I have been working on a site preperation job for about a week now and we have encountered a rock bluff right where the house foundation is going. The rock is a mixture of decomposing granite and hard granite. I have to take it down about 6' in back and 3' in the front. The pad is about 75' by 120' in size. I can break chunks out with a 315 and I can rip small chunks of it with a 5N dozer. I do not have a hammer on a excavator available. I called all the rental yards and im at least a month out on getting a excavator and hammer. I can get a brand new D8T with a single shank ripper. Price is the same on both. I have ripped shale with a older D8k but have never tried granite with a newer D8T. Has anybody ever tried one in granite. I called the blasters and they were 3 weeks out as well. I have a deadline on this project. Any suggestions?:beatsme
Do you happen to know the seismic velocity of the material? Cats performance handbook says your good till 6k fps, marginal to 8, and leave alone after that... I'd imagine that if you can get it up with a 5n, then an 8t should play with it. I'd think that a ripper on a dozer would be more efficient than breaking it all up with a hammer. What about a ripper tooth on a 330 size hoe? Do you have other work for the d8 other than the basement ripping? From watching 8t's in limestone and shale, you shouldnt be there for more than a short morning, and thats with using the 8 to push the rock out as well.
There is not a single large hoe within 400 miles to rent. I don't know the the volocity of the rock. I can use the dozer for other parts of this project which would help my bottom line. My 250 kolbelco was doing as good as the 315 when trying to chunk it out.
The definite answer yes or no would be in the seismic velocity of the rock, but if as you say a 5N will take chunks out of it an 8T ought to lift it out in lumps the size of a table top. When you say the 5N will take "small chunks out of it" - is that the decomposing material or the hard granite..? If it's the hard granite I would reckon an 8T would rip it out no trouble. A lot might depend also on the width of the track shoes on the 8T, the narrower the better for ripping in my experience, you get more ground pressure.
I think the 8 should work, and if you cant rip them you can just push the chunks out!
I think you should be ok with a 8T. Unless your out in the Dover area with all that wonderfull granite. That stuff out west of town is tough to rip even after its been blasted! (I'm from Naples)
We call granite solid Canada here. Usually needs drilling and blasting to deal with it. This area is mostly granite, part of the Canadian Shield. Unusual to even see rippers on a dozer here.
If the rock is solid ,no natural fractures it will be tough.the best method with the ripper would be to locate the natural fracture point of the rock and work from that point on.
I would call the nearest CAT dealer. They should be familiar with the terrain and machine capabilities. Or be able to direct you to sources that can give seismic data, etc. Can't hurt to ask.
Awww, yep i am up in Elmira off Bloom Lake Rd.
Ill let you guys know how she went tomorrow. I take some pics and post them up. I have located a 320 hoe and a 5000 lbs hammer. So at least I have a plan B.
so... how did it go?
Gottcha. Built a few little spurs up behind the gate up past the lake about 12 years ago with a 6C (no ripper):Banghead and a 200 Komatsu with new teeth. Should'nt have any trouble with a new 8T.:thumbsup
So I'm curious about what happened. Did you get a D8 or use an excavator? Great info here on rippability and how to test with a knife or hammer. http://www.lonestarbit.com/mining/415n.pdf The ripping stuff is at the bottom pg 196 but especially pgs 201-209.
you just really need to watch the track spin. granite is very bad on them!! and buy some extra boots with it. have fun!