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

After Sussex was rocked with the news the Picadilly mine would be closing, citizens are now getting some good news – the flooded mine can likely be used for geothermal heating.

The core idea behind geothermal heating involves extracting the heat of the water deep inside the mine.

Officials in Sussex are hosting a public meeting Monday to discuss the results of a feasibility study commissioned in July into the future possibilities for the now-closed Picadilly potash mine. (CBC)

More than two years after Sussex was rocked by the closure of the Picadilly mine, the town is getting some good news about the mine —  it can 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 of the mine, which PotashCorp announced in 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, and 430 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.

Hatcher said it appears from the feasibility study that the model that would most 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 through a conductive medium, 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 and 10 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.

Scott Hatcher, chief administrative officer for the town, said a new report suggests geothermal heating is feasible for the flooded mine. (Scott Hatcher/Submitted)

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

Amec Foster Wheeler, the engineering 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 company analyzed how much heat the water absorbs and whether salt in the mine could cause any problems with 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," Hatcher said.

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 is also 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 buildings would 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 is for a giant greenhouse.

Of the $11.3 million the town expects to pay for the whole geothermal project, $5.7 million would go toward creating 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."

About the Author

Joseph Tunney

Joseph Tunney is a casual reporter for CBC News in Saint John. He can be reached at joe.tunney@cbc.ca