They were putting up tables at hundreds of booths Tuesday, preparing for the big GJX jewelry and gem show.

Workers put coverings on the table tops, stapled skirts to them and hung up signs for the exhibitors, among them: Noor Gem Japan Ltd., RC Gemas Ltda. of Brazil, and from Los Angeles, the elegantly named 1-800 Loose Diamonds.

All of it took place inside two giant, high-tech tents, between West Cushing Street and Interstate 10 downtown. No, it was not in a permanent exhibition hall.

For more than 20 years, Allan Norville has been talking about building a gem-show exhibition hall on his downtown property. Then, in 2014, he made that exhibition hall part of his winning proposal to the Rio Nuevo board to redevelop the land next to his property, a parcel east of I-10, between West Congress Street and Cushing known as the arena site. In Norville’s proposal, made under the name of his company Nor-Generations LLC, he said that if he won, construction would begin on the exhibition hall in March 2015.

It has not happened.

There are, of course, reasons — there are always reasons for these things.

Norville did not want to explain the reasons for the long time it is taking to build anything on the property he owns there, or on the adjacent property that he vigorously competed for at the Rio Nuevo board. He referred me to attorney Pat Lopez, who has been working with Norville on the project for years. Lopez said there’s not a single, simple reason that neither the exhibition hall nor the adjacent property has had construction work begin.

“It’s not one thing. It’s not that any one of these things is outrageous. It’s the cumulative effect of all of them,” Lopez said.

The first thing was moving the Greyhound bus station off the formerly city-owned site next to the freeway, which took until March 2017.

The second thing, Lopez said, “was the Roadrunners wanted a practice facility. Nor-gen spent time, money, effort trying to do that. For various reasons, that fizzled.

“The third thing was the idea of putting a soccer stadium on the site. Not a Nor-Gen idea, but ... to be a good citizen, they worked on that.”

None of these ideas panned out, Lopez said. So Nor-Generations has gone back to the original ideas: Housing, a hotel, maybe parking and retail on the parcel along the highway, and an exhibition hall on the property Norville has owned for years alongside Cushing. The exhibition hall would not just serve as a gem-show location but could also be useful for conventioneers — it’s directly across the street from the Tucson Convention Center.

A clock is ticking, but not that quickly.

Under the terms of the deal that Rio Nuevo struck with Nor-Generations on Jan. 27, 2015, the company has a deadline to invest $10 million in “hard construction costs” such as buildings, parking and infrastructure. The deadline to do so is 42 months after the Greyhound bus station was moved off the arena site and into its new building just south of the corner of Euclid Avenue and East Broadway. Since that move happened in March 2017, the deadline is September 2020, about 20 months from now.

If the company doesn’t perform at least $10 million of work by then, it will owe the Rio Nuevo district $2.5 million. The company has put in a good bit of money on drainage work, but nothing else that would count. And it is well aware of the pressure to start performing, which has come from some of the same people who also asked it to explore alternative uses such as an ice rink.

When I asked Rio Nuevo board vice chairman Mark Irvin about progress on the site, he said, “We not only share that concern but have advised them of that concern.

”We’re doing everything we can to help Allan, but it’s time for him to get going,” Irvin said.

City Councilman Steve Kozachik said the delay in moving forward has made whatever project Norville does more feasible, because hotels and other projects have gone up downtown in the meantime, and the Tucson Convention Center has ever more activity.

“He’s sitting on a really prime piece of land, especially with the anchor tenants at the TCC,” Kozachik said. “He’s in a great position, and not under a rigorous time frame to perform.”

Lopez said that with the other, fizzled proposals behind the company, it now has a good chance to get started.

“Just recently we worked on a contract that we hope will be finalized that we hope will result in development on the site,” he said.

“Things are definitely moving forward.”

Let’s hope so. Back in 2014, when developers Ron Schwabe and Norville were competing for the arena site, I warned that Schwabe had a stronger record of getting projects done. Norville didn’t like my opinion when I mentioned it to him at the time. What he said then resonates with me as a sort of warning to me now, because he referenced the modern tent structures his company puts up every year for the gem show as evidence the company gets things done.

“We’ve built, every single year, a 120,000-square-foot building. We use every square inch of that property for the gem show.”

That was impressive for a decade or two. Not so much anymore.

Contact: tsteller@tucson.com or 807-7789. On Twitter: @senyorreporter