I am looking at a job that has some ledge, vertical shaley stuff but too tough to pick at. I dont have a ton of exp estimating chipping. Anybody have a good formula/experience. Soil is hard glacial till with shale and some Quartz and shist. Probably all in all about 200' of trench and maybe a 20 x 30 x 6ft cut with the last 2 of the 6 possibly being ledge. Thanks, John
we have a greenish rock around here that is almost indestructible... and it's usually just about a foot thick... I used a wrecking ball to break it... we have several hammers that are mounted to 200 and 270 john deere rocks a crap shoot.... some times it break when you look at it ..other times it an all day pound pound pound on the same rock.. we use splitters sometimes on boulder type rocks... blasting is always fun trenchers... well I've done 400' one day then the next day 40'... same area...about 6 to 8 foot deep... the rock was just harder... and this was with a 955 vermeer.... Can't really give a rate... I do know that a lot of jobs are bid with a "rock clause"... The inspector is called out .... measures the depth of rock... records it.. then goes on his merry way.
This is a tough one to answer, as there are lots of variables. What size machine and hammer do you intend to use? Perhaps a ex with a ripper can break through that stuff without the need for a hyd hammer. Hammers work most efficiently when there are two machines, one with a hammer and the other to dig out the loose material but that adds to the cost and if time is not a factor, then swapping attachments between one machine is more cost effective.