BLOOMINGTON, MINN. — Miller Milling Co. is closing its flour mill in New Prague, Minn., at the end of December.

“This decision was very difficult, given the quality and long-serving tenure of New Prague’s employees,” said Takuya Mitani, chief executive officer. “However, this step is necessary so Miller Milling can focus its attention and investment on expanding the business of its other mills.”

The mill, with 18,000 cwts of daily flour milling capacity, is one of six operated by Miller Milling. The closing will reduce the company’s aggregate capacity to 88,000 cwts from 106,000, based on figures in Sosland Publishing Company’s 2020 Grain & Milling Annual.

The company cited the mill’s age and location as primary factors behind the decision to cease production. The mill is 123 years old. According to the U.S. Department of Agriculture, the operating rate of Minnesota flour mills was 69.7% in July-September, the lowest in the United States and compared with a national average of 82.9%.

“Despite the tremendous work of our team at the mill, the age and location of the facility significantly limited our ability to supply customers in a cost-effective manner,” Mr. Mitani said. Mr. Mitani was named c.e.o. of Miller Milling in November.

The New Prague mill was one of four acquired by Miller Milling Co. in 2014 from ConAgra Foods, Inc. and Cargill. The four had a combined capacity of 58,600 cwts, more than doubling the U.S. milling capacity of Miller Milling, which has been owned since 2012 by Nisshin Seifun Group.

In addition to New Prague, the mills acquired in 2014 are located in Commerce and Oakland, Calif., and Saginaw, Texas. In 2016, Miller Milling began a project expanding capacity at Saginaw. The Saginaw project has been completed, and the mill now has daily capacity of 24,000 cwts. Miller’s other flour mills are located in Fresno, Calif., and Winchester, Va.

The New Prague mill was built in 1896 with 1,000 cwts of daily milling capacity and is located about one hour southwest of Minneapolis. The mill originally was named New Prague Flouring Mill Co. and was renamed International Milling Co. in 1910. The business, later renamed International Multifoods Corp., grew to be one of the largest milling and ingredient companies in the United States. Its mills were sold to ConAgra (now Conagra Brands) in 1988.