Geothermal heating a good use of flooded Picadilly mine, report says

More than two years after Sussex was rocked by the closure of thePicadilly mine, the town is getting some good news about the mine itcan likely be used for geothermal heating.

Town officials are holding a public meeting Monday to discuss the results of a feasibility study commissioned in July into the energy possibilities ofthe mine, whichPotashCorp announcedin January 2016 was closing.

"I think the citizens of the greater Sussex region would definitely call that day in January as significant," said Scott Hatcher, chief administrative officer for the town."It was a blow to the local area.

"We've been working very hard and diligently to, not necessarily recover, but see if there are advantages that can be accessed with respect to future opportunities."

Looking at open-loop model

The mine in Penobsquis, near Sussex, was allowed to flood after operations ended there in 2016, and430 jobs were lost.

Geothermal heating involves extracting the heat of the water from inside the mine.

A company could then use that energy cheaply, making Sussex more attractive for new industry.

Hatchersaid it appears from the feasibility study that themodel that wouldmost benefit the town is something called an"open loop" geothermal system, which would involve directly extracting the hot water, drawn through a pipe.

"Once used, it would be injected back into the mine," Hatcher said.

The study suggested the town take this route instead of extracting the heat througha conductivemedium, such as a metal pipe submerged in the hot water, while leaving the water where it is.

20-acre greenhouse a possibility

The suggested open-loop system could heat a 20-acre greenhouse, with a supplemental boiler and10 refrigeration warehouses year-round, the study says.

The town would likely have to invest more than $11.3 million, Hatcher said, but the geothermal project would pay for itself in seven years.

There are caveats, though. The water has to be hot enough and plentiful enough to use.

AmecFoster Wheeler, theengineering and project management company recently acquired by Woods Group,won the contract to conduct the research for the town and has been studying the mine for several months.

The companyanalyzed how much heat the water absorbs and whether salt in the mine could cause any problemswith equipment or heat exchangers.

"We're assuming the mine is physically flooding, that there will be a source water there in the not-too-distant future," Hatchersaid.

When the mine was working, water had to be pumped out to keep things dry. The assumption the consultants and others have made is that by stopping the pumping, the mine will continue to flood.

He said the town isalso assuming the water is hot for use in a geothermal operation.

These assumptions have to be verified before any action is taken, Hatcher said.

No final decision

There are also questions about how the town would deliver the new energy.

One possible setup is a cost-sharing arrangement, where multiple businesses and municipal buildingswould hook up to the system, the way houses are hooked up to a single water system in a subdivision.

One of the more attractive possibilities described in the study isfor a giant greenhouse.

Of the $11.3 million the town expects to pay for the whole geothermal project,$5.7 million would go towardcreating the delivery system for the energy.

At the public meeting Monday a final decision will probably not be reached, said Hatcher.

The point, he said, is to inform people about the report and put the complicated technical language into layman's terms.

"We're hoping the consultant can deliver that in non-technical terms. To hit the highlights."