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 May 14, 2009

MINER Act Requirements June 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 Requirements June 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 Compliance Mesh 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 System If a node fails the system reconfigures itself and determines a new route

Mesh System A power supply and/or battery backup required at each node Power Source

Two-way Communication Coverage Advancing Section Primary Escapeway Secondary 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 Advancing Section Primary Escapeway Secondary Escapeway Feeder Antenna Belt Leaky Feeder

Leaky Feeder: Longwall Primary Escapeway Secondary Escapeway Antenna Leaky Feeder Longwall

Coverage Compliance Medium 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 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 Reader Tag 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 Leaky Feeder

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

Advancing Section 2,000 ft. 400 ft. Feeder Secondary Escapeway Primary Escapeway Node / Reader Belt Electronic Tracking Coverage

Electronic Tracking Coverage: Longwall 2,000 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 ERP Continued 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?