Survivable Intrinsically Safe WiFi based Communications Tracking System for UG Coal Mines

1Belowground DGMS approved I.S.
WiFi over Fiber Infrastructure withTracking and Communications

System installed, operated, maintained under supervision of CMPDIL, Mining
Electronics Department for three-and-a-half years at Central Coalfields Ltd.’sLower Semana Mine in Bhurkunda Project.

Author: Soumya De, M.S. Purdue University, W. Lafayette, IN, USA
Founder Director of AdCept Technologies Pvt. Ltd.

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2ContentsIntroduction ............................................................................................................................................ 3
What CMPDIL has achieved so far? ........................................................................................................ 4
How does the Underground Mine Intrinsically Safe WiFi based Communication and Tracking SystemWork? ...................................................................................................................................................... 4Benefits realized from the I.S. Communication Network Communication and Tracking System .......... 8I.S. WiFi Based Communications and Tracking - A Quantum Leap in Communications Technology ..... 8Conclusion ............................................................................................................................................. 10

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3Survivable Intrinsically Safe WiFi based
Communications Tracking System for UG
Coal Mines
Introduction
When it comes to setting up a WiFi digital network infrastructure in underground coal mines, one
would be faced with simple questions like how is it different than a WiFi network setup on thesurface?
The basic difference between a WiFi network setup on the surface from that in an Underground Coalmine is that all the electronic components that will be deployed in the underground coal mine needs
to be “Intrinsically Safe” (I.S.) certified. “Intrinsically Safe” (I.S.) certified means the powertransmitted by these electronic should be within stipulated limits and conforming to International
Standards IEC Ex ia.
Hence, worldwide I.S. certified WiFi digital network equipment are deployed successfully, so as tofacilitate the underground mine applications such as WiFi voice communications, tracking,environmental monitoring, production monitoring, time and attendance system etc. conforming toMSHA (USA/Canada) / IECEx (Australia/New Zealand) etc.
In India, THE COAL MINES REGULATIONS, 1957 (CMR 1957), under the Mines Act, 1952, states thefollowing among other restrictions and Director General of Mines Safety (DGMS), under Ministry ofLabour, has been given the mandate and authority to monitor that all electronic equipment to bedeployed in the underground mines adhere to these norms. CMR on page 54 states the following:
Where telephones or electrical signals are provided:
1. Signal wires shall be supported on insulators, and shall not be energised at more than 30volts;
2. Contact makers shall be so constructed as to prevent accidental closing of the circuit; and3. In every gassy seam of the second or third degree, all signalling or telephoniccommunication circuit shall be constructed, installed, protected, operated and maintained insuch a manner as be intrinsically safe.
Due to these restrictions most of the popular networking electronic equipment, widely used on thesurface, like the mobile phones or Cisco Wired or Wireless (WiFi) Networking Equipment cannot beused in the underground coal mines as they do not meet the statutory stipulation of Intrinsic Safety.
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4

What CMPDIL has achieved so far?
1. CMPDIL in association with M/S AdCept Technologies Pvt Ltd. has successfully obtained
intrinsically safe certification for all the networking equipment that has been used inunderground coal mines from CIMFR, Dhanbad (I.S. Certificates enclosed in Annexures).
2. CMPDIL has successfully conducted an extensive field trial for a period of three years in theunderground coal mines at Bhurkunda Collieries’ Lower Semana Seam, CCL, Ranchi underclose supervision and monitoring of DGMS, HQ, Dhanbad.
3. CMPDIL has successfully obtained the DGMS approval for all the network equipment to be
used in underground coal mines. (Copy of DGMS Approval enclosed).
4. CMPDIL has successfully demonstrated the functioning of the applications, such as VoiceCommunication, Miner Tracking etc. whereby one could make a two-way voice call fromanywhere on the surface to the underground coal mine and vice-versa and also depict thelocations of the workforce on the mine map of the underground mines. The same is also
visible from anywhere on the surface.

How does the Underground Mine Intrinsically Safe WiFi based
Communication and Tracking System Work?
The setting up of the WiFi digital network in the underground is somewhat similar to a WiFi network
installation that we see in large office buildings. Like in buildings, in the underground mine, we also
create WiFi hotspots by installing Intrinsically Safe Wireless Network Switches at suitable locations
and the Intrinsically Safe wireless clients such as MinePhones, Miner Tags etc. that sends data, voice,etc. to the surface through this network. This is depicted by the following picture:

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5Figure 1: Integrated Intrinsically Safe Network Infrastructure for Degree III U/G MinesThe steps involved are:1.

Create WiFi Hotspots for Voice and Tracking along pre-selected locations in the undergroundmines. Typical System Layout based on WiFi coverage requirement as shown on Mine Map.

Figure 2: Mine, I. S. Wired / Wireless Network Infrastructure at CCL Bhurkunda Mines

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2. After deploying the underground coal mine communication infrastructure, the value-added
applications such as wireless telephony, miner / equipment tracking, environmental
monitoring, production monitoring, longwall tracking, etc. are rolled out.

Figure 4 I.S. Wireless Voice Communications

Figure 3. Longwall Powered Roof Support Active RFID

Some applications that run on the Intrinsically Safe WiFi Infrastructure for Voice & Tracking
Communications are shown below:

Figure 5 I. S. WiFi Voice and Tracking System

3. The concept of WiFi Tracking in U/G Coal Mines, as the I.S. Wireless Network Switches havethe capability to read the miner WiFi tags, in addition to provide wireless connectivity forCopyright & All Rights Reserved 2018. | AdCept Technologies Pvt. Ltd. |Survivable Intrinsically Safe WiFi based Communications Tracking System for UG Coal Mines

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WiFi MinePhones. The I.S. Wireless Network Switches are deployed per the requirement ofthe specific mine.

