The company I work for is contemplating purchasing an acre of land that has alot of rock showing. Are there any rules of thumb for the cost to demo a cubic yard of rock without using dynamite? I am not sure a 300 sized trackhoe with a hammer will get this rock. I have some experience with this rock at another site down the road but we just had to remove a small amount of it that was in the way of a retaining wall. We used 90lb hand jack hammers and it was not easy. I have searched the forum for the alternate ways to remove rock but wouldn't mind hearing any additional comments on what ways you all think are best. Thank you for your time.
first you take the size of the machine in tons, lets say a 30 ton machine. and it will take a pile of money that weighs about the same, to get the rock out. j/k rock is expensive and there isn't really a unit cost with hammering. blasting you can get in to formulas. because it is boring x amount of holes plus moving x amount of material. a hammer is hit or mis unless you have alot of time in that kind of rock with that machine, then you will need to rebuild the hammer which will kill your budget.
What kind of rock is it? If its sedimentary say like sand stone and the layers are one to three feet thick you can start at a fracture, and work into it pulling out layers,the layers form horizontal and vertical you need to study it like a puzzle before you begin. If its solid bed rock drill and blast. If its bed rock with fractures running through it with no order,a big hammer 1000 to 1500 pound can make progress,as far as cost goes its as unpredictable as the fractures in the rock,drill and blast easyer to figure cost.
Thank you both for the replies. I can't use dynamite. There are houses behind us and commercial buildings next door. It is solid bedrock. What do you all think about the alternate techniques that you drill and then fill with water and then stick a very small explosive in the hole and the since water does not compress it supposedly fractures the rock. Do you all have have any experience with that and do you think I can make any time that way? Again thanks for you time.
How deep do you need to go down Below the surface ?or are you just getting it level? How much rock is sticking up above surface? How close are the buildings? Do they have basements? Witch direction in relation to the rock formation are the buildings?, in other words are the buildings built on or into the same rock formation?
I don't know how close your neighboring buildings are, but there are specialized blasting companies that do the "loading and shooting" routinely, though probably for a healthy price. Fewer and fewer contractors do their own blasting--the large quarry operation, the surface mines, the highway contractors, subdivision builders, and pipeline builders around here almost all contract the blasting out, though they might do their own drilling. Modern delay caps/charge wiring distributes the blast impulse so that the maximum seismic force is much reduced. Even the coal miners use "gentle" blasting for the overburden, to avoid shattering the fragile coal below. On the other hand, a large hammer for days and days shakes the neighborhood and creates dust that can be a bigger problem than blasting--I've seen contractors shut down for using hammers and then forced to blast by the local authorities. I'm sure every town/county is different. . . but I wouldn't give up on blasting without looking into it further.
You could us the expanding powder, need to create a glory hole first so the expanding powder has some place to push the rock (brake it) you will still need a hammer to break up the cracked rock, it brakes the rock into a puzzel with inter locking faces would need a huge excavator to pry the rock apart with out a hammer breaking it up. May be able to use the expanding gas cartarges they have very low ground vibration and air over blast, but you will still need to create a glory hole (starter hole that the rock can push into while its being moved by the expanding gas), but for that the expanding gas you will need ATF explosive license to purchase it, and blasting insurance to use it. I like the idea of contacting a blasting company, you drill it they provide manpower and material to break rock, today thats probabily the most cost effect way of doing it. Rock cost big money no way around it.
Could you drill several vertical holes close together and break it up with a hammer? MTI sells a line of excavator mounted drills that fit 4 ton and larger machines that would easily drill the holes. The other thought depending on how high the rock is, is to drill a line of horizontal holes across the bottom and pop it up in a couple pieces. I have seen expanding mortar and things like that, but you still need to drill holes into solid bedrock to use them.
Do you have a rough idea what a small drill attachment goes for?
The smallest unit runs about $60k, options extra. Recommended for a 4 to 10 ton excavator. Expensive for a single job, unless you will have a future use for it. We also have models capable of larger diameter and deeper holes. If you think you may be interested send me an email to [email protected] and I will email you the information. Include a contact number and I will call you.
Has anyone tried this expanding grout stuff? Dexpan: http://www.dexpan.com/index.aspx Bustar: http://demolitiontechnologies.com/
Yes I have used Dexpan and about 1/2 dozen other brands. It works good if you know how to use it and in the right application. Dexpan even has some of my job photos on there web site. Hear are some pics of a reinforced wall and a 8' Tall 3' wide at the top 5' wide at the bottom sea wall we just finished demo.
OK, I'll ask the question, how does it work? how fast is it and what do you have to know in order to use the stuff? How do you dispose of it after your done, is it a one shot deal and after that its junk, I mean for reusing the concrete as fill material, is there any lasting effects that a person needs to worry about?
For the smaller areas, Instead of 90'lb jackhammers, Use pnuematic sinker drills and a Hydraulic rock spliter. Its much easier than breaking your bones with a 90. If U have a whole bunch of rock another option besides powder is the expansion grout. The brand I used was called Daemite. Only u are gonna need a nice face, or ledge, and make sure theres no standing water in the area at time you pour it in the holes.