Pond Boss Forums POND CONSTRUCTION Soil questions Shale rock as stone

I was planning on harvesting bits of shale rock from the creek bed and use it fill a sidewalk and parking area. The shale rock pieces are about the size of a finger tip. There will be no top or base material only shale pieces on subsoil. Does anyone here have any experience or knowledge of shale rock and its use in construction?

jmf

It's soft, crumbly, and tries to turn back into the clay from whence it came if worked/loaded heavily, in my experience. It makes good sidewalk chalk for kids, though.

It depends on the type of shale. There are very soft shales sometimes called claystone that are little more than highly compressed clay. They revert back to clay in a hurry.

I am working on a project now with good Devonian Age shale (250 mil years old) that is very hard and makes great road base. We built a road with 18" of this stuff and it can carry very heavy trucks.


Bang on the shale you plan to use with a hammer. If it doesn't break easily its probaly good.

I can take a pliers and easily crush the pebbles, would this suggest claystone rather than Devonian Age shale? BTW, I am located in western New York State.

jmf

I am located in East Aurora where is your project? If you are in Farnham soil you must be over in Evans or Brant. That is all Devonian aged shale although some of it is quite weathered. We have used this nmaterial for road base on a number of projects with good results.

I am in Orchard Park. The material is the same material as that found in creek wash after a hard rain. Can this be Devonian aged shale if I can easily crush it with a pliers?

jmf

jmf, all the shales in OP are Devonian age and unless excessively weathered make good road base. Typically the top 1-3' of the shales areound here are weathered. As you travel south on the 219 you will see some good sections exposed in the rock cuts.

So you think the creek wash, is Devonian even though it crushes easily with a pliers? Also would you recommend it as a parking lot, I mean can I drive on it without crushing it into clay or having it stick to the tires when wet? I think maybe you are talking about shale left in place after removing the subsoil and I'm talking about those little shale bits (rounded and worn) that get washed down the creek that you can shovel like gravel. But yes, I have removed the subsoil to the Devonian layer, and now I am thinking about filling the last four inches with weathered creek wash (bits of shale) as the finished stone surface.

jmf