EFFECTIVE DATE: 05/07/2012 EXPIRATION DATE: 03/31/2014 

 (Reissue PIL I10-V-07) 

PROCEDURE INSTRUCTION LETTER NO. I12-V-07 

FROM: GEORGE H. GARDNER

 Acting Director of Technical Support 

 KEVIN G. STRICKLIN

 Administrator for

 Coal Mine Safety and Health

SUBJECT: Reissue of I10-V-07 - Tensioned Cable Bolts 

Scope

This Procedure Instruction Letter (PIL) applies to Coal Mine Safety and Health 

(CMS&H) District Managers and coal mine enforcement personnel. 

Purpose

This PIL establishes procedures to evaluate tensioned cable bolts for use as required 

support for compliance with Title 30 Code of Federal Regulations (30 C.F.R.) § 75.204(b) 

and 75.221(a)(9). 

Procedure Instructions

Because tensioned cable bolts are not addressed in ASTM F32-95 CMS&H District 

Managers shall evaluate requests for approval of tensioned cable bolts. In determining 

whether to approve tensioned cable bolts, the District Manager should base his decision 

on the demonstration or tests specified in 30 C.F.R. § 75.204(b). These tests or 

demonstrations may include: 

Component Tests: Laboratory tests should be conducted to determine the strength and 

compatibility of all of the individual components of the cable bolts. Any components 

covered by ASTM F432-95 must meet those specifications. The manufacturer should 

specify all other components. Any changes to the original components or additional 
components added to the support would warrant additional testing. Once a specific 

design has been successfully tested, no further testing should be required unless the 

quality of the components is suspected of being inferior. 

Installation Procedure: Roof bolter operators should be trained in safe handling and 

proper installation techniques. In-mine testing should be conducted to determine if the 

supports can be installed safely and reliably. These tests should ensure that the safety 

of the operator is not jeopardized during the handling and installation of the tensioned 

cable bolts. 

Pull Tests: Underground pull tests should be completed to determine the anchorage 

capacity and displacement characteristics of the support for the anchor length used. If 

the anchor length or type is modified, additional anchorage tests should be conducted. 

Tension Tests: Underground tests should be conducted to determine the installed load 

range of the supports and verify that the tension level can be achieved and maintained 

as required in 30 C.F.R. § 75.204(f). These tests should be done with a load-measuring 

device that is capable of indicating the installed load of the support. Any anomalies 

that occur during the test, e.g. spring-back, should be noted in order to determine the 

effect on the installed load and the ability to comply with the regulations. 

Test Area: Depending on the District's experience with tensioned cable bolts as 

required support and the roof conditions at a specific mine, a test area may be 

warranted. If deemed necessary, a test area could be established to demonstrate the 

effectiveness of the tensioned cable bolts. A test area can range from an area of the mine 

where a number of bolts are installed for observational purposes up to a fully 

instrumented area monitoring roof sag and bolt loading. 

Based on District experience with the test area, the District could then review the tests 

or demonstration results of the bolts at the mine for possible inclusion in the mine's roof 

control plan. 

The Mine Safety and Health Administration (MSHA) shall require that tensioned cable 

bolts, approved as required support, list specifications in the approved roof control 

plan. Technical Support will be available to assist in the evaluation of tensioned cable 

bolts. Some manufacturers have multiple designs of tensioned cable bolts. Listing a 

specification in the roof control plan will eliminate confusion between MSHA and the 

mine operator regarding the approval of a particular tensioned cable bolt. The listed 

specifications should include the following: 

• Each component of the system should be specified including all dimensions. For 

example, if a threaded tube is used, the tube length, tube thread strength, and 

thread length should be listed. 
• A drawing depicting all components used with the system. This drawing should 

show the location of each component. 

• For the cable itself, the plan should have a specification that includes the type of 

strand, (e.g. 7-strand epoxy coated), a minimum strength requirement, and the 

head/housing should be capable of breaking the cable without failing. 

• Each cable bolt should have a marking to identify the length, manufacturer, and 

type of cable (epoxy, galvanized, or etc.). 

• Minimum resin cartridge length (actual length of the cartridge and not the

grouted length), cartridge diameter and hole diameter should be listed. 

• The installation procedure and remedial action if a bolt is improperly installed. 

For example, if the bolt is not properly tensioned, the head sprung back, or a 

spinner occurs, then another bolt should be installed. 

• Tension range and a method of determining it in order to comply with 30 C.F.R. 

§ 75.204(f)(4) of the regulations. Also, a procedure should be established to 

verify this method.

Background

Tensioned roof bolts have been used successfully to control mine roof since the 1940s. 

Tensioned cable bolts represent a unique and somewhat complex approach to this wellestablished means of roof control. The key elements of these supports are substantial 

anchorage, the ability to be tensioned, strength of components and the installation of 

long supports without couplings. 

The ability to maintain tension is an essential component to any partially grouted 

system used as required support. It has been determined that several factors should be 

addressed when considering tensioned cable bolts as a required roof support system. 

Additional factors may also need to be considered to address mine specific conditions, 

such as highly corrosive mine water in the roof strata. The component tests and 

demonstration may then require an evaluation of the measures to be taken to arrest or 

slow corrosion or to limit the expectations as to the safe, useful application life of a 

specific roof support appliance. 

Authority

30 C.F.R. Part 75.204(b) 

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

Pittsburgh Safety and Health Technology Center

Roof Control Division

William J. Gray, (412) 386-6787 

E-mail: gray.william@dol.gov

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