EFFECTIVE DATE: 4/14/2011 EXPIRATION DATE: 3/31/2013 

(Reissue of P08-V-2)

PROGRAM POLICY LETTER NO. P11-V-11

FROM: KEVIN STRICKLIN

Administrator for

Coal Mine Safety and Health

NEAL H. MERRIFIELD

Administrator for Metal and Nonmetal 

Mine Safety and Health

LINDA F. ZEILER

Acting Director of Technical Support

SUBJECT: Approval of Communication and Tracking Devices Required by 

the Mine Improvement and New Emergency Response Act of 

2006 (MINER Act)

Scope

This program policy letter (PPL) is intended for Mine Safety and Health Administration 

(MSHA) personnel, equipment manufacturers, repair facilities, underground mine 

operators, underground independent contractors, miner’s representatives, and other 

interested parties. 

Purpose

This PPL is issued to establish approval guidelines for communication and tracking 

devices under Title 30 Code of Federal Regulations (30 C.F.R.) Part 23, Telephones and 

Signaling Devices, to address the provisions of the MINER Act. This PPL is revised to 

clarify interpretations of the requirements of 30 CFR Part 23 and to ensure consistency 

with Program Policy Letter No. P09-V-01 “Guidance for Compliance with Post-Accident 

Two-Way Communications and Electronic Tracking Requirements of the Mine 

Improvement and New Emergency Response Act of 2006 (MINER Act)” issued on 

January 16, 2009.
2

Policy

The following guidelines are being administered by the Approval & Certification 

Center when processing applications for approval of communication and tracking 

products for those underground mines or operations required to have permissible 

equipment:

1. Any component or system used to provide voice, text, or signaling data (e.g., 

tracking) that is intended to remain operational in the event of an emergency is 

considered a telephone or signaling device and evaluated under 30 C.F.R. Part 

23.

2. Line powered devices must be equipped with a standby power source to allow 

continued operation in the event the line power is lost during an emergency. 

The standby power source must be capable of providing additional operating 

capacity (24 hours minimum) based on a 5% transmit time, 5% receive time

and 90% idle time, denoted as 5/5/90, duty cycle.

3. Untethered communication devices, such as hand-held radios, and 

individually worn/carried tracking devices, such as tracking tags, must 

provide at least 4 hours of operation in addition to the normal shift duration (a

minimum of 12 hours of operation) based on a 5/5/90 duty cycle. 

Additionally, these individually-worn/carried tracking devices must provide a 

low power warning. 

4. When operating under standby power, all components of a communication or 

tracking system must be MSHA-evaluated as intrinsically safe, or housed in an 

MSHA certified explosion-proof enclosure. Communication and tracking 

system components include any interconnecting cables. The standby power 

source must be intrinsically safe within 20 seconds after loss of line power. 

This would include the in-coming line power cable (back-feed protection).

5. The cable supplying power to the system and all cables between 

communication and tracking components must be MSHA-approved as flameresistant or enclosed in MSHA-approved, flame-resistant hose conduit. These 

cables must be protected from mechanical damage by position, MSHAapproved, flame-resistant hose conduit, metal tubing or troughs. Cables worn 

by the miner are exempt from these requirements.

6. All non-intrinsically safe cables of a communications and tracking system must 

be provided with short-circuit protection. Cables shall be protected against 

short circuits by devices set to trip at no more than 70% of the minimum 

available short circuit current. The clearing time of the short-circuit protective 

device must be less than the time required to cause cable damage by any short-
3

circuit or 10 seconds whichever is less. Cables supplied from non-intrinsically 

safe low-energy sources need not be protected by short-circuit protection 

devices provided:

a. The cable receives power from a Class 2-listed power supply (maximum 

voltage of 30 Volts and maximum power of 100 VA), and 

b. The output is protected with a fuse or circuit breaker with a trip setting 

less than or equal to the ampacity of the cable, and 

c. The system can identify short circuits in the cable and an operator can 

manually remove power from the cable. 

