Good morning! New member, first post. Our company paid to have some Cat representatives come in and tell them how to move coal. One of the new procedures that came out afterwards was front-to-back dozing. The area being worked is a coal pile for a coal-fired thermal electric plant. The coal comes in via rail, is pushed out onto the coal pile, then pushed into several different reclaims scattered about the periphery of the pile. In the past, it was always considered important to keep the pile groomed so that the pile didn't destroy itself during rainstorms. Now the operators are being told to slot-doze and push front-to-back, and we don't have time to take out the slots. I googled "front-to-back" and read a couple of articles that described why Caterpillar feels it's more efficient. Less time spent backing up, less wear on undercarriage, etc. But nobody likes front-to-back dozing, and in reality nobody does it unless they're specifically told to. So, I'd like some feedback from you guys. Is front-to-back the best answer, regardless of the situation? Is f-to-b more efficient, regardless of the push lengths? I ask this because sometimes we're pushing at least 500 feet. Any input on this would be great! Thanks!
First off, welcome to HEF. I would like to say that is how I push anytime there is the opportunity. Basically any time you are moving a large volume. I was taught in different terms though. Never move dirt (or coal, or whatever) over other dirt that you need to move. Move the close dirt first. It helps reduce the grade you are pushing, and you spend less time backing. You also get more out of slot dozing this way. When you start at the back, think how many passes it takes untill you have a slot built. When you start at the front, you build your slot as you go, and always get the added effeciency of the slot. What I do for bulk pushing is start at the end of the cut closest to the fill, the front as you call it, and take a good deep cut for a short distance. When you back up, you come to the hump you left when you started, back up on it, and go just far enough that when you dig down, your blade gets full. With a D-8, it is about 10 ft or so. After a few times you get a good feel for it. I start out trying for a 3 to 4 ft cut, then the windrow builds over the sides to 5 ft or so, depending on what size tractor you have. Usually for me I keep my slot about the middle of the final drive. I was on a job pushing down a 2 mile long overburden pile once, and was runnung a D-10N. I pushed front to back as you say, and cleaned my slots up back to front on the finish. There was another D-10N with a 20+ year veteran operator working with me, but he refused to push that way, and started every pass at the back. My production was at least 50% more than his, but he would not change his methods. This resulted in him going home before the job was done, and more work for me. I read that you "don't have time" to take out the slots, but if done right, it really takes no time at all. When you cut slots, don't overlap them, or you loose the advantage pointed out above. Cut several slots side to side with each other, then clean behind you. Go to the back of the outside berm, and catch it at about a 45 deg. angle. push the berm ahead into the slot a couple lengths, then back up and get another bite at the angle. Depending on material, it takes 2 or 3 passes to fill the slot for one push to the end. Doing it this way, you keep the effeciency of the slot untill it is all gone. Then move over and do the next one. With practice, you can leave a well groomed surface behind you and never loose the added production of slot dozing. The simple rule for me is "never push dirt over dirt"
OK, I think I understand what you're getting at. Let me throw a few curveballs at you. Pretty much all we do is "push dirt over dirt". The coal pile's base is bottom ash (a by-product of burning the coal) and as soon as we see the lighter ash starting to peek thru, we try to avoid burrowing into it. Most of us try to keep at least a few feet above the ash. A much bigger issue is that the reclaims are usually underneath at least 30 or 40 feet of coal. The feeders feed better, we get a longer runtime between pushes, etc. so if we cut right down to the bricks we've just gotta go back up the ramp to get the coal into the hole. Because of the 24/7 nature of feeding the two big hungry boilers, it's considered very bad form to shove in the nearby coal and leave your relief with no nearby material. If there's lots of coal, this isn't an issue. But when there's lots of coal we're always pushing uphill from the rail facility anyway. It's when the pile's starting to get thin that everyone's expected to bring coal up from the back of the pile. The operator who doesn't bring coal up from the back and instead takes the "easy" coal is considered a deadbeat. Your example of the 2 mile long stockpile is very illustrative. The other guy brought material up from the back, but moved much less than you. But in our world that's what we do a lot, is bring coal from the back so that the nearby coal doesn't disappear. From your description, it's clear that you moved more material. Who moved more from the back? Another problem - when it's raining (47" rain yearly average) it's imperative to avoid the dreaded "bathtub effect", where water pools in the hollow between the ramp of coal over the reclaim and the coal that's further back on the pile. The coal on the blade goes thru the tub, picks up a thousand gallons of water, then surges out the reclaims and belts. So, although it's becoming clear to me that we're not following textbook "best practices", most of the operators feel that the pile's lowest point should be the back of the coal pile, and it should slope gradually up to the reclaims. Rain moves away from the reclaims, and nobody feels like they got pooched by the previous operator. I don't know if I explained all of that very well. I guess it comes down to this: is front-to-back always best? Can you do front-to-back and still maintain the desired slope, away from the reclaims? If one person pushes front-to-back, then his relief does not, does that make for problems? Have we been pushing incorrectly for 30 years? Or does the nature of the work sometimes dictate operating in a manner that doesn't come straight out of the manual?
