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U.S. Department of Labor          

Mine Safety and Health Administration
1100 Wilson Boulevard
Arlington, Virginia 22209-3939                    

EFFECTIVE DATE:  December 12, 2008 EXPIRATION DATE:  03/31/2010


                        Administrator for
                       Coal Mine Safety and Health

SUBJECT:     Roof Bolt Spacing

This instruction letter applies to Coal Mine Safety and Health (CMS&H) enforcement personnel.

The purpose of this letter is to provide guidance to CMS&H enforcement personnel for the inspection of roof bolt spacing specified in approved roof control plans.

Procedure Instructions
When evaluating roof support spacing to determine compliance with an approved roof control plan, enforcement personnel should measure the lengthwise and crosswise distances between roof bolts. Inspection personnel should use reasonable judgment in determining from these measurements whether enforcement action is appropriate.

The Agency recognizes that roof bolt spacing specified in a plan represents nominal dimensions and that reasonable tolerances for installation are permitted. To require roof bolt operators to reach inby and make exact measurements may introduce hazards. Therefore, an occasional inadvertent deviation that slightly increases the spacing of roof bolts but does not detrimentally affect support performance may not constitute a violation. Typically, roof bolt spacings that occasionally exceed the approved spacing pattern by less than 6 inches at intermittent locations and do not create a specific hazard should not be cited.

Permanent roof support systems approved in roof control plans are designed to ensure a minimum safe standard for the installation of roof support appliances. The Agency recognizes, however, that under normal mining circumstances inadvertent deviations can occur in the installation of roof bolts as a result of machinery limitations or human error. When this occurs the integrity of the support system may not be necessarily compromised.

Section 302 of the Federal Mine Safety and Health Act of 1977, as amended, and 30 U.S.C. Subpart 862; 30 C.F.R. pt 75, Subpart C.

Internet Availability
This PIL may be viewed on the World Wide Web by accessing the MSHA home page (www. and choosing "Compliance Info" and "Procedure Instruction Letter."

Filing Instructions
Mine Safety and Health Administration (MSHA) personnel should file this procedure instruction letter behind the tab marked "Procedure Instruction Letters" in the binder title MSHA Program Policy Handbooks and Procedure Instruction Letters.

Issuing Office and Contact Person
Coal Mine Safety and Health, Safety Division
Casey A. Sears, (202) 693-9530

MSHA Coal and All-Volume Program Policy Manual Holders
CMS&H Special Interest Group

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Mine Safety and Health Administration (MSHA)
1100 Wilson Boulevard, 21st Floor
Arlington, VA 22209-3939
Phone:    (202) 693-9400
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