pscBISMARCK, N.D. (AP) – Montana-Dakota Utilities Co. is asking North Dakota regulators to approve a natural gas rate increase.
 
     MDU is seeking a 3.4 percent overall rate increase, which would raise $4.3 million a year more than current rates. If approved by the Public Service Commission, it would increase the monthly bill of residential customers by an average of about $3.50.
 
     The utility says it needs the rate increase to cover the cost of increased investment in natural gas facilities. MDU’s natural gas investment in the state is projected to be $212 million by the end of the year, up 15 percent from last year.
 
     MDU serves about 105,000 natural gas customers in 74 North Dakota communities.