Telkwa Good points there. One thing I see is I was not clear enough about the 2 mile long pile example. It was long, but the push to do reclaim was over the side, which was about 120 ft tall, and had to go from existing 1.5:1 slope to a 3:1 slope. The push I was comparing was equal distance, about 250 ft average on slope length. I understand about the reclaim feeders underneath, and the need to keep the pile built over them. You can still push front to back and get more production without destroying that set up. If you go about midway up the pile, where you would like to add to it, and start your short push, then with each pass, you move back while staying in the same slot untill you reach the tail end of the pile. You have now pushed material evenly from the middle to the rear, and piled it to the front. Next, move over one slot and repeat. Knowing how the piles spread out, your slots will converge, so leave a little gap at the end. When you get several slots cut, then start taking the windrows from back to front as I described above, pushing at an angle untill the slot is full, then carrying it forward. After the first shift doing it this way, you could tell a good point in time to stop cutting slots, and start cleaning them up. You will be working from the front, middle, and back of the pile evenly, and time it to leave a well groomed pile by the end of the shift. I think by doing this you can avoid the "deadbeat" label, because you took coal evenly front to back, not just the easy coal in the front. That is what gets some operators put off by the method, because they get in trouble by starting with the easy material in front, then they never move back, so they get hollered at. Since your pile is going uphill all the time, you will not have a hole for the rain, except maybe a small area where you start the cut, and it will be constantly moving with each pass, so it wil never get much in it. At the end it will be groomed out anyway. I hope I did better explaining it this time. Have you been doing it wrong? Not if the boilers were running. The nature of dozer work is such that you can't always use every production aiding method, but if you use as many as possible, you will do fine.
Welcome to the forum Telkwa, how about a few pics of the coal pile if you get time. With no grade to cut and a never ending pile the dozing strategy may well be different than some of us are used to. I would think if you have plenty of coal up front that would be the time to work farther back on the pile making the longer push, can't quite visualize it though.
Jerry nailed it with that last post. You don't just short push whats close to boilers and dig a hole. You start there making your slot and work your way all the way back then move over. Making a even cut the whole way. I have done very similar work working with Petcoak and it was particularly a PITA since we had to get the old material out of there too before it went "bad". Me and the other "operators" didn't see eye to eye they like to push long. It was surprising though when with the other 2 pushed long loading the conveyor and I dozed my slots we kept the hopper full loading over 30 tons a min. Something they rarely did pushing long in fact I was told to slow down. Just think of the design of a dozer blade. U blades are made to carry material not cut. So when you see that coal "boiling" over the blade the whole way your doing something wrong. You should pick up the material. Then when its just over the top of the blade you should lift the blade just enough that it stops boiling and carry it. Now if your not working in a slot its going to spill off the sides of the blade and you will have 1/2 a blade full at the end of your push. Now when your unloading rail cars slot dozing just about goes out the window. You still make the fill the same way pushing the material longer and longer. I liked to work out of a good size pile though the other other guys liked to keep the pile small working right under the conveyor discharge.
