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Large cable loading shovels - Questions

Discussion in 'Excavators' started by Alaska Sunrise, Nov 16, 2009.

  1. Alaska Sunrise

    Alaska Sunrise Active Member

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    I am trying to learn as much as possible about equipment but a couple things about cable loading shovels confuse me so I'll ask here. (Sorry if these questions sound dumb.)

    1. How does the shovel drop its material into the haul truck without the bucket bottom swinging back wildly and destroying the side of the truck box? 90T of rock dumped in one pass can't be too good for the truck.

    2. Does the bucket bottom just use gravity to close? Or is there some other device that can draw the bucket bottom shut?
     
  2. willie59

    willie59 Super Moderator

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    That's some very good questions AK Sunrise.

    Since it's been years since these type of machines were used, it might take a while before someone with knowledge can answer the questions. Let's hope someone does. :)
     
  3. Lashlander

    Lashlander Senior Member

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    Psssst! Hey ATCO, there's hundreds of the big cable shovels in operation all over the world. They still make them!

    Okay now Alaska Sunrise from Canada. Here's a little video I found on you tube that explains it a little. I suppose the bottom of the bucket could hit the side of the truck if the operator wasn't paying attention. The angle of the bucket keeps the material from dropping all at once onto the truck. Gravity closes the bottom back up.

    YouTube - 4100 p&h shovel,mining
     
  4. alco

    alco Senior Member

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    I work with 8 of them everyday, so they're definitely still used. We're getting a new shovel in January from what we hear, so it'll soon be 9 of them.

    Anyhow, like the video Lashlander posted shows, the door is closed by gravity. As the bucket is lowered and drawn back to start another pass, the weight of the door and the momentum of the movement push the door closed and allow the latchbar to lock into the dutchman. The latchbar is a large bar that runs vertically inside the door, and gravity as well as the weight of the latchbar and latchbar lever hold the bar down. The dutchman is a hole in the bottom of the bucket that the latchbar hooks into and hold the door closed. When you want to dump the bucket, you move the lever inside the cab, or push the button on the joystick as is the case on the newer P&H controls, and that engages the trip function. That means that the winch mounted at the base of the boom pulls on the small cable called a trip rope. That rope is attached to the latchbar lever which runs horizontally across the back of the door and pulls up in the latchbar, which then lifts out of the dutchman and the door swings open. To put it in simpler terms to grasp, think of it as being like a door latch on a door in your house. Now, instead of a round door knob, imagine you have a lever type door handle. When you move the handle, the latch pulls into the door and out of the corresponding hole in the door frame...and the door swings open. Very similar to that.

    Now, as for the door not hitting the side of the box......well, it happens. Mostly it has to do with the operator. If you are any good, you shouldn't be hitting the truck box at all. That being said, sometimes it happens.....and for some, it happens alot...lol.

    There are systems out there like P&H's Snubrite system. It's basically a big fluid powered snubber that helps to slow the door down through resistance and leverage. Keep in mind, the door opens and material starts to fall out before the door is all the way open, so it helps to lessen the impact a bit. Also, you should be tripping the door fairly low above the box......unless you're mad at the trucker, then it's bombs away with some folks.

    I've attached a picture a friend sent me from down in the states that shows the back of a bucket. We use a different style bucket, but I have no good pictures that show the back side of them so you can see the different components. Sorry about the labelling I put on it, I could have done a better job.

    I'll also attach a picture of one of ours that shows the bottom of the bucket so you can see the dutchman. Also another pic that shows a Snubrite setup. There are two of those on each P&H bucket.

    Hopefully that helps to answer the questions you have, but feel free to ask any more and I'll try to do a better job of answering....lol.
     

    Attached Files:

  5. willie59

    willie59 Super Moderator

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    Well, learn something new everyday...cool! Really nice pics and vids guys. :notworthy
     
  6. Ross

    Ross Senior Member

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    Aye ... Snubber ...

    Snubby.jpg

    After the first big hit a decent operator will lower the bucket onto the already dumped material, Throw the latch and lift the bucket, Filtering the Material into the Box.
     
  7. Alaska Sunrise

    Alaska Sunrise Active Member

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    Thanks for the great info! I didn't think the bucket mechanism would be so complex. (was the guy filming the video teasing the operator about only getting small scoops?)
     
  8. heavylift

    heavylift Senior Member

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    we have one out in eastern Kansas.... left to rust... It now a museum.... used to strip coal I think... It's called Big Brutus ,supposedly the second largest in the world.
    http://www.bigbrutus.org/index.html

    I think the main cables are 4" or 5" in diameter... They used some of the old cable to line the parking lot and paths.

    We went there years ago, before they closed the the arms to climbing.... it's a view..
     
  9. heavylift

    heavylift Senior Member

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    I don't think he was teasing.... sending a half loaded truck cost money..
    Plus the extra swings.... light loads means more money to haul the material and load the material

    the best signal is when you see a foreman holding his hardhat out like a scoop... this means his hardhat holds more than you had in your bucket..
     
  10. cummins05

    cummins05 Senior Member

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    Looks like teach the secretary to run the loading shovel day at the mine LOL
     
  11. JDOFMEMI

    JDOFMEMI Senior Member

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    Definatley not a regular production shovel operator there.

    Three scoops should have material falling off of at least 3 sides of the truck.
     
  12. alco

    alco Senior Member

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    I'd say they're training a new operator there. Whoever it is seems to be reaching for their dirt. At any rate, at least they aren't jacking the boom.
     
  13. RonG

    RonG Charter Member

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    Maybe the operator was shooting the video?Ron G
     
  14. Ross

    Ross Senior Member

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    Plenty of Arm-Chair-Quaterbacks on the boards :rolleyes: .. Gung Ho with a Multi-Million $ machine :pointhead

    Pretty Decent Video of a Shovel loading an Haul-Pak 830.

    YouTube - The bucket
     
  15. cummins05

    cummins05 Senior Member

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    I prefer armchair operator LOL
     
  16. alco

    alco Senior Member

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    Call us what you want Ross, running a shovel is what I do for a living.
     
  17. Ross

    Ross Senior Member

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    Arm-Chair-Quarterback's .. Refers to the people who criticise the trainee Op when they probably havent even seen a Big P&H shovel never mind been in control ... We could all operate that shovel better sitting in-front of our Laptops :notworthy

    Not refering to you Brian ... I have other Choice (Kind :D) words for the operators :tong
     
  18. HoJay

    HoJay Well-Known Member

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    What dictates why a mine chooses a cable shovel over the hydraulic shovels? I think I have heard mobility for diesel vs electric but don't both types of shovel have comparable bucket capacities and cycle times? Are there certain conditions that favor the cable or hydraulic?
     
  19. cummins05

    cummins05 Senior Member

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    who cares if people havent seen one up close or ran a big shovel if you seen a good shovel operator you would know he was not a very good one yet. its called having an opinion. just like im not the worlds best grader operator but i have skided a few cause they sucked so please dont isult me over this cause you feel your so much better
     
  20. Ross

    Ross Senior Member

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    All I said was "Arm-Chair-Quarterback's" If anybody thinks they could do a better job on a big shovel then thats fine .. But until you get some chair time then its really only speculation? Brian was right when he said "He is not jacking the Boom" so hes doing Ok.

    If he was pounding the crap out of the truck and shovel to keep up production would he then be a good operator?

    And regarding the last line (in bold) Please keep this grown up thanks.