Implementation of MINER Act for Communication and Tracking Using MSHA’s Program Policy Letter (PPL) P09-V-01 as Guidance Salwa El-Bassioni Electrical Engineer.

Implementation of MINER Act for Implementation of MINER Act for Communication and Tracking Using Communication and Tracking Using MSHA’s Program Policy Letter (PPL) MSHA’s Program Policy Letter (PPL)

P09-V-01 as GuidanceP09-V-01 as Guidance

Salwa El-BassioniElectrical Engineer

May 14, 2009

MINER Act RequirementsJune 15, 2006

• A redundant means of communication with the surface, such as secondary telephone or equivalent two-way communication.

• Above ground personnel to determine the current, or immediately pre-accident location of all underground personnel.

MINER Act RequirementsJune 15, 2009

• Post-accident communication between underground and surface personnel via wireless or alternative to wireless, PPL provisions.

• Electronic tracking system to determine location of persons trapped underground

Untethered Devices

• One device for each group of miners working or traveling together.

• One device for any miner working or traveling alone.• How many would we need on a working section?

– One device for each group working or traveling together and one device for each miner working or traveling alone. For example; on advancing sections, each CM operator, roof bolter crew, and scoop operator would need their own device.

Untethered Communications Device

Miner

Continuous Miner Section

Feeder

Advancing Section

Longwall

Miner

Untethered Communications Device

Longwall

Coverage for Two-Way Communications

• Throughout the working section.– Miners inby the loading point are able to communicate

with the surface.

• Continuous in each escapeway.– Primary and secondary.

• 200 foot zone inby and outby strategic areas.– Strategic areas = where miners are normally required

to work or likely to congregate in an emergency.

Coverage ComplianceMesh System

Components of a mesh system:• Untethered devices (radios).• Nodes (wired/wireless or both).• Antennas• Power supplies.• Gateway nodes, hub or controller on the surface.• Communication facility on the surface for monitoring

network.

Note: power supplies used in areas where permissible equipment is required must be IS or in X/P enclosures.

Mesh SystemIf a node fails the system reconfigures itself and determines a new route

Mesh SystemA power supply and/or battery backup required at each node

Power Source

Two-way Communication Coverage

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Primary EscapewaySecondary Escapeway

Node/ Antenna

Feeder

Belt

Two-Way Communications: Longwall

Node / Antenna

Coverage Compliance LF System

Components of a Leaky Feeder:• UHF and VHF Radios• Power supplies • UHF amplifier• VHF amplifier• Surface base stations• Splitters• Antennas• Termination units

Note: power supplies used in areas where permissible equipment is required must be IS or in X/P enclosures.

Leaky Feeder

Miner 1 Transmitting

Miner 2 Receiving

Radiating Mode

Coupled Mode

Functions as a power line, communications link, and a distributed antenna

Leaky Feeder: CM Section

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Primary Escapeway

Secondary EscapewayFeeder

Antenna

Belt

Leaky Feeder

Leaky Feeder: Longwall

Primary Escapeway

Secondary Escapeway

AntennaLeaky Feeder

Longwall

Coverage ComplianceMedium Frequency (MF) System

Components of MF system:

• Conductors in a mine (track, metal pipes..)

• Hand held radios

• Base transmitter (transceiver in central area)

• Repeaters (transfers frequency)

• Node (repeater used in a network)

Coal Seam

Metal Pipes/Conduits

Tracks/Rails

Medium Frequency (MF) Radio Communications

• Doesn’t require special cable.• Radio signal couples to other conductors to increase

range.

• UHF signal is converted to/from MF signal

• MF Signal is carried by un-powered conductive infrastructure in mine

Medium Frequency RepeaterMedium Frequency Repeater

Survivability

Redundant pathways to surface:

• One system with two or more pathway to the surface.

• Two or more systems installed in two or more entries and different pathways to the surface.

