For many years geologists have known about a huge deposit of non-ferrous metals in Northeastern Minnesota.

Now a perfect storm of circumstances has created a situation making it worthwhile to go after them.

George Kessler continues our special report on the earth's crust with a look at the process for extracting the bounty.

At the start, the process is a lot like mining taconite.

So you basically take a four or five foot slab and crush it down to the size of your fist, and there are two more stages of crushing in the fine crusher where you go from fist-sized to the size of your thumbnail.

There's two stages of grinding in the concentrator, a rod mill and a ball mill, and when it comes in here it's about a half inch, and when it comes out of the ball mills it's about face powder consistency.

Here's where the process goes high tech... The fine powder is fed into a series of tanks where it is separated from the waste rock by flotation- with bubbles in a special liquid floating the valuable minerals to the top, where they're skimmed off.

The next step is to feed the concentrated material into vessels where it will be heated and subjected to high pressures.

This causes a reaction which liberates the metals from the sulfur.

The solution is then run through a series of tanks where the various minerals are separated out.

They aren't in a useable form at this point, and require further processing to finish the extraction.

Right now Polymet only plans to purify the copper portion of the solution through a process known as electro-winning.

There's tanks underneath here, and these are stainless steel plates that are lowered down into the slot.

And you have this solution that's pregnant with copper, you add an electrical charge, the particles get excited and slap against the plate and in about 4-8 days you get an eighth inch to a quarter inch of copper on each side of the plate, you pull 'em up, pop it off and they go back in.

The copper that comes off the plates is well over 99% pure, and easily sold to a wide variety of customers.

Nickel can be extracted using a similar method, but for the near future it will be more cost effective to ship it elsewhere for final processing.

It's a complicated and technically demanding road from the mine pit to the final customer, but it's now possible, and it opens a whole new vista for a part of our region.

On the Iron Range, George Kessler, the Northland's News Center.

If you're still wondering about the gold...around 10,000 ounces a year will be produced.