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Federal Register: December 9, 1997 (Volume 62, Number 236, Page 64789-64790)


Mine Safety and Health Administration

30 CFR Parts 57 and 75

RIN 1219-AA94

Safety Standards for the Use of Roof-Bolting Machines in Underground Mines

AGENCY: Mine Safety and Health Administration, Labor.

ACTION: Advance notice of proposed rulemaking.


SUMMARY: Recent accidents in underground coal mines involving roof- bolting machines indicate the need to modify the design of such machines and require additional safety features. The accident history involving use of these machines prompted the Mine Safety and Health Administration (MSHA) to evaluate roof-bolting machines currently in use, primarily focusing on potential hazards to the machine operators during the drilling and roof-bolt installation procedures. As a result of the evaluation of accidents, MSHA is in the early stages of establishing design criteria and operating procedures for roof-bolting machines in underground mines. This notice seeks to obtain additional information and data on machine design, operating procedures, and miners' experiences with roof-bolting machines.

DATES: Submit comments on or before February 9, 1998.

ADDRESSES: Send comments to the Office of Standards, Regulations, and Variances, MSHA, Room 631, 4015 Wilson Boulevard, Arlington, Virginia 22203. Commenters are encouraged to submit comments on a computer disk or via e-mail to psilvey along with an original hard copy or via telefax to: 703-235-5551.

FOR FURTHER INFORMATION CONTACT: Patricia W. Silvey, Director, Office of Standards, Regulations, and Variances, 703-235-1910.


I. Background

An estimated 2,500 roof-bolting machines are currently in use at underground coal, potash, trona, and salt mines in the United States. The machines are used to install many types of roof bolts and other support materials into the mine roof.

Between January 1984 and April 1994, 16 fatal accidents occurred involving the operation and maintenance of roof-bolting machines. In a six-week period in early 1994, three operators of roof-bolting machines were killed while operating the machines in coal mines. Two were crushed between the drill head and machine frame while bolting the rib, and the other was crushed between the drill head boom and canopy when the fast-feed boom lift lever was inadvertently activated. Responding to these accidents, on April 4, 1994, MSHA formed and chaired the Roof- Bolting-Machine Committee (committee) with representatives from the U.S. Bureau of Mines and the West Virginia Office of Miners' Health, Safety, and Training, to review accident data, to visit mines to observe roof-bolting practices, and to interview miners. Additionally, the committee met with four major roof-bolting machine manufacturers, who provided data and technical information on machine design and function.

The study focused on boom and mast-type roof-bolting machines and did not include continuous mining machines with integral bolters. Primarily, the committee examined the potential hazards to the roof- bolter operators during the drilling and roof-bolt installation procedures.

Following this study, the committee issued a Report of Findings (Report) on roof bolter safety on July 8, 1994 outlining problems and potential solutions for reducing roof-bolting accidents. These findings are summarized below. Copies of the Report are available to the public at all MSHA district offices; from MSHA's Office of Standards, Regulations, and Variances, by calling 703-235-1910; and through MSHA's Home Page on the Internet, at

The committee was reconvened on October 21, 1996. The purpose of this meeting was to determine whether any new technology or design changes had occurred beyond those included in the committee's 1994 Report. The committee identified one design change, a new valve developed by a manufacturer to prevent its two-handed, fast-feed valve from being bypassed.

The committee also reviewed MSHA accident data for the period from April 1994 through December 1996. (The report covered January 1984 through March 25, 1994.) Although there have been numerous accidents and injuries, there have been no fatalities related to the operation of roof-bolting machines in either coal or metal and nonmetal mines since the issuance of the roof-bolter safety report. An analysis of the data confirmed that accidents directly related to the operation and maintenance of roof-bolting machines continue to occur.

II. Findings

The committee identified several roof-bolting-related problem areas which may have contributed to or caused the accidents. These included: (1) inadvertent actuation of controls, particularly the drill-head, fast-feed control lever, which contributed to approximately 50 percent of the fatal accidents; (2) work position location; (3) retrieval of drill steel; (4) resin insertion; (5) location of controls; and (6) control malfunction. In addition, the committee identified various other areas for improvement in future roof-bolting machine design.

