Page 3 of 4 FirstFirst 1234 LastLast
Results 31 to 45 of 57

Thread: Large cable loading shovels - Questions

  1. #31
    Senior Member JTL's Avatar
    Join Date
    Dec 2008
    Location
    Pacific Nortwest U.S.A.
    Posts
    761
    Pretty impressive stuff guys. I learned a little bit just from your posts. Its all makes perfect sence to me.

    My only expierince with cable ran machines was an old 98 Link Belt set up with a heel boom, Coeur d' Alene log grapple and a 80 year old whisky drunk A- hole that could toss that grapple about 100 feet to fetch a log! That was really impresive.
    Jason
    Jason
    Work harder. Millions on welfare depend on you!

  2. #32
    Member
    Join Date
    Dec 2007
    Location
    stillwater N.J.
    Posts
    89
    I used to operate a Northwest 180D shovel, I never had a problem with hitting the side of a Haul Truck the bucket was always above the body but when I was learning I would sometimes overshoot the dump body and dump on cabshield, too much swing.

  3. #33
    Senior Member
    Join Date
    Nov 2006
    Location
    CA
    Posts
    167
    Thereís been some good shovel talk on here lately, hopefully itíll keep up.

    Since Iíve spent a grip of time in meetings lately discussing the merits of hydraulic and cable machines to assist in some acquisition decisions, Iíll weigh in here as well.

    Most of the merits of hydraulic machines and cable machines have already been well covered in previous posts, but one thing that hasnít been brought up is the vitally important component of any mining operation: cost-per-ton.

    For several reasons, cable shovels will achieve a (sometimes drastically) lower cost-per-ton than equivalent hydraulic shovels will in equal digging conditions and operating circumstances.

    Using 789 haul trucks, equivalent operating circumstances, and comparing an O&K RH200 and a P&H 2800XPC as loading tools under equal digging conditions, the O&K RH200 will move material for approximately $1.54/CY. The P&H 2800XPC will move material for approximately $1.32/CY.

    I donít consider the comparison between the RH200 and the 2800XPC the most accurate because they donít equally pass-match to a 789, but itís a good enough baseline to use as an example.

    One of the biggest reasons for the lower cost-per-ton offered by a cable machine is attributed to their ability to work out of a greater face height than a hydraulic shovel. This allows greater bench height which decreases mine production costs for several reasons.

    By increasing bench height (if rock mechanics allow the increased highwall height to be achieved safely), the total number of graded drill pads can be decreased, decreasing the total number of blasts; which reduces costs. By increasing bench heights, the powder factors can be increased which increases rock fracturing in the shot material. This provides several benefits: easier loading for the shovel, as bucket fill factors are increased, GET life is prolonged, which decreases downtime. It also increases load consolidation in the haul trucks, which is especially important in lighter materials.

    Depending on material, and blasting methods, a deeper or overshot bench can also create a better floor as the face advances across the new bench, which prolongs the life of expensive haul truck tires and the tires of the RTD that maintains the floor.

    The increased reach of cable shovels allows them to more safely work higher benches than a hydraulic machine. If you keep up with MSHAís documentation of highwall failures, itís not hard to find hydraulic shovels that worked dangerously tall faces that subsided onto the loading shovel; which has lead to fatalities in some cases. There are numerous videos on Youtube of hydraulic machines working dangerously high faces. Cable machines safely allow greater bench and face height, which helps to decrease cost-per-ton.

    The increased reach of the cable machines also allows safer and more flexible dual-side loading as trucks can be spotted at a greater (read that as ďsaferĒ) distance off the counterweight of the shovel than with a hydraulic machine. Utilizing cable overpasses allows the trail cable to be wrapped in along the crest of a lower bench or toe of highwall, and then cross the path where the trucks need to access the off side of the shovel, allowing dual-side loading, thus increasing production.

    In lighter excavation conditions (coal, lignite, phosphate, sedimentary overburdens, etc.) where shovel footwork patterns allow parallel tracking; an electric shovel with a cable sled can stand alone and keep truck spot-time constant; only having to stop trucks while handling his sled. Most of the time studies Iíve reviewed show that even with that hiccup in production, the increased yield off the cable shovels equates to a 53-55 min/production hour [average] for the haulage units. In this scenario, an equivalent hydraulic machine can maintain 58-60 min/production hour [average] for the haulage units due to no handling of a trail cable. The material moved per hour in this scenario will usually be equal between the two machines.

