The nickel and copper sulphides were not solid when they were deposited. I don't know what was said that might have suggested that they were part of a solid chunk that was pushed along by the flowing magma, but that's not the process that led to the Eagle 1 deposit.
The nickel and copper sulphides separated out of the peridotite flow because they have different properties, something like oil separating from water, or cream rising from whole unhomogenized milk. The difference here is that the ni/cu sulphides don't float on the magma, they sink out of it. Kind of like upside down cream and milk. In this case, the good stuff is heavier, and sinks.
As the magma flowed through what must have been irregular gaps in the older granitic rocks, the conduit was anything but a uniform tube. It had narrow points where the flow was rapid, and wider regions where the flow could slow. Wherever it slowed enough, or where there was a dip in the conduit, the nickel and copper were afforded an opportunity to collect together in a pool at the bottom. As the molten sulphides cooled, they cooled slowly enough to solidify into visible crystals of pentlandite and chalcopyrite.
The Eagle 1 deposit is not lens shaped, as it would be if it formed in a large pocket (magma chamber) within the host rock, so it can be presumed to be a smaller sample that formed directly in a conduit. There's a pretty good likelihood that there is a far larger body of the same sulphides, the mother lode if you will, that would have settled out of the magma in a magma chamber.
Lar
