Question About Milling Rock?

Hey all, I am working on the conceptual design for a rapid bridge replacement project in NH. The major issue with this location is not the bridge....its the profile of the roadway. To meet modern standards for vertical curves, grades, and sight distance, the road needs to come down up to 2.5 feet for several stations. The problem is.....bedrock is only 5' below the existing road grade. Due to the need to accelerate this replacement (only detour is 12 miles), we are looking into the feasibility of milling the bedrock down to grade. Drill and blast is not going to happen here. Being in the Northeast, surface mining equipment like Vermeer Terrain Levelers aren't common. Can a modern cold planer mill rock (Diorate, slightly weathered....its the Granite State!)?

Yair . . . CraneInnovation You mention two and a half feet has to come off . . . how many square yards at that depth and is it a contiguous mill run or in different sections. Cheers.

Scrub Puller said: Yair . . . CraneInnovation You mention two and a half feet has to come off . . . how many square yards at that depth and is it a contiguous mill run or in different sections. Cheers. Click to expand... Scrub Puller.....looking at 2700 square yards. That's not all at 2.5-3', it tapers to nearly zero on the ends. Basically 700' of road at a roughly 35' width. Probably half of it is NOT going to interfere with bedrock, but we're hampered with sparse info. Only two borings in this area....one near the end of our cut area has bedrock below 30' below grade....200' farther in and around the middle of our cut has bedrock at 5'.

Yair . . . Gotcha CraneInnovation . The reason I asked is because once in another life me and two equally brainless mates carved a road through solid granite boulders with Husky/Stihl saws and jack hammers, about 200 square metres all told with up to five feet of cut on the topside. It was in the early days of those saws and blades and I don't know how blades we broke and we dusted/burnt out a couple of engines . . . the point I make is that with gear available these days in the way of rocksaws and hammers for excavators that old carpentry method of sawcuts and a chisel may another option and it may be easier to hire gear in for than the mill approach. Cheers.

I've milled concrete with a Wirtgen W2100 and specialized teeth with no issues. I'm sure you could mill the rock if you set the mill up properly, perhaps some extra water and HD teeth.

Wouldn't it be in your best interest to do some more borings of your own ? Or some test holes with a backhoe of some sort ?

Try this company. I'm sure they have something that will do the job. http://alpinecutter.com/en/

And Vermeer has some too. https://www.youtube.com/watch?v=U4ad6QsXZEU

Here you go....... https://www.heavyequipmentforums.com/showthread.php?52601-With-the-Giant-Rock-Cutters-Of-Texas

Vermeer Terrain Leveler, Tesmec Rock Hawg, and Trencor Road Miner will all do the job. They are modified rock trenchers with a large drum equipped with 38mm shank teeth rather than the 20mm tools used for road planning.