Theres a good chance Apple care will fix the repair but they may try to weasel out of it if they knew you were bit mining with it.
Would there be any basis for that though if there was no evidence of overclocking or warranty voiding modification? Just running a taxing program on a computer and having it die seems more like a design/manufacturing flaw. Apple seems to have a history of that happening with certain models, e.g. the G4 cube. I think they believe the noise of a fan detracts from the zen experience of using their computers, or something along those lines.