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Large cable loading shovels - Questions

cummins05

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Didnt say i could do a better job i was stating the fact that other shovel hands could outperform him/her and you dont have to run one to figure somthing like that out.

im sure there not an easy thing to operate i ran a small hyd shovel for a bit and it was tough to get used to after runnin a hoe for so long.

But by you coming on here and stating that we are "Arm-Chair-Quarterback's" makes me think that you would think your opinion is worth more
 

tdozer

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Feb 23, 2006
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A quick question from someone who has never been around cable shovels(Me). What is "Jacking the boom"? Im assuming that it means, letting it crowd too far in so it slams or hoisting it too far up so it comes in contact with the pulleys.
 

JDOFMEMI

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Tdozer
You are close.

It is when the operator crowds too hard with the dipper and it lifts the boom, slacking the cables that hold the boom up then letting it fall against the cables. It is harsh on the machine to do that.

Hoisting too far up and contacting the pulleys would be "two blocking" the dipper.

I am not sure what it would be called when you crowd too far in, but I know it also would not be a good thing.

Alco will probably know the answer though.
 

Alaska Sunrise

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Lots of opinions I see. I don't know if that was an experienced operator or not, but they were doing way better than I could do.
 

alco

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Yep, JDOFMEMI pretty much hit the nail on the head. Although, a boom jack doesn't necessarily have to involve the boom coming down hard on the suspension ropes. It can also be lowered gently in most cases.

Raising the bucket too far is usually known as hitting your hoist limits. Crowding in or out to far is hitting your crowd limits. Thankfully, the shovels are computer controlled these days, so the computer usually stops over hoisting, or overcrowding by slowing and stopping the movement before any contact is made. Now, that being said, I have heard of crowd limits not functioning right and two blocking the bail bar or padlocks into the point sheaves. I've also heard of the sticks...or dipper handles....being shot right out the end of the saddle blocks when the crowd limits didn't limit....lol.

On another point, if you lower the bucket too far, you can put slack into your ropes and throw them right off the point sheaves. Which, thanks to one of our "operators", I have had the pleasure of dealing with a few times now. It requires a crane and a couple guys in fall restraints standing on the tip of the boom 70 feet in the air. It always seems to happen at night in the wind and rain too.....
 

alco

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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?

Sorry, I missed this question earlier.

There are lots of different factors that would determine which would be better suited for different situations. Mobility is definitely one of them. If you will be moving the shovel around a fair bit, then not being tethered to a power cable is a big advantage.

There may not be adequate electrical supply available to run an electric shovel also. So in that case, a diesel powered machine would be a better option.

Mine life is a big factor. A hydraulic machine has a shorter lifespan than a cable shovel. They tend to rate the life of a cable machine somewhere around 20 to 25 years depending on who you talk to. A hydraulic tends to be around 10 to 15 years as the most viable. Of course, they can be run longer, but in some cases, it starts becoming too expensive past that point. If the mine is projected to have very long life, then a cable machine can make more sense, but if it's a 10 year mine life, a hydraulic would be better suited since you'll never get the full life out of the cable machine there.

The type of digging will also play a big role in the decision. If it's straight production loading, the cable machine will be more productive. If there is varied digging, like having different grades of ore, or having to be selective about what you dig and load, then a hydraulic will be a better fit.

There are literally dozens of factors that will determine which would be a better fit. And of course, there are exceptions to every rule that would help to determine which to choose. They both have similar cycle times, but typically, the hydraulics are a lighter machine and swing a smaller bucket. Not always, but usually. A comparably sized (bucket wise) cable machine should pretty much always out dig a hyd. machine.
 

willie59

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A comparably sized (bucket wise) cable machine should pretty much always out dig a hyd. machine.


Wow, that's an amazing statement. I mean, considering, all the modern technology that is incorporated in todays hyd shovels, that they can be "out dug" by a design (cable shovels) that was the origin of the power shovel...when they were powered by a steam engine a century ago! That's crazy. :cool:
 

alco

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Wow, that's an amazing statement. I mean, considering, all the modern technology that is incorporated in todays hyd shovels, that they can be "out dug" by a design (cable shovels) that was the origin of the power shovel...when they were powered by a steam engine a century ago! That's crazy. :cool:

You'd be amazed at how much modern technology is involved in the cable machines these days. They're fast, and really powerful.
 

JDOFMEMI

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For all the improvements in hydraulics, one of the main limiting factors is heat. Compressing hydraulic fluid and moving it at the rate modern shovels do to be productive creates a lot of heat.

On the other hand, electronics benifit from modern computer controls to keep the drive motors working at the optimum rate. There is still a heat issue, but less than a hyd. machine, and the electric machine gets the power applied in a more controlable manner. True, the digging function is the same as 100 years ago, but if it is not broke, don't fix it.

The cable machines also seem to be built heavier, so that is part of the reason they have a longer life. There is less moving parts to wear out on a cable machine. Only one main pivot point on the dipper arm to boom connection, instead of 3 main points and a slew of lesser ones on the hydraulic machine. Cables do have their problems, like wearing out and breaking the hoist cable, and either cable or rack and pinion crowd, but it is still less than a hydraulic machine.

The hydraulic can vary the angle of attack, dig high or low, and have more positive control than cable does, but for purely digging and loading, a cable machine usually has a higher capacity, and that gets a production rate in most materials.

Alco can expand on the benifits of hydraulic in the oil sands. They seem to be at home there.

Look at most of the hard rock mines, at least the major ones, and you will find P&H 4100's and Bucyrus 495's are the norm. The newest ones are 100 ton, and up to 120 ton dippers to match up to the 360 to 400 ton trucks.
I think the largest hydraulics are up to 80 ton buckets now. 3 passes in a 240 ton truck is a good match.
 

JTL

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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
 

celticcrusader

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Dec 10, 2007
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stillwater N.J.
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.
 

Mass-X

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There’s been some good shovel talk on here lately, hopefully it’ll keep up.

Since I’ve spent a grip of time in meetings lately discussing the merits of hydraulic and cable machines to assist in some acquisition decisions, I’ll 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 hasn’t 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 don’t consider the comparison between the RH200 and the 2800XPC the most accurate because they don’t equally pass-match to a 789, but it’s 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 MSHA’s documentation of highwall failures, it’s 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 “safer”) 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 I’ve 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 machine’s. 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, it’s 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 shovel’s 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 RTD’s 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.
 

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Ross

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^^^ Yeah I can agree on most of the Excellent :notworthy 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:

JDOFMEMI

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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.
 

Mass-X

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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 789C’s, 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 … Ive worked on sites where theres 6-7ft between coal seems, Now you cannot blast this .. I 2800XP wouldn’t 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 657’s 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. I’ve spent the last year working on that exact thing in the field, and I’m 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&K’s are pure workhorses.
 

JimBruce42

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I for one have been enjoying this thread a great deal. Learn something new every day here on HEF:drinkup

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

Ross

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Some excellent answers :cool:

The figure was calculated using equal operating conditions and circumstances for both machines. Four CAT 789C’s, 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?

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 657’s 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. I’ve spent the last year working on that exact thing in the field, and I’m 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.

I agree. It goes to show how impressive the performance of the newer hydraulic shovels and excavators are. And the O&K’s 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.
 

alco

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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?
 

Ross

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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!
 
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