Limestone Excavation

sitegrader

I'm new to this site and hope to gain some insight in pricing limestone rock excavation. I'm an excavating contractor who runs several JD 9520's with pull pans and have always avoided projects with a lot of rock excavation mainly because the tractor and pan setups don't do rock. Most of my projects are in the 150,000 cy dirt range and are relatively easy to calculate. My next project will involve excavating approximately 246,000 cy, of which 136,000 cy is North Texas Limestone. This material typically has a blow count of 0-5 feet of rock-100 blows/inch, 5-10 feet of rock-100 blows/1/2 inch, and over 10 feet is typically 1/4 inch per 100 blows. All of the material excavated will be used onsite as processed fill.

My plan of attack is to use a D-8R to rip the rock, large excavator and 6X6 trucks to load and transport onsite, and an 825 to compact in place. My preliminary estimate has me around $4.25 per cy to rip, load, haul, place, water and compact. Has anyone had any experience with this quantity of material at todays fuel prices? I've searched TXDOT historical bid data but can't seem to find anything that quantifys rock excavation. Any suggesstions would be appreciated.

Cole

Where in North Texas would this be at?

Welcome to the site!

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sitegrader

Project is located in West McKinney area.

tgeb

Welcome to the site.

Sorry...I can't help you out on this one. Our jobs are all very small.

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rino1494

Seems pretty cheap to me for rock excavation. That is the approximate rate per yd that we get for dirt. I couldn't imagine having a ripper tractor on the job. That D8 would add about another $1 - $1.25 per yd. How much yardage do you figure for a 8 per day ?? We figure around 1200 yds ripped and pushed.

Of course, I am in a different area with different overhead. I have a large rock job coming up prolly next year. I would know better then, but of course that would be too late. Also, the haul distances play a big impact.

Also, I have never worked with limestone, so I do not know the characteristics of the rock. Is it rippable rock ?? Are you planning to give it a little bump with powder to break it up a bit to enable the 8 to do its job ?

BTW.....welcome to the site !!!

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kapena

Instead of a D8, why not use two excavators? One should be outfitted with a hoe ram when the limestone needs ripping.

jmic

There's a lot of different characteristics to limestone. I've seen it where you could dig through it with a hand shovel, but again a couple years ago I did one job where a hammer hoe had all it could do to break it up. It was right next to an existing house so blasting was not an option.

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rino1494

It is simply not cost effective to run a hammer on large projects like this. It would take forever. Good idea though

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sitegrader

Thanks for the input on my post about limestone excavation. I've come to the conclusion that one large rip tractor isn't going to be enough. Based on ripping and processing 1500 cy per day, this becomes a 90 day job that the owner wants completed in under 60 days. We've never been able to utilize blasting in this area to help loosen the material but good idea anyway. The area we will be excavating the bulk of the rock in covers 8 to 9 acres, with the shallowest cut of 2.50 feet and the deepest cut of 21.50 feet so we need to be able to cover alot of area as quickly as possible.

The limestone in this area is rippable material. Processing time can be a major factor in that sometimes the material will breakout in thin small pieces and then sometimes you get material the size of truck tires. I have one operator who has a lot of experience ripping and processing rock, which may be my lifesaver on this project. Any other suggestions are still appreciated.

kapena

I have never seen a multiripper bucket in action, but it seems like a good idea.

http://www.leadingedgeattachments.co...pperbucket.htm

jmic

That would be good if he was digging a trench, but for what this guy is talking about that bucket would be useless.

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