| U.S. Department of
Labor |
Mine Safety and Health Administration 1100 Wilson Boulevard Arlington, Virginia 22209-3939 |
 |
| EFFECTIVE DATE: April 19, 2012 | EXPIRATION DATE: 03/31/2014 (Reissue of PIL I10-V-04) |
PROCEDURE INSTRUCTION LETTER NO. I12-V-08
FROM: KEVIN G. STRICKLIN 
Administrator for
Coal Mine Safety and Health
SUBJECT: Roof Bolt Spacing
Scope
This Procedure Instruction Letter (PIL) applies to Coal Mine Safety and Health (CMS&H) enforcement personnel.
Purpose
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 operator 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 spacing that occasionally exceed the approved spacing pattern by less that 6 inches at intermittent locations and do not create a specific hazard should not be cited.
Background
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.
Authority
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
The PIL may be viewed on the World Wide Web by accessing the MSHA home page (www.msha.gov) and choosing "Compliance Info" and "Procedure Instruction Letter."
Issuing Office and Contact Person
Coal Mine Safety and Health, Safety Division
Johnny P. Calhoun, (202) 693-9507
E-mail: calhoun.johnny@dol.gov
Distribution
MSHA Coal and All-volume Program Policy Manual Holders