    In hard rock excavation (metals, minerals, etc.), one of the biggest constraints on production off a cable shovel is time to handle and move the trail cable once the direct face has been mined to maximum reach. In a larger mining operation, with good controllers who are on the ball and not relying on CAES and FleetCommander to do everything for them, they can lull the trucks to a particular shovel to allow the machine to reset his sled or sling, realign, track back into the face and stage. When the electric shovel is the only loading tool for the haulage units; an advancing bench cut design and loading on-the-fly is more suited in most situations, but still causes a decrease in the haulage units production due to stand-by time while waiting on the shovel to handle the trail cable and realign.

    Cable shovels have much greater floor level digging reach than hydraulic shovels, which increases the amount of time they can mine from a static position without needing to reposition in the face. In smaller ore bodies or scenarios that require lots of movement in the face, a hydraulic shovel will greatly outperform a cable shovel.

    The digging forces of a cable shovel are greater than a hydraulic machineís. The loading radius that an electric shovel operates on also assists in bucket fill factors, as when the bucket clears the face on a cable shovel, itís higher, and usually close to the necessary elevation to dump into the truck bed without additional movement. That said, in free-digging, or poorly blasted material, the hydraulic shovelís ability to curl the bucket allows much more finesse and precise handling of large rocks. As mentioned in a previous post, cable shovels require their material to be blasted.

    Cable shovels require more assistance from RTDís to maintain floor quality to save integrity of expensive haul truck tires; while hydraulic units can clean and maintain their floors better.

    These diagrams are pretty strong P&H propaganda, but they do a good job illustrating some of the above points.
    Attached Images Attached Images     

  4. #34
    Senior Member Ross's Avatar
    Join Date
    May 2007
    Location
    In the Rockies
    Posts
    347
    ^^^ Yeah I can agree on most of the Excellent Info above. The Hydraulic machine can Dig unblaster material and doesnt require back-up equipment like an RT ...

    Does the $/cy figures above include the additions of extra staff required for a Cable machine and all the extra infastructure required to actually get the machine digging? Also do the figures include other extras like Blasting? etc

    If a mine has a Projected life of 2 year then a Hydraulic machine will be favoured as it can be ripped down, Re-located, Re-built and digging with in a few weeks MAX with a small crew of mechanics.

    Another factor is the actual mining ... Ive worked on sites where theres 6-7ft between coal seams, Now you cannot blast this .. I 2800XP wouldn't be able to dig it.

    2800 XP weight is twice the O&K .. Testement to how good these Hydraulic machines are.
    Last edited by Ross; 11-21-2009 at 05:07 PM.

  5. #35
    Senior Member JDOFMEMI's Avatar
    Join Date
    Jan 2007
    Location
    SoCal
    Posts
    2,629
    Great post Mass-X

    You can tell the illustrations are biased toward P&H, but they do get the message through.
    One thing I notice they don't point out is the crowd force in hard digging. The cable shovel has as much force as the weight of the boom, while the hydraulic machine can put close to half the machine weight into the crowd. That, along with the bucket curl is why the Hydraulic shovel can get by in hard digging.

    As Ross sais, the fact that the hydraulic machine does as well as it does in this argument despite giving up so much in size and weight is a testament to the design.
    Jerry

  6. #36
    Senior Member
    Join Date
    Nov 2006
    Location
    CA
    Posts
    167
    Ross: Does the $/cy figures above include the additions of extra staff required for a Cable machine and all the extra infrastructure required to actually get the machine digging? Also do the figures include other extras like Blasting? Etc
    The figure was calculated using equal operating conditions and circumstances for both machines. Four CAT 789Cís, same haul distance, same elevation gain in haul. The support equipment was the same for both shovels, except the 2800XPC had a 988B with Towhaul cable-reeler as additional support equipment.

    Both shovels were dual-side loading. Shovels and haul trucks were hot-seated at [12 hour] shift changes. Digging conditions were equivalent, in the same types of a material, equally blasted.

    The cost of electrical infrastructure construction/development was not included in the cost-per-ton of the 2800XPC, as the scenario where I ran these numbers was in a mining operation with electrical infrastructure already established. Essentially plug-n-play, only requiring electrician assistance for major tie-ins and transitions for the 2800XPC.