Figure 6 Underground mine Tracking System

4. On the Surface Control Room Screen – Miner and Equipment Location shown in real-time,
this information can be shared anywhere, depending on the customer’s specificrequirements.

Figure 7 Manpower & Equipment Tracking Dashboard

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8Benefits realized from the I.S. Communication Network Communication andTracking System
Now the benefits of “on-the-go” wireless connectivity available to all of us on the surface could beexperienced by the workforce in underground coal mines. The underground miner:
1) Can call another miner, a group of miners, anyone around the world from his MinePhone
2) Can send Text Messages from his MinePhone
3) Can be tracked on the mine map of the surface at all times4) The Miner Tracking System can send alerts of workers approaching pre-designated danger
zones
This basically facilitates extending the communication facilities available on the surface to thebelowground coal mines, hence extending Digital India into the coal mines.
Adoption of such productivity and safety enhancing technology typically would result in attaining
efficient, effective workforce mobilization and utilization, besides reduction of equipment
downtime. Furthermore, the system helps attract attention of nearby miners or mine control center
operator on the surface, for timely rescue using the “SOS” or “Mandown” feature of the MinePhone.
This is possible due to the locationing feature of the MinePhone on the mine map by the surface
operator.

I.S. WiFi Based Communications and Tracking - A Quantum Leap inCommunications Technology
As of now the only communication technology used in the underground mines in India is an age-oldcopper wire based analog telephony system. These systems have channel limitations requiring thewired sets to be interconnected along the gallery. The miners in order to use the system have towalk 1Km or so at times, just to make a call and more often than not there is lot of noise.
Furthermore, being a proprietary analog, having very low bandwidth, often times supporting justsimplex communication. Since this is a wired connection, there is no scope of wirelesscommunication or for that matter cannot support other value adds such as miner / equipment
tracking, duplex real-time wireless voice communications, environmental monitoring, transfer ofproduction data etc.
Features

I.S.

WiFi

basedCommunication

DigitalWireless Copper wired Analog channel basedandTracking Communication System.

Infrastructure
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Coverage Area

Wider coverage per node

9

Limited to fixed points where wired
telephone instrument is installed.

ChannelNo limitations on channels

Limited to a few channels.

1 Gigabits per second

Analog voice channels onlyLimitation
Bandwidth
Scalabilitywith Unlimited options to extend coverageregard

toNot possible, only limited to drawing
wiring to wherever the telephone

deployment

instrument needs to be fixed

Redundancy– Possible, by multiple parallel routes Not possible, only a single line, if

Accident proof

through the mines to the surface damaged then no communication ispossible.

control center

Veryvulnerable

inemergency situations.
Presence at mine Possible as the MinePhone and Tags Not possible
faceare both wireless.

Communicate all Possible. One can make a call from Not
over the world anywhere

intheworldtocommunication

the restricted to analog telephone in thefrom any phone, underground mine and vice versa.
landline

possible,mines.

ormobileSame

Possible, Miner Tracking, Environment Not possible

infrastructure

Monitoring, Time and Attendance,

supports

many Longwall

Tracking,

TripCounting,applications

Conveyor belt monitoring, etc.

Worldwide UsePrevalent in use worldwide; in line with Proprietary copper wire system onlyimproved

communications limited to use in India and havetechnologies on the surface, like become obsolete worldwide.
cellular phones, Internet etc. Enables
digitalcommunications

intheunderground.

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10Conclusion
Since last decade, there has been a sea change in the technological environment the world over, andIndia is no exception. Mining, more particularly underground mining in the Coal sector, is highly
challenging as far as the safety, security of miners, and using real-time communication technologies
to improve productivity are concerned. This is because of the hazardous gaseous environment in thecoal sector and also because of its vulnerability due to inundation, roof-falls/slides, etc. Hence ourendeavour is to bring down the hazards by all available technological and communication means soas to minimize the fatality of accidents by creating an effective communication and tracking
technology in order to save precious lives of our miners in addition to enhancing improvements inproductivity.

Statutory Steps Taken by Government in the field of Adopting Communication andTracking Systems in Underground Coal Mines
The 10th Conference for Safety in Mines had recommended belowground Communication andTracking System. Recommendations of 11th conference on Safety in Mines held on 4th & 5th July,
2013 at New Delhi included initiatives for establishment of appropriate communication system forbelow ground mines including to locate the trapped miners.
With the main focus now being to increase coal production from underground coal mines, at thesame time eliminating or minimising the risk of disasters in mines, and in this context of preventionof accidents and fatality, keeping the inherent benefits of such communication systems in mind, it isnecessary that all underground coal mines install a DGMS approved Intrinsically Safe IP based
switched wireless communication and tracking system.
It is an irony that despite being one of the largest producers of coal globally, India has not adopted
till date such proven IP based wireless communications and tracking systems in the undergroundcoal mines to improve productivity, accountability, and safety of miners/equipment. It is also anirony despite revolutionary development in mobile communication technology, our Indianunderground mining workforce are deprived of even establishing a contact with their family
members for a long stretch of working hours in the most hazardous, gaseous, humid working
conditions. More so, when the same technology is widely deployed (in 100+ mines abroad) andaccepted to improve productivity, efficiency and safety at the same time, all through robust
communication and effective tracking of men and machinery.

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