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 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.
Advancing Section Untethered Communications Device Miner Feeder Continuous Miner Section
Longwall Untethered Communications Device Miner 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 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
Advancing Section Feeder Node/ Antenna Primary Escapeway Secondary Escapeway Belt Two-way Communication Coverage
Node / Antenna Two-Way Communications: Longwall
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.
Coupled Mode Radiating Mode Miner 1 Transmitting Leaky Feeder Functions as a power line, communications link, and a distributed antenna Miner 2 Receiving
Advancing Section Primary Escapeway Feeder Secondary Escapeway Leaky Feeder Antenna Belt Leaky Feeder: CM Section
Longwall Primary Escapeway Secondary Escapeway Leaky Feeder Antenna Leaky 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.
Medium Frequency Repeater • MF Signal is carried by un-powered conductive infrastructure in mine UHF signal is converted to/from MF signal
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
Primary Base Station Secondary Base Station Overland Link Mine Shafts Leaky Feeder
Two Leaky Feeder systems in multiple entries Antenna UHF LF Cable - Trunk 2 Escapeway Belt Track UHF LF Cable - Trunk 1
Coverage extension using low-cost cables and antennas Antenna Low-cost LF Cable Escapeway Belt Track UHF LF Cable
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
Operation of conventional RFID: • Reader senses tags that are within range • Tag transmits a unique ID • Detected tag IDs are sent to the surface Miner B Tag Miner A • Tag location is associated with the reader’s known location and displayed on the tracking computer RFID Reader
Miner B 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 Miner A RFID Reader Leaky Feeder Tag
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-BasedTracking(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 400 ft. 2,000 ft. 400 ft. 2,000 ft. Feeder Node / Reader Primary Escapeway Secondary Escapeway Belt Electronic Tracking Coverage
Node / Reader Primary Escapeway Secondary Escapeway 400 ft. 400 ft. 2,000 ft. 2,000 ft. Electronic Tracking Coverage: Longwall
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.