Question: Where does an 860 billion ton iceberg go? Answer: Wherever it wants!

It's MASS is 860 billion tons and 700 billion tons respectively, its weight is 0 tons and 0 tons respectively other wise they would have sunk. They're NEUTRALLY BUOYANT. With no ocean currents and no winds I could move them around with a pocket fan.

All the question here is whether you can anchor the icebergs against the forces applied by ocean currents and the wind. The fact that these icebergs weigh nothing due to their buoyancy is the problem here, no one would have given a shit if they sank.

Asimov had a short story once in which spacecraft propulsion was dependent on water as fuel, and a colony on Mars (in response to an anti-space-exploration political movement on Earth) started harvesting huge chunks of ice from the outer solar system, wrangling them into Martian orbit with webs of high-strength cabling (and using some of the ice in the process as fuel to move it all around) and letting them crash down in uninhabited areas (where, under Mars' lower gravity and frigid temperatures, they'd hold together enough to be mined for water).

I don't suggest hanging it on strings just pinning it. Hundred was also a symbolic (a lot) rather than real number.