - a short, often steep, mound over the reclaim, a big dip in the middle, and the coal perched at the wrong end of the coal pile. How would you handle that, taking into account that you don't have half the day to reinvent the slope. The feeders are running and they're hungry.

The lower scenario I'm guessing will generate pretty straightforward recommendations - in this case the pile over the reclaim is about as high as we can go, and the only concerns are moving as much material as possible and maintaining a rain-proof slope away from the feeders. The goofy looking "dozer" in the lower sketch is a Tiger 590, a rubber-tired dozer that is not nearly as productive nor easy to operate as the track dozers. The Tiger is handy in some situations, and works very well for compacting, but it's frustrating to operate the rest of the time.

So if anyone wants to take a shot at it, please doodle all over the attachment and send it back!

 

[Truckin4life]

I now see what yall are talking about, with slots and front to back.
I have done the same kind of work but in a 972G loader, i found i was much more productive than the other loaders doing the same push. The pile was being pushed down so it could be loose dirt and easier/faster to load into trucks with yet another loader.

I can say of the time i spent pushing (maybe 100 hours) on that pile, the front to back was most productive by along shot.

 

[Dozerboy]

Lets see if my paint job works to post. If you can't read it PM me your Email and I can send it to you.

Really there is know why for us to tell you what will work, but this is the general idea.

 

[Truckin4life]

Thanks Dozerboy, makes since to me!

 

[Telkwa]

Thanks, DB. Your .jpg came across fine. I saved it to my Desktop. Looks like I can print it, and/or attach to an email then send it to an email account at work.

Your drawing is pretty much what I expected.

That's good for a couple of reasons. I wanted a visual confirmation that we were talking along the same lines. Plus, a picture is worth a thousand words in this case. You and I could write about the situation til the cows come home and we'd never be absolutely sure that we were on the same page. This way I can see what you mean and that helps a lot.

I'll be sharing this with some of the operators. I've been skeptical, mostly because the bosses just came in and said, "You will do it this way", but willing to listen to you guys. Wouldn't be surprised if some of the other workers have a similar reaction.

 

[watglen]

I don't know jack about dozing, and simply cannot comprehend what a d11 is used for, but i think that in this situation, one of the major factors involved in how you handle this pile of coal is where the coal comes from in the first place, how it gets there, and how systematic that part of the move is.

I can imagine that it is very difficult to put a good efficient plan together when the coal delivery method screws your system up all the time.

In your picture you haven't included that end of the problem

Great picture btw, and maybe by the end of this thread i will understand why i need a fleet of monster dozers.

 

[Dozerboy]

My guess it that his is coal is dropped from a conveyor 50' or so in the air into a pile. Which is where the mound on the top left drawing came from. Then they spread it out and move it to feed the reclaimers. You need monster dozers to move 1000s of tons of coal 500' everyday.

 

[diggerop]

Same but different. I would probably but not necessarily fill in the hollow a bit more slowly. You have to keep the feeders fed, so every 2nd, 3rd or whatever push (depending on the feed rate) you have to go right to the feeders so you have to maintain a good running track all the time. Use the front to back method all the time, if the feeders are ok for a few minutes spread a few bladefulls in the hollow, maybe one for the hollow, one for the feeder. Thats something only you or anyone else on the dozer at the time can work out. When you need to go right to the feeder raise the blade a bit and loose a bit of coal as you go through the hollow and then top the blade up with the high stuff near the feeder and push into the feeder. If the feeders are real hungry you can do that ( loose a bit) every push until you have the grade you want and it doesn't usually take too long.

I like to keep the pile near the feeder as big as I can (if there is one there of course) so if I'm getting a bit behind or have to change slots or have a pee, one or two quick ,short pushes will give me that bit of extra time. In post #3 you said the feeders feed better with higher coal and it also gives you more reserve (?) of coal over the feeders so I regard the coal around the feeders as not to be used unless necessary.