Survivability = Redundancy

One system, two Pathways

Mine Shafts

Leaky Feeder

Primary Base Station

Secondary Base Station Overland Link

One Node-Based Mesh System with two pathways

Belt

Track

Antenna

UHF LF Cable - Trunk 1

Escapeway

Two Leaky Feeder systems in multiple entries

UHF LF Cable - Trunk

2

Belt

Track

Low-cost LF Cable

Antenna

UHF LF Cable

Escapeway

Coverage extension using low-cost cables and antennas

Electronic Tracking Coverage

Types of tracking:

• Zone-based– RFID tags and readers

• RSSI -based – Using nodes as those from communication

system.

Conventional Tracking

Miner wears a tag:Radio frequency ID (RFID)Needs ‘readers’ of tags

Miner A

Miner B

RFID Reader

Operation of conventional RFID:• Reader senses tags that are

within range• Tag transmits a unique ID• Detected tag IDs are sent to

the surface

• Tag location is associated with the reader’s known location and displayed on the tracking computer

Tag

Miner A

Miner B

RFID ReaderTag

Operation of reverse RFID:

• Tags transmit RFIDs

• Reader receive RFID from tag(s)

• RFID from reader & tag transmitted to comms system

• Comms system relays reader and tag information to surface

• Tracking computer calculates and displays reader positions

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Electronic Tracking Guidance

• Coverage in working section within 200 feet – Readers or nodes are 400 feet apart.

• Coverage in escapeways– Readers or nodes every 2000 feet

• Coverage in strategic areas– Within 200 feet of where miners are normally required

to work or likely congregate in an emergency.– Belt drives, loading points, SCSR caches, etc.

RSSI-Based Tracking(Node-based Systems)

• Error = difference between estimated and actual location.

• MSHA expects that errors in tracking locations may exist and will work with mine operators until compliance with the MINER Act is gained.

Zone-Based Tracking(Reader-based Systems)

Conventional and Reverse RFID

Error = difference between reported and actual position

• Accuracy of tracking is affected by:– tracking system update rate– motion of miners – reader or tag spacing – Interference

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2,000 ft.

400

ft.

400 ft.

Feeder

Secondary EscapewayPrimary Escapeway

Node / Reader

Belt

Electronic Tracking Coverage

Electronic Tracking Coverage: Longwall

2,000 ft.

2,000 ft.

400 ft.

400 ft.

Secondary Escapeway

Primary Escapeway

Node / Reader

Emergency Response Plan ERP

• No later than June 15, 2009 the ERP must, among other things, provide for:

• Post accident two-way communications

• Electronic tracking

Content of ERP

ERP will be reviewed on a mine-by-mine bases. Reviewers will be evaluating the following:

Wireless communication systems

• Type of system (LF, mesh, Wi-Fi, MF)

• Survivability, how it provides redundancy

Content of ERP(continued)

– Provisions for untethered devices• Accessibility to miners• Text, voice or both• Standby power• Approved (approval #)

Content of ERP(continued)

– Provisions for infrastructure• Type of components (LF, nodes, AP)• Approved components (approval # if applicable)• Location in the working section• Location in escapeways• Location relative to strategic areas• Power supply evaluation # if applicable.

Content of ERP(continued)

Electronic tracking system• Type of system, reader or node-based

– Location of tags– Location of readers or nodes in working section– Location of readers or nodes in escapeways– Location in strategic areas

• Vendor if known• Model number if known• Approval number if known• Standby power for infrastructure• Standby power for tags

Content of ERP(continued)

Surface provisions to address:• Standby power• Communication with and monitoring of

undergrond personnel • Uniquely identifying each miner• Location data is associated with time• How long the data is stored • Frequency of updating location data

Content of ERPContinued

• Maintenance provisions– Manufacturer plan– Restoring backup power

• Examination provisions– Weekly examination for infrastructure– Daily examination of tags and radios

• Backup plans– Communication system fails– Tracking system fails

Summary

• Survivability can be achieved by hardening the system or providing redundancy.

• One way to provide redundancy is to mix and match a primary (LF or mesh system) system with a secondary system ( MF or TTS).

• Error factors depend on system design, system installation, and computer algorithm being used.

Any Questions?