7. Large intrinsically safe batteries (greater than 5 kg) that are evaluated in 

accordance with the battery enclosure requirements of §§ 7.44(a), (b), (d), (e), 

(f), (h), (l) and (m) will not be subjected to the MSHA intrinsic safety drop test. 

8. Standby power sources that include rechargeable batteries must be designed or 

equipped with means to mitigate the explosion hazard of battery off-gassing. 

Examples of available mitigation techniques include venting of the enclosure 

or automatic de-energization when an explosive gas concentration reaches 20% 

of the lower explosive limit of the gas. 

9. A justification detailing the minimum safe distance to blasting circuits, 

detonators, and explosives must be provided by the approval applicant for any 

radio frequency (RF) device. One acceptable method of justification is through 

the calculation of the electric field strength and comparison of this value to the 

acceptable limits published by the Institute of Makers of Explosives (IME) in 

Standard Library Publication (SLP-20). For this calculation, the near field/far 

field boundary is assumed to be three times the wavelength of the radiate 

frequency unless the applicant justifies a different distance. The approval 

applicant must specify the maximum output power, normal operating 

frequency, maximum antenna gain and the minimum safe distance from 

blasting circuits, detonators and explosives. 

10. Person-wearable tracking tags are considered portable apparatus and therefore 

are subjected to the MSHA intrinsic safety drop test. Machine-mounted (asset)

tracking tags are subjected to an impact test. 

11. Cap lamps powering communication and/or tracking related components are 

required to meet the performance requirements specified in § 19.9(a) when 

both the cap light and communication and/or tracking component are in 

operation. To assure sufficient operational capability in various scenarios, the 

cap lamp battery should be capable of providing sufficient power to effectively 
4

operate the communication and/or tracking component for four hours beyond 

the 10-hour minimum for the cap lamp.

12. Where lightning arrestors for conductors between surface and underground 

locations are required, system approval documentation must specify the

lightning arrester used to comply with §§ 57.12069 and 75.521, and to ensure 

that it does not invalidate the Part 23 approval. 

Background

The regulations for approval of Telephones and Signaling Devices are specified in 30 

C.F.R. Part 23. 

The MINER Act included the following requirement for communications and tracking 

equipment:

“Not later than 3 years after the date of enactment of the Mine Improvement and 

New Emergency Response Act of 2006, a[n emergency response] plan shall, to be 

approved, provide for post accident communication between underground and 

surface personnel via a wireless two-way medium, and provide for an electronic 

tracking system permitting surface personnel to determine the location of any 

persons trapped underground or set forth within the plan the reasons such 

provisions can not be adopted.” 

The requirements in 30 C.F.R. Part 23 were intended for audible and visual 

communication devices. However, the concepts of safety and functionality in 

potentially hazardous atmospheres are also applicable to the communications and 

tracking equipment required by the MINER Act. MSHA has therefore provided these 

clarifying interpretations. 

Authority

Mine Improvement and New Emergency Response Act of 2006 (MINER ACT)

Filing Instructions

This PPL should be filed behind the tab marked "Program Policy Letters" at the back of 

Volume II of the Program Policy Manual. 

Internet Availability

This PPL may be viewed on the World Wide Web by accessing the MSHA home page 

(http://www.msha.gov) and choosing "Compliance Info" and "Program Policy Letters."
5

Issuing Offices and Contact Persons

MSHA, Approval and Certification Center

Kenneth Porter, (304) 547-2030

E-mail: porter.kenneth@dol.gov

Coal Mine Safety and Health

John Arrington, (202) 693-9549

E-mail: arrington.john@dol.gov

Metal and Nonmetal Safety and Health

Marvin Lichtenfels, (202) 693-9600

Email: lichtenfels.marvin@dol.gov

Distribution

MSHA Program Policy Manual Holders

Manufacturers of Mining Equipment and Mine Equipment Repair Facilities 

Miners’ Representatives

Underground Mine Operators

Underground Independent Contractors

Special Interest Groups