Hey, guys, thanks for the thoughtful replies. DPete, I'll see what I can do. Maybe I can find one of those computer-generated graphics showing elevations like a topo map. I'm afraid a photograph from a high point on the building would just look like black stuff with a couple of little yellow dots running around. Maybe I'll just make a couple of sketches and scan them. Let me look into that and get back with you. Of course, the pile changes, depending on how much coal we've been burning vs. how many trains we're getting. Sometimes the boilers are down and it gets really ugly trying to hide too much coal in too small of an area. Other times they guess wrong about cutting the trains back and we darn near run out. Anyway, it might be a few days or more. But I will be back; I'm curious to hear what sort of feedback comes from this. The operators have been debating about the changes for a while now, and as I mentioned most of them have just ignored the new front-to-back, slot-dozing mantra. For some reason it never occurred to me until this morning to see if there was a forum talking about this sort of stuff! Hey, there, DB, our posts crossed. Yeah, you're exactly right about when pushing out the trains. We're not slot-dozing then, just trying to get the coal out of the way. The bosses built a rail facility that'll unload a 110 car delivery in about 4 to 5 hours. The bosses were all high-fiving each other after the first coupla trains were dumped. The rest of us, the guys who were supposed to push all the coal outta the way before the next train arrived, were not quite so exuberant. I've been skeptical of the whole front-to-back program until today. Mostly because the bosses just said "You're doing it this way" without any effort to get us on board or explain things. Talking with you guys has caused me to re-think things.
This thread is just screaming for some of that high speed video like the bridge demo video. You GOTTA get a video of this process so non operators have a clue what you are talking about. 30 ton a minute eh? Now i know what dozers are for! :notworthy :dizzy opcorn
We're on dial-up at home, but I can take the laptop down to the library if someone adds links to video clips.
Front to Back These are not video but they do seem to expalin it for "non-operators" http://www.buyerzone.com/industrial/bulldozers/rbic-doze-more-dirt.html http://www.komatsu.com/ce/support/v09202/index.html
Its going to be very hard to get the operators to change there ways. In that environment its very hard to prove what work the best. You just have to have faith in what you there told. A big problem for us was dealing with everyone talking trash. It may not be such an issue for ya'll but where I worked everyone did it daily. "The last crew screwed us" They left a pile of us" "They pushed the wrong way" "They didn't park there dozer out of the way" "They didn't..." Its very hard to get pisc and vid of this work like he said it look like a bunch of yellow dots running around a black pile. I have a few pics in my gallery thread in the showtime section. I took lots of pic but only posted a few since the others didn't turn out very well.
Nothinbetter Thanks for the links. I got to read them, and they pretty much say what I was trying to describe, but it comes out better, and it has pictures. Dozerboy has it right about sites like that coal pile where there are multiple crews. Always too much bickering and hard to get a new method a chance, but I would not give up on it completely.
Front to back is the way they want the production dozers to do it at the mine I work it. Its alot more productive than backing all the way up each time. Before I went to the dragline and was in the push I could outpush some operators by almost double because they insisted on backing up all the way to get their next load.
I'd already found the "buyerzone" link but not the Komatsu link. I'm really enjoying this feedback. Iit's great to hear from different people, and funny how sometimes it's the same old problems no matter where you go - operators who aren't gonna try something different no matter what, crews blaming the other crews, etc. I think the best way to communicate some of the situations I have in mind is to sketch them out, then scan and attach. We give up the advantage of pushing "downhill" most of the year, when rain controls what we can get away with. I haven't seen any discussion of first gear pushing. Is that how you guys so it when you're slot-dozing and/or pushing front-to-back? One of the things I noticed about slot-dozing is you gotta be more careful about backing up. As soon as the wide coal blade tags the edge, the dozer gets pulled into the wall. Do you just pull the blade up high?
First gear all the way when production dozing. You can push three times as much and its alot easier on the machine.
Keep the blade up high going back, you don't need it then and it's out of the way. Same when you are ripping, up high and no snagging on anything when you are/maybe looking towards the back.
Ya first gear only really. I have grabbed 2nd going down hill or feathering out my load. An experienced hand should easily be able to tell what gear he needs to be running in. The blade height really isn't a issue with coal ETC the slot doesn't get that tight. If you have some hands that don't have as good of sight they may have to take a little extra care. Or at least I don't recall ever have to make sure the blade was up very high. Thats another thing you can do to be more productive is to not push your pile all the way off the edge. I would like to leave 3/4-1/2 of it there that a good 10'-15' that you don't have to track. If your carrying your load when you hit it you should have plenty of power to push the pile off the edge. Its handy at night too our site wasn't very well lit and that can help during a long shift.
