So after watching a great video of the new Volvo A60H pulling a K-Tec scraper it got me to wondering, what determines which variety of scraper a contractor would use? When would it be better to use an articulated farm tractor with a pull pan vs a converted ADT with a pull pan vs a dozer with a pull pan vs a regular scraper? I could see the dozer advantage with traction and the regular scraper advantage on very hilly terrain, but what are the other factors? I wouldn't think an A60H pulling two K-Tecs is a whole lot less of an outlay than purchasing a 651 scraper for instance. Those in the know, please let me know...

Hello Wayne,

it is just a guess, but I think the farm tractor and ADT pulled version of scrapers is much more affordable reguarding the purchase price than a classic motor scraper. Plus, the first two can be adjusted to the job size by adding or removing scraper units. So they offer a lot of flexibility to the contractor.

On the other hand, I can imagine that a motor scraper like a CAT 631 can be used under circumstances much harder and abusive then ADT or farm-tractor pulled scrapers. CAT even offered the 641 SA (Special Application) - a scraper exclusively manufactured for loading ripped rock. Here you need a machine with alot of metal to withstand all the punishment during loading. I have heard that a factory-fresh 657 can cost almost 2 million bucks. You have alot of steel, two engines, two automatic trannies, 4 planetary wheel drives, the gooseneck suspension system and on and on....

Imagine a CAT 657 pushed by two or three D9s - you have well over 2.000 HP and tremendous traction by four huge tires and three pairs of tracks. A payload of more then 65 tons is loaded in 20-30 seconds. I doubt that the farm-tractor/ADT pulled version will ever reach such productivity. But in lighter going, maybe even where ground pressure is an issue, ADT/farm-tractor pulled scrapers still offers you all the advantages of a self loading, hauling and dumping earth mover.

And then there is the track-type tractor pulled scraper as they are so popular in the UK. I think that is because in the UK, you have a lot of rain and mud and a well populated island. So quite short hauling distances where the lower speed of a track-type tractor just doesn't matter so much.


Hope this helps!

Max

I work for a mass excavation company in Arizona. Pretty much all we do is move dirt with scrapers, building subdivisions, solar farms, mines, and commercial developments. Scrapers are our bread and butter.

Here, pull pans with ag tractors and ADT's are really only used in soft material (but not totally dry) and long hauls from cut to fill (especially with ADT's).

Paddle wheels (623, 613) are used for balancing and finish work. They can cut accurately to the hundredth of a foot. Paired with a grader, they can finish 6000 square yards a day.

Single engine scrapers (631, 651) are used in hard material. We push them with D10's. Using a pushcat allows the traction of the dozer to transfer into force on the scraper bowl which will load ripped or blasted rock (or kaliche, which is super hard dirt, almost like concrete) 100 times faster than a dual engine system. They're pretty gutless, so short and flat hauls from cut to fill are a necessity. They also get beat up way more than a dual engine, so often contractors will use older machines and run them until the maintenance costs are higher than the money we make.

Dual engine scrapers (637, 657) are used where the material can be loaded quickly and the haul roads might be longer or uphill. In push/pull, a 657 pair is unbeatable in terms of raw earthmoving power. For example, we used a fleet of them to dig cells for the major landfills around here. 637's will usually be used alongside 631's but in another part of the cut, where the material is softer and self loading is more feasible. They're also more maneuverable than single engine scrapers because of the terrain they can handle.

Hope that's useful!

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-Adam