SecProbe.io

February 16, 2011
 David Emery Chief Executive Officer Black Hills Corporation 625 Ninth Street Rapid City, South Dakota 57701
Re: Black Hills Corporation
Form 10-K for the Fiscal Year Ended December 31, 2009 Filed February 26, 2010 File No. 1-31303

Dear Mr. Emery:
We have reviewed your letter dated January 27, 2011 in response to our comment
letter dated December 28, 2010 and have the following comments.  In some of our comments, we may ask you to provide us with information so we may better understand your
disclosure
.
 Please respond to this letter within te n business days by providing the requested
information, or by advising us when you will provide the requested response.  If you do not believe our comment applie s to your facts and circumstances please tell us why in
your response.
 After reviewing the information you provide  in response to these comments, we
may have additional comments.    Form 10-K for the Fiscal Year Ended December 31, 2009

 Items 7 and 7A. Management’s Discussion and Analysis of Financial Condition and
Results of Operations and Quantitative and Qualitative Disclosures About Market Risk,
page 68
 Oil and Gas, page 88

 1. We note your response to our comment th ree that your development of proved
undeveloped reserves “represented appr oximately 0.7 percent, 5.2 percent, and
8.3 percent of proved undeveloped reserves re flected in our reserve reports at the
beginning of the year for 2009, 2008 and 2007, respectively.”  This development rate – an average of about 5 percent ov er three years – indicates 20+ years are
required to develop your PUD reserves.  Rule 4-10(a)(31)(ii) states “Undrilled
locations can be classified as having unde veloped reserves only if a development

David Emery
Black Hills Corporation February 16, 2011 Page 2
 plan has been adopted indicating that they are scheduled to be drilled within five
years , unless the specific circumstances, ju stify a longer time.”  Item 1203(d) of
Regulation S-K requires that  registrants “Explain th e reasons why material
amounts of proved undeveloped reserves in individual fields or  countries remain
undeveloped for five years or more af ter disclosure as proved undeveloped
reserves.”  Please explain to us the step s you will take to comply with Rule 4-
10(a) and Regulation S-K.
 Item 8. Financial Statements and Supplementary Data, page 127

 Notes to Consolidated Financial Statements, page 136

 Note 21. Oil and Gas Reserves and Relate d Financial Data (Unaudited), page 201

Standardized Measure of Discounted Future Net Cash Flows, page 205
 2. In response eight, you present the “Pre viously estimated development costs
incurred during the period” for 2008 as $44.5 million which is about 32 percent of
the estimated future development costs pr esented in 2007.  However, this resulted
in the development of only 5 percent of your PUD reserves during 2008 as we noted in your response three.  Please expl ain to us the reasons for the difference
between your PUD development expend itures and the resulting PUD volume
conversion to developed status.
   You may contact Anthony Watson, Staff Accountant, at (202) 551-3318 or me at
(202) 551-3344 if you have questions regard ing comments on the financial statements
and related matters.  You may contact Rona ld Winfrey, Petroleum Engineer, at (202)
551-3704 about engineering comments.             S i n c e r e l y ,            /s/ William H. Thompson
William Thompson
        A c c o u n t i n g  B r a n c h  C h i e f