I was going to say there is no right or wrong methods but I guess there is wrong methods and different right methods. I first pushed on a coal stockpile in 1983 and off and on until about two weeks ago and still regard it as one of the good jobs.

I think I would have recognized the Tiger At the mines where I have worked and I think it is industry standard in Australia rubber tyred equipment are not allowed on coal stockpiles.
:drinkup

 

[Acivil]

It baffles me why these plants dont use a conveyor system to move the material that 500'. It seems like it would be much more productive to have one machine loading a conveyor, than it is to have multiple dozers pushing that same material. But then again, I dont really have any idea what size of conveyor it takes to move that much volume in that amount of time.

 

[Telkwa]

Hi, watglen, Dozerboy makes a correct assessment. There are just too many variables to come up with a plan that works all the time. Lay a piece of paper on your desktop. Turn it 90 deg. from the typical portrait position to landscape so that the long edges are top and bottom. That approximates the pile. Mark the top "North", left "West", bottom "South", and right hand edge "East". Coal feeders are spread along the lower (southern) edge. The rail facility is parked midway down the right hand "East" edge. There's another big feeder on the left hand edge of the paper.

We have a relatively small Krupp stacker-reclaimer (relatively small compared to some of the monsters I've seen on the internet) that runs on tracks all along the bottom (South) edge of the piece of paper. It can reclaim some of the coal, or stack out over the feeders.

The rail facility's output belt is a radial stacker. When the situation permits, the radial stacker is swung into a position where we can run coal directly into the plant. Whoo-hoo! Or the output from the radial stacker can be fed to the Krupp, which can at least stack the coal closer to the West end of the pile instead of having to doze it all the way over there.

Regardless of the options we have to belt the coal, it sure seems like most of the coal gets handled. It's pushed west, from the big radial stacker on the right hand edge, out into the center of the coal pile, then very often we have to push it roughly 90 degrees from the original push to get the coal into the reclaims along south edge.

Apparently the contract with the railroad makes it difficult to adjust the deliveries week by week. Sometimes the boilers are down and the coal just keeps coming and we're stacking it way up high along the northern edge of the pile because the south and center of the pile's full. Sometimes they cut back the trains too much and we bring the entire northern edge of the coal pile south to the feeders and everyone starts freakin that we're gonna run out.

Acivil is right to some extent. It's certainly cheaper to belt the coal than push it, once the coal is on a belt. If the railcar deliveries were down to a science, and there was never a need to store extra coal, I'm sure the bosses would be happy to fire all of us and sell the dozers. Believe me, it's been discussed. They brought in expensive consultants who came up with some bizarre schemes that had belts and towers and stackers all over the place. But it always came down to no matter how many belts and stackers and reclaims you built, there would always be some handling of coal. Spending millions and millions of dollars building lots of structures in order to get rid of a few dozers apparently never penciled out.

diggerop, thanks for the returned sketch. Can you explain the comment about rubber-tire (oops, rubber-tyred) dozers not being allowed on coal? How come??

 

[Dozerboy]

diggerops sketch would be the ideal way to do it. I was just basing mine as the hole above the reclaimer was to the point you're starting to starve the reclaimer some. Ya just have to find out what works efficiently as far as how you split up your time pushing where. Which can only be found out with trial and error.

Belts and stacker cost a lot of $$$ and there is a lot maintenance on them in our case at least. A dozer is a pretty cheap way to move material and in coal there is VERY LITTLE undercarriage ware.

 

[TyeDozer]

1st post, ladies and gentlemen. It's good to be here. I've been working my way up from page 48. The corpus delicti of dirt, as it were.

Sorry, Telkwa, to interrupt your post. You indeed have a classic conflict of dirt, machine, and budget. Is there any way you could build a bridge section for the railroad from east-->northwest so the dozers could pass underneath the train after it drops a load (sorry)? Never seen it done but I like the idea. I have no idea of the cost of a such a thing.

