now what to do. Start doing it."

Sandra's blonde head was very close to Hilton's brown one as they both
stared into Hilton's plate. "Why, they look like giant armadillos!" she
exclaimed.

"More like tanks," he disagreed, "except that they've got legs, wheels
_and_ treads--and arms, cutters, diggers, probes and conveyors--and
_look_ at the way those buckets dip solid rock!"

The fantastic machine was moving very slowly along a bench or shelf that
it was making for itself as it went along. Below it, to its left,
dropped other benches being made by other mining machines. The machines
were not using explosives. Hard though the ore was, the tools were so
much harder and were driven with such tremendous power that the stuff
might just have well have been slightly-clayed sand.

Every bit of loosened ore, down to the finest dust, was forced into a
conveyor and thence into the armored body of the machine. There it went
into a mechanism whose basic principles Hilton could not understand.
From this monstrosity emerged two streams of product.

One of these, comprising ninety-nine point nine plus percent of the
input, went out through another conveyor into the vast hold of a vehicle
which, when full and replaced by a duplicate of itself, went careening
madly cross-country to a dump.

The other product, a slow, very small stream of tiny, glistening black
pellets, fell into a one-gallon container being held watchfully by a
small machine, more or less like a three-wheeled motor scooter, which
was moving carefully along beside the giant miner. When this can was
almost full another scooter rolled up and, without losing a single
pellet, took over place and function. The first scooter then covered its
bucket, clamped it solidly into a recess designed for the purpose and
dashed away toward the city.

[Illustration]

Hilton stared slack-jawed at Sandra. She stared back.

"Do you make anything of that, Jarve?"

"Nothing. They're taking _pure_ uranexite and _concentrating_--or
converting--it a thousand to one. I _hope_ we'll be able to do something
about it."

"I hope so, too, Chief; and I'm _sure_ we will."

"Well, that's enough for now. You may take us up now, Captain Sawtelle.
And Sandy, will you please call all department heads and their
assistants into the conference room?"

* * * * *

At the head of the long conference table, Hilton studied his fourteen
department heads, all husky young m