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Discussion in 'Shiny Things' started by Sniper X, Nov 14, 2012.
So why was the wire coming off???
The one on the mine where we (when I worked for Henry J. Kaiser) built a coal gasification plant weighed something like 3 million pounds, used a 24KV power cord (not all that big in actual size) and would dim lights on the grid, so it could only be started in the middle of the night. The base pad was 60 feet in diameter made of some exotic steel like plows so it did not erode very fast. It had 4 4" diameter haul ropes, each with its own winch, and two 36" diameter shafts to swing the machine on the pad which had very large bearings as well as gear teeth on it. The dragline is all DC, other than ancillary stuff like lights, and the upper layer in the rear of it, is AC to DC generators. That machine I saw was the first, and was completed for use in 1984, when the mine officially opened, although it was in use for 2 years before that.
The boom was 300 feet long, and at full speed swing, it was going 60 miles per hour (aka 66 feet per second). The bucket was 126 yards as I recall. The Freedom mine now has three of those monsters working at the largest lignite coal mine the world according to information I found on it.
The thing has run 24 hrs a day, 7 days a week since the early 1980's. Taking the overburden (not topsoil) off of a 16 foot deep low grade coal seam in North Dakota, north of Beulah. The mine fine coal goes to the Antelope Valley Generating station the coarse chunks to the gasification plant next door, http://www.basinelectric.com/Electricity/Generation/Antelope_Valley_Station/index.html The gasification plant is the Dakota Gasification Plant http://www.basinelectric.com/Gasification/index.html
If you are inclined go to N 47.36766 W 101.83125 on your favorite mapping program and have a look.
Have to dig around and find some pictures I have of some of the bucket wheel excavators in Europe I have been up close and personal with....also some monster machines. .
The 45,000 ton Krupp Bagger 288?
More Pictures here:
It's so big it once picked up a 70 odd ton Cat D8 bulldozer in the bucket!
This one is a museum...
That's jus' a little guy.
Here's his late uncle:
Can't say I've seen a dragline, but being in the wind turbine business, I get to see some pretty cool cranes. A year and a half ago I spent a lot of time on a job and my office trailer was next to a Manitowoc 18000 that was parked for the winter. Climbed around on that a bit. Awesome. The weight stack had it's own climate. I think they had somewhere north of 700 tons of counterweight. We spent a while with the weather around 0 F. Then it warmed up closer to freezing. The weight stack frosted up (frozen condensation). It took 3 days for the stack to warm enough to clean the condensation off.
But that's not the biggest one. Was out at the National Wind Test Center and got to see one of the biggest hydraulic cranes in North America. I didn't get great photos, but someone else on the web did (different jobsite). Check it out here: http://forums.dhsdiecast.com/default.aspx?g=posts&t=125557
Liebherr LTM11200! Nice machine. Biggest telescopic crane in the world.
Somewhere around $8 to 10 million to buy. 1,500 tons nominal capacity. Not many in the US. They were really designed for wind turbine erection but they came out after the WT boom died out.
Most people prefer crawler cranes for WT work as they can move between the various lifts on site fully erected. Saves a lot of time and money.
The LTM can't do that, and thanks to DOT restrictions, it has to be broken down into quite a few parts for transport.
So it took 6 weeks to rig the crane, how long to actually do the job?
30 days or so.
Practically every component of the crane was a critical lift under the nuclear plant's regulations. It slows things down a lot.
We took it apart in 3 weeks because the job was done, the crew was experienced and the client's attention had moved elsewhere
We once erected the sister crane to this one in 10 days on a job in Malaysia. 100 people in the crew and no paperwork.
Here's the top of a bucket wheel near the Arkansas / Texas border, just off the interestate:
Here's another dragline operating nearby:
Big, but not huge like the classic ones from Bucyrus or Marion.
That coal needs to move to the power plant:
Komatsu I think, possibly from their Haulpak plant, in Peoria IL. That has to piss off Caterpillar, drive down by the river and see a Komatsu factory. A legacy of LeTourneau which makes some big ass electrified equipment.
Check out the L2350:
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LeTourneau was the pioneer of diesel / electric drives in construction equipment. Hybrids in the 1940s. Old Tournapull operators usually have exciting stories of them praying (or cursing) that the steering would start working again. Most of them are also deaf due to the use of Detroit diesels.
If you whack the bucket on the side of the spoil pile, it jumps the shark. He either had bad depth perception, was in a hurry, or drunk because it happened to the same operator twice and the one who came after him once meaning the guy who's fault it was had almost knocked it off again and it finally went when the new shift took over.
Had a thought about the cable used on those big FO cranes.
So, it has 5miles of cable - that weighs a shit load right.
Spectra / Dynema has been used on BIG yachts rigging (both running and standing) for years now - its much lighter.
Is there a reason they are not using similar instead of the normal wire type rope?
I understand that it can be in a dirty (dusty / oil / weather) etc but for the cost of one of those cranes, it would be a small % I think.
I'd have to think about that. They are starting to use composite materials in cranes now, but they are not widespread yet.
Strength is only one aspect. Durability is critical. If a line fails on a sailboat its an inconvenience, if it fails on a crane it's life threatening. Look at the boom hoist cable that failed in New York recently. A laborer was killed.
We looked at using composite materials to make lattice booms. Very light and strong, but we were worried about them being damaged during handling and failing at a later time. Repair is easy with steel, but not so much with carbon fiber.
Hoist ropes work at a 5 to 1 safety factor too, and if you apply that to synthetic rope it rapidly increases in diameter. That would require much larger drums. They also absorb water, so you have a potential issue with sheave (roller) width variances.
We often use synthetic slings for rigging loads. They are very light and easy to handle compared to wire, but are incredibly easy to damage either through rough handling, poor storage or simply getting cut on a sharp edge during lifting. They are also sensitive to heat and chemicals and can deteriorate when exposed to UV for long periods. That's not too much of a problem with slings, but hoist ropes are open to the elements at all times. Replacing them periodically on an expensive sail boat is one thing... On a fleet of large cranes it would be prohibitively costly.
It'll happen one day, but I think it's a long way off, especially in these monster cranes. Too much riding on what is not that big of a maintenance cost.
The largest crawler known to mankind is just down the street from me. :eek1
Yup, this the first one. It's a Liebherr (seeing a pattern here?) LR13000 3,000 metric tonnes capacity.
Here it is up close during the factory open day earler this year:
They went on to do a demonstration lift with it, that earned the respect of every rigging engineer on the planet:
Even the small crane on the end is holding a platform with a 1:50 scale model crane!
are those weights 25 us or metric?
900 tonnes on the crane itself, and up to 1,500 tonnes on the superlift tray hanging out the back.
Its a big bitch...