    Ross: Another factor is the actual mining Ö Ive worked on sites where theres 6-7ft between coal seems, Now you cannot blast this .. I 2800XP wouldnít be able to dig it.
    Coal mine interburdens are scraper dirt. Thin interburden seams are best left to a good scraper crew unless very rocky. With proper coordination and the right schematics, a fleet of 657ís can work in sync with the coal mining operations and decrease the handling costs of the parting ratio greater than any other method of handling the material. Iíve spent the last year working on that exact thing in the field, and Iím finally getting a good system developed. It requires a different pit design, and the dragline has to handle and place spoils differently; but the tremendously low handling cost, and eliminating rehandle of the interburden is making scrapers the choicest tool for interburden stripping.

    Ross: 2800XP weight is twice the O&K .. Testement to how good these Hydraulic machines are.
    I agree. It goes to show how impressive the performance of the newer hydraulic shovels and excavators are. And the O&Kís are pure workhorses.

  7. #37
    Senior Member JimBruce42's Avatar
    Join Date
    Jan 2006
    Location
    Pennsylvania
    Posts
    927
    I for one have been enjoying this thread a great deal. Learn something new every day here on HEF

    Thanks for asking the question and welcome to the board Alaska Sunrise
    -Jim

    "Hit any key to continue "

  8. #38
    Senior Member Ross's Avatar
    Join Date
    May 2007
    Location
    In the Rockies
    Posts
    347
    Some excellent answers

    Quote Originally Posted by Mass-X View Post
    The figure was calculated using equal operating conditions and circumstances for both machines. Four CAT 789Cís, same haul distance, same elevation gain in haul. The support equipment was the same for both shovels, except the 2800XPC had a 988B with Towhaul cable-reeler as additional support equipment.

    Both shovels were dual-side loading. Shovels and haul trucks were hot-seated at [12 hour] shift changes. Digging conditions were equivalent, in the same types of a material, equally blasted.

    The cost of electrical infrastructure construction/development was not included in the cost-per-ton of the 2800XPC, as the scenario where I ran these numbers was in a mining operation with electrical infrastructure already established. Essentially plug-n-play, only requiring electrician assistance for major tie-ins and transitions for the 2800XPC.
    Head to Head the Cable machine is better for the job if the conditions above where present, In reality it isnt most of the time.

    You have to factor in the Down-time for electrical issues resulting in an Electrician required, Also an Electrician is required (Not all mines) To isolate a piece of equipment before and work is carried out.

    Then the Purchase cost of both piece's? Any figures?

    Quote Originally Posted by Mass-X View Post
    Coal mine interburdens are scraper dirt. Thin interburden seams are best left to a good scraper crew unless very rocky. With proper coordination and the right schematics, a fleet of 657ís can work in sync with the coal mining operations and decrease the handling costs of the parting ratio greater than any other method of handling the material. Iíve spent the last year working on that exact thing in the field, and Iím finally getting a good system developed. It requires a different pit design, and the dragline has to handle and place spoils differently; but the tremendously low handling cost, and eliminating rehandle of the interburden is making scrapers the choicest tool for interburden stripping.
    Scrapers .. MM yeah they would work great in certain conditions. I have some Video of an O&K lifting the 6-7ft Inter burden, Not even a D9R (Biggest on site) Couldn't rip the material in question, Only other method would be to Pek it, Requiring more equipment on site. No way a Cable machine would move this. Again this is part of the discusion why the two machines vary.

    I will post the video up in this thread later.

    Quote Originally Posted by Mass-X View Post
    I agree. It goes to show how impressive the performance of the newer hydraulic shovels and excavators are. And the O&Kís are pure workhorses.
    Work Horses No doubt as well as the P&H's .. The must have more longevity giving the extra Meat involved.

    Very interesting to here from people who have actually studied this as a job and not just fact based opinion.

  9. #39
    Senior Member alco's Avatar
    Join Date
    Apr 2006
    Location
    here
    Posts
    1,139
    Mass-x posted a lot of really good information there, thanks for that. The only thing I can say against it is that in some conditions and situations, the outcomes between the electric and hydraulic would be reversed. However, that would be the exception rather than the rule.

