Is this a great idea? or a really bad idea?

I’m in Vermont. On my land I found a stack of slate roofing tiles. Actually two stacks it looks like someone went through them and made a stack of “good ones”. Good chance they came from a house that was once on the property.

I’m in the process of designing a kitchen cabinet that will be 23″ deep and 3′ wide. It can’t be normal depth because of a window in the way, that the cabinet will cut off at the bottom. My plan is eventually to replace window and once that’s done give the cabinet and the 1′ counter to it’s left a 4’contiguous counter.

So I need a “temporary” counter-top. I mean it might be 2-4 years before I do the actual window replacement.. with luck it will be next summer. Looks like I have to build it, since most premade counter tops are 25″ or more.

I was thinking about using the found roofing slate. It’s got holes but grout could fill them? I could color the group to match slate. I’ve never done tiling work – so suggestions are welcome. I’m assuming I’d make a wooden frame to hold the edges and the grout. And lay them on plywood???

Thanks