Black Mountain is a fat-bottom, sludgy psyche rock band from Canada. Their second LP “In the Future” (Jagjaguwar) follows its predecessor’s footsteps to the T, which is a good thing because that syrupy combination of heft and power is not only compelling, it’s exhilarating and there isn’t enough of it. These are the kind of albums that muscle-heads listen to at the gym when they’re trying to bench press twice their body mass in front of a full-length mirror. Actually, they don’t listen to Black Mountain; they’re not that cool …