    Anybody wanna buy some 495HFs really cheap, it's getting to the point where we might be able to convince them to sell the junkers off! Of course that'll never happen, but a guy can dream, right?
    Throwin' dirt at truckers all day long.

  10. #40
    Senior Member Ross's Avatar
    Join Date
    May 2007
    Location
    In the Rockies
    Posts
    347
    Quote Originally Posted by alco View Post
    Anybody wanna buy some 495HFs really cheap, it's getting to the point where we might be able to convince them to sell the junkers off! Of course that'll never happen, but a guy can dream, right?
    They no Good for the Crap they dig out Brian .. Or are they going down to much?

    Here is a Video I shot a few year back .. Watch the shovel slide back near the end and watch the Op track it into the face while crowding. (Brings all 4 pumps up)

    O&K Having the time of its life!

  11. #41
    Senior Member alco's Avatar
    Join Date
    Apr 2006
    Location
    here
    Posts
    1,139
    Quote Originally Posted by Ross View Post
    They no Good for the Crap they dig out Brian .. Or are they going down to much?
    A little from column A, a little from column B. They do much better if they are run in easy digging, but put them into tough to dig material, and they literally fall apart before your eyes. Not to mention how rough they are....shaking, shuddering, and bucking around wildly. They should put them in the top cut bench and leave them there. The material is easy to dig, and the floor is soft enough to settle down the bucking motion a fair bit.

    Love the RH120 video, man I hate chasing a low face like that and loading 930Es. Thanks for posting it...in fact, post more!
    Throwin' dirt at truckers all day long.

  12. #42
    Senior Member Ross's Avatar
    Join Date
    May 2007
    Location
    In the Rockies
    Posts
    347
    Quote Originally Posted by alco View Post
    A little from column A, a little from column B. They do much better if they are run in easy digging, but put them into tough to dig material, and they literally fall apart before your eyes. Not to mention how rough they are....shaking, shuddering, and bucking around wildly. They should put them in the top cut bench and leave them there. The material is easy to dig, and the floor is soft enough to settle down the bucking motion a fair bit.
    Ah right .. So what Shovel (pound for pound) is Best for the hard stuff up at the sands?

    Quote Originally Posted by alco View Post
    Love the RH120 video, man I hate chasing a low face like that and loading 930Es. Thanks for posting it...in fact, post more!
    Aye .. RH120 was having some bother with that stuff ..

    I have more on the Laptop yet to be uploaded .. See if I can load a few more up

  13. #43
    Probationary Member
    Join Date
    Jan 2010
    Location
    Perth, WA, Australia
    Posts
    2
    A lot of interesting experience to learn from in this thread, unfortunately discontinued. Anyone still looking in here? I could really use some first hand information on shovels and how they operate in a mine, as I am compiling a simulation of Truck & Shovel operation.

  14. #44
    Senior Member Chris5500's Avatar
    Join Date
    Oct 2009
    Location
    Australia
    Posts
    217
    What type of shovel; hydraulic or electric rope? Just out of curiosity what is the purpose of the simulation?

  15. #45
    Probationary Member
    Join Date
    Jan 2010
    Location
    Perth, WA, Australia
    Posts
    2
    It's about comparing several discontinuous mining systems, based on loading equipment as hydraulic or rope shovel, or front end loader.
    I have to describe the operation of each part of the system, and their interaction. As I don't have any practice with such equipment, I'm short of information I can't retrieve from manufacturer's docs.
    Example: a shovel digs until no sufficient material is in its reach, so it has to move forward using its crawlers. How many meters does it move towards the face to start digging the next section or "slice" of the block, i.e. how thick is that "slice" a shovel can dig betweeen two moves? How long does that moving forward take? I could thus calculate how many of such steps I have to make for a given block length.
    Other questions would be:
    - what is a common block width and length, bench height?
    - how often is dual side loading possible?
    - what times do you have on a shovel through which it isn't digging, although technically it could (e.g. because you eat, drink or take a p..., make a transfer at start and end of shift etc.)?
    - how frequent is blasting, how much time each time that the shovel can't dig?
    - what is the extension of a section to be blasted?

    Only a small part of the open questions - it's quite a project as you see.
    Cheers!

Page 3 of 4 FirstFirst 1234 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •