EXHIBIT 31.2 CERTIFICATION OF CHIEF FINANCIAL OFFICER AND
SECRETARY
PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT I, Craig R.
Mackus, certify that: 1.
I have
  reviewed this quarterly report on Form 10-Q of Bucyrus International, Inc.2.
Based on my
  knowledge, this quarterly report does not contain any untrue statement of a
  material fact or omit to state a material fact necessary to make the
  statements made, in light of the circumstances under which such statements
  were made, not misleading with respect to the period covered by this
  quarterly report;3.
Based on my
  knowledge, the financial statements, and other financial information included
  in this quarterly report, fairly present in all material respects the
  financial condition, results of operations and cash flows of the registrant
  as of, and for, the periods presented in this quarterly report;4.
The
  registrants other certifying officer and I are responsible for establishing
  and maintaining disclosure controls and procedures (as defined in Exchange
  Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial
  reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the
  registrant and we have:a)
Designed
  such disclosure controls and procedures, or caused such disclosure controls
  and procedures to be designed under our supervision, to ensure that material
  information relating to the registrant, including its consolidated
  subsidiaries, is made known to us by others within those entities,
  particularly during the period in which this quarterly report is being
  prepared;b)
Designed
  such internal control over financial reporting, or caused such internal
  control over financial reporting to be designed under our supervision, to
  provide reasonable assurance regarding the reliability of financial reporting
  and the preparation of financial statements for external purposes in
  accordance with generally accepted accounting principles;c)
Evaluated
  the effectiveness of the registrants disclosure controls and procedures and
  presented in this report our conclusions about the effectiveness of the
  disclosure controls and procedures, as of the end of the period covered by
  this report based on such evaluation; and    d)
Disclosed in
  this report any change in the registrants internal control over financial
  reporting that occurred during the registrants most recent fiscal quarter
  that has materially affected, or is reasonably likely to materially affect,
  the registrants internal control over financial reporting; and5.
The
  registrants other certifying officer and I have disclosed, based on our most
  recent evaluation of internal control over financial reporting, to the
  registrants auditors and the audit committee of registrants board of
  directors (or persons performing the equivalent function):a)
all
  significant deficiencies and material weaknesses in the design or operation
  of internal control over financial reporting which are reasonably likely to
  adversely affect the registrants ability to record, process, summarize and
  report financial information; andb)
any fraud, whether or not material, that involves management or other
  employees who have a significant role in the registrants internal control
  over financial reporting.Date: May 9,
  2006/s/ C. R.
  MackusCraig R.
  MackusChief
  Financial Officerand
  Secretary