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. But thats what I try to do for a production push application wont work for everybody
10-4 on the "3:00 in the morning" comment. Depending on the clay content of the coal, rain, and how long it's been since the pile's been cut down, some of our reclaims can rathole pretty badly. We've had guys fall in, and spend half the shift trying to get them back out. When you hear someone get on the radio and ask the gallery operator to please turn off reclaim #_ as soon as possible, and he sounds pretty shook up, it's not hard to guess what happened...
Thanks for all the info. This is great for us operator-wannbes!
+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.
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.?
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.
Best wishes and all the luck in the world to ya mntman!
Found the old "13 dozers pushing" thread. That's pretty impressive. HeavyEquipmentForums
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!
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.
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.
Thanks Dozerboy, makes since to me!
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.
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.
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.
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
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.
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??
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.
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
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
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.
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.
Just a quick message ,just had a good idea while having a shower before I go to work (night shift). Check out google earth for an over head pic of your stockpile.. Here is the one I work on a bit.
Hi, diggerop - Thanks for reminding us what century we work in. I didn't think of Google Earth. Stuck with dial-up at home; will go to library with laptop and see what I can come up with. I'd still like to hear from you about the "no rubber-tired dozers on coal pile" edict and why that is... Can also provide a sketch. Will work on that. Good talking with all of you, will be back in a day or two.
I believe front to back to be one of the best ways to move material and try to use it. But like all things it has to be fine tuned to work. In this case "Front" should be defined as to the front of the cut, not necessarily the closest point to the feeder. Example: Feeder is 0, no cut for 150 feet, cut starts at 150 feet, at 300 feet cut ends. So in this example the front of this cut is at 150 feet from the feeder and the back 300 feet. Let the slots build up in the 150 feet in between by backing up and getting a new load whenever you lose enough off the side of your blade that you can push your next blade full through it. This builds a slot and with the closer material (faster cycle time so you can build the slot) and by the time you get to the back you have a nice slot clear to the front. Cleaning up the slots was explained well in the second post by JDOFMENI.
Hi, kent - Something else to think about. This occurred to me the other day as I was thinking about some of the replies in this thread, but it kind of ties in with your comments about not starting right at the reclaim. Let's say the feeder is pulling 400 tons/hour. Wherever you start front-to-back slot dozing, chances are you'd be bringing up too much coal at first, then as you kept stepping back you'd meet a balance point, then at the back edge of the coal pile maybe the feeder would be going mt between pushes. I imagine the simplest solution when you were bringing too much coal up would be to let some of the coal off under your blade as you approached the feeder? But that would fill your slot. Maybe stockpile some of the coal to the side of the feeder? But that ruins your slot too, and results in extra manoeuvring around to crawl out of your slot, get behind the stockpile, shove some of it in, then drop back into your slot. Anyone got any thoughts on that?
Kent Great explanation. You really clarified what I was trying to say as well. Telkwa My thought is that you need to have multiple slots going at the same time, probably 3. Start one slot close, one mid way, and one from the farther reach. Picture your pile in 3rds and start each slot at the front of that 3rd. Then rotate which slot you push in depending on the needs of the feeder. Push in the short one for a while to get started, then go to the long one a couple of passes, then the middle slot. If you start to get behind, jump back up close for a few passes. If it works out, you will get a rotation going, and soon the close slot will work back to being the middle, the middle will become the farthest, and when you reach the end at the farthest slot, come back to the front with it. It is a related problem when pushing down stopckpiles, like my first example. If you take one pass all the way to the bottom, then move over and take another all the way down, then you get too much at the bottom, and don't have enough room for the final clean up material. I get around this by staggering my slots so the only one to get all the way to the bottom is the last one, on the side that is finished. Each slot going towards the unfinished side is staggered, and the amount varies by the conditions. The first slot pushed is very short, just to take the point off. You end up with a diagonal working face that way. Not saying you work the coal on a diagonal, just using it as an example.