III. General Issues

The committee developed ten possible solutions to address problems with existing roof-bolting machines. The solutions are as follows:

1. Installing two-handed, fast-feed controls that prevent actuation of drill-head feed controls while the machine operators are positioned in pinch-point areas.

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2. Installing a drill-head raise shutoff. This device would be installed in the drill-head raise pinch point and would immediately stop the hydraulic oil flow to the drill-head feed cylinder, thus preventing the feed cylinder from being raised and accidentally injuring the operator.

3. Installing auxiliary controls for the canopy raise/lower and boom swing functions to eliminate the pinch point where operators have been injured by the swinging boom.

4. Installing control guarding or double-acting fast-feed controls, or both, to prevent inadvertent activation.

5. Providing visual identification of pinch-point areas to alert the operator of the danger area.

6. Installing self-centering controls to prevent continued machine movement when the control lever is released.

7. Securing the rotating drill steels or wrench to prevent the operator from becoming entangled in these moving machine components.

8. Installing insertion/retrieval devices (resin insertion tools or drill steel retrieval) to eliminate the need for the operator to extend his body into a pinch point or climb onto the boom.

9. Standardizing location of controls to prevent inadvertent actuation of controls due to different roof-bolting machine control layouts.

10. Conducting a pre-operational inspection of machine controls to detect malfunctions prior to operation.

These possible solutions are intended to address the problems with roof-bolting machines and to prevent accidents. MSHA requests miners, mine operators, manufacturers, and other interested parties to comment on the qualitative and quantitative potential benefits and costs of compliance associated with adoption of these solutions, and any alternatives to these solutions.

Although MSHA is considering development of a proposed rule to address the hazards associated with roof-bolting machines, the Agency also solicits comment from the public on alternatives, other than rulemaking, to address safety hazards on roof-bolting machines used in the mines today.

IV. Specific Issues

Because a roof-bolting machine standard would apply to both coal and metal and nonmetal mining industries, commenters should provide specific justification for their positions based on sound engineering, work practices, and mining conditions. MSHA requests comment on the technological and economical feasibility and benefits of the solutions suggested in the Report of Findings and in this notice. Specifically, MSHA seeks input on the following issues: the current availability of technology to retrofit existing machines with two-handed fast-feed controls, double-acting fast-feed controls, control guarding, visual identification markers to alert the operator of the pinch point area, self-centering controls, or insertion/retrieval devices; the impact on the design and operation of existing machines if retrofitting were to be required; the impact of available technology on newly-purchased machines; the costs to manufacturers and mine operators of available technology; and any other information that is relevant to the findings in the Report. Commenters are encouraged to provide information specific to their mining conditions.

V. Impact

Executive Order 12866 requires that regulatory agencies assess both the costs and benefits of intended regulations, and propose regulations on the basis that the benefits justify the costs. Regulatory agencies also are required to base decisions on the best reasonably obtainable scientific, technical, economic, and other data and information concerning the need for and the consequences of the proposed regulations.

MSHA is in the early stages of developing a proposed rule. The Agency anticipates that the benefit of a safety standard addressing design criteria and operating procedures for the use of roof-bolting machines in underground mines would be the prevention of fatalities and injuries which occur when these machines are operated.

VI. Public Participation

MSHA requests comments on the specific issues addressed in this notice as well as those addressed in the Report of Findings. Interested parties are particularly encouraged to be as specific as possible in addressing each of MSHA's possible solutions and in suggesting alternatives to these solutions. MSHA also requests that commenters include specific examples and cost estimates to support their rationale to assist the Agency in evaluating and analyzing their comments.

List of Subjects in 30 CFR Parts 57 and 75

Mine safety and health, Underground mining.

Dated: December 3, 1997.
J. Davitt McAteer,
Assistant Secretary for
Mine Safety and Health.
[FR Doc. 97-32203 Filed 12-8-97; 8:45 am]