Bronco Drilling Company, Inc. Announces Monthly Operating Results

OKLAHOMA CITY--(Business Wire)--
Bronco Drilling Company, Inc. (Nasdaq/GM:BRNC) announced today
operational results for the month ended and as of March 31, 2008.

Utilization for the Company's drilling fleet was 74% for the month
of March compared to 70% for the previous month and 73% for the fourth
quarter of 2007. The Company had an average of 45 marketed drilling
rigs in March compared to 45 in the previous month and 48 for the
fourth quarter of 2007. The average dayrate on operating drilling rigs
as of March 31, 2008, was $16,657 compared to $16,891 as of February
29, 2008, and $17,258 for the fourth quarter of 2007.

Utilization for the Company's workover fleet was 75% for the month
of March compared to 74% for the previous month and 75% for the fourth
quarter of 2007. The Company had an average of 50 marketed workover
rigs in March compared to 48 in the previous month and 42 for the
fourth quarter of 2007.

The Company cautions that several factors other than those
discussed above may impact the Company's operating results and that a
particular trend regarding the factors above may or may not be
indicative of the Company's current or future financial performance.

About Bronco Drilling

Bronco Drilling Company, Inc. is a publicly held company
headquartered in Edmond, Oklahoma, and is a provider of contract land
drilling and workover services to oil and natural gas exploration and
production companies. Bronco's common stock is quoted on The NASDAQ
Global Market under the symbol "BRNC". For more information about
Bronco Drilling Company, Inc., visit http://www.broncodrill.com.

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Bronco Drilling Company, Inc.
Rig Status Report
as of March 31, 2008

Est. Duration
(2)
---------------
Rig Rig Status
No. Horsepower Type Basin (1) Contract Days Date
---- ---------- ----- --------- ------ ------------ ---- ----------
1 2 400 hp M I
2 4 950 hp M Piceance O Term 239 11/25/2008
3 5 650 hp M Anadarko O well to well
4 6 650 hp M Anadarko O Term 332 2/26/2009
5 7 650 hp M Woodford O well to well
6 8 1000 hp E Williston O well to well
7 9 650 hp M Arkoma O Term 276 1/1/2009
8 10 1000 hp E Anadarko O well to well
9 11 1000 hp E Woodford O well to well
10 12 1500 hp E Anadarko O well to well
11 14 1200 hp E Woodford O Term 102 7/11/2008
12 15 1200 hp E Cotton O well to well
Valley
13 16 1400 hp E Anadarko O well to well
14 17 1700 hp E Anadarko O well to well
15 20 1400 hp E Anadarko O well to well
16 21 2000 hp E Woodford O 3 wells
17 22 1000 hp E Woodford O well to well
18 23 1000 hp E Piceance O 3 wells
19 25 1500 hp E Woodford O 2 wells
20 26 1200 hp E Anadarko O 3 wells
21 27 1500 hp E Piceance O Term 210 10/27/2008
22 28 1200 hp E Anadarko O 3 wells
23 29 1500 hp E Woodford O 3 wells
24 37 1000 hp E I
25 41 950 hp M Anadarko O well to well
26 42 650 hp M Anadarko O well to well
27 43 1000 hp M Cotton O Term
Valley 82 6/21/2008
28 51 850 hp M Anadarko O well to well
29 52 850 hp M Anadarko O well to well
30 53 850 hp M I
31 54 850 hp M Woodford O Term 415 5/20/2009
32 55 1000 hp M Anadarko O 3 wells
33 56 1100 hp M Anadarko O well to well
34 57 1100 hp M Woodford O Term 355 3/21/2009
35 58 800 hp M Cotton O well to well
Valley
36 59 850 hp M I
37 60 850 hp M I
38 62 1000 hp M Anadarko O well to well
39 70 450 hp M Anadarko O well to well
40 72 750 hp M Barnett O 6 wells
41 75 750 hp M Woodford O Term 136 8/14/2008
42 76 700 hp M I
43 77 1200 hp M Anadarko O 2 wells
44 78 1200 hp M I
45 97 850 hp M Anadarko O well to well