Telkwa, I would stockpile as time permits right in the slot. I like to only push full blade fulls. So at first when I'm close and could make two pushes to the feeder and it only needs one; I would just back up and leave the second push in the slot near the feeder. My next push I would loose enough material right before I got to the pile in the slot that I could just push right through it on to the feeder with a full load. Now as you are working back further in your slot you really fine tune this by how far you push the second load towards the feeder. This would be determined by time. Be sure and give yourself enough time to get a load and get it to the feeder. At first in this example you could push 2 to the feeder when needing 1 (2 to1) As you work back the second load will keep being left further and further away from the feeder, as the first load takes more time. Some where towards the back of the cut it will take the full amount of time to keep the feeder full (1 to 1). Then if you start getting to where the slot is to long to keep up, start cutting closer on your second push cleaning back up the material you left there earlier. When you started the slot, the first push is shorter so the second push gets longer. As you work back and the first push gets longer the second push gets shorter. Then you will be balanced for a bit pushing all loads to feeder. Then after the balance point the second push changes to cutting in the slot rather than stockpiling in the slot. Now the second push is cut to keep up with the feeder. From being balanced (where all pushes go to feeder) your second push will gradually get closer and closer to the feeder to give you enough time to back up further and further with the first push. I have never pushed coal and perhaps there are reasons this would not be practical. But I would like to try it!
I'm not sure how it came about but it's got to do with stability and such, with a track dozer you could (I know no one here would ) if you weren't concentrating hang the front of the tracks over the hole or if you went in depending on the size maybe get back out or if the edge collapsed you would have a better chance with a track dozer. With a RTD (rubber tyre dozer) the distance from the blade to the front wheels is not real good and if you are not leaving a bit on top each time and pushing right to the hole there is not much of a safety margin. I believe that is the main reason, others would be that quiet often someone will work one area and leave drop offs or vertical edges which are bad enough with a track dozer if you don't see them. Backing up to the edge of the stockpile would also be an area of concern. I'll go backwards or frontwards over the edge (35-38 degrees) no worries in a track dozer but I don't reckon I would in a RTD. Getting parallel to the edge would be dangerous with a RTD, I've seen track dozers stuck on the edge/side a RTD would probably have rolled or would have been a lot more difficult and dangerous to recover. Traction? Safety!!! So its probably a combination of a number of reasons. Dozerboy Not having a go at you ,I miss stuff too but I mentioned in the text to use the F to B method, but in saying that if I'm not busy I'l go right back and do long pushes to bring coal in from the back in closer to the feeders. With the setup we have here sometimes there will be coal coming off the stacker and we will have it pretty easy so we will do some long pushing. I've just came off night shift , gotta have some brekky and go to bed, two more to do.:sleeping
I've spent lots of time in the Tiger, so I know what you mean about stability and rollover. The Tiger is flat-out scary in situations that would be mildly unnerving or even uneventful in a track dozer. And with all the weight perched on four points instead of spread across the tracks, the Tiger is prone to getting itself in trouble near highwalls. The really exasperating thing about the Tiger is that it's so touchy about blade pitch. I imagine the Tiger you drove had a similar arrangement on the underside of the blade? Ours has a big plate of metal that acts as a shoe to assist in making half-way smooth pushes. If you pitch the blade too far forward by a degree or two so that the cutting edge contacts the pile well before the shoe the Tiger tries to find the bottom of the coal pile. I've seen guys who didn't know about the blade pitch control jump on the Tiger with the blade pitched too far forward. Their work area looked like someone had whacked at it with a giant hatchet. As the Tiger digs in the tires compress. Then when the operator realizes he's gotta get some coal off the blade he'll pull up on the blade. The Tiger lets go of the cut and the tires sproing the whole machine up in the air. You end up with the sharp hatchet marks. Not a pretty sight. I've seen other guys pitch the blade back onto the shoe so that they get a smooth push. When they realize the blade is empty, they try to push down on the blade like you would a track dozer. They keep pushing til the Tiger's front tires are off the ground and the Tiger's skidding on the shoe. Of course the blade's still empty. So I've found the key is constant tweaking on the blade pitch. Which gets very tiresome after several hours. The Tiger's quieter inside the cab than a track dozer, but it's frustrating to work so hard at keeping the blade full when a track dozer can push half again as much coal without all the fussiness. Does that come close to your experience with rubber-tired dozers? EDIT: To everyone else, thanks for the suggestions, please keep 'em coming. I want to try some of this stuff out and see if anything clicks.
Bump. A super thread.
Yair . . . I'll second that Tarhe Driver As folks on here know I have been pretty vocal on this subject for some time. It just plain annoys/frustrates me when I see an operator burning fuel and wearing out a tractor thinking he's doing fine when I know with some tuition he could move twice the dirt in the same time for the same cost. Cheers,
Ah, Scrub Puller, and you must have some of the ScoT's in you, too!!