I don't know what a reclaimer is or does. Is it like a conveyor that gobbles up scraps?

I spent some time in college (quite a few years ago) doing geology surveys up the Rockies into Whitehorse, from Wisconsin. We visited an aggregate mine in Alberta that had flat-topped a mountain and was dozing material to the center of the clearing, where there was a vertical shaft about 24ft in diameter that disappeared into complete darkness. At bottom of said shaft was a rock-crusher, the mortle and pestle type, about 500HP, I believe. We drove a 12-passenger van through an adit in the mountain, where the shaft emptied into a large room where this rock crusher was. The crusher had huge anchor chains above it, looped over a big drum that metered rock into the crusher. That thing would explode rocks the size of refrigerators in one good pinch and just keep going. There was a second tunnel that paralleled the first, which was used by the miners to get above a blockage in the main shaft. In the winter, ice-dirt-ice layers would form in the shaft and block it up totally. These guys would dynamite the rock in the tunnel. The guys working the rock crusher said it sounded like a freight train coming down the shaft when that rock let loose, and it blew by the anchor chains and rock crucher bowl like they weren't there and filled the room with huge boulders. Yeow.

Anyway, after the rocks were pulverized, they used a big conveyor to get them out of the adit and into railroad cars waiting outside the mountain. Your operation is essentially the reverse of that, so why can't you use the dozers to load material onto a conveyor and bring the coal in?

Hello to the rest ya'll

 

[watglen]

just to confuse things...

http://www.midwestenergy.com/about/images/coal2.jpg

http://www.carmanindustries.com/Pages/drawdowns.html

http://www.ulancoal.com.au/img/mining_methods_ug2.jpg

http://www.elginindustries.com/~/me...tion/Project Media/Amax Coal Wabash_web1.ashx

Just studying these pictures helps to understand what needs to be done. Very interesting for the uninitiated like me.

opcorn

 

[Telkwa]

Those are some interesting links, watglen.

TyeDozer, we have two different types of reclaims. They all do the same thing. You shove coal into the reclaim, and the reclaim meters the coal onto a belt.

Three of our reclaims are just a metal funnel buried into the ground, with a very strong metal grid (called a "grizzly") at ground level so dozers can drive right on top of the reclaim if they have to. At the bottom of the funnel there's a metal pan that feeds coal onto a belt. A motor is connected to the pan. The motor has two big counterweights attached. The counterweights have air lines running to them. Maximum air pressure to the counterweights makes them spin very smoothly and no coal is shaken off the pan at all. Zero air pressure allows a metal cylinder inside the counterweight to change position so that the counterweight shakes violently and puts lots of coal onto the belt. When the counterweights are working correctly you can dial in anything from no coal to "ludicrous speed". The gallery operator inside the building can control the reclaims remotely by changing the air pressure. The belt runs up an incline, comes up out of the ground, then feeds into the conveyor system that takes coal upstairs and into the plant or to the Krupp.

We also have seven smaller reclaims that are virtually identical to the Carman feeders in watglen's latest post (second link). Ours are FMC Syntrons. The Syntrons' feed rates are controlled by a new-fangled speed control on the shaker motor, rather than a constant speed motor and air pressure.

Anyway, that's all our reclaims do, is provide a hole in the ground for the dozers to shove coal into and get coal onto a belt.

It'll take me a coupla weeks, but I think I'll take some pictures and show you guys what we've got.

Dozerboy, your illustration was very helpful because I wanted to see what you meant with the front-to-back method. diggerop illustrated the way most of us had been operating before the Cat consultants came in.

 

[Dozerboy]

Even though Digger pic doesn't show it I'm sure he intended the F to B method to be used. He just didn't draw in the steps of cutting the slots, but just the slots themselves.

From a birds eye view can you make us a pic of how you push? With the locations of the stackers ECT I'm not really grasping how its laid out.. That is if it isn't straight forward there might be a way to make it a little more efficient.