Key Operating Data 2006-8 (Please Register for 2008 data)

All Financial Data in US Dollars.
Black Hills Corp
  2006 2007
 Oil & Gas Operational
  Key Operating Data
     Production
       World Crude/NGL Output (Inc. Assoc. & Syncrude) (000 b/d) 1 1
       World Gas Production (Inc. Associates) (mmcf/d) 32 32
       World Crude/NGL/Gas Output (Inc. Assoc. & Syn.) (000 boe/d) 6 6
 
     Reserves
       Total Oil/NGL Reserves (mln bbls) 6 6
       Total Gas Reserves (bcf) 165 173
       Total Oil/NGL/Gas Reserves (mln boe) 33 35
 
     Drilling & Acreage
       Successful Exploration Wells (No.) 5 3
       Unsuccessful Exploration Wells (No.) 1 0
       Total Acreage (000 net acres) 394 436
 
     Refining & Marketing
 
     Key Operating Ratios
       Oil Reserve Replacement Ratio (Total Additions) (%) -177% 121%
       Oil Reserves/Production (years) 14 14
       Gas Reserve Replacement Ratio (Total Additions) (%) 414% 170%
       Gas Reserves/Production (years) 14 15
       Exploration Drillling Success Rate - World (%) 90% 92%