Running a dozer is not rocket science . Sometimes you can keep the blade full , other times not . Depends if you are cutting or spreading . Every job will have variables that have to be dealt with . GPS a pad in is a whole lot different than dragging a chain through the woods .
Yair . . . Kevin 37b That quote is exactly right and my comments over the years have referred to production dozing. Pushing front to back slots and back to front rills will always be the most cost effective method and the more the operator diverges from the tried and proven the more the dirt will cost. Cheers.
Believe it or not I'm up against the same resistance right here & now regarding slot dozing with a D10T to push into a feeder hopper.
Yair. . . Gotcha Nige. Bad habits die hard. The only way some operators will be convinced is if their income depends on production. As documented in previous posts I was once in the unusual position of being able to demonstrate how a properly operated cable blade and ripper D7 out produced a hydraulic D8 by a considerable margin. It still seems to be in the mindset of dozer operators that, to be productive, they have to get a "good boil" going in front of the blade. A large tractor pushing dirt will there for bulk production not for final trim. In good going (I believe) front to back dozing requires the ground to be in such condition that the blade will bury in (say) half the length of the track frame which means by definition a larger tractor is always working in a decent slot. Apart from sand there are very few soils/gravels in my world that can be pushed without first being ripped. Cheers.
Preach on mate ! Spot on when moving dirt with a blade . We call it " Hoggin " . The " rills " are the wind rows of dirt on each side of the blade for members that that aint hip to the slang . Had to move some dirt on the last job with the 16 about 650 feet . Slot all the way while Hogging the pile to the final destination , then back up & grab the " rills" on finish up . Where is Scrub when I need him ? http://www.heavytruckforums.com/showthread.php?263-Some-Holmes-750-action&p=2671&viewfull=1#post2671
They are pushing saperlite so there are no rocks in it, it's almost like a red clay. The operators don't have enough experience to even know what slot-dozing is, I'm having trouble convincing the Mine Damager (sorry, that should be manager but hey if the cap fits.....) that slot dozing will be a more efficient form of moving the dirt into the feeder. Problem is he has no idea what I'm talking about .........
Yair . . . Nige. It was said up thread that running a dozer is not rocket science but, in my working life I found only two men (out of dozens) who understood and applied the principles of earth moving with a dozer. On these pages I comment about tractors not having rippers and the reply is often they are not needed in the soft soils of Iowa or what ever. That may be true but I doubt it, just because the soil is soft and easily dug does not mean that it does not need ripping for maximum production. In places we too have beautiful soft soils and I once watched a big lump of a Fiat-Allis pushing up a flood mitigation embankment using scraper techniques. That is to say a six inch cut and boiling the dirt up the blade and all the government wallas were oohing and aahing and saying how magnificent it was . . . the council engineer even pointed out to me what a good operator they had and seemed a bit put out when I told him the bloke was probably a good hand but knew jack**** about pushing dirt. Caterpillar had 16mm instructional movies in the early sixties demonstrating front to back slots, pushing scrapers, ripping and so on and I am surprised that less than optimum utilization of a machine such as a D10 would be tolerated in the mining industry today. Cheers.
So am I mate, but as I always say if these guys weren't so stupid I'd be out of a job.......
Yair . . . S'pose you gotta look oin the bright side. (wry grin) Cheers.
Poor practice abounds. I see what are considered good operators on a site with 40 feet of cut to go, and it looks like it is ready for a final trim pass. I explain that there should be slots and windrows, and I get a blank stare most of the time. I can even show them how, and then as I leave the first thing they will do is smooth it all back out:Banghead:Banghead:Banghead
Yair . . . JDOFMEMI. I find quite amazing. In other threads I mentioned how I was once in a situation where operators were paid by production . . . that is the only way of getting the point across. Effective dozers have been made now for close on seventy years and the techniques long establish and yet in 2016 (from my experience) about two per cent of the machines are used to their full potential on production blade work. As was said up thread, it ain't rocket science and once it "clicks" an interested operator can quite conceivably double his/her production with just a half an hour of instruction, it is that simple. . . in most cases fuel burn and track wear will remain the same. I know I go on a bit but this inability of dozer operators to grasp the basics has been bugging me for over fifty years. Cheers.