In our spotlight on Business Report tonight.

Don't expect the commute on Route 80 to improve any time soon.

Eastbound lanes are still shut down by exit 15 near Wharton, with traffic being detoured due to ongoing emergency repairs to a sinkhole which began to buckle in early February.

Since then, the State Department of Transportation says it's discovered nearly 100 other potential voids that will need to be investigated and possibly repaired.

It's all linked to abandoned mines from the days of being an iron producing state.

Ted Goldberg has the latest on the emergency work and why parts of New Jersey are so prone to these sinkholes.

There's no sugarcoating it.

Driving around the construction on I-80 is an absolute slog.

It's a slow process.

Corridors that normally take about 3 to 4 minutes are taking 45 minutes, 50 minutes, depending on, you know, time of day.

Drivers going east on I-80 are rerouted because of ongoing construction work concerning a sinkhole and an underground void associated with a long abandoned mine.

Roxbury Mayor Sean Pattillo says additional traffic from trucks and commuters is more than just annoying.

Businesses have told me that they're down 15, 25% in the last two weeks.

That congestion is certainly leading to, you know, residents maybe not wanting to come out and go and stop at our local restaurants or stop at our local store.

And it's a it's a it's unfortunate butterfly effect of what's happening due to the traffic.

New Jersey has about 600 abandoned mines statewide, most of them iron.

The mines themselves generally don't collapse because they're so far underground, but the mine shafts do, especially if they're not covered in concrete.

If it's done properly, especially with the cap, which is the big concrete piece, you can pretty much do anything you want.

Yeah, Interstate building, you know, anything you want over top.

These mines weren't made with the best of, you know, regulations to keep them.

Okay.

And so that's the problem now, is you got people building houses and roads and things like that on something that may not be as stable as you would hope.

Alec Gates is a distinguished service professor at Rutgers.

Newark and says it's no coincidence that these abandoned mines are clustered around the mountains of northwest Jersey or the Highlands.

The early railroads were made out of iron, you know, with iron from the Highlands.

So the Highlands is a really important area, strictly as far as producing higher part of the rocks.

And there were more volcanic rocks which contained a lot of iron.

And then it just took off in the whole region, became just peppered with iron mines.

After a better iron was found in the Midwest and Minnesota, New Jersey's mines closed one by one.

But not before the land was seriously disturbed.

In some places.

In a star drill where they hammered this building out and they packed it with dynamite and boom, they blew everything up and then picked through it and got all the magnetite out.

So the problem with that, of course, is it weakens all the rock around the.

When you're blasting through these things.

Some mines were capped properly in Wharton.

These buildings are built on top of abandoned mine shafts and haven't fallen into the earth.

Other mines were not properly capped and instead filled with things like trees.

I guess they figured they would hold up forever because they were so big and thick.

You know, if it was a hardwood, like an oak or an ash, sometimes they would fill the hole with steel.

They would drop up, they would cut up a boxcar or a train car.

Sam Morris is the mayor of Mind Hill, a three square mile township with 18 abandoned mines.

One of them had a mine shaft cave in about a decade ago.

You pull up here now, you go into their sidewalk and they scratch everything.

But this was a really large mine hole.

But we repaired it correctly.

You can find other holes nearby that are either abandoned mine shafts or look like them.

That's an apartment complex and that's a crater in the ground.

It's about.

It's about car.

Sized.

Let's put it this way.

Is it a mine?

I don't know.

But I can tell you that is a very scary subsidence.

It's definitely a dangerous hole.

I mean, that's more than just a hole That looks like it.

It collapsed.

Professor Gates says abandoned mines can and do pose problems.

But it's not terribly common for them to cave in so dramatically.

For regular houses, most of the time you're going to be okay.

But for any of those things, big buildings, big construction, big highways, those things are the ones that are going to cause the problems.

Mayor Pattillo says Roxbury and surrounding towns have asked the state to step in and provide relief for businesses.

The Department of Transportation did not give us a comment by deadline and says repairs are at least weeks away.

In Morris County, I'm Ted Goldberg.

NJ Spotlight News.