UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
(Amendment No. )*
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Mine Safety Appliances Company
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(Name of Issuer)
Common Stock
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(Title of Class of Securities)
602720104
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(CUSIP Number)
December 31, 2005
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(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:
[X] Rule 13d-1(b)
[ ] Rule 13d-1(c)
[ ] Rule 13d-1(d)
*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.
The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).
Page 1 of 11 pages
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CUSIP No. 602720104 13G Page 2 of 11 Pages
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1 NAME OF REPORTING PERSON
S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Columbia Wanger Asset Management, L.P. 04-3519872
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2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
(a) [_]
(b) [_]
Not Applicable
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3 SEC USE ONLY
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4 CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
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NUMBER OF 5 SOLE VOTING POWER
SHARES 3,472,300
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BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY 0
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EACH 7 SOLE DISPOSITIVE POWER
REPORTING 3,472,300
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PERSON 8 SHARED DISPOSITIVE POWER
WITH 0
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9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
3,472,300
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10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
[_]
Not Applicable
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11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
9.5%
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12 TYPE OF REPORTING PERSON*
IA
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CUSIP No. 602720104 13G Page 2 of 11 Pages
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1 NAME OF REPORTING PERSON
S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
WAM Acquisition GP, Inc.
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2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
(a) [_]
(b) [_]
Not Applicable
- --------------------------------------------------------------------------------
3 SEC USE ONLY
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4 CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
- --------------------------------------------------------------------------------
NUMBER OF 5 SOLE VOTING POWER
SHARES 0
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BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY 3,472,300
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EACH 7 SOLE DISPOSITIVE POWER
REPORTING 0
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PERSON 8 SHARED DISPOSITIVE POWER
WITH 3,472,300
- --------------------------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
3,472,300
- --------------------------------------------------------------------------------
10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
[_]
Not Applicable
- --------------------------------------------------------------------------------
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
9.5%
- --------------------------------------------------------------------------------
12 TYPE OF REPORTING PERSON*
CO
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Item 1(a) Name of Issuer:
Mine Safety Appliances Company
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Item 1(b) Address of Issuer's Principal Executive Offices:
121 Gamma Drive
RIDC Industrial Park
O'hara Township
Pittsburgh, PA 15238
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Item 2(a) Name of Person Filing:
Columbia Wanger Asset Management, L.P. ("WAM")
WAM Acquisition GP, Inc., the general partner of WAM ("WAM GP")
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Item 2(b) Address of Principal Business Office:
WAM and WAM GP are located at:
227 West Monroe Street, Suite 3000
Chicago, Illinois 60606
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Item 2(c) Citizenship:
WAM is a Delaware limited partnership and WAM GP is a Delaware
corporation.
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Item 2(d) Title of Class of Securities:
Common Stock
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Item 2(e) CUSIP Number:
602720104
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Item 3 Type of Person:
(e) WAM is an Investment Adviser registered under section 203 of
the Investment Advisers Act of 1940; WAM GP is the General
Partner of the Investment Adviser.
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Page 4 of 11 pages
Item 4 Ownership (at December 31, 2005):
(a) Amount owned "beneficially" within the meaning of rule
13d-3:
(i) WAM: 3,472,300
(ii) WAM GP: 3,472,300
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(b) Percent of class:
(i) WAM: 9.5%
(ii) WAM GP: 9.5%
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(c) Number of shares as to which such person has:
(1) sole power to vote or to direct the vote:
(i) WAM: 3,472,300
(ii) WAM GP: 0
(2) shared power to vote or to direct the vote:
(i) WAM: 0
(ii) WAM GP: 3,472,300
(3) sole power to dispose or to direct the disposition
of:
(i) WAM: 3,472,300
(ii) WAM GP: 0
(4) shared power to dispose or to direct disposition
of:
(i) WAM: 0
(ii) WAM GP: 3,472,300
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Item 5 Ownership of Five Percent or Less of a Class:
Not Applicable
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Page 5 0f 11 Pages
Item 6 Ownership of More than Five Percent on Behalf of Another Person:
The shares reported herein include the shares held by Columbia
Acorn Trust (CAT), a Massachusetts business trust that is advised
by WAM, a Delaware limited partnership. CAT holds 8.0 % shares.
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Item 7 Identification and Classification of the Subsidiary Which Acquired
the Security Being Reported on by the Parent Holding Company:
Not Applicable
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Item 8 Identification and Classification of Members of the Group:
Not Applicable
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Item 9 Notice of Dissolution of Group:
Not Applicable
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Item 10 Certification:
By signing below I certify that, to the best of my knowledge
and belief, the securities referred to above were acquired and are
held in the ordinary course of business and were not acquired and
are not held for the purpose of or with the effect of changing or
influencing the control of the issuer of the securities and were not
acquired and are not held in connection with or as a participant in
any transaction having that purpose or effect.
Disclaimer
In accordance with Rule 13d-4 of the Securities Exchange Act
of 1934, each of the persons filing this statement expressly
disclaim the beneficial ownership of the securities covered by this
statement and the filing of this report shall not be construed as an
admission by such persons that they are the beneficial owners of
such securities.
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Page 6 of 11 Pages
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.
Date: February 13, 2006
The undersigned corporation, on the date above written, agrees
and consents to the joint filing on its behalf of this Schedule
13G in connection with its beneficial ownership of the security
reported herein.
WAM Acquisition GP, Inc.
for itself and as general partner of
COLUMBIA WANGER ASSET MANAGEMENT, L.P.
By: /s/ Bruce H. Lauer
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Bruce H. Lauer
Senior Vice President and Secretary
Page 7 of 11 Pages
EXHIBIT INDEX
Exhibit 1 Joint Filing Agreement dated as of February 13, 2006 by and among
Columbia Wanger Asset Management, L.P., WAM Acquisition GP, Inc.
and Columbia Acorn Trust.
Page 8 of 11 Pages
EXHIBIT 1
JOINT FILING AGREEMENT
The undersigned hereby agree to the joint filing of the Schedule 13G to
which this Agreement is attached.
Dated: February 13, 2006
WAM Acquisition GP, Inc.
for itself and as general partner of
COLUMBIA WANGER ASSET MANAGEMENT, L.P.
By: /s/ Bruce H. Lauer
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Bruce H. Lauer
Senior Vice President and Secretary
COLUMBIA ACORN TRUST
By: /s/ Bruce H. Lauer
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Bruce H. Lauer
Vice President, Treasurer and
Secretary