Excavators - rights, wrongs and guesswork.
Hi, Folks.
I have been unable to post here for a while now 'cos of that "You have been banned" mesage, so it's been interesting catching up on this thread.
Today, I was running a Cat 771D dump truck loading under an old Cat 245B excavator. A dozer had cut a bench for the excavator to load from but had left a mound of material at the far end of the bench because to push it further would have contaminated some feed rock for a crushing plant.
The excavator had to start at the far end where the mound was and work his way out to the start of the bench. He began by (sorta) flattening the mound so that he could stand on it to begin loading. Trouble was he started loading out too early and cut himself off from being able to reach right to the very end of the excavation.
(The reason for the excavation was to widen a haul road leading to the above-mentioned crusher. There is also a feed storage area there at the end of the road where a loader can feed into the crusher when the face trucks aren't running.)
In addition to cutting himself off from reaching the end of the excavation, he was struggling to reach as far as he could, standing right on the edge of a drop-off, with one track on natural ground and the other on un-compacted fill. He was all outa level, sliding over the edge and the end, trying to cut a level floor while out of level and countering the events of being out of level on his swing.
This gentleman is generally reckoned to be a pretty fair operator but for the lack of another 3 or 4 minutes of preparation, I'd reckon his load rate was down by at least 30% for the first hour of the 5 1/2 that it took to do the job. And he had to have a Cat D10N come in and clean up his floor and push all the material he had missed forward to him. Figure the percentages there.
My opinion of this operator went downhill dramatically today and it wasn't high before that. F'rinstance. I have a method of bench loading with an excavator that leaves my next bench already prepared and ready for me to walk straight on to when I get to the end of a face. I was using this method one day when this operator had a day off and I was operating this same excavator and I had the new bench well advanced by the day's end.
This operator came in the next day and immediately started digging out my second bench. He got to the end of that, moved over on to the original bench, dug that out and then had to leave the trucks standing for almost 15 minutes while he cut his next bench.
He also spends quite a lot of time digging behind himself and swinging up to 180 deg. to load the material into the truck. He then has to back up and push the mounded material from his digging back into the resultant trench so that he can move further along the face. And he dooes it EVERY bench. NOT the way I would do it after the first bench.
Many excavator operators also tend to drag the bucket up the face from the bottom when they dig. The easiest way to fill the bucket is to work your way down in layers from the top, pulling the bucket toward the machine and filling it as you come. Doing it this way also takes advantage of the lesser distance to lift from digging higher up the face.
Having said that, some years ago, I was running an old Kato 1880 Mark2 42 tonner with 6,500 hours on it alongside a 'Kummagutsa' PC400 40 tonner that had a mere 2,500 hours on it. Everybody reckoned that the 'Kummagutsa' was the better machine - except me. And I proved my point. That old Kato would dig 5 buckets to the PC400's 4 buckets all the time and 4 to the snivelling PC400's 3 most of the time. The Kato was swinging the bigger bucket by about 0.3 of cubic metre and it just sat there and dug while the 'Kummagutsa' slid all over the place and the operator was forever having to re-set himself.
The Kato was just under 2/3 the purchase price of the 'Kummagutsa' two years earlier than the 'Kummagutsa' and had had exactly ONE anything like major repair done to it in its 6,500 hours - a radiator reconditioning.
I still remember that old 1880 with some fondness for its ability to move material. I also remember very fondly a Kato 1220 Mark2 for the delicate touch of its controls. I STILL regard it as the smoothest excavator that I have ever operated and it didn't have a computer anywhere on it, just beautifully balanced hydraulics and valving and great machine balance.
Experience of different brands of earthmoving machines around where I live and work - South-east Queensland, Australia - seems to indicate that there might be some false economies in buying the (Slightly) cheaper makes instead of Cat. It seems to be a bit remarkable the number of times that you ring the dealer for a part for a non-Cat brand machine and there is a wait of a week or more to get it - if they can. Cat mostly seem to have them there overnight if they don't already have them on the shelf.
On top of that, many of the non-Cat brands seem to need parts - and rebuilds - earlier and more regularly than their Cat competitors. And Cat re-sale values almost always seem to hold up better than most of their competition.
Is that 0.02 cents worht yet?????????????
You all have a wonderful day. Best wishes. Deas Plant.
P.S. Pullpan, is it time for the 'grand FINALE' yet?