M - Mechanical I - Idle
E - Electric O - Operating
1 Rigs classified as "operating" are under contract while rigs
described as "idle" are not under contract but are being actively
marketed and generally ready for service.
2 The estimated contract duration is derived from discussions with
our customer regarding their current projection of the days
remaining to complete the project.
Changes from the prior month are highlighted.
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Important Information

On January 23, 2008, Bronco Drilling Company, Inc. entered into a
merger agreement with Allis-Chalmers Energy Inc. ("Allis-Chalmers"),
providing for the acquisition of Bronco by Allis-Chalmers. In
connection with the proposed merger, Allis-Chalmers filed a
registration statement on Form S-4 (Registration No. 333-149326) with
the Securities and Exchange Commission (the "SEC") on February 20,
2008, and filed an amendment to such registration statement on Form
S-4 with the SEC on March 27, 2008, which registration statement
contains a joint proxy statement/prospectus of both companies.
Allis-Chalmers and Bronco may file other relevant documents concerning
the proposed merger, including any amendments to such registration
statement. INVESTORS ARE URGED TO READ THE JOINT PROXY
STATEMENT/PROSPECTUS AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE
SEC, BECAUSE THEY CONTAIN IMPORTANT INFORMATION REGARDING THE MERGER.
Investors and security holders may obtain a free copy of the joint
proxy statement/prospectus and the other documents free of charge at
the website maintained by the SEC at www.sec.gov.

The documents filed with the SEC by Allis-Chalmers may be obtained
free of charge from Allis-Chalmers' website at www.alchenergy.com or
by calling Allis-Chalmers' Investor Relations department at (713)
369-0550.

The documents filed with the SEC by Bronco may be obtained free of
charge from Bronco's website at www.broncodrill.com or by calling
Bronco's Investor Relations department at (405) 242-4444.

Investors and security holders are urged to read the joint proxy
statement/prospectus and the other relevant materials before making
any voting or investment decision with respect to the proposed merger.

Allis-Chalmers and Bronco and their respective directors and
executive officers may be deemed to be participants in the
solicitation of proxies from the respective stockholders of each
company in connection with the merger. Information about the directors
and executive officers of Allis-Chalmers and their ownership of
Allis-Chalmers common stock is set forth in its proxy statement filed
with the SEC on April 30, 2007. Information about the directors and
executive officers of Bronco and their ownership of Bronco common
stock is set forth in its proxy statement filed with the SEC on April
30, 2007. Investors may obtain additional information regarding the
interests of such participants by reading the joint proxy
statement/prospectus for the merger.

THIS PRESS RELEASE IS NOT AN OFFER TO SELL THE SECURITIES OF
ALLIS-CHALMERS AND IT IS NOT SOLICITING AN OFFER TO BUY THESE
SECURITIES.

Cautionary Note Regarding Forward-Looking Statements

The information in this report contains forward-looking statements
within the meaning of Section 27A of the Securities Act of 1933, as
amended, and Section 21E of the Securities Exchange Act of 1934, as
amended. These forward-looking statements include, but are not limited
to, comments pertaining to estimated contract duration. Such
statements are subject to risks, uncertainties and assumptions,
including, but not limited to, early termination by the customer
pursuant to the contract or otherwise, cancellation or completion of
certain contracts or projects earlier than expected, operating hazards
and other factors described in Bronco Drilling Company, Inc's. Annual
Report on Form 10-K filed with the SEC on March 17, 2008 and other
filings with the SEC, which are available free of charge on the SEC's
website at www.sec.gov. Bronco cautions you that forward-looking
statements are not guarantees of future performance and that actual
results or developments may differ materially from those projected or
implied in these statements.

Bob Jarvis
Investor Relations
Bronco Drilling Company, Inc.
(405) 242-4444 EXT: 102
bjarvis@broncodrill.com

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