0001130464-02-000026 8-K 2 20020524 4 20020531 BLACK HILLS CORP /SD/ 0001130464 4911 460458824 SD 1231 8-K 34 001-31303 02667718 625 9TH STREET PO BOX 1400 RAPID CITY SD 57709 6057212343 625 9TH STREET PO BOX 1400 RAPID SD 57709 BLACK HILLS HOLDING CORP 20001222 8-K 1 form8k_401k.txt ACCT CHG - RETIREMENT SAVINGS PLAN EX-16 3 ex16form8k_401k.txt ACCT CHG - 401K