Antimony plant offloaded at Port MacKenzie; up to 40 jobs planned

What you need to know:

• A mining company is building a small antimony processing plant at Port MacKenzie, with more than 40 containers of equipment unloaded Sunday. The plant is expected to employ about 40 people during assembly and processing and begin operating by fall of next year.
• The federally backed project will process antimony for defense and other uses. NovaMinerals received a $43.4 million federal grant for the plant, which will process and refine ore into antimony trisulfide. Antimony is considered a critical mineral used in munitions, batteries, semiconductors and flame retardants.
• The pilot plant could lead to a larger Alaska critical-minerals operation. If successful, NovaMinerals hopes to expand the facility into a commercial-scale plant and potentially process antimony from other Alaska deposits, making Port MacKenzie a regional hub for critical minerals.
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Equipment for a pilot plant at Port MacKenzie that will process antimony ore and employ about 40 people over the next two years was unloaded Sunday from a barge. 

The barge pulled into port at about 2 a.m., and more than 40 containers were moved ashore starting mid-morning, borough officials said.

“It’s probably our largest cargo offloading by barge,” said Dave Griffin, the port director.

Port MacKenzie is on Cook Inlet’s Knik Arm and is owned and operated by the Matanuska-Susitna Borough.

Over the next few months, the plant will be assembled at a site leased from the borough, and it is to be operating by fall of next year under an agreement with the federal government, according to Christopher Gerteisen, CEO of NovaMinerals, the company exploring a discovery of antimony and gold in the western Mat-Su region.

The federal government gave a $43.4 million grant to NovaMinerals for the project late last year. The pilot plant would process and refine ore into antimony trisulfide, a chemical important to the military for the manufacture of munitions and in advanced technologies, Gerteisen said.

Nova expects to hire up to 30 people to assemble the plant and up to 10 for the processing project, Gerteisen said.

Antimony trisulfide is a hazardous chemical that can cause skin irritation on contact, but workers in the plant will take protective measures. Nova has a minor source air quality permit from state environmental regulators, and the project is considered safe for local residents because of its location.

“Being in the Port Mac Industrial Commercial zone, we are well outside the distance thresholds for potential air quality impact to any residential areas,” Gerteisen said.

The material will be stored in sacks for shipping during the pilot plant stage. If the pilot program is considered successful and a larger plant is constructed, the project would instead use closed shipping containers, he said.

Antimony is considered a critical mineral, and U.S. defense officials have made securing a domestic supply a priority, moving away from imports as the primary source. Its uses include munitions, flame retardants, batteries and semiconductors.

The project is important to the borough and Port MacKenzie because it would be the first industrial manufacturing project established at the port, which is mostly used for bulk cargo and maritime support. If it is successful, NovaMinerals hopes to expand it into a larger commercial-scale plant, Gerteisen said.

Port MacKenzie, located directly across Cook Inlet from the Port of Anchorage, has historically struggled to become the industrial hub Mat-Su Borough officials envision. The Nova plant, paired with news of federal funding for port improvements and the stalled port rail line, could help turn that around.

NovaMinerals has been exploring a gold discovery on a large block of state mining claims for several years and maintains an 80-person camp and support facilities at the 3,800-foot Whiskey Bravo airstrip west of Skwentna.

The antimony deposit was found while the gold exploration was underway, Nova officials said. The two metals are often found together.

Scientists at the University of Alaska Fairbanks’ Institute of Northern Engineering are assisting NovaMinerals with technical aspects of antimony processing.

Gerteisen said work is continuing on the gold find with three mineral exploration drill rigs and about 60 people at the site this summer, but NovaMinerals is also making antimony a priority because of its importance to national defense and the financial support provided by the federal government.

Bulk ore samples stored at the mine site will be moved to Port MacKenzie either by air or by winter trail when cold weather sets in, officials said. The company will do a preliminary sorting of raw ore near the mine using technology to identify higher-grade material for shipment to Port MacKenzie, Gerteisen said.

The plant itself involves a process of crushing and milling the ore to a small size for further processing using techniques that are conventional in mining operations. A second stage involves refining the product to a fine powder as antimony trisulfide.

Gerteisen also said the pilot plant will test the processing of ore not only from NovaMinerals’ Mat-Su deposit but also from antimony deposits near Fairbanks, where the metal is also found in association with gold. The company’s vision is that the plant would become a regional support “hub” for critical minerals mined in Alaska.

The pilot plant will also be a new power customer for Matanuska Electric Association, with a requirement of about 3 megawatts of electricity. MEA already has power infrastructure at Port MacKenzie.

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