The company formerly known as Aquila has begun work on a $120,000 natural gas system improvement project in Spencer.

About 50 customers will see occasional service interruptions over the next four weeks, according to a statement the company released Friday. The project will include replacement of 2,100 feet of older gas main and 50 gas service lines.

Black Hills Energy officials said the work will take place on West Fourth Street between Fourth Avenue West and Ninth Avenue West and on Eighth Avenue West between West Fourth Street and West Fifth Street.

"We appreciate the patience and understanding of our customers while this work is being done, and apologize in advance for any inconvenience this project may cause," said construction coordinator Doug Wittrock. "We'll do our best to accommodate our customers and will work as quickly and safely as possible to complete the project to minimize inconvenience."

When the project is complete the company said upgrades will increase system integrity and the safe and reliable delivery of natural gas.

Black Hills Energy serves 150,000 natural gas customers in 130 Iowa communities.